Parâmetros nutricionais em ovinos submetidos à dieta com pastagens naturais manejadas com diferentes alturas

Abstract

This work aimed to evaluate the different sward heights of natural pastures in the Pampa biome and their characteristics related to nutritional parameters, nitrogen balance and methane emission when used in sheep diets. Through this, we sought to identify an ideal time for the use of natural pastures to obtain better feed efficiency by evaluating losses during metabolic processes when subjected to diets on natural pastures at three sward heights: 8, 12 and 16 cm, relating it to the quality of the forage offered in the diet for sheep. Fifteen male sheep with an average weight of 43.78 kg and a standard deviation of 3.26 kg were used, confined in metabolism cages. During the evaluation there was a period of adaptation to the diet of 16 days and another five days for collecting samples of feces, urine, gas emissions and rumen fluid. During the evaluation, data related to the chemical composition of the diet, forage intake, methane emission, digestibility, energy balance and nitrogen balance were collected. The data were analyzed using linear and quadratic regression analysis, taking 5% as a significance level. The results had similar values for most parameters, however, dry matter digestibility was higher in the sward height treatment of 8 cm, NDF intake had a higher average in the sward height treatment of 12 cm, while propionate production was higher in the treatment with 16 cm of canopy. This study finds that the sward height of the herbage at 8 cm has a positive influence on diet digestibility, propionate production is greater at heights of 16 cm and nitrogen retention is greater at 12 cm in the diet of small ruminants.