Curvas de lactação de vacas F1 Holandês x Gir ordenhadas na presença ou ausência de suas crias

Abstract

Lactation curves of 105 F1 Holstein x Gir cows, being 53 milked without the calf (SB) and 52 milked in the presence of the calf (CB) until 60 days of postpartum, were compared. The milked milk was monthly controlled as well as that one consumed by the calves (estimated by the difference between the calf's weight before and after suckling). The analysis were done in two steps. Firstly, a linear model considering the classificatory effects of the interaction between the variables calving season, calving order (first or second) and calve sex and the linear effect of gestation days inside system (CB or SB) as a covariable. In a second analysis, total and milked milk productions, adjusted by the effects described above were modeled by non linear regression on lactation month for studying the calf effect on the lactation curves. For the milk milked, lactation curves were identical for the systems CB and SB, except for lactation length that was 35 days longer in the system CB. For the total milk, lactation curves were different for both studied systems.