Diferentes níveis de extrato de tanino de acácia negra na terminação de cordeiros em sistema de confinamento

Abstract

This study aimed to evaluate the effect of different inclusion levels of black wattle tannin extract on nutrient intake, performance, carcass traits and ingestive behavior of feedlot finished lambs. Forty lambs, male, not castrated, weaned at 50 days old and from a cross between the Texel and Ile de France breeds were used. The diet consisted of roughage, which is corn silage, and concentrate, composed of disintegrated corn, soybean meal, calcitic limestone and common salt. The treatments consisted of five levels of inclusion of tannin extract in the diet (% of total DM in the diet), as follows: 0 (control), 1, 2, 3 and 4%. Intake of dry matter (DM), organic matter (OM), crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), total carbohydrates (CHT), non-structural carbohydrates (NEC) and digestible nutrients totals (NDT) in the different ways in which they were expressed, were influenced in a quadratic way by the increase in the inclusion of tannin extract in the diets. The average daily weight gain (ADG) was influenced in a quadratic way, being at the maximum point of 0.303kg, with a level of 1.6% of tannin extract. The time spent in feeding activities, rumination, total chewing time and the time the animals remained idle were not influenced (P>0.05) by the treatment. Other activities (in minutes/day and in % of time in the 24 hours) were influenced in a quadratic way (P≤0.05). The highest concentration of feeding activities occurred around the period of supplying food to the animals (8-12 and 16-20 hours), while the highest concentration of rumination activities occurred between 00:00 and 8:00 in the morning. The number of times and time spent feeding and ruminating and the number of times the lambs drank water were not influenced (P>0.05). The use of 1.6% of black wattle tannin extract in the total DM of the diet of feedlot lambs receiving corn silage and concentrate in a 45:55 ratio is recommended to obtain better weight gain and carcass characteristics with satisfactory quality standard. The inclusion of black wattle tannin extract up to the level of 4% of the total DM of the diet does not significantly change the characteristics of the ingestive behavior of the animals.