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| Watanabe, Keitaro; Lewis, Brian; Mlewah, Taurayi Belo; Tetsuka, Masafumi. |
| 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... |
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Palavras-chave: Age at first service; Conception rate; Service interval. |
| Ano: 2017 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4566 |
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