Balance de nitrógeno en vacas de leche en pastoreo
- A.I. Roca-Fernández
- Mª.D. Báez Bernal
- A. González-rodríguez
- López-Carrasco Férnandez, Celia (coord.)
- María del Pilar Rodríguez Rojo (coord.)
- Alfonso San Miguel Ayanz (coord.)
- Federico Fernández González (coord.)
- Sonia Roig Gómez (coord.)
Editorial: Sociedad Española para el Estudio de los Pastos
ISBN: 978-84-614-8713-4
Ano de publicación: 2011
Páxinas: 453-458
Congreso: Sociedad Española para el Estudio de los Pastos. Reunión Científica (50. 2011. null)
Tipo: Achega congreso
Resumo
The milk production based on farm resources systems in humid areas, need studies of the balancebetween the nutrients on offer to fit the animal requirements. The nitrogen (N) balance in theanimal on a rotational grazing system, was analyzed, considering the inputs from food (grass, silageand concentrate) and the outputs (milk and live weight), in four herds of Holstein-Friesian dairy cows(n = 72), at two stocking rates, (1) low or (2) high, in cows and two stages of lactation, (A) start or (B)end, during two grazing periods: (P1) pasture at early spring, with supplementation and (P2) later grazing,without it. The N inputs and outputs (g/cow/day) were higher in groups A (189 and 121) than inB (163 and 105), higher in high stocking rate groups (182 and 115) than in low (170 and 111), andhigher in period P1 (237 and 140) than in P2 (114 and 86). The N excretion was higher in P1 thanin P2 (479 vs. 68 g/ cow/ha) with no differences between stages of lactation or stocking rates.