Optimal Body Condition Scores for Breeding Mares

Making sure that your mare is in good body condition going into the breeding season is extremely important for optimizing conception and maintaining a healthy pregnancy.  By visually and manually evaluating the mare at certain places on her body (neck, shoulders, withers, ribcage, backbone, and tailhead) you can assign horses a body condition score (BCS) between 1-9, with 1 designating extreme emaciation and 9 being extremely obese.  Broodmares are typically maintained in the condition score range of 5-7.

Descriptions of these three body condition scores are given below:

5, Moderate -- Back is flat (no crease or ridge); ribs not visually distinguishable, but are easily felt; fat around tailhead beginning to feel spongy; withers are rounded; shoulders and neck blend smoothly into the body

6, Moderately Fleshy -- Might have slight crease down back; some fat cover over the ribs, along the sides of the withers, behind shoulders, and along the side of the neck; fat around tailhead is soft

7, Fleshy -- Might have crease down back; individual ribs can be felt but noticeable fat deposition between the ribs; fat deposited along withers, behind shoulders, and along neck

Numerous research studies have shown a direct relationship between body condition and fertility in mares.  Mares with a low body condition score are least likely to conceive.  In one study, mares with a BCS of less than 5 had a 71% conception rate, mares with a BCS of 5-7 conceived at 92%, and mares over BCS of 7 achieved 96% conception. 

In this same study, mares with a low BCS required 2.8 heat cycles per conception compared to 1.4 for mares in better body condition.  Low body weight at the onset of the breeding season may result in first ovulation being delayed 3-4 weeks when compared to higher BCS mares.  Early fetal survival is also dependent on body condition, with more significant early losses in mares with BCS of 4 or less.  Some people may fear that a mare with BCS of 6 or higher will result in foaling complications.  Extensive research has shown that mares of 7 or higher did not encounter problems often associated with obesity such as prolonged pregnancy, decreased foal size, or vitality at birth.

It is important to evaluate body condition score of your mares leading up to breeding and throughout pregnancy.  Don’t rely simply on visual appraisal, but be sure to use palpation as well along the withers, behind the shoulder, and around the tailhead.  If you need help evaluating BCS or help with the nutrition program to achieve proper BCS contact your local Extension agent.

Resource:  http://www.equinews.com/article/optimal-body-condition-scores-for-breeding-mares