Growth curve of lambs from three systems of production in Northeastern Brazil

Abstract

The objective was to analyze nonlinear models to describe growth of lambs in three production systems. The models used were: Brody, Von Bertalanffy, Gompertz and Richards. In a 1 production system was used lambs in "creep feeding", weaned at 60 days old and kept on pasture until they reach average 20 kg, when they were confined, slaughtered between 28 and 30 kg. In the 2 production system, lambs weaned at 90 days and kept on cultivated pasture and slaughtered between 28 and 30 kg, were used. In 3 Production System, lambs weaned at 90 days old and kept in an area of native pasture supplemented with elephant grass and leucena, in the critical period of the year and slaughtered at 28 to 30 kg were used. 17 weights of 30 animals, 10 animals for each system, from birth to 450 days, were used. Based on the study of the growth curves that are best adapted to predict the results of growth were those of Richards and Brody models, however none of the models simulated curve showed satisfactory results for the three production systems.