Mature Bulls Research Articles

Assessing bull breeding soundness exam parameters following vaccination with modified-live or killed vaccine

Breeding bulls are often placed on a similar herd health plan and vaccinated for the same pathogens as the mature cow herd. The timing of the yearly vaccination is impacted by labor and time constraints with some bulls receiving vaccinations at the time of annual, complete breeding soundness exams or at the time of turnout prior to the breeding season. However, the potential impact of vaccination on spermatogenesis, if any, is unknown. Therefore, the study objective was to determine the impacts on normal sperm morphology through a complete spermatogenic cycle after vaccination of mature beef bulls against bovine herpesvirus 1 and bovine viral diarrhea virus using commercially available modified-live virus (MLV) or killed virus (KV) vaccine. Semen was collected from Bos taurus bulls (n = 11),which were randomly assigned prior to the first breeding soundness exam to vaccine treatment groups: 1) modified-live virus (MLVa); or 2) inactivated/killed virus (KVb). Breeding soundness exams were completed at days -7, 0, 5, 7, 17, 28, 61 following vaccination. No differences were found between vaccine treatment groups MLV and KV (P = 0.46) on the percentage of normal sperm over time (d = -7 through d = 61) as evaluated by two boarded theriogenologists. In conclusion, we found no detrimental effect of the administration of multivalent MLV or KV vaccines on percentage of normal sperm morphology of mature bulls over a 61 – day period.

PSI-13 The impact of divergent nutritional planes on systemic immune status in mature bulls

PSI-13 The impact of divergent nutritional planes on systemic immune status in mature bulls

Ultrastructure of the Bovine Testis in Cattle (Bos taurus): New View.

The purpose of this study was to analyze the ultrastructure of the testes of sexually immature calves and reproductive bulls of the Polish Holstein-Friesian Black-and-White breed. Utilizing TEM, this study identified three distinct stages of seminiferous tubule development in calves, characterized by varying shapes, distributions, and arrangements of individual cells. In immature animals, early developing spermatocytes, prespermatogonia, and pre-Sertoli cells were observed within the seminiferous tubules. In sexually mature bulls, all cells of the spermatogenic series were observed, situated on a thin, multilayered basal lamina, which forms characteristic undulations. An abundant smooth endoplasmic reticulum was observed in the cytoplasm of spermatogonia in both groups of animals, forming characteristic membranous swirls. In adult bulls, spermatogonia maintain contact with each other through numerous cytoplasmic bridges and cell connections, forming small spaces with visible microvilli between them. The ultrastructural analysis facilitated the identification of morphological changes occurring during the maturation of pre-Sertoli cells, transitioning from a large euchromatic nucleus to a nucleus in which the formation of characteristic vesicles and tubules could be observed. It should also be emphasized that two types of Sertoli cells, namely dark and light electron-dense cells, can be found in cattle. These cells differ from each other, indicating that they may perform different functions. The widespread recognition of the presence of two types of Sertoli cells in cattle will undoubtedly contribute to a better understanding of the processes occurring within the testes and provide a basis for further research in this area.

Molecular quantitative trait loci in reproductive tissues impact male fertility in cattle.

Breeding bulls are well suited to investigate inherited variation in male fertility because they are genotyped and their reproductive success is monitored through semen analyses and thousands of artificial inseminations. However, functional data from relevant tissues are lackingin cattle, which prevents fine-mapping fertility-associated genomic regions. Here, we characterize gene expression and splicing variation in testis, epididymis, and vas deferens transcriptomes of 118 mature bulls and conduct association tests between 414,667 molecular phenotypes and 21,501,032 genome-wide variants to identify 41,156 regulatory loci. We show broad consensus in tissue-specific and tissue-enriched gene expression between the three bovine tissues and their human and murine counterparts. Expression- and splicing-mediating variants are more than three times as frequent in testis than epididymis and vas deferens, highlighting the transcriptional complexity of testis. Finally, we identify genes (WDR19, SPATA16, KCTD19, ZDHHC1) and molecular phenotypes that are associated with quantitative variation in male fertility through transcriptome-wide association and colocalization analyses.

Side of chute and handedness does not affect the sensitivity of Tritrichomonas foetus sample collection in bulls

Tritrichomonas foetus, a sexually transmitted pathogen of cattle, continues to plague the cattle industry despite control efforts. Pre-analytical diagnostic considerations such as sample collection and sample handling continue to be a shortcoming in the diagnosis of T. foetus in bulls. Preputial scraping is the most common means of sample collection. Previous studies have shown an effect of handedness of the sample collector and the side of the chute that collection was made from as factors that affected the diagnostic sensitivity of the test. The aim of our study was to determine if being right or left-handed and the side of the chute the collection occurred on impacted the diagnostic sensitivity or specificity. Eleven sexually mature bulls naturally infected with T. foetus were enrolled in a 2-factor cross-over study design. Samples were taken once a week for 8 weeks by either a right-handed or left-handed veterinarian from either the left then the right side of the chute or right then left side of the chute, only using their dominant hand to make the scraping motion used to obtain the sample. Utilizing a 2-way ANOVA, we found no significant difference in the chance of acquiring a positive sample per bull (P = 0.8708) regardless of whether the sample was taken from the right or left side of the chute and regardless of dominant hand. In conclusion, using current RT-qPCR methods, the authors found no effect of handedness or side of chute on diagnostic sensitivity.
 
 
 
 
 
 
 
 
 

EFFECT OF ADDING RESVERATROL TO SOYBEAN-LECITHIN EXTENDER ON SOME SEMEN ATTRIBUTES OF BUFFALO BULLS

This study was conducted to explain the effect of adding different resveratrol (Res) concentrations to soybean-lecithin extender on some post-cryopreserved (PC) semen characteristics of the Iraqi buffalo bulls for different preservation periods. Eight mature bulls were used, and polled semen was equally divided into four groups within one trial. Three Res concentrations (100, 150, and 200 μM) were added to the soybean-lecithin extender, and comparisons in the response were made with the control group (soybean-lecithin extender, Res-0). The differences among groups in sperm cell individual motility percentages at different preservation periods lacked significance. Greater (P≤0.01) sperm acrosome integrity percentage was noticed for the Res-150 group compared with the C and Res-200 groups at cooling, 48 hrs., and 2 months PC. Lesser (P≤0.01) malondialdehyde concentrations and sperm DNA damage percentage were observed for the Res-150 group as compared with the other groups, 2 months PC. Higher (P≤0.01) total antioxidant activity was shown in Res-150 and Res-200 groups as compared with the control and Res-100 groups, 2 months PC. In conclusion, adding Res to the soybean-lecithin extender enhanced some of the PC semen characteristics of Iraqi buffalo bulls at different preservation periods.

Evaluation of sperm and hormonal assessments in Wagyu, Nellore, and Angus bulls.

Wagyu bulls are known to have a highly exacerbated libido, as shown by the intense sexual interest of young calves. Therefore we believe that Wagyu male animals have specialized Sertoli and Leydig cells that are directly involved with the sexual precocity in this breed as mature bulls have a small scrotal circumference. This study aimed to evaluate whether there were differences in the hormone and sperm characteristics of Wagyu bulls compared with the same characteristics of subspecies Bos indicus and Bos taurus sires. Frozen-thawed semen from Wagyu, Nellore, and Angus sires were analyzed for sperm kinetics (computer-assisted sperm analysis), plasma membrane integrity, chromatin integrity, acrosome status, mitochondrial activity, lipid peroxidation and hormone [luteinizing hormone (LH) and testosterone] serum concentration. The results showed that Wagyu had lower total motility and an increased number of sperm with no motility when compared with Nellore and Angus bulls. Wagyu breed did not differ from those breeds when considering plasma and acrosome membranes integrity, mitochondrial potential, chromatin resistance, sperm lipid peroxidation or hormone (LH and testosterone) concentrations. We concluded that Wagyu sires had lower total motility when compared with Nellore and Angus bulls. Wagyu breed did not differ from these breeds when considering plasma and acrosome membranes integrity, mitochondrial potential, chromatin resistance, sperm lipid peroxidation, or hormone (LH and testosterone) concentrations.

Immunohistochemical analysis of extracellular signal-regulated kinase expression in mature and immature bulls' testes and epididymides.

Extracellular signal-regulated kinase (ERK) has been implicated inmammalian testicular and epididymal development. This study aimed toinvestigate ERK expression inthe immature and mature testes and epididymides ofbulls. Weevaluated ERK expression using immunoblot analysis and immunohistochemistry. Immunoblot analysis revealed that immature bull testes and epididymides had higher phosphorylated ERK (pERK) expression than mature bull testes and epididymides. pERK immunoreactivity was higher inimmature epididymides than inimmature testes. pERK was localised mostly inspermatogonia, undifferentiated sustentacular (Sertoli) cells, and interstitial (Leydig) cells inimmature testes, aswell asin some spermatocytes and spermatids inmature testes. Inimmature epididymides, the body and tail had higher pERK expression than the head, whereas pERK was broadly distributed throughout the stereocilia, basal cells, and connective tissues. pERK distribution inthe head ofmature epididymides was similar tothat inimmature epididymides, whereas few connective tissue cells were expressed inthe body and tail ofmature epididymides. Collectively, these results suggest that ERK isexpressed inthe testis and epididymis ofimmature and mature bulls with varying intensities, and therole ofERK inmale reproductive organs may include the specific function ofits development.

Bulls fed a high gain diet decrease blastocyst formation after in vitro fertilization.

Bulls used in cattle production are often overfed to induce rapid growth, early puberty and increase sale price. While the negative consequences of undernutrition on bull sperm quality are known, it is unclear how a high gain diet influences embryo development. We hypothesized that semen collected from bulls fed a high gain diet would have a reduced capacity to produce blastocysts following in vitro fertilization. Eight mature bulls were stratified by body weight and fed the same diet for 67 d at either a maintenance level (0.5% body weight per day; n = 4) or a high gain rate (1.25% body weight per day; n = 4). Semen was collected by electroejaculation at the end of the feeding regimen and subjected to sperm analysis, frozen, and used for in vitro fertilization. The high gain diet increased body weight, average daily gain, and subcutaneous fat thickness compared to the maintenance diet. Sperm of high gain bulls tended to have increased early necrosis and had increased post-thaw acrosome damage compared with maintenance bulls, but diet did not affect sperm motility or morphology. Semen of high gain bulls reduced the percentage of cleaved oocytes that developed to blastocyst stage embryos. Paternal diet had no effect on the number of total or CDX2 positive cells of blastocysts, or blastocysts gene expression for markers associated with developmental capacity. Feeding bulls a high gain diet did not affect sperm morphology or motility, but increased adiposity and reduced the ability of sperm to generate blastocyst stage embryos.

Age and Social History Impact Social Interactions between Bull Asian Elephants (Elephas maximus) at Denver Zoo

Wild bull Asian elephants spend time in all-male groups. Therefore, managers of ex situ populations increasingly house bulls together. We examined the social interactions of five bull Asian elephants at Denver Zoo, using instantaneous sampling to compare social interactions across adolescent and mature bulls, and bulls with a social history prior to the integration of this group compared to bulls with no social history. Both age and social history significantly affected bull behavior. Adolescent bulls exhibited more affiliative and submissive behaviors when housed with mixed-age and mature social partners compared to with only adolescents, and less non-contact agonistic behavior and less time in proximity to a conspecific with mixed-age groups compared to with only other adolescents. Mature bulls exhibited more affiliative behavior when they were with only adolescent bulls compared to only mature bulls, and more time in proximity to a conspecific and increased contact agonistic behavior with at least one adolescent compared to only mature bulls. Bulls in new social groups engaged in more affiliative, agonistic, and submissive behaviors, and spent less time in proximity, than when they were in previously established social combinations. As more institutions house bulls socially, our results provide insights into factors that may affect bull social interactions.

Intervention by an older, dominant bull elephant (Elephas maximus) during an agonistic interaction between adolescents at Denver Zoo

Bull Asian elephant (Elephas maximus) sociality is complex and understudied. Increasingly, researchers recognize the role of mature bull elephants in teaching adolescent bulls appropriate social and reproductive behaviours that enable them to have normal intra-species relationships after the adolescents leave their natal herds. We describe a specific intervention event by a mature, dominant bull in a novel social group with adolescent bull elephants at Denver Zoo, Colorado, USA. The mature bull intervened on behalf of an adolescent elephant, allowing this adolescent to escape from two other adolescents who were repeatedly chasing him, marking boundaries of appropriate behaviour for the adolescent bulls. This example provides evidence for adolescent bull elephants learning appropriate social behaviours from mature conspecifics and suggests that mature bulls play an active role in this relationship. Overall, this intervention behaviour supports the inclusion of mature bulls in social groupings of bull elephants in managed care.

A Comprehensive Sequencing Analysis of Testis-Born miRNAs in Immature and Mature Indigenous Wandong Cattle (Bos taurus).

Micro RNAs (miRNAs) have been recognized as important regulators that are indispensable for testicular development and spermatogenesis. miRNAs are endogenous transcriptomic elements and mainly regulate the gene expression at post-transcriptional levels; however, the key role of miRNA in bovine testicular growth is not clearly understood. Thus, supposing to unveil the transcriptomics expression changes in the developmental processes of bovine testes, we selected three immature calves and three sexually mature bulls of the local Wandong breed for testicular-tissue sample collection. The cDNA libraries of experimental animals were established for RNA-sequencing analysis. We detected the miRNA expression in testes by using high-throughput sequencing technology, and bioinformatics analysis followed. The differentially expressed (DE) data showed that 151 miRNAs linked genes were significantly DE between immature and mature bull testes. Further, in detail, 64 were significantly up-regulated and 87 were down-regulated in the immature vs. mature testes (p-value < 0.05). Pathway analyses for miRNA-linked genes were performed and identified JAG2, BCL6, CFAP157, PHC2, TYRO3, SEPTIN6, and BSP3; these genes were involved in biological pathways such as TNF signaling, T cell receptor, PI3KAkt signaling, and functions affecting testes development and spermatogenesis. The DE miRNAs including MIR425, MIR98, MIR34C, MIR184, MIR18A, MIR136, MIR15A, MIR1388 and MIR210 were associated with cattle-bull sexual maturation and sperm production. RT-qPCR validation analysis showed a consistent correlation to the sequencing data findings. The current study provides a good framework for understanding the mechanism of miRNAs in the development of testes and spermatogenesis.

Characterization of Longitudinal Testosterone, Cortisol, and Musth in Male Asian Elephants (Elephas maximus), Effects of Aging, and Adrenal Responses to Social Changes and Health Events.

Simple SummaryThe conservation of endangered species and sustainability of managed populations requires good health and welfare of individuals. Male elephants experience a biological phenomenon called “musth”, characterized by a suite of physiological and behavioral changes which serve to facilitate copulation between the sexes, but can also pose unique challenges under human care. This study characterized longitudinal patterns of circulating testosterone and cortisol in relation to musth in four adult Asian elephant bulls and assessed age-related effects on musth activity and adrenal responses to social changes and clinical health events. All bulls exhibited regular annual musth cycles, and there was no clear evidence of chronically elevated cortisol secretion outside of musth. Circulating cortisol covaried positively with testosterone and musth, highlighting intrinsic patterns that should be considered when evaluating the impact of changes on adrenal glucocorticoid activity. Testosterone decreased with age in sexually mature bulls, whereas age-related changes in cortisol varied across individuals, with the three older bulls showing the greatest rate of change during musth. Changes in cortisol were associated with treatment for Mycobacterium tuberculosis in two bulls, but not with activation of disease. In contrast to physiological factors, there was no evidence that social changes involving male herdmates impacted adrenal glucocorticoid activity in the short term. This study highlights the importance of longitudinal hormone monitoring to track changes in physiological function and identify factors that may influence welfare, which is important for making more informed decisions on how to manage male elephants under varying degrees of human care.The conservation of endangered species and sustainability of managed populations requires considerations to ensure the health and welfare of individuals. Male elephants experience a biological phenomenon called “musth”, which is characterized by increased testosterone production, temporal gland secretion and urine dribbling, heightened aggression and sexual behavior, and therefore can pose unique challenges for human safety and animal welfare. This study characterized longitudinal (9 to 22 years) patterns of circulating testosterone and cortisol in relation to musth in four adult Asian elephant bulls spanning ages from 12 to 54 years. Age-related effects on musth activity and adrenal responses to social changes and clinical health events were also examined. All bulls exhibited regular annual musth cycles. Circulating cortisol covaried positively with testosterone and musth, highlighting intrinsic patterns that should be considered when evaluating the impact of social, health, and environmental changes on adrenal glucocorticoid activity. Except for an end-of-life cortisol increase in one bull, there was no clear evidence of chronically elevated cortisol secretion outside of musth in any individual. Testosterone decreased with age in sexually mature bulls, whereas age-related changes in cortisol varied across individuals, with the three older bulls showing the greatest rate of change during musth versus inter-musth periods. In contrast to physiological factors, there was no evidence of social factors, such as addition of a new male and death of male herdmates, impacting adrenal glucocorticoid activity in these bulls in the short term. Changes in cortisol were associated with treatment for Mycobacterium tuberculosis (M. tb) in two bulls, increasing after start of treatment and decreasing with cessation of treatment, but were not clearly associated with activation of disease. This study highlights the importance of longitudinal hormone monitoring to track changes in physiological function and responses to social, health, and environmental change in elephant bulls, which is important for making more informed decisions on how to manage male elephants under varying degrees of human care to ensure welfare and safety.

Evaluation of dietary betaine on post-thawed semen quality in mature bulls during summer heat stress.

Heat stress (HS) has caused relative hypoxia, oxidative stress and high level of homocysteine, which contributes significantly to fertility failures in bulls. The aim of present study was to evaluate the role of dietary betaine (BET) in improving dual purpose Simmental (Fleckvieh) post-thawed semen quality especially during the hottest summer days. A total number of 16 mature bulls were randomly assigned to three equal groups including: 1) Control condition (without betaine), 2) BET1: 57.00 mg of betaine kg-1 per day and 3) BET2: 114 mg of betaine kg-1 per day, through daily intakes for 90 days in summer. Plasma levels of homocysteine, seminal plasma antioxidants levels and sperm parameters such as DNA fragmentation, chromatin integrity, motility, viability, morphology and membrane integrity were evaluated. Under maximal HS, serum homocysteine concentrations were reached 16.67 ± 0.09 µmol L-1. Dietary betaine supplementation influenced DNA fragmentation of sperm and was higher in the control group compared to BET2 group. There were significant decreases in seminal plasma superoxide dismutase (SOD), glutathione peroxidase (GPx) activity and sperm viability and motility in bulls treated with betaine. The activity of GPx and SOD in the control group was increased up to 0.08 ± 0.00 U mg-1 protein and 0.52 ± 0.01 U mg-1 protein in seminal plasma. There were no significant differences between groups in the percentage of swollen spermatozoa, membrane integrity, sperm morphology, abnormal head morphology and percentage of spermatozoa stained with aniline blue. In conclusion, BET supplements improved semen parameters in sperm motility, sperm viability and influenced DNA fragmentation during HS with reduction in serum homocysteine concentrations.

Heritabilities and genetic correlations between young bulls and mature bulls for semen production traits in Japanese Black cattle

Heritabilities and genetic correlations between young bulls and mature bulls for semen production traits in Japanese Black cattle

Longitudinal genetic analysis of semen production traits in Holstein bulls according to a random regression animal models on age.

Here we used random regression animal models (RRAMs) to investigate genetic change over age in the semen volume (VOL) and sperm concentration (CON) of Holstein bulls. We used 35,294 collection records from 1284 Holstein bulls and their 4166 pedigree records. The models included year and month of collection, collection place, collection method, and number of collections attempted for each day and month of age (second-order regressions) as fixed effects; technician as a random effect; and additive genetic and permanent environment as random regressions (first-order regressions). We examined two RRAMs with homogeneous and heterogeneous residual variances (RRAM1 and RRAM2, respectively). By using RRAM1, heritability for VOL and CON increased from 0.08 to 0.61 and 0.18 to 0.57, respectively, between 10 and 126 months of age. By using RRAM2, heritability for VOL increased from 0.11 to 0.28 between 10 and 24 months of age for young bulls and increased from 0.08 to 0.48 between 25 and 126 months of age for mature bulls; heritability for CON ranged from 0.18 to 0.19 for young bulls and increased from 0.10 to 0.48 for mature bulls. Posterior genetic correlations between young ages and older ages were strongly positive for VOLs but weak for CONs.

A phenotypic characterization of Rarámuri Criollo cattle introduced into the Southwestern United States

Our objective was to describe key phenotypic characteristics of a population of Rarámuri Criollo (RC) cattle introduced from the Copper Canyon of Chihuahua, México into the Southwestern United States almost two decades ago. We recorded 26 phenotypic traits of 37 RC individuals including mature cows, first-calf heifers, and mature bulls raised at the USDA-ARS Jornada Experimental Range in southern New Mexico. This herd of RC cattle exhibited intermediate body sizes compared to the smaller Corriente and larger Texas Longhorn and Florida Cracker cattle. Coat colors were similar to those described for other Criollo biotypes but horn shape and size of RC appear to be different than that of other US-based Criollo breeds. Though smaller than commercial beef breeds, RC cattle appear to be well-matched to the Southwestern US environments as evidenced by previous studies that evaluated their grazing behavior, weight gains, and carcass quality. Rarámuri Criollo cattle are a genetic resource whose conservation could be critically important for climate change adaptation of ranches in the desert Southwest.

Sperm DNA 5-methyl cytosine and RNA N6-methyladenosine methylation are differently affected during periods of body weight losses and body weight gain of young and mature breeding bulls.

Aiming to characterize the effects of nutritional status on epigenetic markers, such as DNA 5-methyl cytosine (mC) methylation and RNA N6-methyladenosine (m6A) methylation, of bovine sperm, 12 Angus × Hereford crossbred breeding bulls were submitted to nutritional changes for a period of 180 d: no change in body weight (BW) (phase 1 = 12 d), BW loss (phase 2 = 78 d), and BW gain (phase 3 = 90 d) in a repeated measures design. Animals were fed Beardless wheat (Triticum aestivum) hay and mineral mix. Statistical analyses were performed using SAS 9.4 (SAS Inst., Cary, NC). Higher levels of RNA m6A (P = 0.004) and DNA methylation (P = 0.007) of spermatic cells were observed at phase 2 compared with phase 1. In phase 3, sperm RNA m6A methylation levels continued to be higher (P = 0.004), whereas the DNA of sperm cells was similar (P = 0.426) compared with phase 1. Growing bulls had a tendency (P = 0.109) of higher RNA m6A methylation levels than mature bulls. Phase 2 altered scrotal circumference (P < 0.001), sperm volume (P = 0.007), sperm total motility (P = 0.004), sperm progressive motility (P = 0.004), total sperm count (P = 0.049), normal sperm (P < 0.001), abnormal sperm (P < 0.001), primary sperm defects (P = 0.039), and secondary sperm defects (P < 0.001). In phase 3, bulls had scrotal circumference, sperm volume, sperm motility, sperm progressive motility, total sperm count, normal and abnormal spermatozoa, and primary and secondary spermatozoa defects similar to phase 1 (P > 0.05). Serum concentrations of insulin-like growth factor-1 and leptin decreased during phase 2 (P = 0.010), while no differences (P > 0.05) were detected between phases 3 and 1; growing bulls tended (P = 0.102) to present higher leptin levels than mature bulls. Specific for mature bulls, DNA methylation was positively correlated with leptin concentration (0.569, P = 0.021), whereas for young bulls, DNA methylation was positively correlated with abnormal spermatozoa (0.824, P = 0.006), primary spermatozoa defect (0.711, P = 0.032), and secondary spermatozoa defect (0.661, P = 0.052) and negatively correlated with normal spermatozoa (-0.824, P = 0.006), total sperm count (-0.702, P = 0.035), and sperm concentration (-0.846, P = 0.004). There was no significant correlation (P > 0.05) between RNA m6A and hormones and semen traits. In conclusion, the nutritional status of breeding bulls alters epigenetic markers, such as DNA methylation and RNA m6A methylation, in sperm, and the impact of change seems to be age dependent. These markers may serve as biomarkers of sperm quality and fertility of bulls in the future. Detrimental effects on sperm production and seminal quality are observed at periods and places when and where environmental and nutritional limitations are a year-round reality and may carry hidden players that may influence a lifetime of underperformance.

SPERM PRODUCTIVITY AND FERTILIZATION CAPACITY OF SPERMATOZOA OF HOLSTEIN STUD BULLS IN CONDITIONS OF LLC “UKRAINIAN GENETIC COMPANY”

Effective selection and breeding in dairy farming is impossible without artificial insemination, results of artificial insemination largely depend on the quality of semen of bulls-improvers. Objective. To ascertain parameters of sperm productivity and fertilization capacity of spermatozoa of Holstein stud bulls of foreign selection in conditions of LLC “Ukrainian Genetic Company”. Methods. We have analyzed ejaculates of 20 mature Holstein stud bulls elite-record class brought to animal breeding enterprise from Germany and the Netherlands. The duration of use of bulls at the breeding enterprise is on average 4–5 years.Quantitative indicators of sperm were taken per year to avoid the influence of seasonal factors. Semen was collected twice a week by artificial vagina on the false stud. Ejaculates obtained were analyzed according to the DSTU 35.35-97 incertified production laboratory of LLC “Ukrainian Genetic Company”, equipped with up-to-date equipment for sperm quality assessment, packing, freezing and storage. Quantity and quality characteristics of sperm were analyzed on computer sperm analyzer IVOS (HamiltonThorneResearch, USA). Sperm fit for cryopreservation is diluted at a temperature of +35°С in the environment AndroMed (Germany) at rate no less than 20 million spermatozoids for one sperm dose and packed into 0.25 ml straws. Frozen sperm doses after check are kept in the special bio-storage in liquid nitrogen at a temperature of -196°С.&#x0D; Results. Fertilization capacity ofthe spermatozoaof experimental stud bulls was measured by the percentage of quantity of cows and female calves that were impregnated after the first insemination in Zhytomyr (PAF “Ierchyky”, SPDG “Nova Peremoga”, ALLC “Ptakhoplemzavod “Korobivskyi”) and Kyiv (LLC “Agrofirm “Kyivska”) regions. On the whole results of insemination of 12525 cows and 1230 female calves of puberty age were analyzed.&#x0D; Sperm productivity index and average fertilization capacity of spermatozoa of stud bulls was assessed by the method of M. M. Maiboroda, S. H. Hermanchuk, Yu. P. Polupan, and D. M. Basovsʼkyy.&#x0D; It was revealedsignificant variability of sperm productivity indicators of experimental stud bulls, which vary within: number of obtained high-quality ejaculates within one year –32–173 pcs., total volume of native sperm – 201–1016 ml, average value of spermatozoa concentration in 1 ml – 1.51–3.52 milliard, average sperm motility in ejaculate – 7.2–83 points. Bull studs of LLC “Ukrainian Genetic Company” are characterized by a rather high index of sperm productivity which equals from 5.19 to 15.29 billion of motile spermatozoids in ejaculate.&#x0D; Average fertilization capacity of spermatozoa of experimental Holstein bulls in conditions of 4 farms of Zhytomyr and Kyiv region ranges from 37.1 to 61.4%, average figure for examined livestock is 50.9%. During the research we found that stud bulls whose sperm fertilization capacity was above 50% in most cases (6 out of 8) had index of sperm productivity above average – 9.86–15.25billion of motile spermatozoids in ejaculate.&#x0D; We have detected positive and statistically significant correlation between fertilization capacity of spermatozoa and the average value of concentration, motility of spermatozoids in ejaculate (+0.474 and+0.417 respectively) and sperm productivity index (+0.639). Conclusion. Our research proves dependence of fertilization capacity of sperm on its quality parameters. The results we obtained suggest that it is expedient to use index of sperm productivity to assess quality of sperm and prove its importance for breedingbulls selection.

Surgical management and outcome of acquired inguinal hernias in mature bulls: 13 cases (2005-2017).

To describe rates of surgical complications, survival, and return to breeding soundness following herniorrhaphy for bulls with inguinal hernias. 13 sexually mature bulls with acquired inguinal hernias. Medical record databases of 3 veterinary teaching hospitals were searched to identify records of bulls that underwent herniorrhaphy for correction of an inguinal hernia from 2005 to 2017. Information extracted from the medical records included breed, age, duration and side of the hernia, surgical procedure details, postoperative complications, and information regarding subsequent fertility. All 13 bulls had a left inguinal hernia and were anesthetized and underwent herniorrhaphy via an inguinal approach. The left testicle was removed during the surgical procedure in 2 bulls. Nylon or polypropylene mesh secured with size-5 polyester suture was used to facilitate inguinal ring closure in 2 bulls. The inguinal ring was closed with size-5 or size-2 polyester suture in the remaining bulls. Postoperative complications included hernia recurrence (n = 4), excessive scrotal swelling (3), and transient radial nerve paralysis (1). Follow-up information was available for 7 bulls. All 7 bulls had impregnated cows or heifers following surgery, including 1 bull that had hernia recurrence and underwent unilateral castration during the second herniorrhaphy. Inguinal herniorrhaphy with or without mesh was a safe and effective procedure for inguinal hernia repair in bulls and was associated with a good prognosis for subsequent fertility. However, sparing the ipsilateral testicle during the herniorrhaphy procedure might increase the risk for hernia recurrence.