EFFECT OF MATING SEASON AND LEVEL OF BODY RESERVES ON FERTILITY AND PROLIFICACY OF MANCHEGA EWES

A flock of 530 Manchega ewes, under semi-intensive regime and a reprod uctive program of three births per 2 years, was used to study the effe ct of mating season (MS), level of energy reserves at mating, measured by body condition scoring at mating (BCM), and live weight at mating (LWM) on fertility and prolificacy. Fertility of the flock was affecte d by BCM (P < 0.05), while LWM had no influence and MS was found to ha ve an effect with a P-tail of 8%. December matings gave highest value for fertility (89.9%) compared to April (82.1%) and August (80.4%). In order to study the relationship between BCM and fertility, a logistic regression model was used, with which a good prediction was obtained (P < 0.05). Prolificacy was only affected by LWM (P < 0.05) with a sig nificant prediction (P < 0.01) through a logistic regression. As LWM i ncreased, the probability of twin birth increased. Body condition scor e (BCS) evolution has also been studied at different points of the rep roductive cycle for the effect of the previous cycle on fertility and prolificacy. Fertility was affected by BCM, while prolificacy was infl uenced not only by LWM but also by live weight in the next phase.