Abstract
Relationships of predicted sire value for milk, reproductive efficiency, time in herd and herd level of milk yield for Holsteins in Mexico and Colombia were examined. Sires were evaluated by best linear unbiased prediction (BLUP) procedures. Age at first calving, calving interval, days open and days dry were measures of reproductive performance. Daughters of high-value sires had longer calving intervals and lower herd life. Highest-producing herds in Mexico had shorter calving intervals and fewer days open and days dry. Within-herd correlations between sire values and calving intervals were low in high and low production herds. Sire values for milk of 17 sires from the United States with progeny in both countries ranged from 365 to -368 kg in Mexico and from 313 to -229 kg in Colombia. Rank correlation between values in the two countries was low, 0.26. First lactation milk yield averaged 7082 kg in Mexico and 5071 kg in Colombia. Progeny of high-producing sire in Colombia had longer calving intervals, more days open and days dry and lower herd life. Differences between corresponding groups in Mexico were similar. Small numbers and low heritability of reproductive traits prevented making general conclusions; however, there may be some economic significance when using highly selected sires to provide progeny which perform best in tropical or subtropical environments.
