Perennial peanut hay nutritive value

Abstract

A. pintoi (Fabaceae and Papilionoideae subfamily) or perennial peanut is a tropical legume forage native of Brazil, tolerant of low fertility soils. Used as pasture, ground cover and as an ornament were found from North to South of the country, besides Argentina, Uruguai, Colombia, Australia and United States. 1-3 Legumes have a typical foliar anatomy of the three-carbon metabolic pathway (C3) species, present higher protein content and digestibility and are recommended to increase crude protein availability to grazing animals. When compared with tropical grasses, C4 plants, possesses high protein and digestibility levels. 2,4 Considering the costs of feeding in animal husbandry, to offer appropriate nutritional formulas with diversification of ingredients is essential for the animal production. 5 However, only to evaluate the amount of nutrients supplied to the ruminant by the nutritional composition can be insufficient. The in vitro anaerobic incubation of the food with ruminal fluid is a valuable tool to estimate the degradability with high precision and using small amount of sample. 6 To mimetize the ruminal digestion in 48h, the food is placed under anaerobic conditions, in contact with the ruminal liquid containing viable microorganisms, with constant temperature of 39°C and buffered pH. Subsequently the digestion is done with pepsin and weak acid, for 24hours. 6 This procedure allows simulating the natural conditions of the digestion and obtaining representative and reliable results. In addition, it is possible to estimate the degradability of several samples at the same time. 6-8 Despite several studies made with tropical grasses, few researches are conducted with this forage, especially in the North of Minas Gerais, Brazil. The objective of this work was to determine the nutritional composition and in vitro dry matter degradability of A. pintoi hay. Material and methods The experiment was conducted in the Institute of Agrarian Sciences, in Montes Claros, Minas Gerais State, Brazil. The weather of the region is tropical wet with dry summer (As) according to the Köppen classification. 9 Were utilized five flowerbeds, with 3.99m² each, of A. pintoi cv. Belmonte previously established as a study field five years ago. The soil presented medium fertility in the laboratory analysis, with low exchangeable aluminum, high levels of potassium, phosphorus and magnesium, and a good ratio of alkaline content. The fertilizing utilized was bovine tanned manure (40Kg/m²) in a unique use 40days before the first cut and watered daily as a field capacity.