A Mare's Choice of Stallion Based on Smell

Back in April we posted a reference to an article (by Kentucky Equine Research) that talked about how a stallion responds to the smell of a mare in heat - his blood testosterone level can change, and he can adjust the quality of his semen and seminal fluid depending on what he detects by smell.

Now a recent article on theHorse.com reports on how mares in heat can respond to the smell of a stallion. Smell can influence whether a mare will choose a particular stallion, and that smell can also affect whether the mare gets pregnant, or keeps the pregnancy. 

From the article:
“Our study indicates that the female organism has a high level of control over reproduction in two ways: through the choice of partner and through the spontaneous resorption of an early embryo, even before gestation can be detected,” said Dominik Burger, DVM, a scientist at the Swiss Institute of Equine Medicine (University of Bern and Agroscope), in Avenches.

And her choice is based on smell. Body odor can be modified by something called the major histocompatibility complex (MHC), a set of proteins within certain genes - and this change in smell is what drives the stallion's response in the earlier article, and the mare's reaction to a stallion as described in this research.

Read the full article here.