Non-return Rate Research Articles

Sperm Functional Status: A Multiparametric Assessment of the Fertilizing Potential of Bovine Sperm.

Sperm viability is routinely assessed for the quality control of cryopreserved bovine sperm batches but is not usually conclusive regarding their fertilizing potential. In this study, we investigated the fertility predictive value of bull sperm viability in combination with DNA integrity or the functional status of viable sperm. In addition to sperm viability, we flow cytometrically assessed the percentage of sperm with high DNA fragmentation index (%DFI) and the fraction of viable sperm with low intracellular Ca2+ content and functional mitochondria using the Sperm Chromatin Structure Assay and a five-color staining panel in 791 and 733 cryopreserved batches with non-return rate (NRR) records after ≥100 first services, respectively. Using linear mixed-effects models and conditional inference trees, we examined the potential of sperm viability combined with either DNA integrity or the functional status of viable sperm to predict the batch-specific NRR. Batches with a %DFI of ≤6.86% were more likely to have a NRR of >60%, whereas %DFI values of >6.86% were more likely to be associated with a 55-60% or lower NRR. Combining post-thaw viability with the functional status of viable sperm did not reliably predict the NRR of individual batches. Concluding, the incorporation of DNA integrity assessment can considerably improve sperm fertility prognostics.

Predictive Indicators of Cryotolerance and Fertility in Bovine Sperm: Evaluating Fresh Semen Quality to Improve AI Outcomes With Frozen-Thawed Sperm.

The success of artificial insemination (AI) with frozen-thawed semen in cattle is influenced by both female factors and sperm quality. In terms of sperm quality, prior studies indicate that the ability of frozen-thawed bovine sperm to fertilise an oocyte is dependent on their quality and resilience to cryopreservation. Cryopreservation induces oxidative stress, leading to ultrastructural damage in the sperm. This study aimed to determine whether the quality of fresh semen can identify bulls with good and poor sperm freezability. This difference between fresh and frozen semen from the same bull allows us to predict fertility. Motility and kinetic parameters were assessed using computer-assisted sperm analysis (CASA), while six functional variables were evaluated through flow cytometry, both before and after the freeze-thaw process on the sperm from 13 bulls. Invivo fertility was measured using 90-day non-return rates. The principal component analysis (PCA) of eight sperm variables post-thaw identified one principal component explaining 81.19% of the total variance and classified the bulls into two groups: Poor freezability bulls (progressive motility: 48.12% ± 8.41%; viability: 77.51% ± 7.61%) and good freezability bulls (progressive motility: 58.64% ± 6.64%; viability: 88.12% ± 2.52%). Bulls with higher freezability showed better sperm viability and motility, as well as lower levels of ROS, superoxides and intracellular calcium before cryopreservation that were significantly correlated with higher non-return rates (NRR). The results underscore the importance of assessing the quality and functionality of fresh semen to predict the fertility potential of cryopreserved sperm. This approach can aid in selecting ejaculates with the best potential for successful artificial insemination, ultimately improving reproductive performance in dairy cattle.

121 Copy number variation: From mapping to variance components in Holsteins

Abstract Copy number variations (CNVs) modify transcription levels mainly through changing genes and regulatory elements dosages. Hence, CNVs can contribute to the additive genetic variance of quantitative traits, which might not be fully captured by SNPs. Here, CNVs were mapped from 3,601 Holsteins and their contribution to complex traits was explored by i) quantitative trait loci (QTL) enrichment analysis, and ii) variance component analysis for metritis (1 = disease, 0 = no disease). The 4,113 CNVs derived from high-density (777k) genotypic information were compiled into 1,184 CNV regions (CNVRs) overlapping 7,832 QTLs reported in dairy cattle and available in the AnimalQTLdb. Fisher’s exact test was applied to perform the QTL enrichment analysis followed by False Discovery Rate (FDR) correction. Then, QTLs overlapping CNVRs were enriched for traits when the corrected P-value (PFDR) was lower than 0.05. For variance components estimation, genomic information from all CNVs loci was used to build the CNV-derived genomic relationship matrix (CNV_GRM). CNV loci showing double deletions, single deletions, and normal state in the population were coded as 0, 1, and 2, respectively, whereas CNV loci presenting normal state, single duplications, and double duplications were coded as 0, 1, and 2, respectively. Given that some CNVs presented both deletions and duplications at the same position in the population, these mixed-CNVs were treated as two distinct CNVs loci, one to represent deletions and the other to represent duplications. The variance components for metritis were estimated by fitting either only a SNP-derived GRM (SNP_GRM) or jointly SNP_GRM and CNV_GRM considering 3,272 cows in models that included the female category and farm-year-season as fixed effects. QTLs overlapped with CNVRs were enriched for milk (e.g., milk fat yield, milk yield, and milk protein percentage), reproduction (e.g., calving ease, non-return rate, and heat intensity), exterior (e.g., teat length, udder depth, and udder height), production (e.g., length of productive life, lifetime profit index, and net merit), and health traits (e.g., immune globulin G level, somatic cell, and bovine respiratory susceptibility). Regarding variance components, copy number variations were able to capture a fraction of the additive genetic variance not captured by SNPs alone, increasing the heritability estimate for metritis. In summary, our findings suggest that CNVs overlap QTLs associated with economically important traits more than only by chance and CNVs can capture additional additive genetic variance not fully captured by SNPs alone.

Colorectal cancer prevalence in faecal immunochemical test non-returners: potential for health inequality in symptomatic referral pathways.

This study aimed to describe the faecal immunochemical test non-return rate of those referred with high-risk symptoms of colorectal cancer from primary care, and the clinical outcomes of the 'non-returners'. From January 2019 to July 2021, patients referred to secondary care with symptoms suspicious of colorectal cancer and a referral priority of urgent or urgent suspicion of cancer were sent a faecal immunochemical test. All patients were investigated regardless of faecal immunochemical test return or result. Demographics and clinical outcomes such as colorectal cancer prevalence were compared between those who returned a faecal immunochemical test and non-returners. Of 7345 patients included in the study, 874 (11.9%) did not return a faecal immunochemical test. Non-returner characteristics included male sex (P = 0.040), younger age (median age 57 versus 65 years, P < 0.001), per rectal bleeding (P < 0.001) and lower socioeconomic status (median Scottish Index of Multiple Deprivation, 6 versus 7, P < 0.001) compared with those who returned a faecal immunochemical test. Of 6294 patients undergoing colorectal investigation, there was a greater prevalence of colorectal cancer (5.4% versus 3.6% P = 0.032) and significant bowel pathology than in the non-returners (15.3% versus 9.8%, P < 0.001). With a median follow-up of 25 months, the colorectal cancer prevalence for the entire 7345 cohort was equal between those who returned and did not return a faecal immunochemical test (3.2% versus 3.8%, P = 0.108). Of note, the non-returners diagnosed with colorectal cancer were younger (median age 64 versus 73 years, P < 0.001) and from a lower socioeconomic area (median Scottish Index of Multiple Deprivation 4 versus 7, P = 0.015) than faecal immunochemical test returners. Patients referred to secondary care, with symptoms suspicious of colorectal cancer, that did not return a faecal immunochemical test had a similar colorectal cancer prevalence to those that returned the test.

Sow reproductive performance following artificial insemination with semen doses processed using Single Layer Centrifugation without antibiotics in the tropics

Single Layer Centrifugation (SLC) through a low density colloid offers an alternative solution to antibiotic use in boar semen extenders, with lower costs compared to high density colloids. The aim of this study was to explore the reproductive performance of sows when using SLC-prepared semen doses without antibiotics, employing low density Porcicoll to prepare semen doses for artificial insemination in a commercial swine herd in Thailand. Ejaculates were divided into two equal parts to create insemination doses, with each dose containing 3000 × 106 sperm/80 ml for intra-uterine insemination in individual sows. The sows were inseminated twice, with the interval between the two inseminations ranging from 8 to 16 h. The CONTROL group consisted of 206 semen doses treated with antibiotics, prepared for insemination in 103 sows, while the SLC group comprised 194 SLC-prepared semen doses without antibiotics for inseminating 97 sows. Fertility and fecundity traits, including non-return rate, conception rate, farrowing rate, and litter traits (i.e., the total number of piglets born per litter, number of piglets born alive per litter, number of stillborn piglets, and number of mummified fetuses), were compared between groups. Furthermore, data on piglet characteristics, including live-born and stillborn piglets (i.e., the prevalence of stillbirth (yes, no), birth weight, crown-rump length, body mass index (BMI), and ponderal index (PI)), were determined. No significant differences in non-return rate (75.7 % vs. 77.3 %), conception rate (73.8 % vs. 73.2 %), and farrowing rate (71.8 % vs. 73.2 %) were observed between the CONTROL and SLC groups, respectively (P > 0.05). Nevertheless, the total number of piglets born per litter in the SLC group was higher than in the CONTROL group (14.6 ± 0.9 vs. 12.3 ± 0.6, respectively, P = 0.049). Interestingly, the prevalence of stillbirth in the SLC group was lower than in the CONTROL group (6.2 % vs. 11.6 %, respectively, P < 0.001). Moreover, the newborn piglets in the SLC group exhibited higher birth weight and BMI compared to those in the CONTROL group (1.36 ± 0.03 vs. 1.26 ± 0.02 kg, P = 0.005, and 18.3 ± 0.3 vs. 17.3 ± 0.2 kg/m2, P = 0.003). In conclusion, employing sperm doses after SLC through a low density colloid in artificial insemination within a commercial breeding operation did not have a detrimental impact on either fertility or fecundity traits but showed potential benefits in increasing the total number of piglets born per litter. Moreover, improvements were observed in the birth weight and body indexes of piglets, and the percentage of stillbirths was reduced. Our findings introduce new possibilities for antibiotic alternatives in semen extenders to reduce the risk of antimicrobial resistance in the swine industry. Additionally, they provide compelling reproductive outcomes supporting the integration of SLC-prepared semen doses into artificial insemination practices.

Genome-wide association analyses reveal copy number variant regions associated with reproduction and disease traits in Canadian Holstein cattle

This study aimed to evaluate the impact of copy number variants (CNVs) on 13 reproduction and 12 disease traits in Holstein cattle. Intensity signal files containing Log R ratio and B allele frequency information from 13,730 Holstein animals genotyped with a 95K SNP panel, and 8,467 Holstein animals genotyped with a 50K SNP panel were used to identify the CNVs. Subsequently, the identified CNVs were validated using whole genome sequence data from 126 animals, resulting in 870 high-confidence CNV regions (CNVRs) on 12,131 animals. Out of these, 54 CNVRs had frequencies higher than or equal to 1% in the population and were used in the genome-wide association analysis (one CNVR at a time, including the G matrix). Results revealed that 4 CNVRs were significantly (p-value < 3.7 × 10−5) associated with at least one of the traits analyzed in this study. Specifically, 2 CNVRs were associated with 3 reproduction traits (i.e., calf survival, first service to conception, and non-return rate), and 2 CNVRs were associated with 2 disease traits (i.e., metritis and retained placenta). These CNVRs harbored genes implicated in immune response, cellular signaling, and neuronal development, supporting their potential involvement in these traits. Further investigations to unravel the mechanistic and functional implications of these CNVRs on the mentioned traits are warranted.

Conception Rate of Filial Friesian Holstein Cows After Being Inseminated Using Unsexed and Sexed Semen

This research aimed to increase the reproduction of dairy cows with artificial insemination (AI) in Filial Friesian Holstein cows using sexed semen. This research was conducted in Pandesari Village, Pujon District, Malang Regency, East Java. The 114 Filial Friesian Holstein cows were used in this research and divided into three Treatments: T1: 38 cows were inseminated using unsexed semen, T2: 38 cows were inseminated using albumin sedimentation sexed semen, and T3: 38 cows were inseminated using Percoll density gradient centrifugation (PDGC) sexed semen. The material was selected by purposive sampling with a minimum body condition score (BCS) specification of 2.5 (scale 1-5); the material had normal reproductive organs and showed signs of heat/estrus. The parameters of this study are the percentage of non-return rate (NRR) 1, NRR 2, and conception rate (CR). The data obtained were analyzed using descriptive analysis. The differences in NRR and CR between the unsexed sperm, sexed sperm with albumin sedimentation, and sexed sperm with PDGC were analyzed with the chi-square test and were considered significant at p &lt; 0.05. The chi-square test was carried out to compare the observed values with the expected values. The results showed that the success of artificial insemination was greater by using albumin-sedimented sexed semen compared to unsexed semen or PDGC-sexed semen, with NRR values of 1 (95%), NRR values of 2 (87%) and CR values of 63%. The conception rate of artificial insemination using albumin-sedimented sexed semen was 63% greater than that of artificial insemination using unsexed semen and PDGC-sexed semen, which obtained the same value of 47%.

Lipidomic profiling of cervical mucus reveals the potential role of pro-inflammatory derived metabolites on sperm transport across the ovine cervix

Internationally, cervical artificial insemination (AI) in sheep yields low pregnancy rates when frozen-thawed semen is used. An exception to this is in Norway where vaginal AI of frozen-thawed semen to a natural oestrus yields non-return rates in excess of 60%, which has been attributed to the ewe breed used in Norway. This study used both metabolomics and an RNA-sequencing approach to assess the lipid production and composition from cervical mucus and tissue of four European ewe breeds (n = 28–30 ewes per breed) with previously reported differences in pregnancy rates following cervical AI with frozen-thawed semen. These breeds included Suffolk (exhibiting low fertility), Belclare (medium fertility) as well as Norwegian White Sheep and Fur (both with high fertility and pregnancy rates > 60%) at both a synchronised and natural oestrous cycle. The aim was to explore the differences between ewe breeds in the lipidomic profile and to identify candidate biomarkers associated with an optimal environment for cervical sperm transport. The results revealed the identification of 255 lipids, of which 170, 102 and 83 were different between ewe breeds, types of cycle and affected by their interaction, respectively (P < 0.05). Reduced levels of lipids involved in the resolution of inflammation (i.e. 14-HDoHE,17-HDoHE, 15-HETE) were identified in the low-fertility Suffolk breed compared to high-fertility ewe breeds. However, there was an up-regulation of the COX pathway accompanied by increased levels of prostaglandins in the Suffolk breed. These findings indicated a sub-optimal and pro-inflammatory environment that could have a negative effect on cervical sperm transport.

Effect of Suplementation Tomatoes Juice in Fresh Semen Egg Yolk Citrate Diluent on the Quality of Spermatozoa and the Success of Artificial Insemination in Thin Tailed Sheep

This study aims to determine the effect of adding tomato juice in fresh semen egg yolk citrate diluent to the quality of spermatozoa and the success of artificial insemination in thin tailed sheep. This research was conducted using a completely randomized design research method with 3 treatments and 5 repetitions. The treatments consisted of a solution of egg yolk citrate (P0), egg yolk citrate added 20% tomato juice (P1), and egg yolk citrate added 40% tomato juice (P2). Data analysis on spermatozoa quality included motility, viability, and abnormality using one way anova followed by Duncan’s test, while artificial insemination success included Non Return Rate (NRR) and Conception Rate (CR) using descriptive analysis. The results showed that the best diluent was found in P1 with the addition of 20% tomato juice resulting in motility percentages and viability are 75,52 ± 1,92 and 87,70 ± 1,04. It can be concluded that the addition of tomato juice had a significant (P&lt;0,05) effect on the motility and viability of spermatozoa. The addition of 20% tomato juice in egg yolk citrate diluent can improve the quality of spermatozoa. The CR and NRR values obtained from artificial insemination with P1 diluent were 53% and 60%

Estimation of genetic parameters for fertility traits in Chinese Holstein of south China.

Introduction: Chinese Holstein in South China suffer heat stress for a long period, which leads to evolutionary differences from Chinese Holstein in North China. The aim of this study was to estimate the genetic parameters of fertility traits for Chinese Holstein in South China. Methods: A total of 167,840 Chinese Holstein heifers and cows from Guangming Animal Husbandry Co., LTD farms were used in this study. The fertility traits analyzed were calving interval (CI), days open (DO), age of first service (AFS), age of first calving (AFC), calving to first insemination (CTFS), first insemination to conception (FSTC), gestation length (GL), non-return rate to 56days (NRR), and number of services (NS). Results: The descriptive statistics revealed that the same trait in heifers performed better than in cows, which was consistent with the other studies. The heritabilities of fertility traits in this study ranged from close to 0 (for NS of cows) to 0.2474 (for AFC of heifers). The genetic correlation of NRR between heifers and cows was 0.9993, which indicates that the NRR for heifers and cows could be treated as one trait in this population. Conclusion: The heritabilities of fertility traits in Chinese Holstein in south China were quite different from the heritabilities of fertility traits in North China. NRR56, NS, AFC, and CI were suggested to be included into the selection index to improve fertility performance of Chinsese Holstein of south China. The results of this study could provide genetic parameters for the animal breeding program of Chinese Holstein in the south of China.

Quantifying Al Impact: Non-Return Rate Analysis of cows in Thakurgaon, Bangladesh

Quantifying Al Impact: Non-Return Rate Analysis of cows in Thakurgaon, Bangladesh

Pengaruh umur dan pengalaman inseminator terhadap keberhasilan inseminasi buatan pada sapi perah di wilayah kerja Koperasi Peternak Sapi Bandung Utara (KPSBU) Lembang

This study aimed to evaluate the success rate of artificial insemination (AI) in dairy cows at KPSBU Lembang District based on experience and different ages of inseminators. The research was carried out on December 26, 2022 - January 31, 2023, in Lembang District. The research was conducted using a survey method and the variables measured were the success of artificial insemination including service per conception (S/C), Conception Rate (CR), Non-Return Rate (NRR), and Calving Interval (CI). Data analysis used in this study is a simple correlation analysis and quantitative descriptive. The results showed that the average age of the inseminator was 39 years old, the average inseminator work experience was 19 years. Meanwhile, the average of S/C value was 1.84 time, the CR value was 64.50%, the NRR value was 93%, and CI value with an average of 13 months. The correlation analysis showed that (X) experience and age have no significant effect (p&gt;0,05) on the success of AI based on (Y) S/C and CR. It can be concluded that the success rate of artificial insemination of dairy cows based on S/C and CR in Lembang District was good, but the experience and age of inseminators had not affected the success of artificial insemination in Lembang District

Evaluation of the Oriented Strand Board Properties Produced Using Tropical Wood Mixtures

The objective of this study was to evaluate the composition of OSB panels created using the Amazonian species Caryocar villosum Aubl., Erisma uncinatum Warm., and Hymenolobium excelsum Ducke. The OSB was produced using a phenol–formaldehyde adhesive at a ratio of 30:40:30 for each layer. Different mixtures of Amazonian wood and Pinus caribaea var. caribaea. were tested. Physical (water absorption and thickness swelling after 2 and 24 h of immersion in water and non-return rate in thickness) and mechanical (internal bond and parallel and perpendicular static bending) tests were performed. The OSB panels composed of wood mixtures absorbed less water after 2 and 24 h of immersion when compared to the OSB produced using pine wood. After 24 h of immersion in water, the T3 panel (40% Pinus caribaea + 40% Hymenolobium excelsum + 20% Caryocar villosum) presented the lowest absorption value. In terms of swelling in thickness at 2 h and 24 h, the panel composed of 100% pine strands showed the highest swelling value, while the T3 treatment exhibited the lowest swelling value at 2 and 24 h, as well as for the rate of non-return in thickness. Regarding mechanical properties, we observed that all panels exhibited similar resistance for both parallel and perpendicular Modulus of Rupture, as well as parallel and perpendicular Modulus of Elasticity, except for the internal bond, where T3 demonstrated the highest resistance. Additionally, some OSB panels met the requirements of the EN 300 standard for OSB panels.

Reproductive performance of Horro and Horro-crossbred dairy cows in Ethiopia's subhumid tropical environments.

Estrus detection, timing of insemination, feeding, and health care practices are all factors that can significantly affect cattle breeding efficiency and lifetime production. In Ethiopia's subhumid environment, the age at first calving, number of days open, duration from calving to first heat, and number of services per conception are economic traits that affect reproductive performance of Horro and Horro-crossbred dairy cows. Data collected at Ethiopia's Bako Agricultural Research Center between 1980-2019 was used to study the reproductive performance of Horro and Horro-crosses with Holstein Friesian and Jersey dairy cows. We identified overall mean ± standard error values of factors that affect reproductive performance, including age at first service (AFS) (29.2 ± 0.2 months), age at first calving (AFC) (39.8 ± 0.2 months), number of services per conception (NSC) (1.76 ± 0.4 months), calving interval (CI) (13.2 ± 0.3 months), days open (DO) (94.3 ± 4.3 days), conception rate (CR) (75.0 ± 1.3%), and replacement rate (RR) (28.4 ± 0.3%). The odds ratios of the 60-day and 90-day nonreturn rates (NRR) were 0.22 and 0.96, respectively. Sire and dam breed and birth period had significant (P < 0.001) effects on AFS and AFC, while season and dam parity had significant effects on CI and DO. Inconsistencies regarding feeding, heat detection, inseminator skills, insemination timing, animal health, and other husbandry practices may extend periods of AFS, AFC, CI, and DO. To optimize reproductive performance in Horro cows and Horro crossbreeds in Ethiopia's subhumid environments, improving management practices should be a priority.

Supplementation of Thymoquinone Nanoparticles to Semen Extender Boosts Cryotolerance and Fertilizing Ability of Buffalo Bull Spermatozoa.

Thymoquinone nanoparticles (TQNPs) are broadly utilized in numerous pharmaceutical applications. In the present study, we tested the effects of TQNP supplementation on sperm quality and kinematics, acrosome exocytosis, oxidative biomarkers, apoptosis-like and morphological changes of frozen-thawed buffalo sperm, as well as the fertilizing capacity. Semen was collected from buffalo bulls, diluted (1:10; semen/extender), and divided into five aliquots comprising various concentrations of TQNP 0 (CON), 12.5 (TQNP12.5), 25 (TQNP25), 37.5 (TQNP37.5), and 50 (TQNP50) µg/mL, and then cryopreserved and stored in liquid nitrogen (-196 °C). The results revealed that TQNPs (25 to 50 µg/mL) provided the most optimal results in terms of membrane integrity (p < 0.001) and progressive motility (p < 0.01). In contrast, TQNP50 resulted in a greater post-thawed sperm viability (p = 0.02) compared with other groups. The addition of TQNPs to the extender had no discernible effects on sperm morphology measures. Sperm kinematic motion was significantly improved in the TQNP50 group compared to the control group (p < 0.01). TQNPs effectively reduced the content of H2O2 and MDA levels and improved the total antioxidant capacity of post-thawed extended semen (p < 0.01). The addition of TQNP significantly increased the number of intact acrosomes (p < 0.0001) and decreased the number of exocytosed acrosomes (p < 0.0001). A significant reduction in apoptosis-like changes was observed in TQNP groups. The non-return rates of buffalo cows inseminated with TQNP50-treated spermatozoa were higher than those in the control group (p < 0.05; 88% vs. 72%). These findings suggested that the freezing extender supplemented with TQNPs could effectively enhance the cryotolerance and fertility of buffalo sperm.

Impact of chilling duration on sperm quality of indigenous buck semen in the Coastal Area of Bangladesh

Background: Assessing semen characteristics is an important step before semen preservation. This study aimed to collect, evaluate, and preserve indigenous buck semen in the coastal area of Bangladesh. Methods: The study was conducted at the Theriogenology and Animal Reproductive Biotechnology Laboratory, Department of Medicine, Surgery and Obstetrics, Patuakhali Science and Technology University, from July 2021 to June 2022. We selected four bucks based on non-return rate, pregnancy rate of does, and various parameters including age, body weight, scrotal circumference, and testicular epididymal length. These selected animals received a regimen of vitamins, minerals, anthelmintics, and concentrated feed. Semen was collected using the artificial vagina method, and data on color, odor, volume, viscosity, mass activity, consistency, concentration, and individual sperm motility were recorded and analyzed after collection. Results: The semen of bucks exhibited a creamy white color and a fishy odor. The mean (±SD) of scrotal circumference (SC) of four bucks was 20.43±0.52, while the testicular epididymal length (TEL) was 11.03±0.59. Buck-2 (B-2) and buck-1 (B-1) showed significantly (p&lt;0.05) higher volumes than buck-3 (B-3), and buck (B-4). B-1 also displayed significantly (p&lt;0.05) higher mass activity compared to B-2, B-3, and B-4. In addition, B-2 and B-1 showed significantly (p&lt;0.05) greater consistency than B-3, and B-4. The highest concentrations were observed in B-2 and B-1 compared to B-3 and B-4. In terms of individual sperm motility, B-1 showed significantly (p&lt;0.05) higher motility (81.0±05.16) than B-2 (71.0±03.94), B-3 (66.0±03.94), and B-4 (80.0±07.45). Regarding chilling duration, a significant reduction in sperm motility was observed during storage at 4°C. This indicated that sperm motility varied significantly (p ≤ 0.000) with varying chilling durations. Conclusions: The study suggests that the individual progressive sperm motility at 4°C gradually decreases but remains suitable for artificial insemination up to 72 h (≥50±7.65). B-1 and B-2 demonstrated relatively promising results in semen evaluation and preservation. Further study is necessary to determine the pregnancy rate of does after insemination with chilled semen.

Effects of gelatin and oxytocin supplementation in a long-term semen extender on boar semen quality and fertility potential.

This study investigated the efficacy of different concentrations of gelatin supplementation in long-term semen extender on boar semen quality during storage for 10 days at 17°C. Additionally, oxytocin was added to stored semen to enhance fertility. In Experiment 1, boar semen was collected, diluted with gelatin at concentrations between 0% and 2.5% (w/v) and mixed with a semen extender. Then, it was kept in a refrigerator at 17°C and stored for 10 days. In Experiment 2, the sperm quality was examined after adding 0, 5, and 10 IU oxytocin per artificial insemination dose to the most effective semen extender from Experiment 1 and placing it in a refrigerator at 17°C for 10 days. In Experiment 3, the fertility potential in terms of non-return rate and litter size was determined using the most effective solid-stored semen supplemented with oxytocin. The results indicated that sperm quality decreased with increasing storage time (p<0.05). The sperm quality in terms of total motility, progressive motility, and viable sperm with intact acrosomes and high mitochondrial potential was the highest with 1.5% gelatin supplementation (p<0.001) on all days of storage. Treatment with oxytocin did not affect sperm quality (p>0.05). The non-return rate and litter size after insemination with semen supplemented with 1.5% gelatin and 10 IU of oxytocin after 8 to 10 days of storage were comparable to those of the control group (p>0.05). A semen extender as a solid medium supplemented with 1.5% gelatin successfully preserved boar semen for a long storage duration. Treatment with oxytocin did not affect sperm quality. In addition, the fertility capacity using 1.5% gelatin with 10 IU oxytocin and stored for 8 to 10 days was acceptable and comparable to that of short-term storage.

Influence of Equilibration Time and Bull-Specific Extender for Cryopreservation on Semen Quality and Fertility in German Holstein Friesian Bulls: A Controlled Field Trial.

Equilibration with an extender is necessary to allow cryopreservation of bovine sperm. The aim of trial 1 was to assess the effect of 24 h versus 4 h equilibration time with three different extenders on sperm quality and to select the preferred extender for each bull. The aim of trial 2 was to investigate the effect of using a 24 h equilibration time with a bull-specific extender on field fertility. For trial 1, three ejaculates each from eight Holstein Friesian breeding bulls were used as the split-sample, including two equilibration times (4 h and 24 h) and three extenders (BioXcell, Triladyl, and OptiXcell). For trial 2, from 5 to 10 ejaculates from the same bulls were collected and treated (split-sample) as BioXcell with 4 h equilibration and either Triladyl or OptiXcell, both with 24 h equilibration. A total of 11,059 straws were used for insemination of cows and heifers. For Triladyl, progressive sperm motility, acrosome defects, and plasma membrane and acrosome integrity improved with a 24 h compared to a 4 h equilibration time. Four bulls each were used with Triladyl and OptiXcell for trial 2. In trial 2, non-return rates did not differ among groups. Therefore, using a 24 h equilibration time might improve in vitro sperm parameters, depending on the extender used. Moreover, it would be possible to change from 4 h to 24 h equilibration time without impairing field fertility.

Genome-wide association studies for epistatic genetic effects on fertility and reproduction traits in Holstein cattle.

Non-additive genetic effects are well known to play an important role in the phenotypic expression of complex traits, such as fertility and reproduction. In this study, a genome scan was performed using 41,640 single nucleotide polymorphism (SNP) markers to identify genomic regions associated with epistatic (additive-by-additive) effects in fertility and reproduction traits in Holstein cattle. Nine fertility and reproduction traits were analysed on 5825 and 6090 Holstein heifers and cows with phenotypes and genotypes, respectively. The Marginal Epistasis Test (MAPIT) was used to identify SNPs with significant marginal epistatic effects at a chromosome-wise 5% and 10% false discovery rate (FDR) level. The -log10 (p) values were adjusted by the genomic inflation factor (λ) to correct for the potential bias on the p-values and minimize the possible effects of population stratification. After adjustments, MAPIT enabled the identification of genomic regions with significant marginal epistatic effects for heifers on BTA5 for age at first insemination, BTA3 and BTA24 for non-return rate (NRR); BTA16 and BTA28 for gestation length (GL); BTA1, BTA4 and BTA17 for stillbirth (SB). For the cow traits, MAPIT enabled the identification of regions on BTA11 for GL, BTA11 and BTA16 for SB and BTA19 for calf size (CZ). An additional approach for mapping epistasis in a genome-wide association study was also proposed, in which the genome scan was performed using estimates of epistatic values as the input pseudo-phenotypes, computed using single-trait animal models. Significant SNPs were identified at the chromosome-wise 5% and 10% FDR levels for all traits. For the heifer traits, significant regions were found on BTA7 for AFS; BTA12 for NRR; BTA14 and BTA19 for GL; BTA19 for calving ease (CE); BTA5, BTA24, BTA25 and in the X chromosome for SB; BTA23 and in the X chromosome for CZ and in the X chromosome for the number of services (NS). For the cow traits, significant regions were found on BTA29 and in the X chromosome for NRR, BTA11, BTA16 and in the X chromosome for SB, BTA2 for GL, BTA28 for CZ, BTA19 for calving to first insemination, and in the X chromosome for NS and first insemination to conception. The results suggest that the epistatic genetic effects are likely due to many loci with a small effect rather than few loci with a large effect and/or a single SNP marker alone do not capture the epistatic effects well. The genomic architecture of fertility and reproduction traits is complex, and these results should be validated in independent dairy cattle populations and using alternative statistical models.

Metabolic signature of cervical mucus in ewe breeds with divergent cervical sperm transport: a focus on metabolites involved in amino acid metabolism

IntroductionCervical artificial insemination (AI) with frozen-thawed semen in sheep has yielded unacceptably low pregnancy rates. The exception is in Norway where vaginal AI yields non-return rates in excess of 60%, which has been attributed to the ewe breed used.Objectives and methodsThis study aimed to characterise, for the first time, the ovine follicular phase cervical mucus metabolome, with a focus on the amino acid profile. Cervical mucus was collected from four European ewe breeds with known differences in pregnancy rates following cervical AI with frozen-thawed semen. These were Suffolk (low fertility), Belclare (medium fertility), Norwegian White Sheep (NWS) and Fur (both high fertility).ResultsA total of 689 metabolites were identified in the cervical mucus of all the four ewe breeds. Of these, 458 metabolites were altered by ewe breed, which had the greatest effect in the dataset (P < 0.05). We detected 194 metabolites involved in the amino acid pathway, of which 133, 56 and 63 were affected by ewe breed, type of cycle and their interaction, respectively (P < 0.05). N-methylhydantoin and N-carbamoylsarcosine (degradation products of creatinine pathway) exhibited the greatest fold change decrease in the Suffolk breed compared to Fur and NWS (P < 0.001). Oxidized metabolites were also decreased in Suffolk compared to high fertility breeds (P < 0.05). In contrast, other metabolites such as 3-indoxyl-sulfate, putrescine, cadaverine were significantly increased in Suffolk at the synchronised cycle.ConclusionThe suboptimal amino acid profile in the cervical mucus of the low fertility Suffolk breed may have negative consequences for sperm transport.