Body weights at weaning and 18 months of Zebu, Brown Swiss, Charolais and crossbred heifers in south-east Mexico.

摘要: Summary The objective of this study was to evaluate the body weights up 18 months age 12 breed groups Zebu (Z), Brown Swiss (BS) and Charolais heifers (CH), their crosses under tropical conditions. A total 1434 data on weaning adjusted 240 days (WW8), average daily gain (ADG8) 1025 550 days (BW18) postweaning (ADG18) born from 1981 1995 were used. Cows calves remained together birth grazed Guinea grass (Panicum maximum). Years grouped in three periods, because small numbers observations per year (1981–85, 1986–90 1991–95). Similarly, months seasons: dry (February May), rainy (June September) windy (October January). Ages dams classified six (≤3, 4, 5, 6, 7 ≥8 years). Breed animals with 12.5%, 25.0%, 50.0%, 62.5%, 75.0% 100% BS genes CH also Z undefined crossbred animals. Data analysed using a fixed model that included effects period, season birth, dam group heifer. Analyses variance showed significant (p   0.05). gained least weight but similar at age. heavier than heifers, not weaning. Body 1/8 1/4 (p > 0.05) lower F1 (BS × Z) (p < 0.05); however, later higher grades had highest CH × 3/4 heifers. Undefined better performance group. Environmental factors important sources variation for pre- traits. Under conditions study, generally performed