Age at First Calving and Factors Influencing it in Dairy Heifers Kept by Smallholder Farmers in Southern Malawi

JARQ : Japan Agricultural Research Quarterly
ISSN 00213551
書誌レコードID(総合目録DB) AA0068709X

Delayed age at first calving (AFC) is known to decrease productivity in dairy cattle. In the present study, we investigated AFC in heifers kept by smallholder farmers in southern Malawi and the reproductive factors influencing it. Data were obtained for 1,620 heifers over a 13-year period from 1999 to 2012. The age at first service (AFS), first service to conception interval (FSCoI), number of services per conception (NSC), conception rate (CR) and service interval (SI) were investigated in relation to AFC. The median AFC was found to be 41 months. This is a relatively high value and shows no improvement from the values reported in the 1970s and 1980s. The median AFS was also high (23 months). Overall, the 1st service CR was 42%, and the median SI was 83 days. AFS appeared to be the most crucial factor that affected AFC. A lengthy SI in combination with a low CR was found to be the critical factor that delayed AFC in heifers that had failed to conceive on previous occasions. These results suggest that the appropriate reproductive management of heifers, particularly initiating the first service at the optimum time and shortening the SI, is necessary for improving dairy productivity.

作成者 Keitaro WATANABE Brian LEWIS Taurayi Belo MLEWAH Masafumi TETSUKA

age at first service

conception rate

service interval

公開者 Japan International Research Center for Agricultural Sciences
国立情報学研究所メタデータ主題語彙集(資源タイプ) Journal Article
開始ページ 357
終了ページ 362
DOI 10.6090/jarq.51.357
権利 Japan International Research Center for Agricultural Sciences
関連するリソース : J-STAGE
言語 eng