Utilização de três fontes de nitrogênio associadas à palma forrageira (Opuntia ficus-indica, mill.) cv. gigante na suplementação de vacas leiteiras mantidas em pasto diferido

Abstract

The cactus forage only feed for herd not attend nutritional requeriments, because it is poor in protein and fiber. Protein supplementation sources upon the dairy cows performance fed with cactus forage, grazing at differed pasture, and botanic composition of pastre, were evaluated. Three treatments were tested: T1 = differed pasture (DP) + cactus forage (CF) + broiler litter; T2 = DP + CF + soybean meal; T3 = DP + CF + urea/ammonium sulphate mixture. It was used a randomized block design.The experimental animals were twelve 5/8 holstein/Zebu multiparous cows, with an average of seven years of age, milk yield of 5.6 kg/cow/day, and mean of 452 kg of live weight. The experimental period was 121 days and the first 21 days was used as an adaptation period. The results to fresh milk yield (3.38, 5.33 and 3.38 kg/cow/day), 4% fat adjusted milk yield (3.15, 4.98 and 3.11 kg/cow/day), daily live weight gain (-351, 77 and - 401 g/cow/ day) and fresh cactus forage intake (26.3, 37.8 and 26.3 kg/cow/day) considering T1, T2 and T3, respectively, showed the best performance to cows fed with soybean meal as supplemental protein source. It was identified 18 families, 32 genus and 36 species in the pasture. The "capim-milhã" (Brachiaria plantaginea (Link) Hitch.) was the main component in the botanical composition (28.72%).