Resumen de Rendimientos de vacas primíparas con parto a dos años en función de su ritmo de crecimiento en lactación y recría
J.A. Rodriguez Sánchez, A. Sanz, Isabel Casasús Pueyo
An experiment was conducted to analyse the performance in primiparous cows calving at two years, depending on their growth patterns from birth to first mating (Timed Artificial Insemination at 15 months). Twenty-five Parda de Montaña heifers, born in autumn, were assigned to two nutrition levels during lactation (0-6 months: High vs. Low) and rearing periods (6-15 months: High vs. Low). Primiparous cows’ performances were not significantly affected by the earlier first service at 15 months or the different growth patterns registered. Only the postpartum anoestrous interval was markedly longer in the animals with low nutrition level during the rearing period (77.7 vs. 106.5 days, for in High and Low, P<0.05). It would be feasible to advance the first calving at two years guaranteeing growth rates close to 1 kg/d during rearing period without impairing productive and reproductive parameters.
