Dairy heifers have important ovarian and endocrine differences during the estrous cycle compared to lactating cows, according to University of Florida researchers Fabio Lima and Jose Santos.
That’s why traditional fixed-time A.I. synchronization programs were not as successful at achieving pregnancy in heifers compared to cows. But Lima and Santos recognized the importance of reaching calving-age targets to efficiently move heifers into the lactating herd. They point out that delayed pregnancy in heifers results in $2.00 to $2.50/day in additional rearing costs with feed prices at 8¢ to 9¢/lb. of heifer ration dry matter).
Lima and Santos have developed a hormone-based, timed A.I. breeding program specifically for heifers. Their initial results have yielded pregnancies per insemination for the first and second service ranging from 52.2 to 61.0%. They estimate that, even factoring extra costs for treatment and labor, the program could result in $10 to $20 reduced cost per pregnancy in heifers.
To view the program, visit http://dairy.ifas.ufl.edu/dairyupdate/DairyUpdateWinter2014.pdf
Source: Florida Dairy Update