MORPHOLOGICAL COMPONENTS AND NUTRITIONAL VALUE OF TWO Urochloa HYBRIDS UNDER DIFFERENT AGRONOMIC MANAGEMENT

Abstract

Grasses are the main source of food in ruminant production systems, which are catalogued as a source of food of low nutritional value due to their high structural carbohydrate content; however, there are agronomic management techniques, such as cutting interval and intensity that influence yield and modify the nutritive value of forage. The objective of this research was to evaluate the morphological composition and nutritive value of forage from hybrid grasses of the genus Urochloa at different mowing interval and intensity. The experiment was carried out in rainfed conditions during the season of maximum rainfall. In 2020 and 2021, Camello I (GPB3025) and Camello II (GPB3207) hybrids were evaluated at different intervals (5 and 7 weeks) and mowing intensities (10 and 20 cm). The eight treatments were evaluated using the cutting variables dry matter yield (kg ha^-1) of leaf, stem, inflorescence, dead matter and content (g kg^-1) of crude protein (CP), neutral detergent fiber (NDF), acid (ADF) and lignin (LIG). Data were analyzed in a randomized complete block design. The Camello II hybrid presented the highest leaf and dead matter yield values (17 and 46 %, respectively), compared to Camello I; however, the latter had the highest CP content (90 vs. 82 g kg^-1). At 5 weeks and 10 cm intensity, the yield for most morphological components was lower. The highest CP content was obtained when harvested at 5 weeks and 10 cm (108 g kg^-1). The highest values of NDF, ADF and LIG were obtained at 20 cm intensity in both hybrids. Regardless of the hybrid, the highest forage yield and nutritive value were obtained when forage was harvested at 7 weeks interval and at 10 cm intensity.