[Effect of weight, age and season on the productive and reproductive efficiency of Holstein heifers in the central southern zone]
1991
Gimenez R, Jose Miguel
A study was carried out, based on information gathered between 1987 and 1990 for 157 Holstein heifers, in three farms, which were submitted to computerized dairy control. The purpose was to establish the relation between age, weight and the season of the year in which heifers begin lactation, with the productive and reproductive efficiency reached. The total number of heifers was divided into two groups, according to the season of the year when they began lactation: autumn-winter (45 heifers) and spring-summer (112 heifers). The results obtained show that with a higher corporal weight of animals at the moment of pregnancy and calving, a positive effect is produced over the absolute milk production on heifers. The intercalving lapse diminishes as heifers get pregnant at a major weight. The age of animals at the moment of pregnancy produces a positive effect over milk production, which is less than the one produced by the corporal weight. With lactations started in autumn-winter, the absolute production that heifers reach is bigger than the ones obtained during spring-summer
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