Productive responses of dairy goats fed on diets containing elephant grass (Pennisetum purpureum) associated or not with cactus (Opuntia stricta) cladodes, and extra-fat whole corn germ as a substitute for corn

Abstract

This study evaluated the effects of partial replacement of elephant grass (Pennisetum purpureum) with cactus cladodes (Opuntia stricta (Haw.) Haw.), and the replacement of corn with extra-fat whole corn germ (EFWCG) on the intake and digestibility of nutrients, and milk yield and composition of dairy goats. Twelve Saanen goats with an average body weight of 54 ± 2.0 kg and with 45 days in lactation were distributed into three simultaneous 4 × 4 Latin squares according to milk yield and assigned to four dietary treatments in a 2 × 2 factorial arrangement corresponding to two roughage sources (elephant grass associated or not with cactus cladodes) and two energy sources (corn or EFWCG, at 9.5 % of diet dry matter (DM)). The diets with cactus cladodes provided greater intake (P ≤ 0.01) of organic matter (OM), crude protein (CP), ether extract (EE), non-fibrous carbohydrates (NFC), greater digestibility (P ≤ 0.04) of dry matter and OM, shorter feeding and rumination times (P ≤ 0.0003), and lower urea nitrogen content in milk (P ≤ 0.003). Diets containing EFWCG provided a higher intake (P ≤ 0.004) of EE, lower intake of NFC, and higher concentration of fat and total solids in milk (P ≤ 0.04). Both diets without cactus cladodes and diets without EFWCG provided greater digestibility (P ≤ 0.003) of neutral detergent fiber (NDF). The diets with cactus cladodes and EFWCG showed higher intake (P ≤ 0.04) of DM, NDF, and metabolizable energy, and total and fat-corrected milk yields (P ≤ 0.03). The grass and EFWCG diets showed higher digestibility (P ≤ 0.03) of CP and EE. Partial replacement of elephant grass with cactus cladodes and inclusion of EFWCG as a substitute for corn increased DM intake and energy intake, which was associated with an improved productive performance of dairy goats. Therefore, this diet could be an interesting option for dairy goats in semiarid regions where cactus is an essential fodder for ruminant production.