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Produ??o de leite e desempenho dos bezerros de vacas Nelore e mesti?as

DOI: 10.1590/S1516-35982007000900018

Keywords: lactation curve, limousin, simmental.

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Abstract:

the research was carried out to evaluate the lactation curves of nellore and crossbred f1 limousin-nellore (ln) and simmental-nellore (sn) cows and the performance of the progeny. thirteen cows from each breed group, with age ranging from 5 to 9 years, and the respective calves were used. from 15 days after calving until weaning of the calves (210 days), the cows and calves were kept in individual pens. the nutritional requirements of the cows for maintenance and lactation were met. the same ration was offered to the calves from the 90 days of age, in limited amounts to supply 30% of the nutritional requirements. the ration was formulated with 30% of concentrate and 70% of silage, dm basis. monthly, milk production of the cows was estimated, utilizing the weigh-suckle-weigh method. by means of nonlinear model, it was estimated the time needed for the cows to reach the peak of lactation, the production at the peak of lactation; the persistence of milk production and total and daily average milk production. nellore cows showed lower production at the peak of lactation, total and daily average milk production, but higher persistency than crossbred cows. the productions in the lactation peak, total and daily average, in cows sn, were higher than in cows ln, however, no difference was observed between these groups for lactation persistence. calves from nellore cows had lower birth weight, weaning weight and preweaning weight gain than those from crossbred cows. there was no difference between calves from the two crossbred groups. it is concluded that crossbred cows have higher maternal ability than nellore cows.

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