title: An assessment of dairy herd bulls in southern Australia: 1. Management practices and bull breeding soundness evaluations.
abstract: In the 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. Bull breeding soundness evaluations (BBSE) were performed on 256 bulls from 32 dairy herds in southwest Victoria, using guidelines produced by the Australian Cattle Veterinarians, before and immediately after a single natural mating period. At the same time, herd managers were questioned regarding the management of the bulls. The objectives of this study were to describe the management practices of dairy herd bulls; to describe the causes of increased risk of reduced fertility in dairy herd bulls, as measured by a standard BBSE; and to describe the reasons for bull removal by herd managers during mating. At the premating BBSE, 19.5% of bulls were classified as high risk of reduced fertility, mostly due to physical abnormalities and reduced semen quality. At the postmating BBSE, 36.5% of bulls were classified as high risk of reduced fertility, mostly due to physical abnormalities, primarily lameness. Of the bulls used, 15.9% were removed from normal mating use by the herd manager, predominantly due to lameness and injuries. A premating BBSE is recommended in dairy herd bulls to identify bulls at risk of reduced fertility. Lameness is the most common problem in dairy herd bulls during the natural mating period, and risk factors associated with lameness in these bulls should be identified to better manage herd bulls.
authors.affiliation: Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria 3030, Australia; The Vet Group, Timboon, Victoria 3268, Australia. Electronic address: a_s_hancock@hotmail.com.
authors.forename: A S
authors.initials: AS
authors.lastname: Hancock
authors.affiliation: The Vet Group, Timboon, Victoria 3268, Australia.
authors.forename: P J
authors.initials: PJ
authors.lastname: Younis
authors.affiliation: Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria 3030, Australia.
authors.forename: D S
authors.initials: DS
authors.lastname: Beggs
authors.affiliation: Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria 3030, Australia.
authors.forename: P D
authors.initials: PD
authors.lastname: Mansell
authors.affiliation: Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria 3030, Australia.
authors.forename: M A
authors.initials: MA
authors.lastname: Stevenson
authors.affiliation: Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria 3030, Australia.
authors.forename: M F
authors.initials: MF
authors.lastname: Pyman
mesh_terms: D000818:Animals; D001947:Breeding / Q000379:methods*; D002417:Cattle / Q000502:physiology*; D003430:Cross-Sectional Studies; D003612:Dairying / Q000379:methods*; D008297:Male; D014739:Victoria
keywords: bull breeding soundness evaluation; dairy herd bull; lameness; seasonally calving herd