SUMMARY The main objective of this study was to evaluate the effect of cultivated winter pasture, during different periods, on the maternal ability of beef cows. First calf Charolais and Aberdeen Angus cows were submited to one of the following treatments: T1 - Native pasture; T2-Cultivated pasture during September and October; T3 - Cultivated pasture two hours daily during July and August; T4 -Cultivated pasture for two hours daily during July and August plus cultivated pasture during September and October. With exception of the period that animals were kept on cultivated pasture, according to each treatment, they remained on the same native pasture. Average daily milk production of T4 cows (4.05<img border=0 width=20 height=20 src="../../../../../../img/revistas/cr/v21n1/a14img01.gif">) was higher (P<0.05) than T1 cows (2.95<img border=0 width=20 height=20 src="../../../../../../img/revistas/cr/v21n1/a14img01.gif">). T2 and T3 cows had an intermediat milk production (3.78 and 3.27<img border=0 width=20 height=20 src="../../../../../../img/revistas/cr/v21n1/a14img01.gif">; P>0.05). Milk composition was the same for the four treatments (P>0.05). Calf birth weight was not affected (P>0.05) by the cow's treatment. However, T4 calves gained more weight (P<0.05) from birth to weaning than T1 calves (0.541 vs 0.446kg/day), and were heavier (P<0.01) at weaning (160.6 vs 135-5kg). Correlation between average daily milk production and calf weight gain from birth to weaning was 0.75 (P<0.01).
beef cattle; milk production; milk composition; weight; gain; weaning weight; cultivated
