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Reproductive performance in South Australian dairy herds
Author(s) -
WILSON TD,
MCLEAN DM,
SALTER CF,
BARTSCH BD
Publication year - 1994
Publication title -
australian veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.382
H-Index - 59
eISSN - 1751-0813
pISSN - 0005-0423
DOI - 10.1111/j.1751-0813.1994.tb03331.x
Subject(s) - milking , herd , artificial insemination , ice calving , zoology , deferral , insemination , biology , agricultural science , veterinary medicine , medicine , pregnancy , business , lactation , finance , genetics
SUMMARY 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.