Planos nutricionais no período seco e chuvoso sobre a taxa de crescimento e características reprodutivas de machos em pastejo.

Abstract

Objective to evaluate the performance, consumption, digestibility, carcass composition and reproductive characteristics of Nelore cattle submitted to different nutritional plans during the dry, rainy and/or both. The trial period consisted in 293 days, divided into 112 days of dry period and 161 days of rainy, being the 20 initial adaptation days. 28 animals were used in Nellore, whole, males with an average age of 14 months and average initial live weight 327,93 kg ± 4,22. The experimental grazing area destined to animals was composed of nine 1.0 pickets ha each, formed with Brachiaria brizantha CV. Marandú, equipped with water trough and trough. Was conducted in accordance with completely randomized design with four treatments and seven repetitions, randomly distributed to animals. SMS + SMc: mineral Supplementation in rainy and dry periods; SMS + SCc: mineral Supplementation in the dry period 0,8% PV concentrated Supplementation during the rainy season; SCS + SMc: supplementation with 0.8% concentrated PV in the dry period + mineral Supplementation during the rainy season; SCS + SCc: supplementation with 0.8% concentrated PV during dry and rainy seasons. The animals were weighed at the beginning and end of the experiment, as well as in the transition, after being subjected to fasting of solids for 16 hours. ANOVA was performed, comparing the mineral supplementation strategy versus concentrating on dry period. For the other variables, the sum of square for treatments was broken down as per diagram 2 x 2 factorial (S-supply of concentrated or mineral supplement in the dry period and Csupply of concentrated or mineral supplement during the rainy season). Was not checked interaction effect between supplementation strategies undertaken during dry and rainy seasons (P>0,05) for all variables of the study. Animals that received mineral supplement during the rainy season had higher forage consumption, neutral detergent fiber (NDF) and NDF indigestible. Performance variables influenced (P<0,05) additional strategies carried out in two periods independently, being that animals that received concentrated supplement had higher weight gain (P<0,05). The proportion of muscle in the casing was lower for the animals that received concentrated supplement (P<0,05). There were no differences for reproductive characteristics, except for the length of the testicles, which was higher for animals receiving supplement focused on the dry period and/or rainy.