Substituição total do milho e parcial do farelo de soja por palma forrageira e uréia para vacas em lactação

Abstract

The experiment was carried out with the aim of assessing the effect of the total replacement of corn meal and partial replacement of soybean meal with spineless cactus and urea in the diet of 5/8 Holstein-Gir dairy cows on the milk yield and composition as well as intake and apparent digestibility of nutrients. Eight cows with a mean body weight and daily milk production of ±540 and ±14 kg, respectively, were distributed in two 4x4 Latin squares. The experimental diets were composed of increasing levels of spineless cactus (45, 50, 55 and 60% DM) plus urea, completely replacing corn meal and partially replacing soybean meal. Each experimental period lasted 15 days, 10 of which were for the adaptation of the animals and five were for the data and sample collection. The intake of dry matter, organic matter, neutral detergent fiber, total carbohydrates, non-fibrous carbohydrates; content and production (kg/day) of fat, protein, total dry extract of the milk, digestibility of the dry matter, crude protein or ether extract, neutral detergent fiber, total carbohydrates and non-fibrous carbohydrates, Plasma Urea Nitrogen, milk Urea Nitrogen and urinary excretion of urea were not affected by total replacement of corn meal and partial replacement of soybean meal with spineless cactus and urea, with medians of 6,72; 14,59; 6,79; 12,49; 5,76; 3,88; 0,48; 3,25; 12,47; 61,08; 66,52; 55,79; 49,61; 65,64; 83,03; 14,69; 14,92 e 589,55, respectively. The milk production was reduced linearly with the inclusion spineless cactus and urea in the diet, ranging from 13,51 kg/day to 11,54 kg/day. The total replacement of corn meal and partial replacement of soybean meal with spineless cactus and urea were not affected feeding and rumination time or feeding, rumination efficiency (kgDM/h), total mastication time and idle time. However, The rumination efficiency (kgNDF) showed a quadratic effect. The total mastication time and idle time were not affected by total replacement of corn meal and partial replacement of soybean meal with spineless cactus and urea. However, the depression of milk can be tolerated under certain economic conditions.