Effects of Different Supplementations During the Rainy Season on Nitrogen Metabolism of Beef Cattle Steers on Tropical Pasture.

This article presents two studies focused on animal health and nutrition. The first study evaluated the effects of different supplementation levels combined with phytogenic additives (essential oils, saponins, and spices) on nitrogen metabolism in beef cattle steers grazing tropical pastures during the rainy season. Results showed that supplementation with phytogenic additives reduced urinary nitrogen excretion and increased nitrogen retention, indicating improved nitrogen utilization efficiency compared to mineral supplementation alone. The second study investigated whether gonadectomy (spaying or neutering) affects peripheral T-lymphocyte populations in senior Labrador Retrievers. Findings revealed no significant differences in T-cell subsets or ratios between gonadectomized and intact dogs, suggesting that gonadectomy does not alter adaptive immune function in aging dogs.