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vol.36 issue4Body external components and discard fat of feedlot finished Charolais x Nellore crossbred cows slaughtered with different weightsEffect of increasing dietary urea levels on milk yield and composition of lactating cows author indexsubject indexarticles search
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Revista Brasileira de Zootecnia

On-line version ISSN 1806-9290


RESTLE, João et al. Effects of different preweaning rates of body weight gain and type of pasture during the postpartum on biological efficiency of beef cows and calves. R. Bras. Zootec. [online]. 2007, vol.36, n.4, pp.874-880. ISSN 1806-9290.

The objective of this experiment was to evaluate the influence of different rates of weight gain (low: 340 ± 32 g/day or moderate: 490 ± 29 g/day) of heifers, from birth until seven months of age, and the type of pasture after calving, as cows, on the biologic efficiency of cows and their calves until weaning at 217 days. After calving, the animals were maintained on native pasture (NP) or cultivated pasture (CP). During lactation, cows with low preweaning rate of weight gain showed higher milk production. Similarity between low and moderate rates of weight gain was verified for conversion of litres of milk (7.32 and 6.44 L/kg, respectively) and kg of dry matter of milk produced by cows (1.00 and 0.86 kg/kg, respectively) into kg of calves weight gain, total requirements of net energy for maintenance (maintenance plus gestation plus milk production) of cows (TOTNEm) (2733.7 and 2316.7 Mcal, respectively), TOTNEm per kg of weaned calve (14.7 and 14.7 Mcal/kg, respectively) and kg of weaned calve per 100 kg of cow at weaning (42.0 and 38.7 kg/100 kg, respectively). However, cows with low preweaning rate of weight gain weaned more kg of calves per unit of cow metabolic weight at weaning (1.89 vs. 1.73 kg/g).

Keywords : Charolais; cultivated pasture; milk yield; native pasture; Nellore; total dry solids extract.

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