Frail Broodmare? Expect a Filly

Cold and wet weather combined with a rather hard-keeping breed of horses means that Thoroughbred caregivers must be especially conscientious about the health of their equine charges during the winter months.

In other words, winter is a rough time of year to be a Thoroughbred owner.

It becomes an even more crucial -- and difficult -- responsibility for Thoroughbred breeders, who must keep broodmares in top condition throughout the lean months.  I know from experience that some mares are just harder to manage than others -- blanketing, multiple grain rations, and high-quality hay are just the bare requirements for some mares when they're in foal or preparing to be bred. 

A few months back, I read a fascinating story on (Researchers: Mare's Condition Appears to Impact Sex of Foal) that associates the relative condition of the mare (at the time of breeding) with the eventual sex of her foal. With Thoroughbred breeding season ramping up in just a few weeks, I thought it was a good time to share the article.  In a nutshell, the author reports research that shows an overwhelming percentage of mares that were gaining condition at the time of conception produced colts, while mares that were losing condition at the time of breeding tended to produce fillies.  (Read the article for some additional analysis.)

The best practice -- and one that results in an equitable distribution of colts and fillies -- is for broodmares to maintain condition throughout the year. 

That's a tall order when you have a hard keeper.  During the winter, I feed one of my mares a spectacular quantity of feed to make sure she keeps good form.  High-protein sweet feed is augmented with mashes containing beet pulp and flax,-- fed twice daily. High-quality hay is free-fed, and supplemented with soaked alfalfa cubes. That plus blanketing in sub-30 degree temperatures does the trick for this particular mare, but I know there are much more difficult cases out there.  (Another of my mares could get fat on a single  flake of grass hay each day.  Go figure!)

Would love to hear your stories about foals you've had from mares that were hard keepers -- or your thoughts on the linked article.

(By the way -- if you found the article interesting, here's a related story:  Foal's Playfulness a Reflection of Gender, Mare's Condition.)

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