Efeito da ureia de liberação lenta e aminoácidos livres no comportamento ingestivo de cordeiros em confinamento

Abstract

This study aimed to evaluate the effect of supplementation with slow-release urea and free amino acids (lysine and methionine) on the feeding behavior of confined lambs fed silage-based diets. Forty lambs were randomly assigned to five treatments: a control group without additives; a group with slow-release urea; a group with urea and lysine; a group with urea and methionine; and, finally, a group with urea, lysine, and methionine. The experimental period lasted 60 days, and the animals' activities — such as ingestion, rumination, rest, and other activities (drinking water, social interaction, and vocalizations) — were observed at 10-minute intervals. The results showed significant differences in ingestion and rumination times between the treatments. Lambs in the treatment with slow-release urea, lysine, and methionine had higher ingestion times (3.18 hours per day), suggesting that this diet may have stimulated increased consumption. This increase in ingestion time may be interpreted as an attempt by the animals to compensate for possible differences in palatability or as a possible reflection of improved digestive efficiency provided by the additives. However, at the same time, this same group showed a reduction in rumination time (6.24 hours per day), which could indicate that, despite the diet not being the most palatable, it possibly facilitated digestion, resulting in less time needed for fiber processing. Regarding time spent on rest and other behavioral activities, such as drinking water and social interaction, the results showed no significant differences between the treatments. The average rest time was 13.54 hours per day, suggesting that supplementation with urea and amino acids did not negatively affect the lambs' rest or social interactions. This may indicate that, although the diet altered feeding behavior, there was no negative impact on the animals' overall well-being in terms of rest or social behavior. Based on these results, it can be suggested that supplementation with slow-release urea and free amino acids altered the feeding behavior of the lambs, promoting greater ingestion time and a reduction in rumination time. These effects may indicate greater nutritional efficiency in the lambs, with a possible increase in diet digestibility. Furthermore, diets containing slow-release urea and free amino acids may represent a strategy to improve feed management and nutrition in confined ruminants, potentially contributing to the reduction of ruminal disorders, such as acidosis. These findings suggest that this type of supplementation could be promising, but further studies are needed to confirm the benefits and optimize its applications.