Postpartum Ovarian Cyclicity of Zebu Cows in Bangladesh

Abstract

Postpartum luteal function and oestrus were studied using radioimmunoassay (RIA) of milk progesterone in relation to body weight, body condition score (BCS) and milk production. Randomly fifty cows were included from selected areas of Mymensingh District of Bangladesh. In 52% of the cows (n=26) ovarian cyclicity resumed by Day 80 postpartum. Thirty-two cows (64%) showed their ovarian cyclicity by Day 120 postpartum. Cows with low body weight (219.2±0.3 kg) at calving required more days (234.1±66.6 days) to initiate postpartum ovarian cyclicity (107.0±5.0 days) than those of higher body weight (286.6±89.0 kg) (p<0.05). Cows with higher BCS at calving (3.0±0.9) and at ovulation (2.7±0.9) had calving to ovulation interval 107.0±5.0 days. Cows with lower BCS at calving (2.5±0.6) and at ovulation (1.9±0.3) required long time (234.1±66.6 days) (p<0.05). Cows with higher milk production (6.3±3.5 kg/L) took shorter (77.4±6.5 days) calving to ovulation interval than that (234.1±66.6 days) of lower milk production cows (1.8±0.9 kg/L) (p<0.05). It can be safely inferred that that by improving the body condition score and body weight at postpartum period, earlier ovarian cyclicity can be achieved.