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• Effects of intrauterine extracellular vesicle microRNAs on embryonic gene expression in low-fertility cows
  

  FASEB J. 2024 Oct 31;38(20):e70116. doi: 10.1096/fj.202401728R.

  ABSTRACT

  Embryo survival and pre-implantation development depend on uterine luminal fluid, which is believed to play a role in early embryonic death and infertility in cows. Extracellular vesicles (EVs) in the uterine luminal fluid contain microRNAs (miRNAs), crucial mediators of intercellular communication. miRNAs regulate conceptus-maternal interactions and participate in embryonic development by suppressing gene expression. Therefore, we hypothesized that miRNAs in the intrauterine EVs of low-fertility cows would hinder embryonic survival and development. EVs were collected from the bovine uterine luminal fluid of both normal- and low-fertility cows 7 days post-estrus. Small RNA-sequencing analysis of miRNAs isolated from these EVs identified eight miRNAs that were highly expressed in normal-fertility cows (normal-fertility miRNAs) and eight with elevated expression in low-fertility cows (low-fertility miRNAs). These two sets of miRNAs were transfected into hatched blastocysts via lipofection. RNA-seq following lipofection with low-fertility miRNAs identified 424 differentially expressed genes (DEGs) relative to the control; in contrast, following lipofection with normal-fertility miRNAs, seven DEGs were identified. Pathway analysis of the DEGs identified following lipofection with low-fertility miRNAs revealed substantial enrichment of mitogen-activated protein kinase (MAPK) signaling. Expression of activator protein 1 (AP1) and interferon-tau (IFNT) mRNA was significantly lower in the low-fertility miRNA transfection group than in the control. IFNT is essential for maternal pregnancy recognition. Therefore, miRNAs in intrauterine EVs from low-fertility cows at 7 days post-estrus may inhibit embryo development and suppress IFNT expression by altering MAPK signaling.

  PMID:39425543 | DOI:10.1096/fj.202401728R

• Improvement of Post-Thaw Quality and In Vivo Fertility of Simmental Bull Spermatozoa Using Ferulic Acid
  

  Vet Med Sci. 2024 Nov;10(6):e70064. doi: 10.1002/vms3.70064.

  ABSTRACT

  BACKGROUND: Artificial insemination and semen cryopreservation have significantly improved the quality and quantity of cattle production. Through cryopreserved semen and artificial insemination, top-breeding bull sperm can be used to inseminate thousands of cows worldwide.

  OBJECTIVES: Our study aimed to determine the effect of adding ferulic acid (FA) to a Tris-based semen extender on frozen and thawed Simmental bull sperm.

  METHODS: Semen samples were collected from three Simmental bulls. Pooled Simmental semen (n = 34 ejaculations) were diluted with a Tris-base extender containing varying FA concentrations (0.1, 0.15, 0.25, 0.35, and 0.45 mM). After the samples were frozen and thawed, the samples were tested for malondialdehyde (MDA), total antioxidant capacity (TAC), superoxide dismutase (SOD), glutathione peroxidase (GPx), total motility, progressive motility, motility characteristics, and plasma membrane functionality.

  RESULTS: The control and the groups with the best FA concentrations, 0.25 and 0.35, were compared for in vivo fertility. Fifty-one cows were inseminated 24 h after the onset of oestrus. A rectal examination was used to diagnose pregnancies at least 60 days after fertilization. Results showed that adding FA-0.45, FA-0.35, FA-0.25, and FA-0.15 to the semen of Simmental bulls improved total and progressive motility, motility characteristics, and plasma membrane functionality. It also increased GPx and TAC levels, reducing MDA and DNA damage after freezing. The addition of FA did not affect SOD values. The fertility rate in the FA-0.25 and FA-0.35 groups was higher than in the control group, 35.29%, with rates of 76.47% and 70.58%, respectively.

  CONCLUSIONS: In conclusion, adding FA (0.15, 0.25, 0.35, and 0.45 mM) to Tris-based semen extenders can improve the quality parameters of cryopreserved Simmental bull semen and increase in vivo fertility using 0.25 and 0.35 concentrations of FA.

  PMID:39422094 | PMC:PMC11487330 | DOI:10.1002/vms3.70064

• Lectin Functionalised Iron Magnetic Nanoparticle-Based Sperm Selection: A Potential Technique to Improve Bull Sperm Quality In Vitro
  

  Reprod Domest Anim. 2024 Oct;59(10):e14733. doi: 10.1111/rda.14733.

  ABSTRACT

  Premature acrosomal exocytosis in cryopreserved semen is one of the reasons attributed to low fertility among livestock. In the present study, we attempted to enhance the cryopreserved semen quality by selective removal of acrosome-reacted spermatozoa using FITC-PNA conjugated iron magnetic nanoparticles (MNPs). Further, the effect of nano purification on other sperm functional attributes was also assessed. Iron MNPs were prepared using co-precipitation method and dextran-coated MNPs were conjugated with FITC-PNA (0.04 mg/mL). A preliminary experiment was conducted to standardise the dose of FITC-PNA conjugated iron MNPs (0.02, 0.05, 0.1, 0.15, 0.2, 0.4 and 0.6 mg). Among the different doses used, 0.6 mg FITC-PNA conjugated iron MNPs significantly (p < 0.05) removed higher acrosomal reacted spermatozoa from the semen, and therefore, this dose was used in further experiments. Cryopreserved semen from Holstein Friesian breeding bulls (n = 6) were thawed and washed using Sperm-TALP to remove residual extender. Washed spermatozoa (2 × 10⁶) were exposed to 0.6 mg of FITC-PNA conjugated iron MNPs for 10 min at 37°C. The nano purified semen was assessed for various vital sperm parameters viz., viability, intracellular calcium, apoptosis, mitochondrial ROS and mitochondrial membrane potential using flow cytometry. We found that nanopurification using FITC-PNA conjugated iron MNPs significantly (p < 0.05) improved the sperm quality. The proportion of viable non-apoptotic spermatozoa with low intracellular calcium levels was significantly (p < 0.05) enriched in nano purified semen. Nano purification did not affect sperm mitochondrial membrane potential and ROS production. In conclusion, these preliminary findings indicate that FITC-PNA coated iron MNPs effectively removed acrosome reacted spermatozoa and significantly improved sperm functional attributes in the purified fraction.

  PMID:39403825 | DOI:10.1111/rda.14733

• Genetic assessment of productive and reproductive traits in Friesian, native, and crossbred cattle in Egypt
  

  Trop Anim Health Prod. 2024 Oct 15;56(8):344. doi: 10.1007/s11250-024-04153-1.

  ABSTRACT

  This study utilized a dataset comprising 3023 lactation records for Friesian cows, 596 records for Native cows (Baladi), and 1189 records for Crossbred cows spanning from 1994 to 2015. The objective was to estimate and assess genetic and phenotypic parameters and breeding values for 305-day milk yield (305-DMY), lactation period (LP), calving interval (CI), and days open (DO) within the Egyptian dairy context. The motivation for this research stemmed from the need to understand the genetic potential of different cattle genotypes in Egypt and identify opportunities for enhancing dairy production. Data were analyzed using the linear mixed model least squares and maximum likelihood (LSMLMW) and multiple-trait derivative-free restricted maximum likelihood (MTDFREML) programs. The analytical model included fixed effects such as season and year of calving, parity, and genotype groups, while random effects included animal and error. Unadjusted means for 305-DMY, LP, CI, and DO were calculated for each genotype group. Genotype groups significantly impacted all studied traits. Heritability estimates varied across genotype groups, with higher estimates observed in Crossbred (0.32, 0.26, 0.25, 0.23) and Native cows (0.26, 0.28, 0.28) compared to Friesian cows (0.24, 0.22, 0.16, 0.17) for productive and reproductive traits, respectively. Genetic correlations among traits ranged from 0.10 to 0.86 for the three genotype groups, while corresponding phenotypic correlations were generally small to moderate and positive. Regarding breeding values, the accuracy estimates suggested that both sires and cows could contribute to genetic improvement. This indicates the potential for enhancing dairy production through selective breeding strategies.

  PMID:39404905 | PMC:PMC11480133 | DOI:10.1007/s11250-024-04153-1

• A genome-wide association study reveals fetal genetic factor for gestation length on chromosome 21 in Japanese Black cattle
  

  Anim Sci J. 2024 Jan-Dec;95(1):e14006. doi: 10.1111/asj.14006.

  ABSTRACT

  Gestation length (GL) in cattle is associated with neonatal health and the subsequent reproductive performance of dams. We performed a genome-wide association study (GWAS) using 25,144 single nucleotide polymorphisms (SNPs) in 4373 animals to detect genetic variants associated with GL as a fetal trait in Japanese Black cattle in Gifu Prefecture. We identified four significant SNPs on chromosome 21 in moderate linkage disequilibrium (LD). The minor allele of the most significant SNP has the effect on -2.47 days GL with a 0.019 allele frequency. Of the 4373 animals, 140 heterozygotes and one homozygote with the minor allele were traced back to a heterozygous sire. The 7.2 Mb LD region harbors three genes: gamma-aminobutyric acid type A receptor subunit beta3 (GABRB3), arrestin domain containing 4 (ARRDC4), and nuclear receptor subfamily 2 group F member 2 (NR2F2, also known as COUP-TFII). RNA expression analysis and its functions suggest that GABRB3, ARRDC4, and NR2F2 (COUP-TFII) are involved in glucose production via the hypothalamic-pituitary-adrenal axis during the fetal stress response at gestation period termination. These results suggest that an increase in the allele frequency of the associated SNPs has an impact on genetic improvement by shortening the GL in the population.

  PMID:39406461 | DOI:10.1111/asj.14006

• Efficient Method for Liposome-Based Gene Transfer in Cattle Embryos
  

  Reprod Domest Anim. 2024 Oct;59(10):e14730. doi: 10.1111/rda.14730.

  ABSTRACT

  In vitro embryo production (IVP) in cattle is crucial for advancing genetic enhancement and preserving valuable genetic lineages, enabling precise genetic modifications and gene studies through modern techniques. Successful genetic manipulation in cattle embryos requires efficient delivery of exogenous DNA/RNA molecules. This research investigates the efficacy of a single embryo culture system for developing genetically modified zona-free (ZF) embryos and examines the use of liposome-based SAMTOR target siRNA transfer in these individually cultured ZF embryos. The findings indicated that the individual culture system resulted in increased cleavage rates, and blastocyst rates were minimally impacted. The new culture system effectively achieved SAMTOR silencing, with 8-16 cell embryos exhibiting reduction in transcript levels compared to control. Measurement of total protein content in the spent culture media was performed to validate the single-culture approach for further analytical applications. Total protein content analysis demonstrated the system’s suitability for comprehensive evaluation of the embryo-media interaction, enhancing the scope for in-depth genetic research and applications. This research sheds light into an innovative method to improve genetic editing techniques in reproduction research.

  PMID:39400401 | DOI:10.1111/rda.14730

• Effect of replacing ground corn with cactus pear Nopalea cochenillifera (L.) on feed intake and digestibility, water intake, milk production and composition in Holstein × Gyr cows
  

  Trop Anim Health Prod. 2024 Oct 14;56(8):341. doi: 10.1007/s11250-024-04155-z.

  ABSTRACT

  The objective of this study was to evaluate the intake and digestibility of nutrients, production and composition of milk, and water intake of lactating dairy cows fed standard diets in which ground corn (C) was replaced by up to 100% in the diet by cactus pear (CP). Eight Girolando cows (½ Gyr x ½ Holstein), 3rd calf multiparous, with 60 to 80 days of lactation and an average weight of 450.0 ± 30.0 kg, were randomly distributed in a double Latin square (4 × 4). Four experimental diets were evaluated: (100% C + 0% CP), (66.6% C + 33.3% CP), (33.3% C + 66.6% CP), and (0% C + 100% CP). There was a difference (P < 0.05) in the intake of CP and EE (kg.day^{– 1}), with a quadratic effect and a linear reduction, respectively, with substitution. The maximum CP intake of 3.05 kg.day^{– 1} was found at 46.07% and EE intake fell by 3.81 g for each percentage unit of cactus pear added to the diet. There was a quadratic difference (P < 0.05) for DM intake in %BW and g.kg BW^0,75, with maximum values of 3.97%BW and 186.8 g.kg BW^0,75 with the substitution of 54.83 and 53.17%, respectively. There was a quadratic effect (P < 0.05) for the intake of NDF in %BW, with the maximum intake of 1.3% at the 74.69% substitution level. There was a linear reduction (P < 0.05) in the digestibility of DM, NDF, and TDN, and for the other nutrients there was no substitution effect (P > 0.05). There was no difference (P > 0.05) in milk production and composition. There was a linear reduction (P < 0.05) in water intake. Cactus pear can be used in a promising way to replace ground corn up to 100% in the diet of lactating dairy cows.

  PMID:39400604 | DOI:10.1007/s11250-024-04155-z

• The skimmed milk proteome of dairy cows is affected by the stage of lactation and by supplementation with polyunsaturated fatty acids
  

  Sci Rep. 2024 Oct 14;14(1):23990. doi: 10.1038/s41598-024-74978-1.

  ABSTRACT

  The impact of nutritional modification to increase functional polyunsaturated fatty acids (PUFA), such as n-3 and n-6 fatty acids (FA) or conjugated linoleic acid (CLA), on milk proteome profile during early lactation remains largely unknown. We used an untargeted proteomics approach to investigate the impact of lactation day and PUFA supplementation on the proteome signature in skimmed milk over the course of early lactation. Sixteen Holstein dairy cows received abomasal infusion of saturated FA (CTRL) or a mixture of essential FA and CLA (EFA + CLA group) from – 63 to + 63 days relative to parturition. Using quantitative proteomics, 479 unique proteins were identified in skimmed milk at days 1, 28, and 63 postpartum. The top discriminating proteins between transition milk (day 1) and mature milk (days 28 and 63), including members of complements (i.e. C2 and C5), growth factor (TGFB2), lipoproteins (i.e. APOE and APOD), and chaperones (i.e. ST13 and CLU), are associated with calves’ immune system and gut development. The EFA + CLA supplementation moderately affected a few proteins associated with regulating mammary glands’ lipogenesis through the (re)assembly of lipoprotein particles, possibly under the PPAR signaling pathway. Collectively, skimmed milk proteome is dynamically regulated initially by cow’s metabolic and physiological changes and to a lesser extent by nutritional PUFA modifications.

  PMID:39402117 | PMC:PMC11473731 | DOI:10.1038/s41598-024-74978-1

• Changes in vaginal cytokines concentrations during artificial insemination and natural service in beef heifers
  

  BMC Res Notes. 2024 Oct 14;17(1):305. doi: 10.1186/s13104-024-06917-2.

  ABSTRACT

  OBJECTIVE: Heifer development is crucial for the optimization of reproductive efficiency in beef production. Heifer development is largely influenced by nutrition. Nutritional status of these heifers can influence immunological responses that are crucial for reproduction. Commercial Angus heifers (n = 9) were utilized, in a pilot study, to elucidate the effects of sampling time (days 0, 7, 14, 21, 28, and 35), pregnancy status, and type of mating on individual cytokine concentrations and cytokine profiles in the vagina following breeding.

  RESULTS: Cytokine profiles were analyzed using MetaboAnalyst 5.0 and one-way ANOVAs were performed in R Studio to identify differences in individual cytokines based on sampling time, pregnancy status, and type of mating. Cytokine profiles were different (P = 0.05) 7 days after either mating type. Cytokines, IL-1β, IL-17a, MCP-1, and TNFα were different based on the mating type and pregnancy status. Multiple cytokines, IL-1α, IL-1β, IL-6, IL-8, IL-10, IL-17a, VEGFa, and MIP1α, were different between days regardless of pregnancy status. In conclusion, vaginal cytokines differ based on pregnancy status, type of mating, and time which may be indicative of vital pathways that need to be activated for pregnancy.

  PMID:39402649 | PMC:PMC11472449 | DOI:10.1186/s13104-024-06917-2

• Repeat Breeder Syndrome Therapies in Dairy Cows: A Review
  

  Reprod Domest Anim. 2024 Oct;59(10):e14732. doi: 10.1111/rda.14732.

  ABSTRACT

  Repeat breeder (RB) cows are clinically healthy animals with regular oestrous cycles that do not become pregnant after three or more services. This syndrome has an incidence ranging between 10.1% and 24%. Repeat breeder syndrome (RBS) in dairy cows leads to economic losses to dairy farmers by increasing the calving interval and consequently reducing milk and calf production. RBS has a complex oetiopathogenesis as many factors are involved in its onset. The causes can be grouped into two categories: causes leading to fertilisation failure and factors leading to early embryonic death. Accurate identification of the cause and early diagnosis of RBS is essential to minimise the problems that this issue brings to the farm, but is not always possible. Hypothesising the underlying aetiology of the syndrome is also crucial for targeted therapy, whether pharmacological or managerial. The aim of this review is to report the different therapies, proposed in the literature, for the treatment of RBS in cattle, based on the knowledge of possible aetiological causes.

  PMID:39392176 | DOI:10.1111/rda.14732

• Effect of the Application of PGF_2α Associated With Ovulation Induction in a Fixed-Time Superovulation Programme for Precocious Nellore Heifers
  

  Reprod Domest Anim. 2024 Oct;59(10):e14734. doi: 10.1111/rda.14734.

  ABSTRACT

  This study evaluated the effect of prostaglandin F2α (PGF2α) associated with gonadotropin-releasing hormone (GnRH) for ovulation induction in precocious indicus heifers submitted to a fixed-time superovulation (SOV) programme. Precocious Nellore heifers (n = 35), aged 13 months, were subjected to the SOV protocol. On day 0 (D0), all animals received intravaginal insertion of a progesterone (P4) device along with intramuscular administration of 2 mg of oestradiol benzoate, plus 200 IU of follicle-stimulating hormone in decreasing doses, with 12-h intervals between D4 and D7, in addition to 150 μg of D-cloprostenol on D6 and device removal on D7. On D8, the donors received 10.5 μg of buserelin acetate and the treatment group received 300 μg of D-cloprostenol/PGF_2α. Artificial insemination was performed 12 h and 24 h after GnRH administration using frozen semen. On D15 of the protocol (i.e., D7 after insemination), the embryos were collected and evaluated. All animals passed through the control and treatment groups. Results were evaluated by analysis of variance using an adjusted mixed-effects model (p < 0.05). There was no difference in the total number of embryos between the control and treatment groups (10.40 ± 1.52 vs. 9.60 ± 1.36; p = 0.63) or viable embryos (6.30 ± 1.22 vs. 4.30 ± 0.71). For precocious indicus heifers, treatment with PGF_2α in association with GnRH did not affect embryo production in the fixed-time SOV protocol.

  PMID:39392191 | DOI:10.1111/rda.14734

• Linseed oil supplementation alters milk fatty acid profile, mitigates heat stress, and improves summer milk yield in grazing dairy cows
  

  Trop Anim Health Prod. 2024 Oct 11;56(8):337. doi: 10.1007/s11250-024-04127-3.

  ABSTRACT

  Dietary supplementation of fat can be an important source of energy to compensate for the reduction in dry matter intake in dairy cows during heat stress periods. Studies have reported that supplementing dairy cow diets with linseed oil (LO) can increase milk yield and enhance the levels of beneficial fatty acids, such as omega-3 fatty acids, in the milk. The objective of this research was to evaluate the effect of LO supplementation on milk fatty acids profile, milk yield and composition, and physiological parameters of grazing cows. The study was conducted in two seasons, one in spring and one in summer. A 2 × 2 Latin square design was used in each experiment. Twelve Holstein and crossbred Holstein x Jersey cows were involved in each season. Cows were divided into two groups: control (TC) with no supplementation and treatment (TL) supplemented with 400 g/day of LO. The results showed that LO supplementation altered the milk fatty acid profile: decreased concentrations of short and medium-chain fatty acids (C10:0 – C17:1) except for C13:0 and increased concentrations of long-chain fatty acids (C18, C18:1 (both trans and cis isomers), C18:2 (specific conjugated linoleic acid – CLA isomers), and C18:3 n3 (omega-3)). Additionally, milk yield increased by 1.5 l per day during summer in LO-supplemented cows, while milk fat, protein, and casein content decreased. Milk stability increased by 2.2% in the LO-supplemented group. LO-supplemented cows reduced internal body temperature and heart frequency in the afternoon and increased daily rumination time by 20 min. In conclusion, LO supplementation can be an effective strategy to improve the nutritional profile of milk by altering fatty acid composition towards potentially healthier fats, mitigate the negative effects of heat stress on grazing cows during summer, as evidenced by reduced body temperature and heart frequency and increase milk yield.

  PMID:39390269 | DOI:10.1007/s11250-024-04127-3

• Behavioral responses to artificial insemination and the effect of positive reinforcement training
  

  PLoS One. 2024 Oct 10;19(10):e0310537. doi: 10.1371/journal.pone.0310537. eCollection 2024.

  ABSTRACT

  Dairy cattle experience a variety of stressors associated with routine farm practices, including injections, pen movements, regrouping, and artificial insemination. The primary objective of this study was to assess ear position (categorized according to 5 positions) and body movement responses of heifers during their first experience of artificial insemination, in comparison with responses during baseline observations before and after this procedure. A secondary objective was to test whether heifers exposed to positive reinforcement training (PRT) responded differently to this procedure. We tested 12 heifers (13 ± 0.7 mo. old); 7 were trained using PRT (as part of another study) and 5 had no experience with PRT. Ear axial and ear forward positions were more frequent during observations before and after artificial insemination relative to during artificial insemination (4.57 ± 0.82 vs. 0.31 ± 0.82 times/period, and 3.45 ± 0.51 vs. 0.50 ± 0.51 times/period, respectively). Backward pinned ear position was observed less frequently before and after versus during artificial insemination (0.12 ± 0.76 vs. 3.76 ± 0.76 times/period). We found no effect of period relative to artificial insemination on any of the 4 body movements assessed (leaning forward, backward, and steps taken with front legs and back legs).We found an effect of PRT on forward ear position (1.00 ± 0.51 times/PRT group vs. 2.95 ± 0.60 times/control group), and found that control heifers leaned forward and took more steps with their front legs than did PRT heifers (0.93 ± 0.57 times/PRT group vs. 3.55 ± 0.67 times/control group and 1.29 ± 0.68 times/PRT group vs. 3.85 ± 0.81 times/control group). We conclude that heifers experiencing artificial insemination for the first time express distinct ear positions that are consistent with responses to a negative emotional state. Further work is required to validate these responses and to determine the extent that they can be used to assess affective responses to this and other procedures.

  PMID:39388492 | PMC:PMC11466390 | DOI:10.1371/journal.pone.0310537

• The Azawak zebu bred at the Toukounous experimental centre in Niger: reproduction performance and estimation of genetic parameters
  

  Trop Anim Health Prod. 2024 Oct 9;56(8):334. doi: 10.1007/s11250-024-04190-w.

  ABSTRACT

  The aim of this study was to estimate the genetic parameters of the reproductive performance of the Azawak zebu, bred on station during the period 1981 to 2007, in order to contribute to the implementation of an effective selection programme for improving the zootechnical performance of cattle herds. The data contained records of 2453 calvings from 650 Azawak cows, daughters of 55 bulls, all bred at the Toukounous experimental centre (Niger). Non-genetic factors were evaluated using linear mixed models and genetic parameters were estimated using REML procedures with a multi-trait animal model. The effects of year and calving rank were significant (P < 0.001) for the three reproductive traits studied. Heritability was low for age at first calving (h² = 0.09 ± 0.03) and calf birth weight (h² = 0.07 ± 0.03). It was moderate for calving interval (h² = 0.30 ± 0.04) indicating the possibility of genetic improvement of this trait by selection. Repeatability estimates for calf birth weight and calving interval were 0.10 ± 0.02 and 0.42 ± 0.03 respectively. Calving interval had very strong and significant genetic correlations with age at first calving (0.84 ± 0.08) and calf birth weight (-0.40 ± 0.20). There was also a significantly favourable genetic correlation between calf weight at birth and age at first calving (-0.32 ± 0.25), implying a simultaneous improvement in all three reproductive traits through selection. An increase in heritability of calf birth weight was observed after the active phase of the program, reflecting an overly open selection scheme. These genetic parameter estimates suggest that the three reproductive traits could be used in selection index with the aim to improve the three reproductive traits of Azawak cattle.

  PMID:39382726 | DOI:10.1007/s11250-024-04190-w

• Elucidation of the pluripotent potential of bovine embryonic lineages facilitates the establishment of formative stem cell lines
  

  Cell Mol Life Sci. 2024 Oct 8;81(1):427. doi: 10.1007/s00018-024-05457-z.

  ABSTRACT

  The establishment of epiblast-derived pluripotent stem cells (PSCs) from cattle, which are important domestic animals that provide humans with milk and meat while also serving as bioreactors for producing valuable proteins, poses a challenge due to the unclear molecular signaling required for embryonic epiblast development and maintenance of PSC self-renewal. Here, we selected six key stages of bovine embryo development (E5, E6, E7, E10, E12, and E14) to track changes in pluripotency and the dependence on signaling pathways via modified single-cell transcription sequencing technology. The remarkable similarity of the gene expression patterns between cattle and pigs during embryonic lineage development contributed to the successful establishment of bovine epiblast stem cells (bEpiSCs) using 3i/LAF (WNTi, GSK3βi, SRCi, LIF, Activin A, and FGF2) culture system. The generated bEpiSCs exhibited consistent expression patterns of formative epiblast pluripotency genes and maintained clonal morphology, normal karyotypes, and proliferative capacity for more than 112 passages. Moreover, these cells exhibited high-efficiency teratoma formation as well as the ability to differentiate into various cell lineages. The potential of bEpiSCs for myogenic differentiation, primordial germ cell like cells (PGCLCs) induction, and as donor cells for cell nuclear transfer was also assessed, indicating their promise in advancing cell-cultured meat production, gene editing, and animal breeding.

  PMID:39377807 | PMC:PMC11461730 | DOI:10.1007/s00018-024-05457-z

• Genome-wide association studies for milk production traits in two autochthonous Aosta cattle breeds
  

  Animal. 2024 Oct;18(10):101322. doi: 10.1016/j.animal.2024.101322. Epub 2024 Sep 12.

  ABSTRACT

  Genome-wide association studies (GWASs) are used to identify quantitative trait loci for phenotypic traits of interest. The use of multilocus mixed models allows to correct for population stratification and account for long-range linkage disequilibrium. In this study, GWASs were conducted to identify the genetic bases of milk production (milk yield, protein and fat composition, and yield) in two autochthonous dual-purpose cattle breeds from the Aosta Valley. Using either the breeding values or the deregressed proofs, common significative single nucleotide polymorphisms have been identified for milk yield, protein percentage, and fat percentage. Two major quantitative trait loci regions have been identified on the chromosomes 5 and 14 for the fat percentage, harbouring the MGST1, CYHR1, VPS28, and CPSF1 genes. For the protein percentage, a candidate region has been identified on BTA 6; in this region, the CSN1S1, CSN2, HSTN, CSN3, and RUFY3 genes are annotated. Most of the identified genes have already been associated with milk composition in other studies on cosmopolitan and local cattle. These results show that the genes involved in milk composition quantitative traits in the Aosta cattle are common also in other cattle breeds and they can be further investigated with the use of whole genome sequencing data.

  PMID:39378607 | DOI:10.1016/j.animal.2024.101322

• Differential gene expression in neonatal calf muscle tissues from Hanwoo cows overfed during mid to late pregnancy period
  

  Sci Rep. 2024 Oct 7;14(1):23298. doi: 10.1038/s41598-024-74976-3.

  ABSTRACT

  Maternal nutrition significantly influences fetal development and postnatal outcomes. This study investigates the impact of maternal overfeeding during mid to late pregnancy on gene expression in the round and sirloin muscles of Hanwoo neonatal calves. Eight cows were assigned to either a control group receiving standard nutrition (100%) or a treated group receiving overnutrition (150%). After birth, tissue samples from the round and sirloin muscles of neonatal calves were collected and subjected to RNA sequencing to assess differentially expressed genes (DEGs). RNA sequencing identified 43 DEGs in round muscle and 15 in sirloin muscle, involving genes related to myogenesis, adipogenesis, and energy regulation. Key genes, including PPARGC1A, THBS1, CD44, JUND, CNN1, ENAH, and RUNX1, were predominantly downregulated. Gene ontology (GO) enrichment analyses revealed terms associated with muscle development, such as “biological regulation,” “cellular process,” and “response to stimulus.” Protein-protein interaction networks highlighted complex interactions among DEGs. Random Forest analysis identified ARC, SLC1A5, and GNPTAB as influential genes for distinguishing between control and treated groups. Overall, maternal overnutrition during mid-to-late pregnancy results in the downregulation of genes involved in muscle development and energy metabolism in neonatal Hanwoo calves. These findings provide insights into the molecular effects of maternal nutrition on muscle development.

  PMID:39375502 | PMC:PMC11458785 | DOI:10.1038/s41598-024-74976-3

• Mechanism of collagen type IV regulation by focal adhesion kinase during retained fetal membranes in dairy cows
  

  Sci Rep. 2024 Oct 6;14(1):23250. doi: 10.1038/s41598-024-74947-8.

  ABSTRACT

  Retained fetal membranes (RFM) is an important reproductive disease in dairy cows, caused by maternal and fetal placental tissue adhesion. The main collagen in maternal and fetal placenta tissues is collagen type IV (COL-IV) and its breakdown is the key to placental expulsion. Focal adhesion kinase (FAK) has been shown to regulate the hydrolysis of Col-IV by affecting the activity of MMP-2 and MMP-9 activity, but the regulation of the mechanisms involved in placenta expulsion in dairy cows after postpartum are still unclear. The aim of this study was to investigate the pathogenic mechanism of RFM by studying the relationship between the FAK signaling pathway and COL-IV regulation. Maternal placental tissues were collected from six healthy and six cows with RFM of similar age, parity, body condition and milk yield at 12 h postpartum. In vitro experiments were performed on bovine endometrial epithelial cells from three groups including a FAK inhibitor group, a FAK activator group and a control group without FAK inhibitor and activator. The abundance of molecules involved in the FAK signaling pathway and COL-IV was detected by immunohistochemistry, quantitative real-time polymerase chain reaction (qRT-PCR) and western blot. The immunohistochemical results showed that the key molecules of FAK signaling pathway FAK, Src, MMP-2 and MMP-9 and Col-IV were expressed in placental tissues. The expression level of FAK, Src, MMP-2, and MMP-9 were significantly down-regulated (P < 0.05) and the abundances of COL-IV were significantly up-regulated (P < 0.05) in maternal placental tissues of RFM cows compared with healthy cows. In the FAK inhibitor treatment group, the relative expression levels of FAK and other related proteins were significantly down-regulated (P < 0.05) and the relative expression levels of COL-IV were significantly up-regulated (P < 0.05) with the results of the FAK activation group the opposite. These results indicated that FAK in maternal endometrial epithelial cells could regulate the hydrolysis process of Col-IV through the expression of key factors of signaling pathways and promote collagen hydrolysis, which in turn facilitated the process of postpartum placenta expulsion in dairy cows.

  PMID:39370419 | PMC:PMC11456596 | DOI:10.1038/s41598-024-74947-8

• Evaluation of thiol/disulphide and oxidant-antioxidant status of dairy cows in periparturient and post-partum period
  

  Vet Med Sci. 2024 Nov;10(6):e70023. doi: 10.1002/vms3.70023.

  ABSTRACT

  BACKGROUND: Thiol/disulphide homeostasis (TDH) has a critical role in many cellular activities such as antioxidant protection. Alterations of oxidative stress in the transition period play an important role in development of some diseases and disorders in dairy cows.

  OBJECTIVES: The purpose of this study is to assess the total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), total thiol, native thiol, disulphide and lipid profile in Simmental and Montofon dairy cows (aged 2-3) before and after calving.

  METHODS: Blood samples were collected 233-280 days of pregnancy and the 30 days of post-partum. Serum total thiol, native thiol and disulphide levels were determined as well as TAS, TOS and paraoxonase-1 (PON-1) levels were measured using colorimetric assays. Triglycerides (TG), total cholesterol, HDL cholesterol and LDL cholesterol levels were measured with an automatic analyser.

  RESULTS: Total thiol (p = 0.038) and disulphide (p = 0.015) levels were higher after calving compare to pregnancy in Montofon. TAS was found lower (p < 0.001), and OSI was higher in both breeds (Montofon p = 0.012, Simmental p = 0.028) after calving than in pregnancy. When compared between pregnancy and after calving levels in the same breed, HDL was found to be higher after calving (p < 0.001) and TG was lower after calving (p = 0.020) in Montofon. PON (p = 0.090), HDL (p < 0.001) and cholesterol levels were found higher (p < 0.001) and TG level was lower (p < 0.001) after calving in Simmental.

  CONCLUSIONS: According to our results, we observed different responses between two breeds before and after calving. There are few studies about TDH in animal research, and this is the first study in the literature that evaluates the TDH along with oxidative stress and lipid profiles in dairy cows in the periparturient and post-partum period.

  PMID:39367787 | PMC:PMC11452905 | DOI:10.1002/vms3.70023

• Evaluating the suitability of placental bovine explants for ex vivo modelling of host-pathogen interactions in Neospora caninum infections
  

  Theriogenology. 2024 Dec;230:305-313. doi: 10.1016/j.theriogenology.2024.10.003. Epub 2024 Oct 3.

  ABSTRACT

  Bovine abortions, often caused by infectious agents like Neospora caninum, inflict substantial economic losses. Studying host-pathogen interactions in pregnant cows is challenging, and existing cell cultures lack the intricate complexity of real tissues. To bridge the gap between in vitro and in vivo models, we explored the use of cryopreserved bovine placental explants. Building upon our successful development of protocols for obtaining, culturing, and cryopreserving sheep placental explants, we applied these methods to bovine tissues. Here, we compared fresh and cryopreserved bovine explants, evaluating their integrity and functionality over culture time. Additionally, we investigated their susceptibility to N. caninum infection. Our findings revealed that bovine explants deteriorate faster in culture compared to sheep explants, exhibiting diminished viability and function. Cryopreservation further exacerbated this deterioration. While fresh explants were successfully infected with N. caninum, parasite replication was limited. Notably, cryopreservation reduced infection efficiency. This pioneering work paves the way for developing ex vivo models to study reproductive pathogens in cattle. However, further optimization of the model is essential. These improved models will have the potential to significantly reduce the reliance on animals in research.

  PMID:39368452 | DOI:10.1016/j.theriogenology.2024.10.003

• Serological and molecular survey of Toxoplasma Gondii in aborted livestock fetuses from Northeast Iran
  

  BMC Res Notes. 2024 Oct 3;17(1):290. doi: 10.1186/s13104-024-06915-4.

  ABSTRACT

  BACKGROUND: Toxoplasmosis not only leads to abortion in humans but also in herbivores, which causes significant financial and quality-adjusted life-year losses. The present study aimed to determine the prevalence of toxoplasmosis in aborted fetuses via serological and molecular assays. Moreover, the genotypes of the obtained isolates were detected.

  METHODS: Serological and molecular methods were used to study aborted fetuses from Bojnourd City, North Khorasan Province, Iran, which included 52 ovines and 16 bovines. Nested PCR of the B1 gene was used to detect parasite DNA in brain tissues. The PCR-RFLP method for the GRA6 gene was used to determine the genotype of T. gondii.

  RESULTS: Out of 68 aborted fetuses, 16.1% showed the presence of anti-T. gondii IgG. Among these, 11.7% were identified in bovine fetuses and 4.4% in ovine fetuses. Additionally, two (2.94%) samples of ovine tested positive for anti-T. gondii IgM. Our PCR analysis detected parasite DNA in two cases (2.94%) among 11 IgG-positive samples. All obtained isolates belong to type I of T. gondii.

  CONCLUSION: Infection with Type I of T. gondii during the neonatal period may partly be responsible for abortion and economic losses in livestock farming in our studied region. To understand the molecular epidemiology and genotypes of T. gondii associated with abortion, further evaluation of aborted samples from different geographical locations is necessary.

  PMID:39363333 | PMC:PMC11451051 | DOI:10.1186/s13104-024-06915-4

• Serosurvey and associated risk factors for bovine viral diarrhea virus infection in cattle in Egypt
  

  Anim Sci J. 2024 Jan-Dec;95(1):e13995. doi: 10.1111/asj.13995.

  ABSTRACT

  Bovine viral diarrhea virus (BVDV), is widely spread, poses a considerable risk of infection in the majority of dairy farms, causing respiratory, gastrointestinal, and reproductive problems. The aim of this study was to determine the seroprevalence and the risk variables associated with the seroprevalence of BVDV infection in cattle in four Egyptian governorates. A total of 680 blood samples were collected from cattle and examined for the presence of antibodies against BVDV using indirect ELISA (iELISA). Reproductive and management factors were considered, and epidemiological surveys were conducted. The total seroprevalence of BVDV in cattle was 18.24% (124/680) and it was significantly higher in females 19.66% (116/590), cattle older than 8 years 22.14% (62/280), dairy animals 22.65% (94/514), introduction of new animals to herd 21.39% (89/416), breeding with artificial insemination 28.46% (74/260), animals with history of abortion 28.76% (49/357), or during lactation stage 23% (89/387). The present findings suggest that BVD is prevalent in Egyptian dairy cattle and has an impact on farm productivity and production. Therefore, older, lactating, and aborted animals should also be identified for the disease, pose a risk of infection, and be handled appropriately.

  PMID:39363599 | DOI:10.1111/asj.13995

• Unraveling the role of sperm retained histones in bull fertility and daughter fertility
  

  Theriogenology. 2024 Dec;230:299-304. doi: 10.1016/j.theriogenology.2024.09.023. Epub 2024 Sep 25.

  ABSTRACT

  During spermatogenesis, a substantial proportion of histones are substituted by protamine to condense the genome within the sperm head. Studies indicate that a minority of histones, typically ranging from 1 to 15 %, persist in mammalian sperm post-substitution. The persistence of histones in the zygote facilitates chromatin accessibility to transcription factors in regions crucial for early embryonic development. Nevertheless, the potential causal relationship between retained histones and fertility phenotypes remains uncertain. This study seeks to investigate this relationship. The results indicate that in mature bovine sperm, regions of DNA associated with fertility that bind to histones are primarily concentrated in promoters and transcription start sites, potentially impacting bull fertility and offspring fertility through the regulation of relevant genes. Furthermore, microRNAs and estradiol/ESR are suggested to be the main regulators of the canonical pathways identified, highlighting the need for additional research to investigate their potential utility as biomarkers.

  PMID:39366208 | DOI:10.1016/j.theriogenology.2024.09.023

• Patterns of variation and relationships among fat, protein, and milk yield of individual dairy cattle in a Thai multibreed population
  

  Trop Anim Health Prod. 2024 Oct 3;56(8):324. doi: 10.1007/s11250-024-04162-0.

  ABSTRACT

  This study systematically examines the patterns of milk yield (MY, kg), fat (FAT, %), and protein (PROT, %) in a diverse population of Thai multibreed dairy cattle, considering the tropical environment’s impact on lactating cows. Using a dataset of 47,205 monthly test-day records from 4,440 first-lactation cows across 446 farms, we analyze variations and interrelationships through mathematical averaging and introduce the fat-to-protein ratio (FPR) to assess acidosis (FPR < 1.1) and ketosis (FPR > 1.5) risks during lactation. Pearson correlation analysis elucidated trait associations. The findings, aligned with established lactation norms, indicate peak production at 297 days in milk (DIM) for FAT (4.08%; SD = 0.96%), PROT (3.43%; SD = 0.47%), and 52 DIM for MY (18.09 kg; SD = 4.91 kg). Nadirs are observed at 72 DIM for FAT (3.27%; SD = 0.74%), 47 DIM for PROT (2.86%; SD = 0.36%), and 299 DIM for MY (9.05 kg; SD = 2.95 kg). FPR variations highlight acidosis (46.48%), normal (43.66%), and ketosis (9.86%), especially during early lactation (100 DIM). Significant negative correlations emerge between MY, FAT, and PROT (P < 0.05), while a positive correlation is identified between FAT and PROT (P < 0.01), with robust correlations during early lactation. This study contributes to understanding tailored nutritional strategies for dairy cows' holistic health and sustainability in tropical environments, guiding efficient production practices and mitigating health-related productivity impediments.

  PMID:39361094 | DOI:10.1007/s11250-024-04162-0

• Detection of putative loci affecting milk yield in Turkish Awassi sheep using microsatellite markers
  

  Trop Anim Health Prod. 2024 Oct 3;56(8):322. doi: 10.1007/s11250-024-04165-x.

  ABSTRACT

  On the basis of comparisons between bovine and ovine genome mapping information, the aim of the study was to analyze the genetic diversity of selected DNA microsatellites from the bovine genome and to investigate their correlation with the average daily milk yield in Awassi sheep. 18 informative microsatellite markers were selected from the significant QTL regions affecting milk yield identified in the bovine genome in previous studies. The selected microsatellite markers were then amplified by PCR as reciprocal amplifications on the genomic DNA of Awassi sheep, with standard daily milk yield records. Thus, in this study, 18 microsatellite markers associated with milk yield in the bovine genome were examined for both determination of genetic polymorphism within the flock and the effects of marker loci on average daily milk yield in Awassi sheep. Allele frequencies of markers were determined based on the results of fragment analysis. The analysis of variance showed that the 123 bp allele at the marker locus BMS1341 on BTA2 significantly influenced the average daily milk yield of Ivesi sheep (P < 0.01). On the other hand, the BMS381 locus with a 115 bp allele on BTA2, the MCM140 locus with a 185 bp allele on BTA6, the BMS2721 locus with a 155 bp allele, the BM1237 locus with 174 and 180 bp alleles on BTA7, and finally, the BMS1967 locus with a 117 bp allele, the BM4208 locus with 176 and 182 bp alleles, and the INRA locus with a185 bp allele on BTA8 showed moderately significant effects on the average daily milk yield of Ivesi ewes (P < 0.05).

  PMID:39361098 | DOI:10.1007/s11250-024-04165-x

• Risk factors underlining reproductive performance in smallholder beef cattle herds of South Africa
  

  Trop Anim Health Prod. 2024 Oct 2;56(8):320. doi: 10.1007/s11250-024-04181-x.

  ABSTRACT

  Improving the historically low reproductive performance of beef cattle in smallholder systems is essential for its productivity and profitability. Therefore, identifying and addressing risk factors associated with low performance in this system present an opportunity for improvement. The study aimed to evaluate the effect of animal and management risk factors on pregnancy rate (PR), fetal and calf loss (FC), calving interval (CI) and days open (DO) in smallholder beef cattle farms. A multi-stage selection approach was conducted in five provinces of South Africa. Cow records (3694) collected from 40 smallholder herds over two years (2018-2019) were analysed. Data on animal and herd management factors including body condition score (BCS), cow age class, breed type, lactation status, culling old/non-productive cows, record-keeping, and breeding and calving seasons were recorded. The GLIMMIX procedure was computed to determine risk factors associated with performance indicators (PR, FC, CI and DO). Risk factors highly associated with performance were breed type, BCS, cow-age class and breeding/calving season (P ≤ 0.05). Indicators FC, DO and CI increased with decreased BCS, autumn calving seasons, and in first calvers and aged cows. Whereas, PR increased with increasing odds of BCS and breeding seasons between December-March, November-February and January-March. Optimizing reproductive performance in smallholder beef cattle herds may involve managing cow body condition, breeding with adapted genotypes and synchronizing breeding with favourable seasons. Therefore, record keeping and regular monitoring of herd nutrition, climate and breed performance may be significant in improving reproductive performance in smallholder herds.

  PMID:39358474 | PMC:PMC11446968 | DOI:10.1007/s11250-024-04181-x

• Changes in mammary infection status in dairy cows during the dry period using dry cow therapy approaches on three farms
  

  Anim Sci J. 2024 Jan-Dec;95(1):e13993. doi: 10.1111/asj.13993.

  ABSTRACT

  This case study evaluated the mammary infection status of dairy cows during the dry periods and explored the associated problems in their quarters with dry cow therapy (DCT). This study assessed intramammary infections, antibiotic efficacy, and antimicrobial resistance of pathogens in 464-quarter milk samples from 59 dairy cows during the dry periods after applying blanket DCT, non-DCT, and selective DCT approaches on three farms. The recovery rates of intramammary infections were 95% (19/20 quarters) with blanket DCT on farm A, 70% (14/20) with non-DCT on farm B, and 19% (4/21) with selective DCT on farm C. Analysis of mammary infections in cows with DCT revealed that mammary infections were controlled by blanket DCT, well controlled by non-DCT, and substantial problems remained in selective DCT. Lower intramammary infection prevalence in the quarters at postpartum appeared to be associated with higher recovery of mammary infections, fewer new infections, and lower uncured mammary infections within the herds. Antibacterial resistance in 14 coagulase-negative staphylococci isolated to six antimicrobial drugs was suggested to be linked to antibiotic use on the farm. Follow-up studies on the quarter-based infection status with DCT will assist in improving mastitis control in cows during the dry period.

  PMID:39352224 | DOI:10.1111/asj.13993

• Productivity and nitrogen metabolism of lactating cows fed pistachio hull with soybean meal partially replaced by slow-release urea
  

  Trop Anim Health Prod. 2024 Sep 30;56(8):305. doi: 10.1007/s11250-024-04123-7.

  ABSTRACT

  Pistachio hull (PH), a rich source of tannin, may interact with nitrogen (N) and affect N metabolism in dairy cows. This investigation aimed to assess the effects of feeding PH and two N sources (soybean meal: SBM or slow-release urea: SRU) on milk production, digestibility, and N metabolism in lactating dairy cows. The study utilized a 4 × 4 Latin square design with 12 Holstein dairy cows (body weight = 611 ± 39 kg; 84 ± 14 days in milk; 45.6 ± 5.3 kg/d milk), with treatments arranged in a 2 × 2 factorial configuration. The main factors were (1) the tannin source [without or with dried PH included at 76.5 g/kg of diet DM] and (2) two N sources [SBM vs. SRU]. Crude protein and total phenolic and tannin contents were greater, but NDF was lower in PH than in sugar beet pulp. Feeding diets containing 7.65% PH resulted in reductions in milk yield, milk urea N, and milk efficiency but milk fat and protein concentration increased. Milk yield was similar between SBM and SRU. Feeding PH in replacement to sugar beet pulp did not interact with N sources, except for feed intake, as the PH + SRU diet tended to decrease feed intake (P = 0.09). Feeding PH was also associated with decreased dry matter, crude protein, and NDF digestibility. Dry matter digestibility decreased when a portion of SBM was replaced by SRU. Feeding PH in replacement to sugar beet pulp lowered ruminal ammonia-N concentration and increased acetate-to-propionate proportion. Feeding PH vs. sugar beet pulp had no effect on N intake and N excretion in urine and milk, but it increased the amount of N excretion in feces and decreased apparent N efficiency (milk N/N intake). Alanine aminotransferase was lower in cows fed SRU only in PH- but not sugar beet pulp-containing diets. Blood creatinine was lower when SRU was included in the PH-containing diet, but the opposite was observed in diets containing sugar beet pulp. Feeding PH instead of sugar beet pulp did not affect blood urea-N but resulted in lower glucose and aspartate aminotransferase concentrations. Overall, cows fed PH in replacement to sugar beet pulp were less efficient in converting feed nutrients into milk production, likely because of its negative effect on nutrient digestion. Partial replacement of SBM with SRU had no influence on lactation productivity and urea-N concentration in milk and blood. This may imply the suitability of SRU in providing a sustained supply of N in the rumen, likely qualifying it as a viable source of N to replace a portion of SBM in dairy diets.

  PMID:39347824 | DOI:10.1007/s11250-024-04123-7

• Developmental Competence of Somatic Cell Nuclear Transfer Embryos and Interspecies ICSI Zygotes From Bovine Small Antral Follicles
  

  Reprod Domest Anim. 2024 Oct;59(10):e14726. doi: 10.1111/rda.14726.

  ABSTRACT

  Assisted reproductive technologies (ART) play a crucial role in conserving threatened wildlife species such as Bos gaurus. ART requires a large number of mature oocytes, and small antral follicles (SAFs) in the ovary are often used to obtain abundant sources of bovine oocytes. However, oocytes from SAFs often experience difficulty completing maturation and obtaining high quality and quantity of blastocyst formation compared to fully grown oocytes. This study aimed to increase the number of high-quality mature oocytes and improve their potential for ART applications in cloned and interspecies intracytoplasmic sperm injection (ICSI) embryos by utilising L-ascorbic acid (LAA) in pre in vitro maturation (pre-IVM) culture. First, oocytes isolated from SAFs were cultured with the duration of pre-IVM 0, 6, 8, 10 h and different concentrations of LAA to determine good conditions for oocyte maturation. Then, mature oocytes were assessed for their developmental competence through parthenogenesis, cloned and interspecies ICSI embryos. The results showed that 8-h pre-IVM with 50 μg/mL LAA improved the maturation rate and developmental competence of parthenogenetic and clone embryos, especially, improving the high blastocyst quality by increasing cell number and expression of histone acetylation at lysine 9 (H3K9ac). In addition, the culture process improved the nuclear reprogramming of somatic cells after nuclear transfer into mature oocytes, resulting in an increased hatching rate of cloned embryos. It also enhanced the activation and the pronuclear formation rate of Gaurus-Taurus zygotes. Overall, the established pre-IVM culture method enhanced the meiotic and developmental competence of embryos. This procedure opened hope for the preservation of endangered species and other applications.

  PMID:39344426 | DOI:10.1111/rda.14726

• Expression patterns of folate metabolism-related enzymes in the bovine oviduct: estrous cycle-dependent modulation and responsiveness to folic acid
  

  Theriogenology. 2024 Dec;230:233-242. doi: 10.1016/j.theriogenology.2024.09.021. Epub 2024 Sep 24.

  ABSTRACT

  Folate metabolism is required for important biochemical processes that regulate cell functioning, but its role in female reproductive physiology in cattle during peri- and post-conceptional periods has not been thoroughly explored. Previous studies have shown the presence of folate in bovine oviductal fluid, as well as finely regulated gene expression of folate receptors and transporters in bovine oviduct epithelial cells (BOECs). Additionally, extracellular folic acid (FA) affects the transcriptional levels of genes important for the functioning of BOECs. However, it remains unknown whether the anatomical and cyclic features inherent to the oviduct affect regulation of folate metabolism. The present study aimed to characterize the gene expression pattern of folate cycle enzymes in BOECs from different anatomical regions during the estrous cycle and to determine the transcriptional response of these genes to increasing concentrations of exogenous FA. A first PCR screening showed the presence of transcripts encoding dihydrofolate reductase (DHFR), methylenetetrahydrofolate reductase (MTHFR), and methionine synthase (MTR) in bovine reproductive tissues (ovary, oviduct and uterus), with expression levels in oviductal tissues comparable to, or even higher than, those detected in ovarian and uterine tissues. Moreover, expression analysis through RT-qPCR in BOECs from the ampulla and isthmus during different stages of the estrous cycle demonstrated that folate metabolism-related enzymes exhibited cycle-dependent variations. In both anatomical regions, DHFR was upregulated during the preovulatory stage, while MTHFR and MTR exhibited increased expression levels during the postovulatory stage. Under in vitro culture conditions, ampullary and isthmic cells were cultured in the presence of 10, 50, and 100 μM FA for 24 h. Under these conditions, isthmus epithelial cells exhibited a unique transcriptional response to exogenous FA, showing a pronounced increase in MTR expression levels. Our results suggest that the expression of folate metabolism-related genes in BOECs is differentially regulated during the estrous cycle and may respond to exogenous levels of folate. This offers a new perspective on the transcriptional regulation of genes associated with the folate cycle in oviductal cells and provides groundwork for future studies on their functional and epigenetic implications within the oviductal microenvironment.

  PMID:39342825 | DOI:10.1016/j.theriogenology.2024.09.021

• Genetic Foundations of Nellore Traits: A Gene Prioritization and Functional Analyses of Genome-Wide Association Study Results
  

  Genes (Basel). 2024 Aug 27;15(9):1131. doi: 10.3390/genes15091131.

  ABSTRACT

  The main goal of this study was to pinpoint functional candidate genes associated with multiple economically important traits in Nellore cattle. After quality control, 1830 genomic regions sourced from 52 scientific peer-reviewed publications were used in this study. From these, a total of 8569 positional candidate genes were annotated for reproduction, 11,195 for carcass, 5239 for growth, and 3483 for morphological traits, and used in an over-representation analysis. The significant genes (adjusted p-values < 0.05) identified in the over-representation analysis underwent prioritization analyses, and enrichment analysis of the prioritized over-represented candidate genes was performed. The prioritized candidate genes were GFRA4, RFWD3, SERTAD2, KIZ, REM2, and ANKRD34B for reproduction; RFWD3, TMEM120A, MIEF2, FOXRED2, DUSP29, CARHSP1, OBI1, JOSD1, NOP58, and LOXL1-AS1 for the carcass; ANKRD34B and JOSD1 for growth traits; and no genes were prioritized for morphological traits. The functional analysis pinpointed the following genes: KIZ (plays a crucial role in spindle organization, which is essential in forming a robust mitotic centrosome), DUSP29 (involved in muscle cell differentiation), and JOSD1 (involved in protein deubiquitination, thereby improving growth). The enrichment of the functional candidate genes identified in this study highlights that these genes play an important role in the expression of reproduction, carcass, and growth traits in Nellore cattle.

  PMID:39336722 | PMC:PMC11431486 | DOI:10.3390/genes15091131

• Hepatic Transcriptome Reveals Potential Key Genes Contributing to Differential Milk Production
  

  Genes (Basel). 2024 Sep 20;15(9):1229. doi: 10.3390/genes15091229.

  ABSTRACT

  BACKGROUND: Despite the widespread adoption of TMR or PMR and the formulas designed to sufficiently cover the cows’ requirements, individual dairy cows’ milk production varies significantly. The liver is one of the most important organs in cow lactation metabolism and plays an essential role in the initiation of lactation.

  OBJECTIVES: This study aimed to investigate the potential key genes in the liver contributing to the different milk production.

  METHODS: We enrolled 64 cows and assigned them to high or low milk yield (MY) groups according to their first 3 weeks of milk production. We performed RNAseq for 35 liver samples with 18 from prepartum and 17 from postpartum cows.

  RESULTS: The continuous milk yield observation showed a persistently higher milk yield in high MY cows than low MY cows in the first 3 weeks. High MY cows showed better feed conversion efficiency. We identified 795 differentially expressed genes (DGEs) in the liver of high MY cows compared with low MY cows, with up-regulated genes linked to morphogenesis and development pathways. Weighted gene co-expression network analysis (WGCNA) revealed four gene modules positively correlating with milk yield, and protein and lactose yield (p < 0.05). Using the intersected genes between the four gene modules and DEGs, we constructed the linear mixed-effects models and identified six hub genes positively associated and two hub genes negatively associated with milk yield (Coefficients > 0.25, p < 0.05). Random forest machine learning model training based on these eight hub genes could efficiently predict the milk yield (p < 0.001, R² = 0.946). Interestingly, the expression patterns of these eight hub genes remained remarkably similar before and after parturition.

  CONCLUSIONS: The present study indicated the critical role of liver in milk production. Activated processes involved in morphogenesis and development in liver may contribute to the higher milk production. Eight hub genes identified in this study may provide genetic research materials for dairy cow breeding.

  PMID:39336820 | PMC:PMC11431119 | DOI:10.3390/genes15091229

• Overexpression of PER2 Promotes De Novo Fatty Acid Synthesis, Fatty Acid Desaturation, and Triglyceride Accumulation in Bovine Mammary Epithelial Cells
  

  Int J Mol Sci. 2024 Sep 10;25(18):9785. doi: 10.3390/ijms25189785.

  ABSTRACT

  The core clock gene Period2 (PER2) is associated with mammary gland development and lipid synthesis in rodents and has recently been found to have a diurnal variation in the process of lactation, but has not yet been demonstrated in bovine mammary epithelial cells (BMECs). To explore the regulatory function of PER2 on milk fat synthesis in bovine mammary epithelial cells, we initially assessed the expression of clock genes and milk fat metabolism genes for 24 h using real-time quantitative PCR and fitted the data to a cosine function curve. Subsequently, we overexpressed the PER2 in BMECs using plasmid vector (pcDNA3.1-PER2), with empty vector pcDNA3.1-myc as the control. After transfecting BMECs for 48 h, we assessed the protein abundance related to milk fat synthesis by Western blot, the expression of genes coding for these proteins using real time-quantitative PCR, the production of triacylglycerol, and the fatty acid profile. The findings indicated that a total of nine clock genes (PER1/2, CRY1/2, REV-ERBα, BMAL1, NCOR1, NR2F2, FBXW11), seven fatty acid metabolism genes (CD36, ACSS2, ACACA, SCD, FADS1, DGAT1, ADFP), and six nuclear receptor-related genes (INSIG1, SCAP, SREBF1, C/EBP, PPARG, LXR) exhibited oscillation with a period close to 24 h in non-transfected BMECs (R² ≥ 0.7). Compared to the control group (transfected with empty pcDNA3.1-myc), the triglyceride content significantly increased in the PER2 overexpression group (p < 0.05). The lipogenic genes for fatty acid transport and triglyceride synthesis (ACACA, SCD, LPIN1, DGAT1, and SREBF1) were upregulated after PER2 overexpression, along with the upregulation of related protein abundance (p < 0.05). The contents and ratios of palmitic acid (C16:0), oleic acid (C18:1n9c), and trans-oleic acid (C18:1n9t) were significantly increased in the overexpression group (p < 0.05). Overall, the data supported that PER2 participated in the process of milk fat metabolism and is potentially involved in the de novo synthesis and desaturation of fatty acid in bovine mammary epithelial cells.

  PMID:39337271 | PMC:PMC11431620 | DOI:10.3390/ijms25189785

• Bayesian approach for assessment of co-variances and genetic parameters of production and reproduction traits in Sahiwal cattle
  

  Trop Anim Health Prod. 2024 Sep 28;56(8):299. doi: 10.1007/s11250-024-04148-y.

  ABSTRACT

  Precise as well as unbiased estimates of genetic parameters of economically important traits is important for framing breeding programmes meant for genetic progress of dairy animals. Present work was carried out to assess the co-variances along with genetic parameters of production and reproduction traits in Sahiwal cattle with Bayesian approach. Records of Sahiwal cattle kept at ICAR-National Dairy Research Institute, Karnal, Haryana for the period 1988-2016 were used. Heritability estimates ± posterior standard deviation for 305 days’ milk yield (305DMY), lactation milk yield (LMY), lactation length (LL), peak yield (PY), days to attain peak yield (DPY), dry period (DP), gestation period (GP), calving to first insemination interval (CFI), days open (DO) and calving interval (CI) as obtained were 0.23 ± 0.03, 0.26 ± 0.03, 0.18 ± 0.03, 0.18 ± 0.03, 0.07 ± 0.02, 0.08 ± 0.02, 0.08 ± 0.02, 0.07 ± 0.02, 0.09 ± 0.02 and 0.02 ± 0.02, respectively and estimates of repeatability for the corresponding traits were 0.23 ± 0.03, 0.26 ± 0.03, 0.21 ± 0.03, 0.21 ± 0.03, 0.12 ± 0.02, 0.14 ± 0.03, 0.16 ± 0.03, 0.16 ± 0.03, 0.17 ± 0.03 and 0.17 ± 0.03. Moderate heritability values for 305DMY and LMY implies that sufficient additive genetic variability is available to obtain selection response. Repeatability estimates for 305DMY, LMY and PY were moderate, pointing towards the possibility of early appraisal of Sahiwal cattle for selection. Antagonistic genetic associations were observed between reproduction and production traits suggesting that reproduction traits need due attention while selecting high producing Sahiwal animals.

  PMID:39340732 | DOI:10.1007/s11250-024-04148-y

• Impact of oil type and savory plant on nutrient digestibility and rumen fermentation, milk yield, and milk fatty acid profile in dairy cows
  

  Sci Rep. 2024 Sep 28;14(1):22427. doi: 10.1038/s41598-024-73138-9.

  ABSTRACT

  Fat supplements are well known for their multiple beneficial effects on ruminant health, reproduction and productivity, and as a source for certain bioactive compounds in ruminant products. On the other hand, numerous phytochemicals have demonstrated the potential to improve rumen fermentation through modifying the volatile fatty acid (VFA) pattern to favour those with greater energy efficiency, boosting microbial protein synthesis, and decreasing methane emission and ruminal ammonia concentration. Savory is an aromatic plant rich in various phytochemicals (mainly carvacrol and flavonoids) that can alter ruminal metabolism of dietary fatty acids, potentially increasing the production of some bioactive compounds such as conjugated linoleic acids (CLAs). This study aimed to investigate combined effects of oil type (fish oil (FO) versus soybean oil (SO)) and the inclusion of savory (Satureja khuzistanica) plant (SP) in the diet on total tract digestibility of nutrients, rumen fermentation, milk yield and milk fatty acid profile in dairy cattle. Eight multiparous lactating Holstein cows were used in a replicated 4 × 4 Latin square design experiment with four diets and four 21-d periods. During each experimental period consisted of 14 days of adaptation and a 7-day sampling period, cows were randomly assigned to one of the four dietary treatments: the diet supplemented with 2% (DM basis) fish oil (FOD) or soybean oil (SOD), the FOD or SOD plus 370 g DM/d/head SP (FODs, SODs, respectively). The experimental diets were arranged in a 2 × 2 factorial design, with the fat sources as the first and SP as the second factor. The FO-supplemented diets had lower dry matter intake (DMI) and higher total tract digestibility than SO-supplemented diets (P < 0.05), and including SP in the diet improved total tract digestibility of dry matter (DM), organic matter (OM), ether extract (EE), and non-fibrous carbohydrates (NFC) (P < 0.05) without negatively affecting DMI. Rumen pH was lower with SO than with FO diets (P < 0.01) and increased with SP inclusion in the diet (P < 0.05). Total protozoa count and ruminal ammonia concentration decreased, and the branched-chain VFA (BCVFA) proportion increased with SP inclusion in the diet (P < 0.05). Milk production, as well as the concentration and yield of milk components (except lactose concentration) were higher with SO than with FO diets (P < 0.05), but these variables remained unaffected by SP. The milk concentrations of both non-esterified fatty acids (NEFA) and beta-hydroxybutyrate (BHB) were lower with SO compared to FO diets, and these variables were reduced by SP (P < 0.01). The proportions of both mono- and polyunsaturated FA (MUFA and PUFA, respectively) in milk were higher with FO than with SO diets (P < 0.01), and their proportions increased by SP at the expense of saturated FA (SFA) (P < 0.01). Including SP in the diet increased the proportions of all the milk n-3 FA (C18:3c, C20:5, and C22:6) by 21%, 40%, and 97%, respectively, and those of conjugated linoleic acids (C18:2 (c9,t11-CLA) and C18:2 (t10,c12-CLA)) by 23% and 62%, respectively. There was no interaction between oil type and SP for the assessed variables. Fish oil, despite reducing milk production and milk components, was more effective than soybean oil in enriching milk with healthy FA. These findings also show promise for SP as a feed additive with the potential to improve total tract digestibility, rumen fermentation and milk FA composition.

  PMID:39341950 | PMC:PMC11438970 | DOI:10.1038/s41598-024-73138-9

• Effects of parity, calving season, and previous lactation's milk yield on fertility of dairy cows on a commercial farm
  

  Anim Sci J. 2024 Jan-Dec;95(1):e13998. doi: 10.1111/asj.13998.

  ABSTRACT

  This study investigated the effects of parity, season, and the previous lactation’s milk yield on fertility in dairy cows. A total of 5,514 calving records for Holstein cows that calved between 2016 and 2018 on a single large dairy farm in Japan were used for analysis. The proportion of cows that get pregnant by 360 days after calving was defined as the percentage of all cows eligible for breeding that became pregnant. In the all-cow model, pregnancy probability associated with both parity and calving season (p < 0.05). Pregnancy probability decreased with an increase in parity, with hazard ratios (HRs) of 1.75 (1.58-1.94) for parity 1, 1.25 (1.13-1.39) for parity 2, 1.15 (1.04-1.29) for parity 3, and 1.13 (1.00-1.27) for parity 4, relative to parity ≥5. In terms of calving season, the lowest pregnancy probability was found in spring, and the HRs relative to spring were 1.16 (1.07-1.26) for summer, 1.35 (1.24-1.47) for autumn, and 1.17 (1.07-1.27) for winter. In the multiparous-cow model, pregnancy probability associated with the previous lactation's milk yield (p < 0.05), but not with parity or calving season. Cows with high and middle previous milk yields had lower pregnancy probabilities than those with low milk yields.

  PMID:39327868 | DOI:10.1111/asj.13998

• An agroecological approach to preparation and use of a milk protein production baseline
  

  PeerJ. 2024 Sep 23;12:e18103. doi: 10.7717/peerj.18103. eCollection 2024.

  ABSTRACT

  Commercial dairy production occurs in a complex management environment, but increasingly, the dairy manager is expected to provide detailed reporting of productivity and environmental outcomes, for which conventional research methods double-blind crossover or case:control trials are inappropriate. This paper demonstrates the development of a milk protein production monitoring tool using a temporal (baseline) control in longitudinal, census-type investigations of modulation of system performance in response to factor change. It utilises farm-derived current and historical data, and contrasts seasonal responses with those achieved on neighbouring farms in a 2 × 2 contingency table. The approach is then shown to be useful in assessing the effect of two approaches to moderating milk urea concentration. Firstly, milk urea content can be monitored as it falls due to reduced feed protein content, and this fall can be arrested when milk protein content starts to decline relative to the value expected for the herd at any lactation stage. Secondly, by providing a dietary intervention aimed at increasing the availability of metabolic energy in the last month before calving, udder development can be augmented, leading to greater protein secretion capacity, meaning greater utilisation of circulating amino acids, and thus more limited substrate for urea synthesis. Thus, the changing impact of differing nutrition practices on dairy herd nitrogen excretion to environment can be followed with daily precision. In principle this approach can provide useful insights into a wide range of practical management interventions.

  PMID:39329138 | PMC:PMC11426323 | DOI:10.7717/peerj.18103

• Effect of supplementing algae to breeding and early gestation first calf heifers on growth and reproduction
  

  J Anim Sci. 2024 Jan 3;102:skae282. doi: 10.1093/jas/skae282.

  ABSTRACT

  Fat supplementation has potential to improve reproductive performance and increase pregnancy rates in cattle by increasing the energy density of the diet. However, some of the positive effects of fat seem to be influenced by the type of fatty acid fed. Docosahexaenoic acid (DHA, 22:6n-3) and eicosapentaenoic acid (EPA, 20:5n-3) are long-chain n-3 poly-unsaturated fatty acids (PUFA) that have important biological effects on reproduction through their involvement in hormone and series 3 prostaglandin synthesis. Ruminant tissues are naturally almost devoid of n-3 long-chain PUFA, specifically EPA and DHA. Algae biomass provides a consistent source of DHA and EPA that could be fed to alter hormonal profiles and improve reproduction of beef heifers. Eighty-eight Angus × Simmental heifers (427 ± 1.8 kg body weight [BW]) were blocked by BW and allotted to 2 treatments (44/treatment, 4 pens/treatment, 11 heifers/pen). Control heifers were fed a diet that contained (dry matter [DM] basis) 52.8% mixed grass silage, 32% corn silage, and 15.2% concentrate. DHAgold (49% fat; 21.8% DHA; DSM Inc.) was included in the algae diet at 1.65% DM, replacing equal parts of corn and DDGS. Diets were formulated to contain 12% crude protein and 0.85 Mcal/kg net energy for gain (NEg). Heifers were fed treatment diets from 54 d prior to the breeding season through the first trimester. Follicular fluid was collected on day 47 for hormonal analysis. Artificial insemination (AI) was from days 54 to 77. Heifers that did not get pregnant to AI were removed from the study on day 109 and placed with a bull. The study ended on day 180. Data were analyzed using the MIXED procedure of SAS. During the pre-breeding period, algae heifers had lesser dry matter intake (P = 0.006) compared to control heifers. Heifers supplemented with algae had a greater average daily gain (P = 0.03) during the breeding period and BW tended (P = 0.06) to be greater for algae compared to control heifers on day 98 and was greater on day 180 (P = 0.03). Dominant follicle diameter and follicular estrogen concentration were unaffected by treatment (P ≥ 0.12). Follicular insulin-like growth factor-1 was greater in algae compared to control heifers (P = 0.03). First service conception rate did not differ between treatments (P = 0.67); however, second service and overall conception were lesser (P ≤ 0.03) in algae compared to control heifers. These data suggest supplementing DHA-rich algae improved growth but decreased conception rates of primiparous beef females.

  PMID:39331020 | PMC:PMC11465387 | DOI:10.1093/jas/skae282

• Influence of different environmental challenges on the expression of reproductive traits in Holstein cattle in Southern Brazil
  

  Trop Anim Health Prod. 2024 Sep 26;56(8):288. doi: 10.1007/s11250-024-04133-5.

  ABSTRACT

  The aim of this study was to assess the impact of genotype-environment interaction (GEI) on the manifestation of traits such as age at first calving (AFC), age at first service (AFS), and calving interval (CI) through the application of the reaction norm model in Holstein cattle raised in Paraná state, Brazil. Utilizing data from the milk testing service of the Paraná Association of Holstein Cattle Breeders (APCBRH), this study analyzed records from 179,492 animals undergoing their first, second, and third lactations from the years 2012 to 2022. These animals were part of 513 herds spread across 72 municipalities in Paraná. The environmental gradient was established by normalizing contemporary group solutions, derived from the animal model, with the 305-day-corrected milk yield serving as the dependent variable. Subsequently, reaction norms were determined utilizing a Random Regression Model. Spearman’s correlation was then applied to compare the estimates of breeding values across different environmental gradients for the studied traits. The highest EG (+ 4) indicates the least challenging environments, where animals experience better environmental conditions. Conversely, lower EG (-4) values represent the most challenging environments, where animals endure worse conditions. The only trait that exhibited a moderate heritability magnitude was AFC (0.23) in the least challenging environmental condition. The other traits were classified as having low heritability magnitudes regardless of the evaluated environmental gradient. While minimal evidence was found for the influence of GEI on CI, a clear GEI effect was observed for AFC and AFS across all environmental gradients examined. A reversal in genotype ranking occurred under extreme environmental conditions. The findings suggest that the best-performing genotype under one environmental gradient may not necessarily excel under another.

  PMID:39327366 | DOI:10.1007/s11250-024-04133-5

• Effects of whole-day versus half-day cow-calf contact on cows' and calves' performance
  

  Animal. 2024 Oct;18(10):101318. doi: 10.1016/j.animal.2024.101318. Epub 2024 Sep 2.

  ABSTRACT

  Cow-calf contact systems (CCCs), where dairy cows nurse their own calves for several weeks while being milked, have some advantages in terms of animal welfare. However, one major challenge is the loss of collected milk due to suckling and milk ejection problems during milking. Reducing daily CCC can decrease milk losses. Our study investigated the effect of half-day CCC during daytime (HC, n = 11 cows) compared to whole-day contact (WC, n = 13) and no contact (NC, n = 14) on harvested milk yield, milk content, udder health, calving interval, and calf weight gain in a dual purpose breed-herd with concentrate-free feeding. ‘Nursing’ (9 weeks postpartum) was followed by separation of cow and calf, but still with visual CCC and twice daily milk feeding by nipple buckets (6 l per day, ‘in sight/milk feeding’). During the 11th-12th week, calves were housed out of sight and gradually weaned. Calves of NC were separated from their mothers 1 day postpartum, obtained 6 l whole-milk per day and were gradually weaned. During ‘nursing’, NC and HC cows gave more milk than WC in the morning. In the evening, HC and WC gave less milk than NC, but HC cows had also a slightly lower milk yield than WC. During ‘nursing’, a reduced fat content (-1% point) pointed at milk ejection problems in both CCC treatments independent from daytime. After separation from the calf (periods: ‘in sight/milk feeding’ and ‘out of sight/weaning’) and over the whole lactation, milk yield between HC and the other treatments did not significantly differ while WC cows gave less milk than NC cows. Protein contents were higher in dams than in NC. There were no indications of differences in the incidence of mastitis, somatic cell score or calving interval between treatments. During ‘nursing’, NC calves gained about 0.3 kg less per day than CCC-calves (n_NC = 12, n_HC = 7, n_WC = 10). After separation from the mother, there was a growth check in both CCC groups. During ‘in sight/milk feeding’, HC gained less weight than NC and WC (n_NC = 11, n_HC = 9, n_WC = 10). Hereafter, weight development did not differ. Two weeks after weaning, nursed calves were still significantly heavier than NC (n = 5-8). Nine weeks of HC during the day compared to WC helped to reduce losses of sellable milk during the nursing period and over the whole lactation while calf development was similar.

  PMID:39326125 | DOI:10.1016/j.animal.2024.101318

• A million-cow genome-wide association study of productive life in U.S. Holstein cows
  

  Genet Sel Evol. 2024 Sep 26;56(1):67. doi: 10.1186/s12711-024-00935-1.

  ABSTRACT

  BACKGROUND: Productive life (PL) of a cow is the time the cow remains in the milking herd from first calving to exit from the herd due to culling or death and is an important economic trait in U.S. Holstein cattle. The large samples of Holstein genomic evaluation data that have become available recently provided unprecedented statistical power to identify genetic factors affecting PL in Holstein cows using the approach of genome-wide association study (GWAS).

  METHODS: The GWAS analysis used 1,103,641 Holstein cows with phenotypic observations on PL and genotypes of 75,282 single nucleotide polymorphism (SNP) markers. The statistical tests and estimation of SNP additive and dominance effects used the approximate generalized least squares method implemented by the EPISNPmpi computer program.

  RESULTS: The GWAS detected 5390 significant additive effects of PL distributed over all 29 autosomes and the X-Y nonrecombining region of the X chromosome (Chr31). Two chromosome regions had the most significant and largest cluster of additive effects, the SLC4A4-GC-NPFFR2 (SGN) region of Chr06 with pleiotropic effects for PL, fertility, somatic cell score and milk yield; and the 32-52 Mb region of Chr10 with peak effects for PL in or near RASGRP1 with many important immunity functions. The dominance tests detected 38 significant dominance effects including 12 dominance effects with sharply negative homozygous recessive genotypes on Chr18, Chr05, Chr23 and Chr24.

  CONCLUSIONS: The GWAS results showed that highly significant genetic effects for PL were in chromosome regions known to have highly significant effects for fertility and health and a chromosome region with multiple genes with reproductive and immunity functions. SNPs with rare but sharply negative homozygous recessive genotypes for PL existed and should be used for eliminating heifers carrying those homozygous recessive genotypes.

  PMID:39327562 | PMC:PMC11426094 | DOI:10.1186/s12711-024-00935-1

• Risk factors and population attributable fractions for displaced abomasum in Iranian dairy cattle: a retrospective analysis of field data
  

  Trop Anim Health Prod. 2024 Sep 26;56(8):283. doi: 10.1007/s11250-024-04164-y.

  ABSTRACT

  Displaced abomasum (DA) usually occurs in the early postpartum period and can negatively affect production and welfare of dairy cows. The objective of this research was to identify predictors for the occurrence of DA in Iranian Holsteins. Therefore, we analyzed data collected from six commercial dairy farms in Iran (calving between January 2011 and October 2020). We used generalized linear mixed-effects model to identify predictors based on estimates of odds ratios (ORs). Population attributable fractions (PAFs) were then calculated, as these are expected to more accurately prioritize risk factors on population level by considering the association between the risk factor and the its prevalence in the population. Over the 6 herds, the average percentage of DA was 2.5% (range 1.1-3.4% across herds). The results showed that calving during winter increased the odds of DA 1.4 times. Cows with high milk fat-to-protein ratio before the occurrence of disease, abnormal calving (including dystocia, stillbirth, and twinning) and long pregnancy length (≥ 280 d) showed increased odds of DA with ORs of 1.52, 1.31 and 1.30, respectively. Milk yield was also positively associated with DA in next lactation. Among the modifiable predictors of DA, the highest PAF was for the ratio of milk fat-to-protein (11.0%); other PAFs were retained placenta (4.1%), metritis (3.1%), abnormal calving (2.7%), and ketosis (2.7%). The results of the present study can provide managers with the a helpful strategy to reduce the occurrence of DA.

  PMID:39322775 | DOI:10.1007/s11250-024-04164-y

• Effect of GnRH treatment as a potential solution for ovarian disorders in dairy cows infected with foot and mouth disease in Indonesian smallholder farms
  

  Open Vet J. 2024 Aug;14(8):2079-2084. doi: 10.5455/OVJ.2024.v14.i8.37. Epub 2024 Aug 31.

  ABSTRACT

  BACKGROUND: The outbreak of foot and mouth disease (FMD) in Indonesia induces reproductive disorders in dairy cows that lead to economic losses to smallholder dairy farms.

  AIM: The study was to assess the influence of FMD on reproductive traits and evaluate the effect of gonadotropin hormone-releasing hormone (GnRH) administrations on the reproductive performance in FMD-infected dairy cows.

  METHODS: The study was conducted in Jemowo village, Taman Sari sub-district, Boyolali district, Central Java, Indonesia. A total of 155 cows were used to identify the reproductive disorders on FMD-infected dairy cows aged 2-10 years old. Cows were raised in similar conditions and fed diets. A single dose of 2 ml GnRH was injected intramuscularly into 96 ovarian disorder cows. Reproductive performance was measured by service per conception (S/C), conception rate (CR), and pregnancy rate (PR). A descriptive study was conducted to demonstrate the results.

  RESULTS: The study showed that 61.9% of FMD-infected cows had reproductive disorders, whereby 53.5% ovarian hypofunction, 4.52% silent heat, 1.94% repeat breeder, 1.29% ovarian atrophy, and 0.65% endometritis. FMD-infected cows injected with GnRH had a 98% reproductive recovery rate. Moreover, the S/C, CR, and PR of cows injected with GnRH were 2.02%, 51%, and 85%.

  CONCLUSION: GnRH administrations enhanced the reproductive traits of FMD-infected dairy cows indicated by the improvement of CR and PR.

  PMID:39308740 | PMC:PMC11415909 | DOI:10.5455/OVJ.2024.v14.i8.37

• Is heat stress a growing problem for dairy cattle husbandry in the temperate regions? A case study of Baden-Württemberg in Germany
  

  J Anim Sci. 2024 Jan 3;102:skae287. doi: 10.1093/jas/skae287.

  ABSTRACT

  Heat stress with measurable effects in dairy cattle is a growing concern in temperate regions. Heat stress in temperate regions differs between environments with different geophysical characteristics. Microclimates specific to each environment were found to greatly impact at what level heat stress occurs and will occur in the future. The landlocked state of Baden-Württemberg, Germany, provides several different environments, hence, a good case-study. Temperature-Humidity Index (THI) from 17 weather stations for the years 2003 to 2022 was calculated and milking yields from 22 farms for the years 2017 to 2022 were collected. The occurrences and evolving patterns of heat stress were analyzed with the use of a THI, and the effect of heat stress on milk yield was analyzed based on milking records from Automated Milking Systems. Daily average THI was calculated using hourly readings of relative humidity and ambient temperature, disregarding solar radiation and wind, as all animals were permanently stabled. Based on studies conducted in Baden-Württemberg and neighboring regions, cited ahead in the section of THI, THI = 60 was the threshold for heat stress occurrence. Findings show that the heat stress period varied between stations from 64 to 120 d with THI ≥ 60 in a year. This aligns with yearly and summer averages, also steadily increasing from May to September. The length of the heat stress period was found to increase 1 extra day every year. Extreme weather events such as heat waves did not increase the heat stress period of that year in length but increased the average THI. Milk yield was found to be significantly (α = 0.05) different between counties grouped into different zones according to heat stress severity and rate of increase in daily average THI. Future attempts at managing heat stress on dairy cattle farms in the temperate regions should account for microclimate, as geographical proximity does not mean that the increase in heat stress severity will be the same in the 2 neighboring areas.

  PMID:39311692 | DOI:10.1093/jas/skae287

• Reproductive outcomes of prepubertal Bos indicus beef heifers raised in a pasture-based feeding system submitted to ovulation induction strategies prior to a timed-artificial insemination protocol
  

  Theriogenology. 2024 Dec;230:183-191. doi: 10.1016/j.theriogenology.2024.09.011. Epub 2024 Sep 11.

  ABSTRACT

  Reproductive outcomes were evaluated in Nelore (Bos indicus) heifers submitted to one, two or no ovulation induction protocols based on progesterone (P4) and estradiol (E2) prior to a timed-artificial insemination (TAI) protocol. A total of 1,437 heifers (13.0 ± 0.8 mo old; 3.1 ± 0.1 of body condition score [BCS] and 279.9 ± 25.8 kg of body weight [BW]) were randomly assigned to 1 of 3 treatments: 0IND (n = 486): no ovulation induction protocol; 1IND (n = 481): one ovulation induction protocol; or 2IND (n = 470): two ovulation induction protocols. On Day -47, heifers from 2IND received a disinfected intravaginal P4 device (2 g, previously used for 21 d), kept until Day -40, when 0.5 mg of E2 cypionate (EC) was given. On Day -19, heifers from 2IND and 1IND underwent the same protocol. On Day 0, all heifers were submitted to the same TAI protocol, starting with a P4 device (0.5 g), 0.5 mg of cloprostenol sodium (PGF), and 1.5 mg of E2 benzoate. On Day 7, P4 device was removed, 0.5 mg of PGF, 0.5 mg of EC, and 200 IU of equine chorionic gonadotropin (eCG) were administered. The TAI was performed 2 d later (Day 9). Blood samples were collected on Days -47 and 0, to determine the presence of CL (circulating P4 concentrations ≥ 1.0 ng/mL). Ultrasound was performed on Days 40, 75 and between Day 150 and parturition to assess pregnancy per AI (P/AI) and pregnancy loss (PL). Statistical analyses were performed using SAS 9.4 (^a-cP ≤ 0.05; ^A,B0.05 < P ≤ 0.10). The proportion of heifers with CL on Day -47 was similar among groups (3.4%). A greater proportion of heifers from 1IND had CL on Day 0, followed by 2IND, then 0IND (87.9^a; 80.4^b; 28.8^c%). There was an effect of treatment on expression of estrus (2IND: 66.6^a; 1IND: 67.2^a; 0IND: 57.4^b%), P/AI on Day 40 (2IND: 53.4^a; 1IND: 43.9^b; 0IND: 46.5^b%), P/AI on Day 75 (2IND: 49.8^a; 1IND: 40.5^b; 0IND: 44.4^ab%) and final P/AI (2IND: 45.5^a; 1IND: 35.8^b; 0IND: 40.5^ab%). No differences were observed in PL (40-75 = 6.3%; 75-final = 9.6%; Total = 15.3%). Particularly within lighter heifers, there was an effect of treatment on P/AI on Day 40 (0IND: 39.2^b; 1IND: 43.3^ab; 2IND: 53.9^a%) and on Day 75 (0IND: 36.6^B; 1IND: 39.0^AB; 2IND: 48.5^A%). At the first pregnancy diagnosis, more nonpregnant heifers from 2IND had CL on Day 40 than 0IND, but 1IND did not differ from the other groups (85.4^a; 74.8^b; 80.8^ab%). In conclusion, ovulation induction protocols performed prior to the TAI protocol increased the proportion of heifers with CL on Day 0. The use of two induction protocols resulted in greater fertility, particularly in lighter heifers, and increased cyclicity among nonpregnant heifers. These results indicate that this strategy may be an optimized method for inducing cyclicity and enhancing fertility of prepubertal Nelore heifers raised in pasture-based feeding systems.

  PMID:39306911 | DOI:10.1016/j.theriogenology.2024.09.011

• Lactational performance and hematological effects of capsaicin supplementation in dairy cows: A meta-analysis
  

  J Dairy Sci. 2024 Oct;107(10):8009-8020. doi: 10.3168/jds.2024-24956.

  ABSTRACT

  A meta-analysis was performed to investigate the effects of capsaicin (CAP) on lactational performance and blood chemistry and cell counts in dairy cattle. The database comprised 11 peer-reviewed studies published between 2011 and 2024. The overall effect of CAP, challenge (e.g., ketosis, glucose tolerance, LPS), and dose were considered explanatory variables in the analysis. Lactation performance response variables included DMI, milk yield (MY), ECM yield, feed efficiency (FE), milk components, and BW. Hematological response variables included red and white blood cell counts and blood BHB, total fatty acids, insulin, and glucose concentrations. Data were analyzed using random- and mixed-effect models in the “robumeta” package in RStudio. Milk yield was increased by 2.9% by CAP when compared with control. Capsaicin supplementation increased FE by 3.4% compared with control. Milk fat concentration and yield were also increased by CAP compared with control by 2.6% and 4.0%, respectively. Blood glucose concentrations were decreased 2.5% by CAP supplementation, whereas insulin levels were unaffected. Cows fed CAP during a challenge had higher MY and FE and tended to have lower blood glucose than their control counterparts. Overall, this analysis suggests that CAP supplementation may be directly affecting host physiology by altering glucose metabolism, but further research to define the mechanism is warranted.

  PMID:39307549 | DOI:10.3168/jds.2024-24956

• Economic values of some important traits for smallholder dairy production in Central Ethiopia
  

  Trop Anim Health Prod. 2024 Sep 21;56(8):267. doi: 10.1007/s11250-024-04159-9.

  ABSTRACT

  Economic value (EV), sensitivity of EV and relative economic importance of milk yield (MY), age at first calving (AFC), calving interval (CI) and herd life (HL) traits were estimated for smallholder dairy cattle production in the central part of Ethiopia. The data on biological and economic parameters were collected using household interview and group discussions methods participating 238 farmers who had crossbred dairy cattle. Bio-economic model was used to calculate EV, sensitivity of EV and relative importance of EV. Cost of animal feed takes the highest share which accounted 81.35% of the total expenditure. The overall average profit per farmer expressed in Ethiopia currency (ETB, 1 US-$ = 39.55696 ETB) was 72,458.10 ± 5068 per year. Profitability of crossbred dairy cattle significantly varied (P < 0.05) between zones. Economic value estimated for MY, AFC, CI and HL in ETB were 13.38/kg, -16.19/day, -33.58/day and 79.55/day. The associated EV per additive standard deviation were 6083.62, -1311.59, -1271.05 and 117.73 ETB for MY, AFC, CI and HL, respectively. Analysis of sensitivity to scenario change (± 20%) showed that milk price had positive association with profit and EV, whereas feed price has inversely influenced both profit and EV. The profit obtained by farmers was altered by ± 29.08% and ± 12.31% as milk price and feed price fluctuated by ± 20%, respectively. Similarly, the EV of MY was changed by ± 20% with change in milk price and ± 7% with feed price. Scenario change in feed price (± 20%) has also caused ± 13.63% change on EV for AFC and ± 17.58% for CI. It can be noted that profit and EV of the traits were less sensitive to the change in price of milk, feed and labor. In general, the results of EV and profitability were encouraging for dairy farmers and the estimates can be used as an input for development of breeding program in the study area.

  PMID:39305331 | DOI:10.1007/s11250-024-04159-9

• Perspectives for reproduction and production in grazing sheep and cattle in Australasia: The next 20 years
  

  Theriogenology. 2024 Dec;230:174-182. doi: 10.1016/j.theriogenology.2024.09.017. Epub 2024 Sep 18.

  ABSTRACT

  We offer a perspective on the major challenges that are confronting the management of reproduction in sheep and cattle in Australia and New Zealand, over the next two decades. An important context is the dominance of grazing systems in which large flocks or herds are managed over large areas where it is challenging to manage reproduction with precision. Consequently, the variable forage supply usually dominates reproductive outcomes, a problem that will be exacerbated by global heating. Thus, in extensive grazing systems, there is a great need for technological solutions to improve the management of nutrition. Global heating will also exert direct effects on reproductive function. Therefore, for the foreseeable future, reproduction will remain a focus for industry. In addition, as the industries develop, we foresee continued societal pressure to reduce medication, mitigate environmental damage, and improve animal well-being. Management solutions for extensive grazing systems must involve minimal interventions with the animals and be applicable to diverse genotypes and environments. Clearly, genetics and breeding will be at the heart of solutions and elegant strategies will be needed that focus on developing animals that are robust, if perhaps a little less productive. A high rate of genetic gain is the main reason for pursuing reproductive technologies, but highly advanced reproductive technology is not likely to be the best fit in extensive management systems. Even for AI, the simplest technology, uptake is limited and lateral thinking is needed to find ways to improve the rates of genetic gain. We conclude that there are many opportunities for improving reproductive performance in sheep and cattle in Australia and New Zealand. As we gain deeper understanding of the processes involved, we should be able to make progress in fertility and fecundity, embryo survival, and postnatal survival. Improvements in reproductive performance will increase productivity, and should also be associated with significantly improved animal well-being and a reduction in methane emissions intensity. To capture these benefits, the development of new management options will require lateral thinking about reproductive technology for extensive grazing systems, and a transdisciplinary approach that brings together the systems biology of grazing animals with an understanding of the barriers to adoption by farmers.

  PMID:39305854 | DOI:10.1016/j.theriogenology.2024.09.017

• Evaluation of the productive and reproductive performance of sexual precocity at different ages in Nellore heifers
  

  Theriogenology. 2024 Dec;230:142-150. doi: 10.1016/j.theriogenology.2024.09.005. Epub 2024 Sep 6.

  ABSTRACT

  This study aimed to investigate the differences between productive and reproductive performance traits of sexually precocious and non-sexually precocious Nellore heifers and to evaluate the genetic correlation of sexual precocity with traits of economic importance. For this purpose, 300,000 Nellore heifers were evaluated for reproductive traits: heifer pregnancy (HP) at 14 (HP₁₄), 18 (HP₁₈), and 24 (HP₂₄) months; heifer rebreeding (HR); number of progenies up to 53 months (NP₅₃); and probability of the cow remaining in the herd until 76 months with at least 3 progenies (Stay). The growth-related traits evaluated included female yearling weight (YW); average daily gain from weaning to yearling (ADG_W-Y); weight at maturity (MW); weaning weight of first progeny (WW_prog); and female visual scores at yearling for conformation (Conf), precocity (Prec) and muscling (Musc). The effects of female YW and ADG_W-Y in six categories on HP₁₄, HP₁₈, and HP₂₄ were analyzed using Generalized linear mixed models (GLMM). Furthermore, a linear mixed model was used to evaluate the impact of HP on WW_prog, MW, and reproductive performance (NP₅₃ and Stay). Genetic correlations of HP evaluated in different months with growth and reproductive traits were estimated using a bivariate animal model. Precocious heifers (HP₁₄) were lighter for YW and MW but had greater ADG_W-Y than HP₁₈ and HP₂₄. The probability for HP₁₄, HP₁₈, and HP₂₄ increased as the classes of YW and ADG_W-Y increased. However, heifers weighing more than 326 kg had a slight reduction in the probability of becoming pregnant at HP₁₄ and HP₁₈. Precocious heifers (HP₁₄ and HP₁₈) produced their first progeny by 3 % lighter than HP₂₄, although they had a greater NP₅₃. Precocious heifers at 18 months (HP₁₈) were 3 % and 6.8 % more likely to remain in the herd than HP₁₄ and HP₂₄ heifers, respectively. Genetic correlations between growth traits (WW, YW, ADG_W-Y, and MW) and heifer pregnancy (HP₁₄, HP₁₈, and HP₂₄) ranged from weak (r_g = 0.27 ± 0.05) to moderate (r_g = -0.47 ± 0.07). The genetic correlation between HR and HP was stronger for HP₂₄ (0.75) against HP₁₄ (0.58) and HP₁₈ (0.64). Although, the genetic correlation between NP₅₃ and Stay with HP₁₄ was higher (r_g = 0.53 and 0.45) than those observed for HP₁₈ (r_g = 0.46 and 0.38) and HP₂₄ (r_g = 0.35 and 0.39). The genetic correlation estimates between HP and visual scores were moderate and favorable for HP₁₄. Selecting HP₁₄ is beneficial for production systems because it increases the NP₅₃ during the productive life without compromising heifer productivity or reproductive performance. However, attention should be given to improving the HR of heifers who become pregnant early.

  PMID:39303500 | DOI:10.1016/j.theriogenology.2024.09.005

• Helminth co-infections have no additive detrimental impact on milk yield and milk quality compared to mono-infections in German dairy cows
  

  Parasit Vectors. 2024 Sep 19;17(1):398. doi: 10.1186/s13071-024-06470-8.

  ABSTRACT

  BACKGROUND: Infections with (tricho-)strongyles, Dictyocaulus viviparus or Fasciola hepatica have been shown to reduce milk production in dairy cows. However, the current published studies focused on one single helminth infection by neglecting helminth co-infections and their possible (additive) effects on host performance. Hence, for the first time, we investigated differences in the impact of patent helminth co-infections versus mono-infections on milk production parameters in individual cows.

  METHODS: A total of 1583 dairy cows from 27 herds were included in this study. Faecal samples were examined in 2015 and 2021/2022 to determine the number of eggs/larvae per gram faeces for (tricho-)strongyles, D. viviparus, F. hepatica and rumen flukes. The cows were classified as non-infected, mono-infected and co-infected. Linear mixed models were applied to analyse the association between infection status (non-infected vs. mono-infected vs. co-infected) with milk yield, milk protein and milk fat content by including potential confounders.

  RESULTS: Infections with (tricho-)strongyles, D. viviparus, F. hepatica and rumen flukes were detected in 100%, 28.6%, 50.0% and 21.4% of herds, and 27.4%, 2.6%, 10.8% and 0.8% of faecal samples in 2015, while 100%, 0.0%, 86.7% and 60.0% of herds and 52.3%, 0.0%, 13.3% and 26.8% of faecal samples were positive in 2021/2022. Co-infections with two or more helminth taxa were detected in 74.4% of herds and 5.0% of faecal samples in 2015, and in 93.3% of herds and 21.7% of faecal samples in 2021/2022. The correlations between strongyle EPG, D. viviparus LPG and F. hepatica EPG were significantly positive in 2015. Significantly higher mean EPGs were identified in 2015 in faecal samples presenting co-infections with F. hepatica and one or two other helminth taxa than in faecal samples presenting F. hepatica mono-infections (P = 0.013). Although expected, the infection status (mono- or co-infected) had no significant impact on milk yield, milk protein and milk fat content in the linear mixed model analyses based on individual faecal examinations.

  CONCLUSIONS: Patent helminth co-infections had no additive detrimental impact on milk production parameters in the present study. This might be a result of presumably low worm burdens, but should be confirmed in future studies.

  PMID:39300583 | PMC:PMC11414050 | DOI:10.1186/s13071-024-06470-8

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