Desempenho e comportamento ingestivo de bovinos de corte mantidos em pastagem irrigada ou em sistema de silvipastoril

Abstract

Beef cattle farming is a strategic economic activity in Brazil; however, its productivity is impacted by climatic seasonality and inadequate management practices, which compromise the continuous supply and quality of forage, reflecting directly on animal performance. In this context, irrigation and silvopastoral systems have been identified as sustainable alternatives to minimize water deficits, improve the nutritional quality of pastures, and promote greater thermal comfort, thereby contributing to the welfare and performance of cattle in grazing systems.The objective of this study was to evaluate the production of African Star grass pasture, the productive performance, and the ingestive behavior of 27 castrated Purunã steers, distributed across nine paddocks of African Star grass, under three management systems: full sun, irrigated, and silvopastoral, from December 2023 to May 2024, at the Beef Cattle Teaching and Research Unit of UTFPR – Dois Vizinhos Campus. The pasture variables analyzed were crude protein, dry matter, acid detergent fiber (ADF) and neutral detergent fiber (NDF), leaf and stem proportion, forage mass production, and accumulation rate. For animal performance, average daily gain, live weight gain, and stocking rate were evaluated. Morphological and bromatological evaluations of the forage were conducted, with the irrigated system standing out due to a higher proportion of leaves (49.9%) and a better leaf:stem ratio (1.80), along with a higher crude protein content (14.77%), a determining factor for weight gain. The average daily gain of the animals was significantly higher in the irrigated system (0.419 kg/day) compared to the full sun and silvopastoral systems.The silvopastoral system was characterized by greater shading, a higher proportion of stems, and increases in ingestive behavior variables, such as number of chews per bolus (NCB = 56.55), chewing time per bolus (CTB = 60.13 seconds), and grazing time (563.24 minutes/day). These results indicate lower forage quality and greater difficulty in ingestion in the silvopastoral system. The data suggest that irrigation enhances both the production and quality of pasture, directly reflecting on animal performance.