Researchers at the USDA-ARS Animal Improvement Laboratory recently unveiled some interesting new data regarding heifer fertility.

After a national review of 362,512 heifers in more than 2,000 herds in 41 states, the researchers learned that Holstein heifers have a 57 percent average conception rate. And they confirmed that heifer age is a critical factor in getting heifers bred. Here are some of the highlights of the research:

  • Conception rates are maximized when heifers are between 15 and 16 months old.
  • Conception rates for heifers 26 months and older drop 10 percent versus the youngest heifers — those between 11 and 12 months of age.
  • Conception rates for heifers 26 months and older decrease about 13 percent when compared to heifers at the optimum breeding age of 15 to 16 months.
  • In contrast to cow fertility, heifer conception rates in the hotter summer months are nearly as good as in cooler months.

The research appeared in the December 2006 issue of the Journal of Dairy Science.

Source: December 2006 Journal of Dairy Science