An assessment of dairy herd bulls in southern Australia: 2. Analysis of bull- and herd-level risk factors and their associations with pre- and postmating breeding soundness results

Abstract

In pasture-based, seasonally calving dairy herds of southern Australia, the mating period usually consists of an initial artificial insemination period followed by a period of natural service using herd bulls. The primary objective of this study was to identify associations between individual bull- and herd-level management factors and bull fertility as measured by a pre- and postmating bull breeding soundness evaluation (BBSE). Multivariable mixed effects logistic regression models were used to identify factors associated with bulls being classified as high risk of reduced fertility at the premating and postmating BBSE. Bulls older than 4 yr of age at the premating BBSE were more likely to be classified high risk compared with bulls less than 4 yr of age. Bulls that were in herds in which concentrates were fed before mating were more likely to be classified as high risk at the postmating BBSE compared with bulls that were in herds where concentrates were not fed. Univariable analyses also identified areas in need of further research, including breed differences between dairy bulls, leg conformation and joint abnormalities, preventative hoof blocking for bulls, and mating ratios.

Breeding soundness examination and herd proficiency of local genetic groups of bulls in tropical environment conditions in Veracruz, Mexico

“…Although libido evaluation and mating ability are not sufficient to predict reproductive success, it is prudent to use bulls that passed all BBSE stages, including libido (Menegassi et al 2015). Lastly, multivariate analysis has been used in the evaluation of the reproductive soundness examination of bulls in order to determine their inclusion and permanence in the herd, in the same way, has been analysed the effects of breed, age, year season, regions on sperm variables (Hancock et al 2016;Felton-Taylor et al 2020), this kind of analysis allows associating intrinsic and extrinsic factor that can affect the physiological performance of bull and with it, be able to explain effects as a whole that in simple analyzes could not be determined. The findings of this study will act as a guide for veterinary practitioners and dual-purpose cattle breeders in find bulls that can be expected to pass the BBSE test and libido based on a robust data set.…”

An assessment of dairy herd bulls in southern Australia: 1. Management practices and bull breeding soundness evaluations

“…The bulls fed concentrate during mating were probably receiving a lactating cow ration in the dairy. The effect of nutrition on the BBSE results in our study is discussed in more detail elsewhere (Hancock et al, 2016).…”

Outcomes following facilitated ankylosis to treat septic arthritis of the distal interphalangeal joint in beef bulls

“…Previous research has been shown that a bull can compensate for mild lameness, and semen quality is not significantly affected by lameness; thus, if able to mount, a bull has a high likelihood of successful insemination. 10 It is possible that even if some lameness remained following FA in a pelvic limb, it was mild enough that the bull was able to compensate. This may explain the lack of difference in outcome between bulls with forelimb lesions and those with hindlimb lesions.…”