Breeding Bulls Research Articles

Evaluation of predictive ability of linear type gonadal traits on reproductive capacity of breeding dairy bulls.

Dimensions of linear type traits facilitate selection of livestock for breeding and rearing. To date, use of linear type traits for selection of breeding bulls is highly concentric to scrotal circumference (SC), with probable overlook to other important traits. Present study reported the importance of various gonadal linear type traits on spermatozoa production, age-related changes in gonadal linear type traits of bulls and predictive ability of these traits on bulls' reproductive potentials. Among all gonadal traits, testicular density (TD), scrotal volume (SV), paired testicular weight (PWT) and SC were found most important predictor variables in order, which can discriminate between good/poor breeding bulls, that is, produced frozen semen doses (FSD) or not. Dimensions of gonadal traits increased significantly up to 36 months age and thereafter, development became slow and negligible. In contrast, TD decreased by 30%, 51%, 64%, 68% and 71% at 12, 24, 36, 48 and >49 months age, respectively, from its base value at 6 months. Bulls of lower TD (≤0.88 g/cm3) had significantly higher ejaculate volume (+9%), sperm motility, sperm concentration (+100 million/mL) and sperm output (+26%)/ejaculate as compared to bulls of higher TD (>0.88 g/cm3). Discriminant function was developed using TD, SV, PWT and SC to identify bulls of superior reproductive potentials. It was concluded that among the investigated traits, TD was the strongest to discriminate between FSD and Non-FSD bulls. Therefore, our findings suggested that TD could be more potential trait than SC for dairy bulls' breeding soundness evaluation and assessment of reproductive ability.

Validation of the Indigenous Technical Knowledge of Cattle Pastoralists of Andhra Pradesh and Telangana, India

Indigenous technical knowledge (ITK) of livestock breeding is often tacit and not necessarily expressed in conventional forms of scientific research and documentation. Indigenous livestock breeding systems rely mostly on qualitative traits than pure quantitative qualities. Qualitative traits are difficult to measure and most of the indigenous knowledge systems are in forms of qualitative traits. The lack of documentation and predominant qualitative nature makes it difficult to validate the ITK related to livestock breeding. In this context a study was conducted to examine the traditional breeding practices associated with two heritage cattle breeds of the Deccan Plateau region of India. The study examines the criteria used for selection of the breeding bulls of the indigenous Poda Thurpu and Nallmala-Pasa/Kamma, cattle breeds native to the study area. Results of the study identifies fourteen traits specific to breeding bulls and four traits that are generic to the breeding stock/cows. These traits/characteristics are ‘deemed desirable’ by the local cattle breeders for the ‘heritage breeds’, believed to have been bred and managed by them for generations. Observations of the present study supports the notion that traditional breeders of heritage breeds lay more emphasis on qualitative traits (ability to warding-off predators, fending off-springs, coat colour and texture, gait of the animal, temperament, and response and obedience to instructions of the master) than quantitative traits. It was found that local breeders give significant importance to the fertility of bovine bulls than cows. Breeding bulls are meticulously chosen with extreme caution and care, following a very long and meticulous selection process that could last for four years. Traditionally local cattle breeders of the study follow open nucleus breeding system for breeding and are strictly against promotion of inbreeding among their cattle herds. Only men are involved in cattle breeding in the study area and women usually stay away.

The keys to success of bull breeding soundness exams

Bull breeding soundness exams are one of the most important tasks that we perform as bovine veterinarians. This exam is de­signed to identify subfertile and infertile bulls which if used in a breeding scenario can result in loss of dollars for the produc­er. This loss of income comes from reduction in calves hitting the ground, a longer calving season, and in total less pounds of calf at the time of weaning.

Survey of Southeast U.S. beef veterinarians regarding methods for bull breeding soundness evaluation

The purpose of this survey was to describe veterinarians’ methods for performing bull breeding soundness evaluations (BSEs). Veterinarians in Mississippi, Louisiana and Arkansas were emailed a survey regarding their experience, demo­graphics, opinions and perceptions of client pref­erences regarding BSEs. Logistic regression was used to test respondent characteristics for associations with dichotomous outcomes including evaluating semen morphology as part of every BSE and detecting the diadem defect. Of 3,757 veterinar­ians solicited, 204 (5%) responded and 83 (2%) qualified for analysis. Of these, 10/73 (14%) indicated they do not evaluate morphology during every BSE. When shown an image of the diadem defect, 18/73 (25%) indicated seeing it often or some­times, and 55/73 (75%) indicated rarely or never. The only fac­tor associated with evaluating morphology as part of every BSE, was indicating belief that morphology was most predic­tive of bull fertility vs. believing motility was most predictive, or being unsure (OR = 11.2, 95% C.I. = 1.3-94.1). Respondents who always evaluate morphology with bright field microscopy at 1,000X (OR = 4.1, 95% C.I. = 1.2-13.3) or with phase contrast microscopy at ≥ 400X (OR = 5.4, 95% C.I. = 1.1-27.7) had higher odds of indicat­ing they detect the diadem defect sometimes/often. There was an interaction between always using 1000X magnification, or not, and always using 400X, or not, on the reported detection of the diadem defect. Veterinarians’ perceptions of which as­pects of the BSE are most predictive of fertility influence their methods for performing BSEs, and influence the frequency of detecting diadem defects.

Evaluation of Aberdeen Angus Breeding Bulls in the Northern Region of the Republic of Kazakhstan.

In this study, we evaluated the progeny quality of proven bulls of the Aberdeen Angus breed in different selections. Reliable information about the productive qualities of the daughters and cows of proven bulls is limited in Kazakhstan's scientific literature. We aimed to identify bull-improvers by comparatively evaluating cows of different genotypes in terms of productive qualities. The study was conducted in the period of 2021-2023, during which four groups of cows were formed based on origin. In conclusion, the high influence of inheritance of breeding features from bull-improvers should be highlighted: 78.6% to the daughters of cows of group I (Estonian selection from Kolos-firma LLP: EE 14465116 ABAJA PORTOS 95283, DK 1989501341 FREDERIK 95220, and EE 16966079 ABAJA PATRICK 95305) and 74.5% to the daughters of cows of group III (Canadian selection from Vishnevskoe LLP: BH BRUIN 54X 1644270 and JL DISTRICT 0311 1594050). There was less influence from proven bulls of deteriorators of the Kazakh selection: 21.4% to the daughters of cows of group II from Kolos-firma LLP (KZP156547191) and 25.5% to the daughters of cows of group IV from Vishnevskoe LLP (Henri KZT157789649 and Argus KZT155778964). Therefore, it is recommended that valuable genotypes of imported selection are used in breeding work in the Kostanay and North Kazakhstan regions for the improvement of Aberdeen Angus cattle.

Summer heat during spermatogenesis reduces in vitro blastocyst rates and affects sperm quality of next generation bulls.

Due to global warming seasonal heat stress is an increasing problem in temperate zones. Heat stress not only decreases fertility in females, but can also be detrimental to male fertility. We studied the effects of natural summer heat stress during spermatogenesis in Holstein bulls on semen quality parameters and on fertilization performance in vitro and possible intergenerational transmission of effects on the next male generation. Semen samples from young Holstein breeding bulls, referred to as F0 founders during this study, were collected during summer (F0 "summer" semen) and the following winter (F0 "winter" semen). Parameters such as ejaculate volume, sperm density, motility, thermoresistance, and in vitro blastocyst rates from these F0 semen samples were determined. In addition, after generation of offspring by artificial insemination, semen samples from F1 male offspring were collected and tested for the same quality and performance parameters to capture intergenerational effects. F1 bulls were raised together under identical conditions and semen was collected at about 1 year after birth. The data showed that in vitro blastocyst rates of F0 "summer" semen samples were lower compared with "winter" semen, whereas blastocyst rates of F1 semen samples did not show significant differences. However, whereas F0 semen samples did not indicate significantly different quality parameters we found that motility of F1 semen samples showed significant differences with higher values when collected from bulls generated with F0 "winter" semen. From our data, we conclude that (i) natural summer heat stress during spermatogenesis can affect in vitro fertility parameters and (ii) the observed effects on sperm motility of F1 semen samples suggest intergenerational paternal transmission.

Survey of Mississippi cow-calf producers regarding factors associated with veterinarians performing bull breeding soundness evaluations and/or pregnancy diagnosis

Reproductive efficiency is a major driver of profitability in cow-calf herds, yet many beef producers do not hire veterinar­ians to perform services intended to improve reproductive ef­ficiency such as bull breeding soundness evaluation (BSE) or pregnancy diagnosis. The objective of this study was to deter­mine reasons Mississippi cow-calf producers do or do not hire veterinarians to perform these services. Anonymous surveys were mailed to 1,500 randomly selected members of the Missis­sippi Cattlemen’s Association. Multivariable logistic regression was used to test respondent characteristics for association with outcome variables (e.g., respondents hire a veterinarian for BSEs and/or pregnancy diagnosis). Of 414 returned surveys, 397 (96%) qualified for analysis for an overall response rate of 26%. Of respondents that answered the respective ques­tions, 155/386 (40%) hire a veterinarian for BSEs, and 103/392 (26%) hire a veterinarian for pregnancy diagnosis. Of 396 re­spondents, 229 (58%) indicated they had some form of a defined breeding season. The most common reasons for not hiring a veterinarian were lack of time/help (82/202, 41%) for BSEs and cost (91/248, 37%) for pregnancy diagnosis. On in­ferential analysis, the factors positively associated with hiring a veterinarian for BSEs were having a defined breeding season (OR = 6.8, 95% C.I. = 4.1-11.1) and raising seedstock cattle (OR = 1.7, 95%C.I. = 1.0-13.3). The only factor positively associ­ated with hiring a veterinarian for pregnancy diagnosis was having a defined breeding season (OR = 4.2, 95%C.I. = 2.5-7.3). Management style and operation type influenced producers hiring a veterinarian for BSEs and pregnancy diagnosis.

The Relation between Plasma Nesfatin-1 Levels and Aggressive Behavior in Pit Bull Dogs.

Aggression is a prevalent and concerning behavioral issue in dogs. Pit Bull dogs, known for their high levels of aggression, are recognized as a focus of concern in society. In our study, we aimed to investigate the behavioral characteristics of Pit Bull dogs and explore the potential roles of peptides involved in the neurobiology of aggression. Initially, female, and male dogs underwent aggression tests, and their aggression levels were categorized. Plasma nesfatin-1, serotonin, oxytocin, and dopamine levels were quantified using ELISA, with blood samples collected after a 24 h fasting period and 2 h post-refeeding. Our findings indicate that aggression in Pit Bull dogs correlates with decreased plasma nesfatin-1, serotonin, and oxytocin levels, while dopamine levels increase. The study's findings indicate that fasted dogs exhibited lower plasma levels of nesfatin-1, serotonin, and dopamine, while plasma oxytocin levels were higher. Furthermore, while the research findings do not suggest a significant relationship between the severity of aggression and the gender of the dog, male Pit Bull breeds appear to have higher plasma nesfatin-1 and serotonin levels compared to their female counterparts. The study's findings demonstrate that nesfatin-1, serotonin, oxytocin, and dopamine play pivotal roles in Pit Bull dogs' aggression, indicating potential interactions among these neuropeptides at the central nervous system level.

Genome-wide 5′-C-phosphate-G-3′ methylation patterns reveal the effect of heat stress on the altered semen quality in Bubalus bubalis

Semen production and quality are closely correlated with different environmental factors in bovines, particularly for the buffalo (Bubalus bubalis) bulls reared under tropical and sub-tropical conditions. Factors including DNA methylation patterns, an intricate process in sperm cells, have an impact on the production of quality semen in buffalo bulls under abiotic stress conditions. The present study was conducted to identify DNA methylome signatures for semen quality in Murrah buffalo bulls, acclaimed as a major dairy breed globally, under summer heat stress. Based on semen quality parameters that significantly varied between the two groups over the seasons, the breeding bulls were classified into seasonally affected (SA = 6) and seasonally non-affected (SNA = 6) categories. DNA was isolated from purified sperm cells and sequenced using the RRBS (Reduced Representation Bisulfite Sequencing) technique for genome-wide methylome data generation. During the hot summer months, the physiological parameters such as scrotal surface temperature, rectal temperature, and respiration rate for both the SA and SNA bulls were significantly higher in the afternoon than in the morning. Whereas, the global CpG% of SA bulls was positively correlated with the afternoon's scrotal surface and rectal temperature. The RRBS results conveyed differentially methylated cytosines in the promoter region of the genes encoding the channels responsible for Ca2+ exchange, NPTN, Ca2+ activated chloride channels, ANO1, and a few structure-related units such as septins (SEPT4 and SEPT6), SPATA, etc. Additionally, the hypermethylated set of genes in SA was significantly enriched for pathways such as the FOXO signaling pathway and oocyte meiosis. The methylation patterns suggest promoter methylation in the genes regulating the sperm structure as well as surface transporters, which could contribute to the reduced semen quality in the Murrah buffalo bulls during the season-related heat stress.

Novel Antioxidant Humanin Analogue Restores Bull Semen Cryosurvivability

The current study was intended to determine the effects of humanin analogue (HNG) supplementation on semen freezability and oxidative stress parameters of cryopreserved bull spermatozoa. A total of 24 semen ejaculates, from Frieswal breeding bulls, were selected for the experiment. Samples with ≥70% progressive motility, ≥500 million spermatozoa/mL, and >2 mL volume were utilized for further processing, supplementation, and cryopreservation. Each sample was divided into four equal groups and the experiment consisted of three treatment groups and one control group. In the control group, the spermatozoa were frozen in an extender without HNG, while in the other three groups, HNG supplementation was done at a concentration of 2, 10, and 20 μM, respectively. The fortification of HNG at a concentration of 10 and 20 µM significantly (p <0.05) improved the percent post-thaw motility and kinetic variables as assessed by CASA, viability, acrosome- and plasma membrane-integrity as compared to 2 µM and control group. The supplementation showed significant (p <0.05) controlled oxidative stress as exhibited by a reduction in lipid peroxidation and reactive oxygen species levels. The supplemented groups also exhibited significant (p <0.05) improvements in total antioxidant levels, increased mean percentage of spermatozoa exhibiting high mitochondrial membrane potential, DNA integrity, acrosome-intact noncapacitated spermatozoa, and zona binding ability. In conclusion, the supplementation of humanin analogue at 10 and 20 µM significantly improved the post-thaw semen quality, functional parameters, and zona binding ability and controlled the oxidative stress in cryopreserved spermatozoa. Thus, the supplementation of its analogue may potentially prove to be a valuable approach for the improvement of semen freezability in crossbred Frieswal bulls.

Эффективность производства говядины при чистопородном разведении французских мясных пород скота

Abstract. The purpose is to study the efficiency of beef production from specialized meat breeds of cattle of French origin in comparison with the Hereford breed. Methods. Zootechnical, statistical and economic methods were used. Results. As a result of the conducted scientific and economic experience, the indicators of weight growth and meat productivity of cattle of the Charolais, Salers, Aubrac, Limousin breeds were studied in comparison with the Hereford cattle breed. Scientific novelty consists in the fact that for the first time in the conditions of Western Siberia, a comparative study of the indicators of weight growth from birth to 18 months of age and meat productivity of French beef cattle breeds with the Hereford breed was carried out. The conducted research has established the advantage in live weight and growth intensity of French beef cattle breeds. The largest live weight at 18 months was in Charolais bulls – 569.4 kg, which is more than in group I bulls by 53 kg (10.2 %) (p ≤ 0.001). In second place in terms of live weight were the bulls of the Obrak breed – 552.4 kg, which is significantly more than the peers of group I by 35.7 kg (10.3 %) (p ≤ 0.001. With intensive cultivation, the highest growth energy was demonstrated by bulls of French meat breeds 903.8–966.1. When slaughtered at the age of 15 and 18 months, heavy animal carcasses were obtained. Carcasses of French bull calves at slaughter at 15 months had a larger mass by 10.6–23.5 kg. By 18 months, the mass of paired carcasses increased to 286.6–318.5 kg. Economic analysis of the research results shows that in the production of beef from Charolais cattle, the profitability level is 66.5 %, Hereford breed – 60.6 %, Salers and Aubrac – 62.3, Limousin – 56.4 %.

Surgical Management of Prepucial Prolapse in 6 – Male Breeding Bulls

6 - Male breeding bulls were presented to VCC of CVAS Bikaner with the history of preputial prolapse and its hardening and paraphemosis. All the six breeding bulls under study had similar anatomical injury and had IV degree prolapse. Initially medicinal treatment was carried out in all bulls to reduce the swelling and infection. In all the animals antibiotic injection Streptopenicillin 5.0 g IM was given for 5 days and; injection Meloxicam @ 0.2 mg/kg IM for 3 days and antiseptic dressing of the prepuce was done with Povidone iodine solution for 5 days to reduce the infection and thereafter surgery was performed. Preputial prolapse was repaired successfully via circumcision technique. After the surgery all bulls were given 60 days of sexual rest. No post-operative complications and recurrence were recorded.

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.

Характеристика быков с разным генотипом гена OLR по продуктивности женских предков

The aim of the research was to assess the origin of Black-and-White breed bulls with different genotypes according to the low-density lipoprotein receptor (OLR1) gene. The object of the study was one sample represented by 58 bulls-producers of black and motley breed belonging to JSC "Head breeding enterprise "Elite" of the Vysokogorsky district of the Republic of Tatarstan. A preliminary assessment of the breeding value of Black-and-White bulls with different genotypes for one of the lipid metabolism marker genes (low-density lipoprotein receptor - OLR1), which are mainly used in insemination of dairy cows bred in the Republic of Tatarstan, is presented. As a result of a molecular genetic study (PCR-RFLP), the animal population was selected by groups, taking into account the genotype at the loci of the OLR1 gene. Evaluation and selection based on indicators of milk productivity of mothers, mothers and fathers of bull mothers showed that producers with AA and AC genotypes of the low-density lipoprotein receptor gene had the greatest breeding significance in terms of milk yield and mass fraction of fat in the milk of female ancestors. Thus, the parental index of bulls with AA and AC genotypes of the OLR1 gene was 9071 kg, 3.90% and 9510 kg, 3.95% in terms of milk content and fat mass, which is slightly higher than in bulls with CC genotype by 817 kg and 1256 kg (P<0.05) of milk, 0.03-0.08% fat, respectively.

Genetic parameters for yearling male reproduction traits in tropical composite cattle population.

Fertility is economically important but is hard to quantify and measure in breeding programs which has led extensive breeding programs to ignore fertility in their selection criteria. While female fertility traits have been extensively researched, male fertility traits have been largely ignored. It is estimated that 20% to 40% of bulls have sub-fertility, reducing the number of calves born and profits, highlighting the importance of investigating bull fertility. The most practical measure of male fertility is a bull breeding soundness evaluation (BBSE) which assesses structure as well as semen quality and quantity. Generally, traits recorded in a BBSE are neither genetically evaluated nor used for selection in breeding programs. All traits recorded during a BBSE were analyzed through a series of univariate and bivariate linear mixed models using a genomic relationship matrix to estimate genetic parameters. All genotype and phenotype data were obtained from a tropical composite commercial cattle population and imputed to 27,638 single-nucleotide polymorphisms (SNPs) with a total of 2,613 genotyped animals with BBSE records ranging from 616 to 826 animals depending on the trait. The heritabilities of the 27 traits recorded during a BBSE ranged from 0.02 to 0.49. Seven of the male fertility traits were recommended to be included in a breeding program based on their heritability and their phenotypic and genetic correlations. These traits are scrotal circumference, percent normal sperm, proximal droplets, distal midpiece reflex, knobbed acrosomes, vacuoles/teratoids, and sheath score. Using these seven traits in a breeding program would result in higher calving rates, increasing production and profitability.

Seminal plasma protein profiles based on molecular weight from different bull breeds as a potential ovulatory induction factor

Seminal plasma is a specific biochemical compound that affects fertility. This study attempts to characterize bull breeds’ seminal plasma (SP) proteins with possible ovulatory induction factor (OIF) activity. The breed samples originated from Friesian Holstein (FH), Belgian Blue Cross (BBx), and Ongole Grade (OG). Centrifug the sperm for 30 minutes at 12,000 rpm. The sample was collected, placed in a microtube, and stored at -20°C. The measurement of protein concentration was done using a Nano-Drop 2000 spectrophotometer. Protein separation was performed using 1D-SDS-PAGE to characterize the protein according to its molecular weight (MW). Protein markers were used to identify the MW proteins, and the acrylamide gels were colored with Coomassie Brilliant Blue. Total protein bands were analyzed with Kruskal-Wallis test, and the identification protein was analyzed descriptively. Proteins of 49-41 kDa and 15-11 kDa were significantly different between breeds (p0.05), while the majority of the MW ranges were not (p>0.05). The proteins with MWs of 22–33 kDa were found to be most commonly in all breeds correlated as potential proteins of OIF. In conclusion, seminal plasma protein was quite varied among the bull breeds. Further research needs to be conducted to obtain the protein from OIF.

Effect of “breeding bull” factor on the milk production of dairy cow

Effect of “breeding bull” factor on the milk production of dairy cow

Comparative assessment of the daughters of servicing bulls of foreign breeding on dairy productivity

Prolonged Holsteinization led to the absorption of the domestic dairy black-and-white Holstein breed. Currently, the widespread use of bulls of various Holstein breeds continues and the study of their effect on the productive qualities of daughters is relevant and has practical significance. It was found that the daughters of the Brandy bull were obtained by outbred selection, and the daughters of the Bourbon and Dancer bulls have an inbreeding level of 0.47-0.39, which allows them to be classified as a group with a moderate inbreeding degree. The daughters of all bulls showed high milk yields in 305 days of the first lactation. In terms of milk quality, they exceeded the standard requirements. The highest productivity indicators - milk yield for 305 days of lactation were found in cows - daughters of the Brandy bull - 9825.7±927.14 kg, which is 502.7 and 473.3 kg more, or 5.1 and 4.8%, respectively, for groups of daughters of other bulls. The evaluation of milk physical and chemical parameters confirmed the superiority in nutritional and biological value of the product obtained from the daughters of the Dancer bull. It had more dry matter and fat in milk, which led to an increase in nutritional value.

Formation of meat productivity and quality of meat of young cattle of the Aberdeen-Angus and Blanc-Blue Belge breeds

Beef differs from meat from other types of animals in quality, taste and versatility in cooking. The reduction in livestock numbers leads to a negative trend in beef production; therefore, crossing beef cattle with Holstein bulls was the optimal solution. However, reducing the number of young animals for fattening does not improve the quality of their meat. In this regard, assessing the efficiency of beef production, depending on the period of cultivation and slaughter, taking into account quality indicators, is relevant and has practical value. Of particular importance is the study of the meat characteristics of bulls of modern meat breeds, in particular Blanc Blue Belge and Aberdeen Angus, in the conditions of the Central Black Earth zone of free-stall housing using existing stationary premises. The research was carried out in accordance with the plan of research work at the Department of Private Animal Science of Voronezh State Agrarian University in LLC “SHP Novomarkovskoe” Kantemirovsky district of the Voronezh region. During the study, the features of the formation of meat productivity of bulls and heifers of the Aberdeen Angus breed in comparison with the Blanc Blue breed were studied Belge. The results obtained were analyzed in terms of live weight and average daily gains of these breeds. The data obtained were presented in the form of diagrams reflecting changes in live weight during the periods of growing, growing and fattening. Significant differences in the chemical composition of meat of the Aberdeen-Angus breeds were also identified and Blanc Blue Belge based on the protein and fat content in the meat of these breeds.

Kansas beef bulls with chronic anaplasmosis demonstrate satisfactory breeding soundness outcomes at breeding soundness examination.

The objectives of this study were to evaluate the prevalence of chronic Anaplasma marginale infection in beef bulls from eastern Kansas and compare breeding soundness parameters between A marginale-infected and uninfected bulls. We hypothesized that bulls with chronic anaplasmosis would have inferior breeding soundness exam (BSE) outcomes as a result of persistent A marginale infection or the consequence of initial clinical disease compared to uninfected bulls. 535 client-owned beef bulls from eastern Kansas undergoing routine BSE. Complete BSEs were conducted by participating veterinarians according to the second edition of the Society for Theriogenology Manual for Breeding Soundness Examination of Bulls. Blood samples were collected for PCV determination and analysis of A marginale infection status via quantitative PCR and cELISA. Logistic and linear regression methods were used to evaluate factors associated with A marginale infection status and BSE parameters. Prevalence of chronic A marginale infection was 46% (245/535) among bulls. Unsatisfactory BSE outcome was not statistically associated with chronic anaplasmosis in this study population, although more bulls with chronic anaplasmosis had unsatisfactory BSE outcomes (15.0 ± 2.4% vs 12.0 ± 2.2%). Chronic anaplasmosis is prevalent among eastern Kansas breeding bulls; however, no negative association between chronic anaplasmosis and breeding soundness at time of BSE was observed.