Escore de condição corporal ao parto e o desempenho reprodutivo de vacas Jersey em pastagem

Abstract

The body condition score (BCS) at calving of dairy cows has always received much attention from researchers and producers worldwide. Peripartum metabolic diseases, drop in immunity against infectious agents and reproductive disorders are associated with inadequate ECC, either high or low. The intensive pasture-based dairy production system can be improved with better understanding of the impacts of body fat accumulation and use to meet the energy demands of the transition period. This study aimed to relate ECC at calving to postpartum reproductive performance of Jersey dairy cows on pasture. The effect of the ECC at calving showed a tendency (p=0.06) of reduction in the pregnancy rate from 93.65% in animals with adequate ECC to 79.59% in lean animals. Similarly, the culling rate was more than 3 times higher in lean animals. The interval between calving and conception (IPC) was significantly (p<0.05) lengthened by 22 days, with 78 days of IPC for cows calving with ECC ≥ 3.0, while cows calving with ECC less than 3.0 needed 100 days to conceive.  Nutritional planning in pasture-based dairy production system should consider ECC goals for drying and calving in order to maintain cow health, promote expression of milk production potential, and ensure new conception within the desired time interval.