REPRODUCTIVE PERFORMANCE OF HOLSTEIN AND BROWN SWISS COWS UNDER INTENSIVE GRAZING IN A HUMID SUBTROPICAL CLIMATE

Abstract

The objective of the study was to determine days to first postpartum estrus (DFPE), days to first service (DFS), days open (DO), services per conception (SPC) and calving interval (CI) in Holstein (HO) and Brown Swiss (BS) cows grazing in an Af(c) climate, during three seasons of the year: windy, dry and rainy. A factorial design that included the effects of breed (BR), calving year (CY), calving season (CS) and the interaction BR*CY was used. Breed did not affect DFPE, DFS, DO and CI (P > 0.05), but it affected SPC (P < 0.01), being higher for HO (1.95±0.05) than for BS (1.74±0.05). The CY affected all variables studied (P < 0.05). The CS affected DFPE, DFS, DO and CI (P<0.05), but it did not affect SPC (P > 0.05). The BR*CY interaction did not affect any of the variables analyzed (P > 0.05). The CI was 390.7±4.01 and 397.8±4.32 d for HO and BS, respectively. During the windy, dry and rainy seasons the DFPE were 63.0±2.26, 69.3±2.1 and 61.7±2.0 d; the DFS 67.3±2.2, 73.8±2.1 and 66.4±2.0 d; the DO 100.5±4.1, 111.2±3.8 and 103.1±3.6 d; and the CI 391.3±4.3, 402.4±4.2 and 389.1±3.8 d, respectively. In conclusion, the HO and BS cows had a similar reproductive performance under humid subtropical conditions, but the BS required fewer SPC.