Produção e qualidade de biomassa de pastagem do gênero Cynodon sob diferentes estratégias de manejo

Abstract

Pastures are the predominant resource used in ruminants’ diet and it is the most economic source in milk production systems. Thus, we aimed to evaluate pastures formed by grass of the Cynodon genus (Cv. Tifton 85 and Coastcross) with different grazing heights through forage production, morphological composition and nutritional composition of forage mass in different grazing horizons. The study was carried out in the experimental area belonging to the Dairy Cattle Teaching and Research Unit at the Federal Technological University of Paraná, Dois Vizinhos Campus. The Cynodon pastures were established in 2015. The treatments were composed of: Tifton 85 with grazing height between 20 and 25 cm; Tifton 85 with grazing height between 35 and 40 cm; Coastcross with grazing height between 20 and 25 cm and Coastcross with grazing height between 35 and 40 cm, randomly distributed in blocks with three repetitions (paddocks) for each treatment. The total forage production, forage mass, structural components, senescent material and invading species in pre and post grazing were evaluated. For the nutritional components, we evaluated the percentages of crude protein, neutral and acid detergent fiber and “in vitro” digestibility of dry mass. The Tifton 85 pasture and managing with 35-40 cm height presented higher available forage mass. The percentages of senescent material increased with the seasons. The invading species developed more in the 35-40 cm height and in the Coastcross pasture. The animal capacity remained constant and the animal load was superior for Tifton 85 pasture in the fall. The qualitative analysis showed higher crude protein content in the 10-25 and 25-40 cm strata, suffering a reduction with the passing of the seasons. The 35-40 cm height increased the neutral and acid detergent fiber contents and the digestibility contents were influenced by the adopted heights, being higher for pastures with grazing height of 20-25 cm.