Search Results (460)

The objectives of this study were to evaluate the effects of different dietary omega-6 to omega-3 (n-6:n-3) fatty acid ratios during timed artificial insemination (TAI) on reproductive responses, luteal development, and offspring characteristics in lactating dairy cows. Holstein cows (n = 60) averaging 109 ± 10 days in milk (DIM) were randomly assigned to receive either a greater n-6:n-3 diet or a lower n-6:n-3 diet for 42 days. All cows were synchronized using a modified Ovsynch protocol. Although synchronized ovulation rates and pregnancy outcomes were not significantly affected by treatment, cows fed the lower n-6:n-3 ratio exhibited significantly greater corpus luteum (CL) volume and cross-sectional area on days 11 and 14 post-TAI, indicating enhanced luteal development. Pregnancy rates following the first AI and cumulative AI, as well as the number of services per conception, did not differ between treatments. However, cows fed the lower n-6:n-3 ratio tended to produce a greater proportion of female offspring (66.67% vs. 42.90%; p = 0.09). In addition, calves born to cows receiving the lower n-6:n-3 ratio had greater birth weights than calves born to cows fed the greater n-6:n-3 ratio diet. Additionally, the lower n-6:n-3 diet tended to increase milk yield and significantly increased lactose and solids-not-fat yields. In conclusion, a lower dietary n-6:n-3 ratio during a TAI program enhanced luteal development, tended to increase the proportion of female offspring and increased calf birth weight. These findings suggest that reducing the dietary n-6:n-3 ratio during the breeding period may enhance luteal development and may influence offspring sex ratio and calf birth weight in lactating dairy cows. Full article

Reproductive efficiency is a critical determinant of productivity and profitability in both dairy and beef cattle systems. Progesterone-based estrus synchronization protocols have emerged as essential tools to control the timing of ovulation, enhance artificial insemination efficiency, and optimize herd reproductive performance. These protocols exploit the physiological regulation of the hypothalamic–pituitary–ovarian axis, maintaining elevated progesterone levels to suppress ovulation and coordinating luteolysis and follicular wave emergence through prostaglandins, GnRH analogues, and, in some cases, equine chorionic gonadotropin. In beef cattle, progesterone supplementation facilitates fixed-time artificial insemination, shortens calving intervals, and improves calf crop uniformity, whereas in dairy cows it mitigates poor estrus detection, enhances service rates, and reduces days open. Fertility outcomes are influenced by cow physiological status, metabolic condition, and protocol adherence, with pregnancy per AI typically ranging from moderate to high in beef cattle and lower in lactating dairy cows. Economic evaluation indicates that these protocols are cost-effective in herds with moderate to large size, low estrus detection efficiency, and intensive management, although labor, drug costs, and handling requirements must be considered. Critical analysis suggests that synchronization cannot compensate for underlying nutritional, health, or metabolic deficiencies, and future research should focus on precision application, individualized protocols, and integration with automated reproductive monitoring to improve both biological and economic efficiency. This review summarizes physiological principles, protocol designs, practical applications, fertility outcomes, and economic considerations of progesterone-based estrus synchronization in cows, highlighting current challenges and perspectives for enhanced reproductive management. Full article

The postpartum period in beef cows is characterized by complex physiological and reproductive changes that may influence the postpartum reproductive changes and estrus expression. This exploratory pilot study evaluated postpartum reproductive responses in Angus cows receiving grape extract supplementation while investigating associations among thermographic, behavioral, hormonal, and reticulorumen temperature indicators associated with estrus expression. Nineteen Angus cows were assigned to a control group (C; n = 10) or a treatment group receiving slow-release grape extract boluses (T; n = 9). From calving until artificial insemination, ocular and vulvar thermographic images, blood samples, and physiological measurements were obtained weekly between 10:00 and 11:00 a.m. Reticulorumen temperature and activity data were continuously recorded using intraruminal sensors. Kaplan–Meier survival analysis demonstrated an earlier onset of postpartum estrus in supplemented cows compared with controls (p = 0.010). Mean time to first estrus was 23.88 ± 1.86 days in the T group and 39.82 ± 5.05 days in the C group. No significant differences were observed between groups for most individual physiological or hormonal variables. Exploratory correlation analysis revealed moderate associations among vulvar temperature, ocular temperature, activity, estrus index, and reticulorumen temperature indicators. However, because diagnostic accuracy was not evaluated, these findings should not be interpreted as validation of estrus detection performance. The results suggest that multimodal physiological monitoring may provide complementary information related to postpartum estrus expression in beef cows, while grape extract supplementation may be associated with earlier postpartum reproductive recovery. Due to the exploratory study design and limited sample size, further studies are required to validate these preliminary observations. Full article

Newborn piglets in intensive pig farms are often prone to pulmonary diseases due to underdeveloped fetal lung neural systems, and ATRA is often regarded as an important morphogen that displays pleiotropic functions during embryonic development. However, information about the effect of maternal administration with ATRA on the peripheral neural system of fetal lungs is still scare. Fifteen pregnant sows were assigned to the ATRA0 (0 mg/kg diet), ATRA4, ATRA8, ATRA16 and ATRA32 treatment groups and offered their own feed from d12 to d95 after artificial insemination; then two neonatal pigs with birth weights similar to the average birth weight were taken out from each litter for the collection of lung samples, and samples were subjected to immunofluorescence staining, RNA-seq and RT-qPCR assays. Results indicated that compared to newborn piglets from the ATRA0 treatment group, newborn piglets from the ATRA4 treatment group had higher percentages of GFAP-positive astrocyte cells (p < 0.05) and GFAP-TUBB3 colocalization (p < 0.05) in the lungs. KEGG (Kyoto Encyclopedia of Genes and Genomes) analysis showed that differential expressed genes are mainly enriched in the pathways of neuroactive ligand–receptor interaction, GABAergic synapses and cell adhesion molecules. Addition of ATRA at 4 mg/kg to the diet of pregnant sows can enhance the healthy development of the pulmonary nervous systems of fetal pigs. Full article

The Houbara Bustard (Chlamydotis macqueenii) is a vulnerable species found in arid and semi-desert regions of the Middle East and Central Asia. In recent decades, Houbara populations have significantly declined due to overhunting, habitat loss, and commercial development. As a result, the International Union for Conservation of Nature (IUCN) has classified this species as Vulnerable. This review examines global conservation efforts and breeding management strategies for the Asian Houbara Bustard, with particular focus on captive breeding programs established in Saudi Arabia and the United Arab Emirates. The study evaluates key reproductive technologies, including artificial insemination and other assisted breeding techniques, and examines the genetic and behavioral risks associated with captive breeding. Findings from the reviewed studies indicate that, while captive breeding programs have achieved notable production goals, they also present critical challenges for conservation. Effective long-term conservation therefore requires integrating reproductive technologies with habitat protection, careful management of genetic diversity, and the establishment of monitoring systems to ensure sustainable population recovery. Full article

In genetics and evolutionary biology, selection signatures refer to distinct genomic patterns that reflect the action of natural and artificial selection on populations over time. Detecting such signatures provides critical insights into adaptive evolution and breed differentiation, especially in livestock populations subjected to diverse production environments and breeding objectives. In this study, a total of 96 samples were collected from four different cattle breeds, namely, South African indigenous Nguni (n = 28), Bonsmara (n = 21), Angus (n = 22), and Simmental (n = 25). The samples were genotyped using the Illumina Bovine SNP 150K BeadChip and subjected to quality control. Selection signatures were identified using the integrated haplotype score (iHS) method and the fixation index (Fst) method to assess the genetic differences between breeds. The complementary application of within-population and cross-population approaches enabled the detection of both recent and divergent selective pressures. A total of twelve regions were found to be under selection, with Bos taurus autosome (BTA) 12 being common between Nguni and Bonsmara. Gene annotation analyses identified several genes, including FAM110B, CDK8, and FLT1 in Bonsmara cattle, whereas Nguni cattle indicated potential genes such as CRB1, PLA2G4A, and VASH2, with CDK8 common between Bonsmara and Nguni on BTA 12. Cross-population analyses further identified PLCXD3, FAM149B1, and GRIK2 as candidate genes differentiating Bonsmara from Nguni cattle, and TSPAN9 distinguishing Simmental from Angus cattle. These results indicated breed-specific adaptive divergence. The study revealed genomic regions that are under selection in South African Nguni, Bonsmara, and Simmental cattle, with less information for Angus cattle breeds. Several candidate genes were found to be associated with reproductive traits (such as sperm count and inseminations per conception), disease resistance (such as bovine respiratory disease), and calving ease. This study identifies breed-specific and shared genomic regions under selection across diverse cattle breeds, providing novel insights into the genetic basis of adaptation and production-related traits. These findings explain the potential application of selection signature analyses in genomic-assisted breeding programmes aimed at improving productivity, resilience, and sustainability of cattle populations. Full article

This study evaluated the implementation of reproductive technologies and their effects on pregnancy rates (PRs) and calving distribution. Producers (n = 11) were enrolled in Level 1 or 2 and subsequently transitioned to Level 2 or 3. Level 1: females were exposed to natural service (NS) only versus estrous synchronization (7d-CIDR) before NS (SynNS). Level 2: SynNS versus fixed-time artificial insemination (SynAI; 7d-CO-Synch + CIDR) with conventional semen. Level 3: conventional versus sex-skewed semen (FTAI-con and FTAI-sexed, respectively). Artificial insemination occurred 60–66 h post CIDR removal (SynAI; FTAI-con; FTAI-sexed) and bulls were introduced on d 0 (NS and SynNS) or 10–14 d post artificial insemination (SynAI; FTAI-con; FTAI-sexed). Breeding season PRs did not differ between treatments (p > 0.50). In Level 2, SynNS had greater 21 d PRs compared to SynAI (p < 0.01). For Level 3, FTAI-con had greater 21 d PRs compared to FTAI-sexed (p < 0.01). In Level 1, the proportion of cows that calved by day 14 was greater for SynNS compared to NS (p < 0.01). In Level 2, SynAI had a greater proportion calved by day 7 (p = 0.01); however, SynNS had a greater proportion calved by day 21 and 42 (p < 0.01). In Level 3, FTAI-con had a greater proportion calved by day 14 and 21 (p < 0.01) compared to FTAI-sexed. In conclusion, reproductive technologies altered the calving distribution with more calves born earlier. Full article

This narrative review summarizes evidence on the bovine β-casein (CSN2) A1/A2 polymorphism as a case study of how intensive dairy selection and global gene flow can reshape allele frequencies in ways that matter for consumers, processing and agroecological resilience. We draw together evidence from (i) population-genetic surveys of CSN2 in contrasting cattle populations, including a descriptive summary of published genotype-frequency studies; (ii) controlled human studies that separate A1-containing from A2-only dairy exposure; and (iii) dairy technology and the authenticity literature relevant to identity-preserved A2 value chains. Across intensively selected Holstein-Friesian populations, A1 was consistently present at substantial frequency (approximately one-third), whereas indigenous, beef and zebu-adjacent populations were typically A2-enriched, highlighting the role of historical breed formation and modern introgression in shaping apparent geographic and climatic patterns. Human intervention studies most consistently support improved short-term gastrointestinal tolerance with A2-only milk in susceptible individuals, while evidence for longer-horizon systemic outcomes remains mixed and insufficient for causal disease claims. Processing and analytical studies suggest that β-casein genotype can modestly affect coagulation and product behavior in a context-dependent manner and that validated proteoform quantification coupled with traceability is essential for credible A2 labeling at scale. We discuss implications for breeding programs, including staged A2 selection that avoids performance trade-offs, and emphasize governance of artificial insemination and supply-chain segregation as levers to limit inadvertent allele diffusion while supporting climate-relevant genetic resources in locally adapted breeds. Collectively, the reviewed evidence suggests that A1/A2 β-casein can be usefully interpreted within a One Health framework spanning animal genetics, dairy systems and human tolerance research. Full article

Background: Antibiotic-free approaches to boar semen preservation are gaining importance to counter emerging antimicrobial resistance. Hypothermic storage at 5 °C, instead of the conventional 17 °C, is a promising strategy to eliminate antibiotics still commonly used in extenders. For practical adoption, the method must be simple and compatible with on-farm routines. Objective: To assess fertility when cooling was initiated on farm one day after delivery, and to evaluate the robustness of cold-stored semen to temporary warming and subsequent re-cooling, mimicking typical handling on insemination days. Methods: Individual ejaculates (n = 34) from six boars were extended in Androstar^® Premium either without antibiotics (5 °C) or with gentamicin (17 °C control). One day after collection, antibiotic-free doses were cooled on farm to 5 °C and used alongside controls in routine insemination of 270 sows. Sperm quality was evaluated by computer-assisted semen analysis and flow cytometry, and bacterial counts were monitored. In a separate test, cold-stored doses were exposed to 20 °C for 60 min and re-cooled to 5 °C. Results: Farrowing rates and litter sizes did not differ between groups (p > 0.05). In antibiotic-free samples after 120 h, bacterial counts were mostly not detectable or low (<10² CFU/mL). Sperm motility and plasma membrane integrity in cold-stored doses remained >80%, comparable to controls (p > 0.05). Temporary warming did not affect sperm quality or bacterial counts. Conclusions: Antibiotic-free semen storage at 5 °C is easy to implement in practice and maintains fertility under field conditions. Broader validation under routine conditions is encouraged in support of the One Health concept. Full article

Efficient reproductive management is essential for optimizing productivity and sustainability in sheep and goat production systems. Estrus synchronization (ES) has emerged as a pivotal tool for coordinating mating, enhancing fertility, facilitating artificial insemination (AI), and supporting out-of-season breeding. Hormonal protocols, including progesterone devices, prostaglandins, and gonadotropin or gonadoliberine treatments, provide the highest precision in estrus and ovulation timing, with estrus response rates exceeding 90% and conception rates commonly between 65–85%. These methods are particularly effective in intensive or AI-based systems but are constrained by cost, labor, regulatory restrictions, and welfare considerations. Non-hormonal strategies, such as the ram effect, photoperiod manipulation, nutritional flushing, and management-based interventions, exploit natural physiological, socio sexual, and nutritional cues to partially synchronize estrus. While these approaches exhibit greater variability and lower precision than hormonal methods, they offer advantages in low input, organic, and extensive systems by improving reproductive clustering, ovulation, and lambing compactness. Among these, the ram effect is the most effective and widely applicable. Integrated reproductive management, combining hormonal or non-hormonal strategies with optimized nutrition, health, and flock management, is critical for achieving predictable and sustainable reproductive outcomes. Future research should focus on refining hormone-sparing protocols and enhancing the reliability of natural synchronization methods. Full article

Bovine ocular squamous cell carcinoma (BOSCC) is the most common ocular tumour in cattle, with a multifactorial aetiology involving ultraviolet (UV) radiation, genetic factors, pigmentation, and management practices. A detailed epidemiological characterisation of BOSCC in the Azores, Portugal, is provided, with particular emphasis on its spatial distribution and potential risk determinants. Data were obtained through an epidemiological questionnaire completed by field veterinarians between August 2023 and March 2025. A total of 85 BOSCC cases were recorded across 62 farms—45 on Terceira Island and 17 on São Miguel Island. All affected animals were adult Holstein Friesian dairy cows, managed under extensive pasture-based systems. The nictitating membrane was the most frequently affected structure (69.5%), and multiple lesions occurred in 20% of the cases. Farms located at 200–400 m of altitude presented the highest number of cases. Continuous exposure to UV under pasture-based management represents the main environmental risk factor. Although periocular pigmentation may provide partial protection, other environmental and genetic factors can also contribute to tumour development. Artificial insemination is considered a promising preventive tool, enabling genetic selection for protective traits such as periocular pigmentation. This research provides the first regional epidemiological characterization of BOSCC in the Azores, highlighting the interplay among environmental, genetic, and management-related factors in disease occurrence. Full article

The recovery and cryopreservation of epididymal spermatozoa enable genetic preservation in male dogs that die unexpectedly or require castration; however, sperm collection is typically performed immediately after surgery, and artificial insemination is often surgical. This study aimed to evaluate whether epididymides stored at 4–5 °C for 24 h prior to sperm recovery retain fertilizing capacity after cryopreservation and whether pregnancy can be achieved using endoscopically guided transcervical intrauterine insemination. Testes and epididymides from an eight-month-old German Shepherd dog were stored in physiological saline at 4–5 °C for 24 h following castration. Spermatozoa were recovered from the cauda epididymis using single-incision aspiration, evaluated, frozen according to the Uppsala method, and stored in liquid nitrogen for two months. After thawing, 62 × 10⁶ progressive motile spermatozoa were inseminated once into a bitch in heat using transcervical endoscopic guidance. Pregnancy was confirmed by ultrasonography, and nine healthy puppies were delivered at term. These findings demonstrate that 24 h refrigerated storage of the epididymis does not impair post-thaw fertilizing ability and that non-surgical transcervical intrauterine insemination represents an effective alternative to surgical techniques for the use of frozen–thawed epididymal semen in dogs. Full article

The effects of reproductive technologies, namely, artificial insemination (AI) and multiple ovulation embryo transfer (MOET), on the production, health, and longevity of Holstein–Friesian cows were evaluated. Data were obtained from the time period between 2017 and 2024 on a Hungarian dairy farm and consisted of 1783 cows (1544 AI and 239 MOET). Deep-frozen semen from identical bulls was used for both the AI and MOET groups. Disease incidence, productive life, and early-lactation milk production phenotypes were collected in these cows. MOET cows demonstrated significantly higher milk yield during the first 100 days of lactation but had a 43.9% greater risk of culling compared with AI cows (p < 0.05). Metabolic and reproductive disorders were the most common reasons for culling cows, with increased frequency of health issues correlating with higher culling risk ratios (p < 0.05). While MOET cows showed lower incidences of metabolic disorders, reproductive problems, and mastitis, their shorter productive lifespan likely limited overall disease exposure. Nevertheless, when MOET cows experienced illness, the impact was more severe, particularly in relation to metabolic issues (p < 0.05). These findings highlight trade-offs between improved genetic potential and health resilience in MOET-derived cows. Despite their higher productivity, their management may require greater health vigilance. This study offers practical insights for dairy producers in selecting reproductive strategies to balance genetic gain, herd health, and longevity under intensive production systems. Full article

Melatonin (MLT) is a potent antioxidant that reduces oxidative stress (OS)-induced sperm damage. However, few studies have explored its effects in the field investigated here. This study aimed to evaluate the effects of MLT supplementation in extenders used for staining, sorting, and freezing on the quality of sorted Nili-Ravi buffalo sperm, embryo development after in vitro fertilization (IVF), and pregnancy outcomes following artificial insemination (AI). Computer-aided sperm analyzer (CASA) showed that progressive motility (PM) and velocity parameters of sorted, frozen–thawed sexed sperm were higher in the MLT-treated groups (p < 0.05). Fluorescence microscopy demonstrated that MLT significantly improved sperm plasma membrane integrity after staining and increased the proportion of frozen–thawed sex-sorted sperm with high mitochondrial membrane potential (HMMP) (p < 0.05). Raman spectroscopy further identified several distinctive Raman bands at 936, 1300, and 1651–1652 cm⁻¹, which may serve as biomarkers for assessing sperm quality. Additionally, cleavage rate, blastocyst formation, and pregnancy rates following IVF and AI were higher in the MLT-treated group (p < 0.05). In conclusion, MLT can serve as a valuable additive during sperm sex-sorting procedures to enhance sperm quality, thereby improving embryo developmental competence and pregnancy outcomes. Full article

Efficient liquid storage of turkey semen is critical for artificial insemination, but its use is limited by bacteriospermia and oxidative damage. This study evaluated the effects of gentamicin supplementation in Glutac and Sperm Motility Medium (SMM) on bacterial load and sperm quality after 2 and 24 h of liquid storage. Semen from turkeys (n = 40) was assessed for motility, viability, plasma membrane and acrosome integrity, mitochondrial and metabolic activity, oxidative profile, apoptosis, DNA integrity, and microbiological status. The sperm motility and kinematic parameters declined significantly after 24 h in all the groups. However, both extenders (particularly SMM) maintained significantly higher motility than the untreated control. Gentamicin further improved the motility, viability, and plasma membrane and acrosome integrity. The mitochondrial activity and mitochondrial membrane potential were significantly higher in the extender-treated groups than in the controls at 2 and 24 h, whereas the superoxide and total ROS production were significantly higher in the controls. The total antioxidant capacity declined markedly in the untreated controls, especially after 24 h. Gentamicin significantly reduced bacterial load, most effectively in SMM, and decreased DNA fragmentation compared with the untreated controls. In conclusion, gentamicin supplementation—particularly in SMM—reduces bacteriospermia and oxidative stress while preserving turkey sperm quality during liquid storage. Full article