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Efeito da suplementação com concentrado no ganho de peso de bovinos d raça Guzerá e de seus cruzamentos, manejados em pastagens

1999; INSTITUTO DE ZOOTECNIA IZ/APTA-SAA/SP; Volume: 56; Issue: 2 Linguagem: Inglês

1981-4100

L. O. Tedeschi, Celso Boin, Romeu Fernandes Nardon, Paulo Roberto Leme,

Genetic and phenotypic traits in livestock

This study dealt with winter (dry season) and year-round supplementation of grazing steers of the Guzera (GU) breed and their crossbreeds with Brown Swiss (PS), Nellore (NE), Chianina (CH), and Caracu (CA). Different genotypes born in two consecutive years (two trials, first and second respectively) were used. The genetic composition of the 53 animals used in the first trial and of the 87 animals used in the second one were: first trial – GU; 3/4GU1/4PS and 1/2NE1/4PS1/4GU; second trial – GU; 3/4GU1/4PS; 1/2NE1/4PS1/4GU; 1/2CH1/4PS1/4GU; 1/2CA1/2GU; and ½CA¼PS¼GU. Animals entered the trials after weaning at the end of the wet season, and were slaughtered after about two years at the end of the second wet season. In the first trial animals were not supplemented (S1) or supplemented only during the first dry season (S2) with 0.5 kg of soybean meal. In the second trial, animals were not supplemented (S1), supplemented during the two dry seasons (S2) or during the whole period (S3, only genotypes GU; 3/4GU1/4PS; e 1/2NE1/4PS1/4GU) with 1.5 kg of a concentrate based on corn, wheat bran and urea. The statistical analysis was carried out using repeated measures with polynomial adjustment. Linear relationship between body weight and age was the best polynomial adjustment (P < 0.01). Guzera breed showed the lowest body weight (P < 0.05). In the first trial, the supplementation effect was significant at the end of each supplementation period and at the slaughter (P < 0.05). The linear multivariate regression showed the best fit for supplementation effects. In the second trial, there was a significant effect of supplementation (P < 0.05) and genotypes (P < 0.05). GU animals showed lower weight at slaughter (454 kg) than the crossbred 1/2CA1/2GU (530 kg). The year-round supplementation (S3) increased weight at slaughter and decreased the slaughter age, however this treatment did not differ from the S2 treatment.