Shrink the Heifer-Freshening Window
Aug 23, 2013
Increase your profits with opportunities that can improve heifer reproductive efficiency.
By John Lee, DVM, Zoetis
Heifers that calve for the first time at 22 to 23 months of age can offer dairy operations a big financial advantage. Every month that first calving is delayed beyond 22 months costs producers over $100 per heifer in lost milk production opportunity and additional raising costs.1 Producers will pay more than $60 per heifer in feed costs alone.1
Keep in mind, raising replacements is one of the largest expenses on a dairy. From birth to freshening, it costs between $1,595 and $2,935, according to industry estimates.2 Maximize investment by shrinking the freshening window for replacement heifers. Lowering the age at first calving is important for achieving the highest economic return from a heifer replacement program.
It takes more than simply setting a goal to reduce age at first calving. The decision to breed heifers to calve between 22 and 23 months of age needs to begin before they are ready for first insemination. Producers need to monitor growth to make sure replacement heifers will reach breeding size targets by 12 to 13 months of age. Heifers must reach height and weight benchmarks to ensure a healthy calving and a smooth transition into the milking herd.
Once heifers have reached breeding size targets, producers need to commit to more aggressive management of heifer reproduction to improve age at first calving. Since gestation is a fixed length, first service conception risk and age at first breeding are big drivers of age at first calving.
The two best opportunities to improve heifer reproductive efficiency are to move heifers into the breeding pen on a weekly basis and to incorporate synchronization tools to help reduce days to conception. In addition, producers should follow these management practices to keep their heifer breeding program on target:
• Move heifers to the breeding pen when they reach size goals. Heifers are ready to move when they reach 55% of their mature size. As heifers reach growth targets, move them into the breeding pen weekly.
• Reduce days to first insemination. Target 100% inseminated within 36 days of reaching size.
• Conduct regular pregnancy checks. Conduct pregnancy diagnosis to identify pregnant heifers to move out of the breeding pen. All heifers should be confirmed pregnant by 15 months of age.
• Monitor and measure. Monitor performance on an ongoing basis using the measures of pregnancy rate, heat detection risk, conception risk and the distribution of age at first insemination. Progress should be evaluated after each pregnancy check.
• Proper nutrition. Heifers need adequate nutrition to support the onset of puberty and growth to 55% of their mature weight. Better nutrition will help heifers reach growth targets at an earlier age so they are ready for movement into the breeding pen. Due to fewer total days on feed from birth to conception to calving, this strategy reduces total heifer-raising costs.
Managing heifer reproduction requires time and attention. That’s a minimal investment compared with the benefits of calving heifers prior to 24 months of age. In fact, producers who routinely achieve an age at first calving between 22 and 24 months capture increased profit returns in the form of reduced raising costs, earlier investment returns, increased herd management flexibility and fewer replacements on the dairy.
1 Lormore MJ. The case for a quality dairy replacement program, in Proceedings. NRAES Dairy Calves and Heifers: Integrating Biology and Management Conference, 2005.
2 Stuttgen S, Kohlman T, Hoffman P, Zwald A. There’s nothing equal when raising heifers. Hoard’s Dairyman 2008:87.
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