Milk yield and calving intervals of Holstein-Friesian and crossbred Holstein-Friesian: Gir cows in a high management level

Abstract

Production records of cows of three grades were studied: 55 black and white Holstein-Friesian (HPB), 35 7/8 HPB: 1/8 Gir and 53 3/4 HPB: 1/4 Gir, having respectively 94, 59 and 82 lactations. All cows were kept in a single herd under the same management at a private farm in Lavras, Minas Gerais State. Traits analysed were: lactation length, lactation milk yield, calving interval, and milk yield per day of calving interval. For each of these four dependent variables a linear model was fitted including the effects of grade, year-season of freshening, parity, and all the two factor interactions. There were no significant differences between grades. Least squares means for HPB, 7/8 HPB and 3/4 HPB were respectively: 318 ± 18, 301 ± 15 and 305 ± 14 days in milk; 4,149 ± 318. 3,894 ± 263 and 4,034 ± 252 kg of milk; 433 ± 23, 431 ± 19 and 406 ± 19 days of calving interval and 9.9 ± 0.8. 9.4 ± 0,6 and 10.1 ± 0.6 kg of milk per day of calving interval.