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Although, it is well understood that sperm DNA damage is associated with infertility, the molecular details of how damaged sperm DNA affects fertility are not fully elucidated. Since sperm proteins play an important role in fertilization and post-fertilization events, the present study aimed to identify the sperm proteomic alterations in bulls with high sperm DNA Fragmentation Index (DFI%). Semen from Holstein-Friesian crossbred breeding bulls (n = 50) was subjected to Sperm Chromatin Structure Assay. Based on DFI%, bulls were classified into either high- (HDFI; n = 6), or low-DFI (LDFI; n = 6) and their spermatozoa were subjected to high throughput proteomic analysis. Liquid chromatography and mass spectrometry analysis identified 4567 proteins in bull spermatozoa. A total of 2660 proteins were found common to both the groups, while 1193 and 714 proteins were unique to HDFI and LDFI group, respectively. A total of 265 proteins were up regulated and 262 proteins were down regulated in HDFI group. It was found that proteins involved in capacitation [heparin binding (molecular function), ERK1 and ERK2 cascade (biological process), PI3K-Akt signalling (pathway), Jak-STAT signalling (pathway)], spermatogenesis [TLR signalling (pathway), gamete generation (biological process)] and DNA repair mechanism (biological process) were significantly altered in the bulls with high DFI%. • Comparative sperm proteomic profile between bulls with high- (HDFI) and low-DNA Fragmentation Index (LDFI) was studied. • Identified 1193 and 714 unique proteins in HDFI and LDFI bulls, respectively. • A total of 265 and 262 proteins were up- and down-regulated in HDFI bulls. • Proteins involved in DNA repair mechanism were significantly altered in HDFI bulls. • Expression of proteins involved in spermatogenesis and capacitation were dysregulated in HDFI bulls. [ABSTRACT FROM AUTHOR]

Abstract Background Bovine genital campylobacteriosis (BGC) is a venereal disease caused by Campylobacter fetus that has a negative impact on animal reproduction. The bull is considered to be a symptomless carrier that spreads the disease agent to breeding cows, causing infertility and sporadic abortion. Aim The study aims to estimate the prevalence, identify risk factors of Campylobacter fetus (C. fetus) infection and antimicrobial resistance pattern of the C. fetus isolates. Method A cross‐sectional survey was conducted in Mymensingh district of Bangladesh. Bull smegma samples (single sample from each bull) were collected from 300 bulls from four farms and tested via culture, biochemical identification and finally 16S rRNA and cdtA gene‐based molecular assays (PCR) for herd and animal‐level prevalence estimation. Herd‐ and animal‐level data on risk factors were collected from the farmers using a pretested questionnaire and analysed by univariable and multivariable logistic regression models with a p value of

Background: Bovine genital campylobacteriosis (BGC) is a venereal disease caused by Campylobacter fetus that has a negative impact on animal reproduction. The bull is considered to be a symptomless carrier that spreads the disease agent to breeding cows, causing infertility and sporadic abortion. Aim: The study aims to estimate the prevalence, identify risk factors of Campylobacter fetus (C. fetus) infection and antimicrobial resistance pattern of the C. fetus isolates. Method: A cross‐sectional survey was conducted in Mymensingh district of Bangladesh. Bull smegma samples (single sample from each bull) were collected from 300 bulls from four farms and tested via culture, biochemical identification and finally 16S rRNA and cdtA gene‐based molecular assays (PCR) for herd and animal‐level prevalence estimation. Herd‐ and animal‐level data on risk factors were collected from the farmers using a pretested questionnaire and analysed by univariable and multivariable logistic regression models with a p value of <0.05 was taken statistically significant for both analyses. Results: Among the surveyed farms, 75% (95% CI: 19.4%–99.4%) were confirmed to have bulls infected with Campylobacter fetus at herd level. However, animal‐level occurrence of C. fetus was estimated to be 8.7% (26/300) (95% CI: 5.7%–12.4%). Natural service increases the odds of campylobacteriosis 38.18 times (95% CI: 13.89–104.94) in comparison to artificial insemination for C. fetus infection in bulls. Significantly, half of the isolates (50%, n = 13) were identified to be multidrug resistant (MDR) for three to five antimicrobial agents. Conclusion: This study highlights the need to develop official guidelines for C. fetus control and prevention in Bangladesh including mandatory artificial insemination in reproductive cows and heifers, routine screening of breeding bulls for C. fetus free status. [ABSTRACT FROM AUTHOR]

The goal of this study is to use indirect ELISA to determine the concentration of major heat shock proteins (Hsps) in Kankrej (Bos indicus) breeding bulls and their relationship with certain male phenotypic traits including sexual behavior, sperm quality, and bull fertility in different seasons. The seasonal fluctuation in the concentration of three major Hsps (60, 70, and 90) was determined using an indirect enzyme-linked immunosorbent assay (ELISA). According to the findings, Hsps levels are significantly higher during the summer season and are associated with both fresh and post-thawed semen quality traits in Kankrej breeding bulls. The better sexual behavior of bulls and seminal parameters of fresh or thawed semen was observed in the winter season together with the lower concentrations of HSPs. These could suggest negative association between HSPs with bull sexual behavior and seminal parameters. As a result, the concentration of Hsps in breeding bulls may be a useful indicator for determining fertility traits. [ABSTRACT FROM AUTHOR]

Abstract Breeding bulls infected with Besnoitia besnoiti may develop sterility during either acute or chronic infection. The aim of this study was to investigate the molecular pathogenesis of B. besnoiti infection with prognosis value in bull sterility. Accordingly, five well-characterized groups of naturally and experimentally infected males were selected for the study based on clinical signs and lesions compatible with B. besnoiti infection, serological results and parasite detection. A broad panel of molecular markers representative of endothelial activation and fibrosis was investigated and complemented with a histopathological approach that included conventional histology and immunohistochemistry. The results indicated the predominance of an intense inflammatory infiltrate composed mainly of resident and recruited circulating macrophages and to a lesser extent of CD3+ cells in infected bulls. In addition, a few biomarkers were associated with acute, chronic or subclinical bovine besnoitiosis. The testicular parenchyma showed a higher number of differentially expressed genes in natural infections (acute and chronic infections) versus scrotal skin in experimental infections (subclinical infection). In subclinical infections, most genes were downregulated except for the CCL24 and CXCL2 genes, which were upregulated. In contrast, the acute phase was mainly characterized by the upregulation of IL-1α, IL-6 and TIMP1, whereas in the chronic phase, the upregulation of ICAM and the downregulation of MMP13, PLAT and IL-1α were the most relevant findings. Macrophages could be responsible for the highest level of gene regulation in the testicular parenchyma of severely affected and sterile bulls, and all these genes could be prognostic markers of sterility.

Breeding bulls infected with Besnoitia besnoiti may develop sterility during either acute or chronic infection. The aim of this study was to investigate the molecular pathogenesis of B. besnoiti infection with prognosis value in bull sterility. Accordingly, five well-characterized groups of naturally and experimentally infected males were selected for the study based on clinical signs and lesions compatible with B. besnoiti infection, serological results and parasite detection. A broad panel of molecular markers representative of endothelial activation and fibrosis was investigated and complemented with a histopathological approach that included conventional histology and immunohistochemistry. The results indicated the predominance of an intense inflammatory infiltrate composed mainly of resident and recruited circulating macrophages and to a lesser extent of CD3+ cells in infected bulls. In addition, a few biomarkers were associated with acute, chronic or subclinical bovine besnoitiosis. The testicular parenchyma showed a higher number of differentially expressed genes in natural infections (acute and chronic infections) versus scrotal skin in experimental infections (subclinical infection). In subclinical infections, most genes were downregulated except for the CCL24 and CXCL2 genes, which were upregulated. In contrast, the acute phase was mainly characterized by the upregulation of IL-1α, IL-6 and TIMP1, whereas in the chronic phase, the upregulation of ICAM and the downregulation of MMP13, PLAT and IL-1α were the most relevant findings. Macrophages could be responsible for the highest level of gene regulation in the testicular parenchyma of severely affected and sterile bulls, and all these genes could be prognostic markers of sterility. [ABSTRACT FROM AUTHOR]

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Genomic selection is a direction of breeding in which the value of an animal is predicted from DNA markers evenly covering the entire genome. This review summarizes information on modern trends in the genomic selection of dairy cattle and on application of reproductive technologies to the improvement of breeding process. The main trends in the development of genomic selection include improvement of the accuracy of breeding value estimations by combination of reference populations; use genotyping of cows in breeding programs; imputation of genotypes for absent SNPs with low marker density microarrays, and prediction of animal genotypes from the genotypes of relatives. Genomic selection can be even more profitable in combination with up-to-date reproductive biotechnologies: semen sexing, multiple ovulation and embryo transfer, ovum pick-up followed by in vitro fertilization, embryo genotyping, cloning of best breeders, etc. In programs of dairy cattle genomic selection, biotechnological procedures with gametes and embryos allow improvement of a variety of parameters determining breeding efficacy: selection intensity, accurate breeding value assessment, and generation interval. Successful methods for embryo genotyping for numerous markers after biopsy at the morula or blastocyst stage are based on whole genome amplification of embryo DNA. Eventually, these achievements will provide grounds for new approaches to the reduction of generation interval, selection of elite cows, reduction of inbreeding rate, etc.

The present study was conducted with an objective to determine the morphometric characteristics of breeding bull of Rathi cattle in its breeding tract. This survey of 250 breeding bulls of Rathi cattle gives a data picture of some physical or morphometric parameters which would add on the information particularly of the Rathi breed in semi arid and arid zone of Rajasthan and this might be useful in future breed conservation or improvement program. [ABSTRACT FROM AUTHOR]

Selection for improved health and welfare in farm animals is of increasing interest worldwide. Peripartum energy balance is a key factor for pathogenesis of diseases in dairy cows. The intravenous glucose tolerance test (ivGTT) can be used to study the metabolic response to a glucose stimulus. The aim of this study was to estimate heritability of ivGTT traits in German Holstein bulls. A total of 541 Holstein bulls aged 7 to 17 mo from 2 breeding stations were subjected to the ivGTT. Serum glucose concentrations were measured at 0, 7, 14, 21, 28, 35, 42, 49, 56, and 63 min relative to glucose infusion. The maximum increase in blood glucose concentration, glucose area equivalent, and blood glucose half-life period were calculated. Heritabilities were estimated using a univariate animal model including station-year-season and age as fixed effects, and animal additive genetic and residual as random effects. The estimated heritabilities were 0.19 for fasting glucose concentration, 0.43 for glucose area equivalent, 0.40 for glucose half-life period, 0.14 for the peak glucose concentration, and 0.12 for the maximum increase of blood glucose concentration. Correlations between ivGTT traits and breeding values for milk yield and composition were not found. The results indicate that heritability for response to glucose is high, which warrants further investigation of this trait for genetic improvement of metabolic disorders. Research is necessary to determine the target levels of ivGTT traits and potential associations between ivGTT traits in breeding bulls and periparturient diseases in their offspring. [ABSTRACT FROM AUTHOR]

Genomic selection implies assessing the breeding value of an animal based on the DNA markers uniformly covering the whole genome. This review summarizes the information on the modern trends in dairy cattle genomic selection and the use of reproductive technologies allowing for the increase of breeding efficiency. The main trends in the advance of genomic selection are the improvement of the accuracy of breeding value estimations by pooling the reference populations; use of female genotyping in breeding programs; imputation of genotypes based on lower marker density SNP arrays; and prediction of animal genotypes from the genotyped relatives. Genomic selection can be even more profitable in combination with the state-of-the-art reproductive biotechnologies, such as semen sexing, multiple ovulation and embryo transfer, ovum pick-up followed by in vitro fertilization, embryo genotyping, and cloning of the best breeders. In dairy cattle genomic selection programs, biotechnological manipulations with gametes and embryos allow for the improvement of many factors determining breeding efficiency, namely, selection intensity, accurate breeding value assessment, and the generation interval. Successful embryo genotyping methods for numerous markers after biopsy at the morula or blastocyst stage are based on the whole-genome amplification of the embryo's DNA. Eventually, these achievements will provide the grounds for new approaches to reducing the generation interval, selecting elite cows, reducing the inbreeding rate, etc. [ABSTRACT FROM AUTHOR]

Bovine infectious infertility represents a problem due to the high impact on animal production and, in many cases, in public health. A lack of information on the characteristics of the bacterial population of the bovine reproductive system can hamper a comprehensive understanding of reproductive pathologies and the role that the microbiome could play. A metagenomic study based on the V3-V4 hypervariable region of the bacterial 16S rRNA gene was performed in 1029 preputial samples from bulls raised in an extensive regimen in Spain (944 from herds with low fertility rates -case group-, and 85 samples from reproductively healthy herds -control group-). The most representative phyla as well as the most 10 abundant bacterial families and their abundance did not show significant differences in both case and control groups. Similarly, the (alpha and beta) diversity of the bacterial populations was similar in both type of herds: the Shannon and Simpson indices show a high diversity of species, while the Bray-Curtis dissimilarity index did not show relevant differences in the bacterial communities. A deeper analysis of the operational taxonomic units showed the presence of one genera, Mycoplasma spp. significantly associated with fertility problems. Our study highlights the promising potential that the application of sequencing techniques (e.g. 16S rRNA-based metagenomics) possesses in examining bovine infertility, as they are able to reveal different pathogens that could go unnoticed using diagnostic approaches for only the main known pathogens., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Johne's disease is caused by Mycobacterium avium ssp. paratuberculosis (MAP) and has been recognized as an important bacterial infection in ruminants. Although MAP has been detected in semen and within the reproductive organs of bulls, the bacterial distribution and shedding patterns are currently not well characterized. Our investigation was performed to detect and quantify MAP in faeces, semen and blood samples repeatedly drawn from a naturally infected but asymptomatic 18-month-old German Simmental breeding bull candidate over a period of 3 years (June 2007-November 2010). Qualitative and quantitative polymerase chain reaction (PCR) techniques were used to correlate the presence and matrix-specific amounts of MAP. In total, 65 sampling dates were selected. Mycobacterium avium ssp. paratuberculosis was detected intermittently in all matrices with MAP-free intervals of up to 18 weeks by an IS900 semi-nested PCR. The number of MAP-positive results from semen and blood samples was higher than from faecal samples. A quantitative polymerase chain reaction detected the highest MAP contents in faeces (103-106 MAP/g), while lower amounts were found in semen and blood samples (102-105 MAP/ml). Although no significant agreement was calculated between the presence of MAP in faeces and blood, a statistically significant positive correlation between its occurrence in semen and blood was determined ( r = 0.38, P < 0.05, n = 29). The present study contributes to a more detailed understanding of MAP distribution patterns in faeces, semen and blood of a subclinically infected breeding bull candidate. It highlights the possible role of breeding bulls as a source of MAP transmission and indicates the need for further monitoring and hygienic measures to prevent the spread of the infection via semen. [ABSTRACT FROM AUTHOR]

This article discusses a study which examined the presence of bacteria in consecutive semen, blood and fecal samples from a Piedmont breeding bull with Johne's disease. The study used a quantitative real-time polymerase chain reaction (PCR) in the examination. It found five out of seven blood samples and all nine semen samples positive in the PCR. It cultured Mycobacterium avium subsp, paratubercldosis from various parts of the intestines, liver tissue and lymph nodes after the animal was euthanized.