REPRODUCTIVE-PERFORMANCE OF MEXICAN DAIRY GOATS UNDER VARIOUS MANAGEMENT-SYSTEMS

Reproductive data from five dairy goat farms in a semi-arid area of Me xico were studied from 1987 to 1993, The study accumulated the results from 1675 births. Three farms had continuous presence of the breeding buck (1005 kiddings) and two farms had seasonal introduction of a buc k from May to December (670 observations), Goats gave birth for the fi rst time at about 14 months (+/-3 months), litter size of goats averag ed 1.67 (+0.2), and interval between kidding was 347 days (+/-56 days) . Quarterly seasonal distribution of births was 25% from January to Ma rch (n=419), 11% from April to June (n=184), 5% from July to September (n=84) and 59% from October to December (n=988). No statistical diffe rence was observed among farms in reproductive performance. Seasonalit y of reproduction was demonstrated, with 1407 kiddings (84%) in the au tumn, Rainfall showed a significant correlation with fertility and oes trus induction (P<0.05) but temperatures did not. Dairy goats were mos tly seasonal. The number of kids per parturition can be partially expl ained by the age of the dam and number of parturition, first kidding h aving the smallest prolificacy (P<0.01). There was no significant effe ct of the month of kidding or kidding interval. Rainfall appeared to b e the key factor to initiate ovarian activity into the breeding season .