Replacement of alfalfa hay for tropical legumes in goats diets / Substituição do feno de alfafa pelo de leguminosas tropicais em dietas de caprinos

Abstract

The aim of this study was to evaluate the effect of alfalfa hay replacement by tropical legume hay on goat diets. Four diets were formulated using: 1) perennial soybean hay; 2) tropical kudzu; 3) macrotiloma and 4) alfalfa, in a roughage/concentrate ratio of 25/75. Eight castrated crossbred (Boer x Saanen) animals, with a mean weight of 17.8 kg (4 months of age), were arranged in a 4 x 4 double Latin Square Design. Intake of dry matter (DM), organic matter (OM), crude protein (CP), total carbohydrates (TC), ether extract (EE), non-fibrous carbohydrates (NFC) and total digestible nutrients (TDN) were not affected by the legume species. On the other hand, the intake of acid detergent fiber (ADF) was lower in the diet formulated with alfalfa, compared to the other legumes (P<0.05), since this presented lower levels in this diet. The digestibility of DM, OM, CP, ADF, TC and NFC did not differ among the four treatments (P>0.05). However, EE digestibility was lower in the diet with alfalfa compared to ration with tropical kudzu and perennial soybeans. The digestibility of this constituent between the diet formulated with tropical kudzu and those formulated with macrotiloma and perennial soybean (P < 0.05), and the digestibility of the NDF of the ration prepared with perennial soybean was higher than the other legumes. There was no difference for the nitrogen balance between the different diets, indicating that these legumes are options for replacement of alfalfa hay in goat diets.