Evaluation of growth and reproduction in dairy heifers grazing legumes under productive conditions

The data from 149 Siboney de Cuba upgraded heifers of 128.9 +/- 5.01 kg of I iveweight (LW) with 9.2 +/- 0.4 Months of age were used, as well as those from 30 yearlings-heifers of 12 months of age and 227.8 +/- 7.01 kg of LW, to study the growth and reproduction in systems of management and feeding with grasses and legumes, in correspondence with the growth stage. The heifers and yearling-heifers were spread in two treatments: A) grazing on a mixture of Pangola grass (Digharia decumbens) and stylo (Stylosanthes guianensis), and B) grazing of Pangola grass without association for calves; A) mixture of tree legumes (Leucaena leucocephala cv. Peru) with Guinea grass Likoni (Panicum maximum) and B) Guinea grass Likoni for yearlings-heifers. The calves were grazing in 12 paddocks and the yearlings-heifers, in six. The grazing time was in the afternoon and at night (4:00 p.m. to 10:00 a.m., with 1.3 LAU/ha, in both groups and categories). The pasture availability, was determined both in rainy and dry conditions. The animals were weighed every 30 d. Blood and soil samples were collected for the analysis. The data were analyzed through linear model. In calves, the grass associated had values of crude protein (CP) of 9.75% and the non-associated grass, of 7.03%. The increment in LW of the calves was different (P < 0.001) and favored that grazing in the association. In yearlings-heifers, the association reached yield of 0.478 t of DM/rotation, and during the study there was daily increase of weight of 513.8 +/- 22.4. The blood metabolites were kept within the physiological ranges established for the species and category. The content of nitrogen in the grass without association was of 5.1% of CP (SD +/- 0.021), whereas in the associated grass it was of 7.37 % (SD +/- 0.110). The age of incorporation to reproduction was of 21.3 months, the interval incorporation-insemination, of 18.5 d, and the gestation, of 22 months. The results show the potentials of legumes and their contribution to the system under study to attain a quality heifer, production, especially when used according to the physiological growth stage.