51 Nili-Ravi buffaloes were selected from 7 commercial farms in Pakistan. Reproductive history of the selected animals was recorded. Postpartum rectal examination of reproductive organs was continued until the occurrence of the first oestrus (PEI) or day 150 postpartum. Ovulation (POI) was confirmed per rectum and milk progesterone levels (MPL). Feed samples were collected and analysed for zinc and copper. Milk samples were collected and analysed for MPL and jugular blood samples for Ca, P, and Mg. The average intake of zinc was higher by 72.5% than NRC requirements for dairy cattle. Increasing Zn intake increased placenta expulsion duration and lochia (r = 0.23, 0.22; P<0.01) but decreased postpartum uterine involution and ovulation intervals (r = -0.50, -0.52; P<0.01). Zinc intake was different at various seasons (P<0.01) and farms (P<0.01). The average intake of copper was higher by 40% than NRC requirements for dairy cattle. Increasing Cu intake decreased postpartum uterine involution and ovulation intervals (r = -0.31, -0.32; P<0.01). Intake of Cu was different at different seasons (P<0.01) and farms (P<0.01). Copper intake was lower in animals calving during normal breeding season (autumn and winter) than those calving during low breeding season. It is concluded that intake of Zn and Cu have favourable effects on various reproductive parameters and blood levels of macro-minerals.
|Journal||Egyptian Journal of Dairy Science|
|Publication status||Published - 2000|