title: Reproductive performance in South Australian dairy herds.
abstract: Herd breeding records (161) were examined from a random 10% sample of dairy farms (96) in South Australia with more than 40 cows and suitable breeding records for 1988 and/or 1989. Of these farms, 53 (55.2%) had a year-round calving pattern, 42 (43.8%) claimed to be seasonal and one was changing from a year-round to a seasonal pattern. Only 14.6% of farmers observed oestrous behaviour outside milking times and 18.8% used tailpaint. Overall, the average proportion of unobserved heats was estimated to be 32%. Artificial insemination (AI) was carried out on 85.4% of farms (16.7% used AI alone and 68.7% also used bulls) of which 32.9% used commercial technicians and 67.1% were do-it-yourself operators. Overall, the average 30-day submission rate was 59.9% and the average 49-day non-return to service rate was 58.9%. Investigation into the probable causes of suboptimal reproductive performance gave a tentative diagnosis of inefficient oestrous detection, deferral of service, inadequate nutrition, poor AI technique, insufficient bulls, and venereal/other diseases in 69.1, 32.1, 27.2, 28.4, 13.6 and 7.4% of records, respectively.
authors.affiliation: Pty Ltd, Saleyard Centre, Mount Barker, South Australia.
authors.forename: T D
authors.initials: TD
authors.lastname: Wilson
authors.forename: D M
authors.initials: DM
authors.lastname: McLean
authors.forename: C F
authors.initials: CF
authors.lastname: Salter
authors.forename: B D
authors.initials: BD
authors.lastname: Bartsch
mesh_terms: D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001947:Breeding; D002417:Cattle / Q000502:physiology*; D003612:Dairying; D004972:Estrus Detection; D005260:Female; D007315:Insemination, Artificial / Q000662:veterinary; D008297:Male; D011247:Pregnancy; D011258:Pregnancy Tests / Q000662:veterinary; D011996:Records / Q000662:veterinary; D012098:Reproduction; D012189:Retrospective Studies; D012621:Seasons; D013021:South Australia