Assessment of the reproductive performance of dairy cows under smallholder production system

Y. Nordin, N. Zaini and W.M. Wan Zahari

Abstract

The reproductive performance of dairy cows under smallholder production system from three regions in Johor and two regions in Melaka states was evaluated based on the progesterone concentration in one milk sampling [taken on the day of artificial insemination (AI)], two milk samplings (taken on the day  of AI and day 10–12 after AI) and three milk samplings (taken on the day of AI, day 10 –12 and day 22– 24 after AI). Overall, 115, 107 and 59 cows had one, two and three milk samplings, respectively. The progesterone concentration in the milk samples was determined by radioimmunoassay (RIA). Cows were diagnosed for pregnancy through rectal palpation two to four months after AI. Based on one milk sampling, 93% of the cows inseminated were in true oestrus, 2.6% were doubtful and 4.3% were not in oestrus. The progesterone concentrations from two milk samplings showedthat 85.7% of the cows hadovulated, 1.9% had luteal cyst, 3.8% had short luteal phase or anovulation and 10.9% had reproductive status that cannot be confirmed. The three milksamplings followed by pregnancy diagnosis revealed that 54.2% of the cows were pregnant, 18.6% had either non-fertilization or early embryonic mortality, another 18.6% had either late embryonic mortality, luteal cyst or persistent corpus luteum (both frequencies contributed a reproductive wastage of 37.2%), 6.8% were in doubtful reproductive status and 1.7% incidence of AI on pregnant animal. Altogether there were a total of 121 AI services for 115 cows in which 43 resulted in pregnancy giving an overall conception rate of 35.5% and 2.8 services  per conception. By milk progesterone RIA, the accuracy of early pregnancy and early non-pregnancy diagnosis (day 22–24 after AI) was 75% and 100%, respectively. The study showed that there was a high occurrence of true oestrus and ovulation in dairy cows under smallholder production system but the conception rate obtained was low due to the high occurrence of reproductive wastage.

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