Suplementação volumosa de bovinos Holandês/Zebu em pastagem de Brachiaria decumbens Stapf

Abstract

Two experiments were carried out at the Estação Experimental de Itambé of Instituto Agronômico de Pernambuco – IPA, in the municipality of Itambé. The first trial, conducted from July 2006 to February 2007, aimed to evaluate the structural sward characteristics, to estimate the forage intake and to evaluate the effect of roughage supplementation of four Pennisetum sp. clones (IRI-381, Venezuela, Elefante B and Hexaplóide), harvested, chopped and supplied in the troughs, on the daily weight gain of crossbred Holstein-Zebu heifers, under continuous stocking, grazing an area of 7.5 ha of Brachiaria decumbens Stapf pasture. Fifteen heifers averaging initial weight of 155 + 27 kg and from 12 and 14 months old were assigned to a complete randomized design. The indigestible acid detergent fiber (iFDA) and the chromium oxide were used as markers to estimate the intake. Average dry matter intake ranged from 2.1 to 2.7% LW. No effect of Pennisetum sp. clones on weight gain was observed. The second experiment, conducted from March to June 2007, aimed to compare the effects of different roughage supplementations on the dry matter intake, on the milk production and quality of crossbred heifers and also on calf weight gain grazing B. decumbens Stapf pasture. Six crossbred heifers averaging initial weight of 430 + 20 kg at 80 + 20 days of lactation were assigned to a 6 x 6 Latin square. The treatments consisted of different roughage supplementation: hay of three elephant grass clones, B. decumbens hay and sugar cane with urea and ammonium sulfate. No treatment effect on the milk production and quality and calf weight gain was observed. Average milk production was 11.0 kg/cow/day and calf weight gain was 628 g LW/day. The different supplementations did not affect dry matter intake. The structural characteristics and yield of B. decumbens pasture were affected by the year seasons and B. decumbens presented greater participation in the evaluated area.