Le poids des chevrettes laitières à la mise à la reproduction : association avec l'âge et la probabilité de mettre bas
Weight at mating has been associated with lifelong productivity in dairy goat. The objective of this study was to estimate the relationships between weight at 210 days old (W210) with subsequent probability of first kidding (PK) and age at first kidding (AFK) of Alpine and Saanen goats, respectively. A convenient sample of 744 Alpine and 217 Saanen dairy goats from 17 farms performing regular milk controls in the province of Québec, Canada, was analysed. Kids’ weights were measured using a heart girth tape between the age of 5 and 9 months. Mixed linear regressions were used to model the weight according to the age of goat, which was then used to predict the W210 of each goat. The PK means were respectively 88.0% and 92.7% for the Alpine and Saanen goats. Based on logistic regression, PK was significantly associated with W210. Mean AFK were 502 ± 129.6 and 445.5 ± 92.6 days for the Alpine and Saanen breeds, respectively. Mixed linear regression showed that Alpine and Saanen goats with higher W210 kidded at younger age than goats with low W210. According to our results, Alpine and Saanen goat kids should weigh at least 30 and 34 kg respectively at the age of seven months to achieve PK of at least 90 %, and a median AFK by breed and herd in a range of ± 30 days.
chevrotage goat kid doeling growth dairy goat weight at mating age at kidding first kidding