USO DE LA Gliricidia sepium EN LA SUPLEMENTACIÓN DE MAUTAS MESTIZAS Y SU EFECTO SOBRE EL CRECIMIENTO Y LA APARICIÓN DE LA PUBERTAD Use of Gliricidia sepium in Feed Supplementation of Crossbred Heifers and its Effect on Growth and the Onset of Puberty

A trial was carried out to evaluate the influence of supplementation with flour of Gliricidia sepium leaves (GS) on the growth and onset of puberty in heifers. The research was carried out over 10 months on a commercial bovine farm located in the “Rio Grande” sector, Tachira State, Venezuela. In this trial, 30 crossbred heifers with average initial body weight of 176.9 ± 24.6 kg and an average age of 17.22 ± 2.23 months were used. The heifers grazed on Tanner grass (Brachiaria arrecta) and were randomly assigned to 3 supplementation groups: (T1) without supplementation (T2) balanced commercial feed concentrate, and (T3) a mixture of 50% corn meal, 30% dehydrated GS flour, and 20% molasses. The body weights was registered every 15 days, and weekly blood samples were taken to determine serum conce ntration of progesterone by radio-immunoassay. Data were subjected to the analysis of variance-covariance using the General Lineal Model (GLM) of the SAS analysis package. The variables evaluated were: average daily gain (GDP), age (EP) and body weight (PP) at puberty. The supplemented heifers (group 2 and 3) values were significantly (P<0.05) better than those allocated in group 1 for the GDP (570 and 556 vs. 457 g/d) and EP (670 and 720 vs. 783 d.). No significant differences were found for PP among groups. Supplementation with treatment 1 and 2 reduced the delay in the onset of puberty in crossbred heifers under tropical conditions; therefore, supplementation with GS improved animal pe rformance.