Composição corporal e exigências nutricionais em cálcio, fósforo, magnésio, potássio e sódio de cordeiros Santa Inês em pastejo no semiárido.

Abstract

This work took place in Santa Terezinha municipality, in the Lameirão Farm of the Federal University of Campina Grande/Center of Rural Health and Technology (CSTR), Campus of Patos, with the objective to determine Santa Inês hair lamb body composition and calcium (Ca), phosphorus (P), magnesium (Mg) and sodium (Na) nutritional requirements. Thirty-two 3-to-4-month-old castrated lambs were used, with an initial mean body weight of 15.8 kg ± 1.4 kg. Eight of them were slaughtered in the beginning of the experiment to represent the initial body composition (“Reference Animals") of the comparative slaughter method. The other animals, as they reached 15 Kg, were divided randomly in groups of three with three levels of food supplements, one animal for each treatment. When the first animal in each group reached 30Kg, the whole group was eliminated. The animals were kept in native rangeland enriched with buffel grass (Cenchrus ciliaris L cv. Biloela). Their diets were supplemented with three levels of concentrated mixture 0, 0 %, 1.0 % and 1.5 % of concentrated/day. Estimated values of body composition, in g/kg of empty body weight, ranged from 17.11 to 14.91 for Ca; from 6.08 to 5.33 for P; from 1.29 to 1.16 for Mg; from 0.77 to 0.87 for K and from 1.45 to 1.36 for Na. Net requirements for body weight gain of 15-to-30 kg lambs, in g/kg gained in live body weight, ranged from 10.87 to 9.47 for Ca; from 3.89 to 3.76 for P; from 0.82 to 0.72 for Mg, from 0.67 to 0.72 for K, and from 0.99 to 0.92 for Na. The observed differences between the values of commonly used tables and the ones obtained in the present study reflect the need of further research on macromineral requirements of lambs under rangeland conditions in the semiarid region.