Pasture quality and productivity | [Calidad de pastos y productividad]
1990
During 1990, the main research activity of the Section has been to evaluate legume-based pastures in terms of animal production in grazing trials conducted at Quilichao and Carimagua. Milk production from upgraded Holstein cows has been consistently higher (16 percent in wet season and 40 percent in dry season) in B. dictyoneura + legume pastures compared with the grass alone. However, with Zebu crosses milk production has not increased significantly due to legumes. Availability and degree of palatability of the legume appear to influence milk yields. Urea concentration in milk has been found to increase in cows grazing grass-legume pastures. It is suggested that increased urea levels in milk could reflect an energy deficiency. In addition, urea in milk could be a suitable marker to determine legume consumption by grazing cows. Liveweight gains (200 kg A(-1) year(-1) and 600 kg ha(-1) year(-1)) in well- established B. dictyoneura/A. pintoi pastures at Carimagua have been the highest ever recorded. In addition, A. pintoi had increased the productivity of B. humidicola, which is a low-quality grass, having a number of positive attributes. Unlike other legumes with no antiquality factors, A. pintoi builds up in the pasture over time at a wide range of stocking rates.
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