Breeding soundness evaluations of 3648 yearling beef bulls using the 1993 Society for Theriogenology guidelines

Kennedy, S.; Spitzer, J.C.; Hopkins, Fred M.; Higdon, H. Lee; Bridges, William C.

doi:10.1016/s0093-691x(02)00911-1

Cited by 55 publications

(36 citation statements)

References 3 publications

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“…Unlike the rejection rates in semen evaluation observed in the present study, Silva et al (1981) reported 46% rejection in 1,902 two-to six-year-old bulls of various breeds, whereas Andrade et al (1995) rejected 48% of 33 two-year-old bulls due to semen defects. Semen quality problems were also the main cause of rejection of 11.6% and 13.7% of the bulls evaluated by Gottschall & Mattos (1997) and Kennedy et al (2002), respectively. It must be noted that the rejection rates due to low semen quality observed in the present study are related to bulls that were previously accepted in general physical and genital tract examinations.…”

Section: Resultsmentioning

confidence: 92%

Causes of rejection of beef bulls in breeding soundness evaluation

et al. 2012

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-The objective of this study was to analyze the rates of rejection in the different steps of the breeding soundness evaluation of beef bulls in the state of Rio Grande do Sul, Brazil. The breeding soundness of 22,113 young and mature bulls of 14 beef breeds, participating in the Program of Reproductive Evaluation (PARTO) was evaluated in the experiment.Data concerning to the causes of rejection in the four steps of the breeding soundness evaluation (general physical examination, genital tract examination, semen evaluation and sexual behavior assessment) were analyzed by the Chi-square test and univariate regression analysis. According to year, general physical examination, genital tract examination and semen evaluation determined the rejection of 0.9% to 2.5%, 5.1% to 7.7%, 1.8% to 5.3%; and 4.2% to 6.7%, 7.3 to 9.3%, and 2.5% to 5.5% of young and mature bulls, respectively. Mature bulls presented higher chances of rejection than young bulls in the general physical examination in every year evaluated; as to the genital tract examination, their chances of rejection were higher in years I and II, but not in year III. In the semen evaluation, there was no difference between the ages assessed in any of the three years evaluated. Sexual behavior assessment accounted for the rejection of 1.9 to 6.0% of the young bulls and 2.9% to 3.9% of mature bulls, in accordance with the years evaluated; in years I and II, mature bulls presented higher rejection rates than young bulls. These results confirm the importance of performing all steps of the breeding soundness evaluation, including the sexual behavior assessment as a work routine, rather than an additional, optional stage of the evaluation, which should be carried out before the breeding season. The results indicate the relationship between bull age and rejection rate in the breeding soundness evaluation.

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Section: Resultsmentioning

confidence: 92%

Causes of rejection of beef bulls in breeding soundness evaluation

et al. 2012

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“…Regarding yearling bulls, the BSE further serves to measure the pubertal advancement of the physical and reproductive systems and the attainment of characteristics considered sufficient to be classified as satisfactory potential-breeders [2]. A temporal limitation of the BSE involves the assessment of only the current status of physical, testicular and seminal characteristics; therefore, a satisfactory classification affords no implied guarantee of future reproductive performance of individual bulls [3].…”

Section: Introductionmentioning

confidence: 99%

Fertility of yearling beef bulls during mating

Ellis¹,

Rupp²,

Chenoweth

et al. 2005

Theriogenology

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Crossbred (Bos taurus) yearling beef bulls were assessed for breeding soundness and physical traits prior to multi-sire natural mating at pasture. Bulls (n = 60) were assigned to six groups of nine or 10 bulls and two bull-groups were rotated on 14-day intervals during a 63-day mating season in each breeding herd (n = 3) of 191-196 cows. The remaining bulls (n = 14) were maintained under similar environmental conditions without mating exposure. Bulls were observed during mating and assessed for breeding soundness and changes following mating. Bulls used for breeding (UFB) lost 77 kg of body weight and declined from body condition scores of 6 to 4.5, whereas bulls not used for breeding (NUB) maintained body condition scores of 6 and gained 27 kg. The UFB bulls incurred a 75% total injury rate with 63% incidence of lameness and 12% incidence of reproductive injuries, resulting in a 22% attrition rate. Only 45% were physically sound at the end of mating. Scrotal circumference declined in UFB bulls (À4.58%) and increased in NUB bulls (2.49%). From the 98% BSE-satisfactory rate (UFB) prior to breeding, only 61% were BSE-satisfactory post-breeding. The NUB bulls declined from 57 to 36% satisfactory. The BSE classification was influenced by significant increases in abnormal spermatozoa (primary and secondary), which was significantly associated with injuries incurred during mating. Group and breed differences in injury rates and BSE-status following mating were evident. Environmental conditions and mating activity influenced bull seminal quality and physical condition. Pregnancy rates in all three breeding herds (91-96%) were similar, with insignificant differences between bull-groups; the effects of physical and reproductive changes on individual bull fertility were immeasurable. #

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“…The likelihood of bulls passing their semen evaluation increases with age [20] and poor semen quality, specifically less than 70% normal sperm morphology is the primary reason for failure of a BSE by yearling beef bulls [20][21][22]. In our study, bulls ranged in age from 10.5 to 13 mo at the time of first BSE, and age was a significant source of variation in the percentage of bulls that passed.…”

Section: Discussionmentioning

confidence: 94%