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

Abstract

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. Key words: Digestion, goats, internal marker, Lactoplus ® , metabolizable energy, weight gain ResumoObjetivou-se com este trabalho, avaliar a ingestão, os parâmetros de desempenho produtivo, a digestibilidade da matéria seca e dos nutrientes de dietas com concentrações crescentes de energia metabolizável contendo gordura protegida, e a análise econômica das dietas para cabritos mestiços ½ Boer x ½ Saanen terminados em confinamento. Foram utilizados 28 cabritos, machos não castrados com peso inicial de 19,02 ± 2,20 kg e idade de 88 ± 5,77 dias, distribuídos em delineamento inteiramente casualizado Com quatro dietas: controle com 2,5 Mcal de EM/kg MS e os demais com 2,6; 2,7 e 2,8 Mcal de EM/kg de MS, onde se utilizou a gordura protegida (Lactoplus ® ) como suplemento energético. Os animais foram mantidos no experimento até atingirem peso aproximado de 32 kg. Para as estimativas de digestibilidade foi utilizado o FDAi como indicador interno. Houve efeito das dietas sobre as ingestões de matéria seca, matéria orgânica, extrato etéreo e carboidratos não fibrosos. Foi observado efeito quadrático das dietas sobre os parâmetros de ganho de peso diário e conversão alimentar. Não houve efeito das dietas sobre as digestibilidade...