How do results compare between heifers, young cows and older cows?
Heifers are consistently unpredictable in both fertilization rate and superovulatory response. Our average number of fertile embryos for heifers is 3.2 per flush. Regarding cows, superovulatory response is consistent through a cow’s reproductive life. However, fertility drops with age. This is not that significant in animals under 8 years old, but after that it drops noticeably. For animals over 12 this drop in fertility is very significant. Please note that the above statements are generalizations. Donors are individuals and may work well for many years. We’ve recovered 12 beautiful embryos from an 18 year old Jersey.
