Production of Brahman and Nelore cows bred to Brahman in the Bolivian tropics

Abstract

To analyze the productive traits of the Bos indicus and their crosses, the gestation data (P; O and 1) were analyzed. at weaning (W; O and 1), birth weight (BW), weaning weight (205W) and weight weaned per cow in the herd (WWCH), corresponding to 42 Nelore (N) and 28 Brahman (B) cows. Seventeen B cows born in this herd were also included. The cows were raised in herds of a father with 8 bulls throughout their productive life, on elephant grass (Pennisetum purpureum) and jaragua (Hyparrhenia rufa) without fertilization. The breeding season lasted 3 months during the rainy season and pregnancy was determined by rectal palpation 45 days after completion. Cows were classified according to lactation status (Li at the beginning of the breeding season (bs): (1) not lactating, (2) calved ≥30 days before bs, (3) calved 0 to 29 days before bs, (4) calved during bs, and (5) heifer Using least squares procedures, the variation of 597 P and 597 W was analyzed including in the model breed (G; B and N), age in bs (C; 2,3 ... II years), father of the pack (5: 1,2, .. 8), year of bs (Y; 1969 - 78), the interaction G x C and, as a linear regression, age in the first bs (A; months). The unadjusted means for P and W were 81.9 ± 1.6 and 76.5 ± 1.8%, while the adjusted ones were 76.2 ± 2.4 and 72 , 8 ± 2.7%, respectively. The age of the first calf was 21.3 ± 0.1 months. 5 and G x C had a highly significant influence (P <0.01) on the variation of P and W. G it only influenced P (P <0.01) The other effects were not significant.