Effect of Body Condition at Calving and its Changes During Early Lactation on Postpartum Reproductive Performance of Zebu Cows in a Tropical Environment

Delgado, R., Magaña, J.G., Galina, C. and Segura, J.C. 2004. Effect of body condition at calving and its changes during early lactation on postpartum reproductive performance of Zebu cows in a tropical environment. J. Appl. Anim. Res., 26: 23–28. A herd was monitored for two years in order to determine the effect of body condition score on the reproductive performance of Zebu cows managed under continuous mating in the tropics of Mexico. Overall cyclicity and pregnancy rates were 60.5% and 37.1% at four months pospartum, respectively. 62.9 percent of the cows were non-pregnant and of these more than 60% were in true anoestrus. Body condition score (BCS) at calving and 60 days postpartum, BCS changes, season and parity had significant effects (P<0.05) on cyclicity and pregnancy at 120 days postpartum. The odds of a cycling or pregnant cow at 120 days postpartum improved with increasing BCS grades. Cows calving in the dry or rainy season had lower odds (0.5 and 0.7, respectively) than those calving during the windy and rainy season. First calving cows had the worst performance, no differences being observed among multiparous cows.