Digestibility and performance in crossbred ½ Boer x ½ Saanen goat kids fed diets containing protected fat

Resumo

The objective of this study was to evaluate the intake, performance parameters, digestibility of dry matter, and nutrients in diets with increasing levels of metabolizable energy containing protected fat, as well as the economic analysis of the diets of ½ Boer x ½ Saanen goat kids finished in a feedlot. Twenty-eight uncastrated male goat kids with an initial weight of 19.02 ± 2.20 kg and an age of 88 ± 5.77 days were used and assigned to a completely randomized design in four diets: a control with 2.5 Mcal ME/kg DM and the others with 2.6, 2.7, and 2.8 Mcal ME/kg DM with protected fat (Lactoplus®). The animals were kept on experiment until they reached approximately 32 kg of weight. In order to estimate digestibility, we used ADFi as an internal marker. There were treatment effects on the intake of dry matter, organic matter, ether extract, and non-fiber carbohydrates. We observed a quadratic effect of diets on daily weight gain and feed conversion. The diets had no effect on the digestibility of dry matter, organic matter, neutral detergent fiber, or gross energy. The digestibility of non-fiber carbohydrates and total carbohydrates showed a linear decrease, and crude protein increased linearly. We observed a quadratic behavior in ether extract digestibility resulting from the inclusion of protected fat in the diets. The serum cholesterol level was influenced by the diets and showed a linear increase. The economic evaluation was favorable, with a larger net revenue value for the diet with 2.5 Mcal ME/kg DM. The increase of energy density of diet for ½ Boer x ½ Saanen goat kid through the inclusion of protected fat influences negatively the intake of dry matter and the digestibility of non-fiber carbohydrates and total carbohydrates without improving the growth performance of the animals.