Resumen de Repercusión del ritmo de crecimiento en lactación y recría de novillas sobre la entrada en pubertad y la fertilidad
J.A. Rodriguez Sánchez, A. Sanz, Isabel Casasús Pueyo
This study analysed the effect of different growth patterns from heifers’ birth to first mating, on their subsequent puberty onset and fertility at Timed Artificial Insemination at 15 months. Twenty-nine Parda de Montaña heifers, born in autumn, were assigned to two nutrition levels during lactation (0-6 months: High vs. Low) and rearing (6-15 months: High vs. Low). The age at puberty onset was affected by the nutrition level offered during lactation (10.3 vs. 12.0 months, in High and Low, P<0.01) and rearing period (9.8 vs. 12.5 months in High and Low, P<0.001). However, no differences were found in the age at conception (16.4 months) or fertility (89%). These preliminary results would confirm the feasibility of advancing the first service from 21 to 15 months of age in beef cattle, if no impact on adult size and dystocia frequency are registered at first and subsequent calvings.
