Distribución de partos e influencia de algunos factores de variación sobre el intervalo entre partos y mortalidad de terneros, bajo paridera continua, en vacas de cría en la dehesa

Abstract

A total of 619 calvings and 547 intervals between calvings (IBC) from 97 cows, 15 Retinta cows and 82 crossbreed (Charolais x Retinta) cows, reared under continuous calving during eight consecutive years were controlled in the Dehesa ecosystem. The 39.25% of the calvings occured from December to February and only the 14.38% from August to October. The heifers and cows of seventh, eighth, tenth and eleventh and following calving showed an IBC higher than the cows of third, fourth, fitth and sixth calving. The variable “cow” had significant effect on the IBC, but the factors “gender of suckled calf”, “year”, “bull”, “calving month”, “fence” and, “body condition score at calving” had not significant influence on IBC. The age at first calving had not significant effect on IBC of heifer and average IBC of cows. Age at weaning of born calves from November to March was significantly lower than those born calves from May to July. The calf’s mortality seems affected by the genetic type of calf and the birth time. The use of Charolais bulls leads to a calves mortality at birth higher regarding Limousine bulls.