Reduced dairy cow fertility during periods of elevated temperature, humidity or both might be associated with low plasma progesterone concentration. Researchers in Israel recently examined whether insertion of a controlled intravaginal drug-releasing (CIDR) insert containing progesterone following artificial insemination (A.I.) on day 5 post-A.I. for 13 days would improve summer conception rate. Their findings were published in the June issue of the Journal of Dairy Science.

Cows in the study were inseminated following estrous detection during July to October in two commercial dairy herds in Israel.

Results showed that treatment did not alter the overall conception rate. However, the probability of conception increased in CIDR-treated cows with low body condition score (BCS) compared with their control counterparts (53 vs. 27%, respectively). Furthermore, a pronounced increase in conception probability was recorded in CIDR-treated cows exhibiting both low BCS and postpartum reproductive disorders, compared with their control counterparts (58 vs. 14%, respectively).

Therefore, the scientists conclude progesterone supplementation can be effective, especially for cows with low BCS and postpartum reproductive disorders.