Feeding the Lactating Broodmare

Lactation is the most nutritionally demanding state a mature horse can be in outside of intense race training. There is a significant increase in the requirement for ALL nutrients, including energy. 

This is one of the reasons we often see thin lactating mares – the correct diet adjustments have not been made. Feeding high quality forage will reduce the amount of concentrate you will need to feed per day. Having the forages analyzed and balancing the total ration based on the analysis will assure all nutrient requirements are met and that you are providing optimal nutrition in the most economical way.

The quantity and quality of mare's milk is primarily genetic, but her nutrition can have an important impact. It is important to make sure the mare’s daily intake of nutrients is AT LEAST equal to the nutrients she is putting out in her milk. If we do not match this nutrient input-output requirement, we cause the mare to deplete her body stores of many nutrients. This negative nutrient balance will eventually reduce the nutrients in her milk and adversely affect the foal. If the mare is not getting enough calories, she will lose weight. If she is low in other critical nutrients, unfortunately, we may not realize it until the foal begins to show poor condition, excessive condition and/or signs of developmental orthopedic disorders (D.O.D.). Further, depletion of nutrient stores can impact future fertility resulting in delayed re-breeding and decreased conception rates.

The amount and composition of mare’s milk changes with the stage of lactation. Milk production gradually increases from foaling to 6-8 weeks post-foaling - so will the need for increased nutrition. After approximately 8 weeks, milk quantity and quality will gradually decline, as will nutritional requirements. During this entire time, the foal is growing, and may be growing rapidly, so we must provide the foal a well-designed diet to provide what the mare’s milk is not. Recognizing this allows us to match the mare’s nutritional program to the natural changes in her milk as well as provide the proper nutrition above what the milk is supplying to the foal in the form of a “creep feed”.

Important to note is that the increase in the demand for calories (digestible energy) is proportionately LESS than the increases in demand for crude protein, lysine, calcium and phosphorous. The demand for copper and zinc may also increase more than the need for calories, and should be addressed in the nutritional program.

What does this mean?? It means merely feeding more of a feed designed for “all horses” or non-breeding horses WILL NOT meet the requirements of the lactating mare. The lactating mare requires a diet significantly different than one designed for other types of horses. Proper nutrition for the lactating mare requires strict management. Attention to hay quality and the design of the concentrate portion of the diet to ensure we provide all the nutrients, in balance, that this challenging situation demands is key. Further, managing mares during lactation starts well before foals hit the ground, through attention to body condition and the nutritional program throughout pregnancy.


Feed a concentrate designed specifically for lactating mares and balanced to the type of forage the mare is consuming.

  1. A concentrate designed for non-breeding animals will not meet requirements during lactation.
  2. See Essential K and Growth for use with grass hay. See Alfa Essentials and Alfa Growth for hay greater than 50% legumes.

Make sure the mare’s daily intake of nutrients is AT LEAST equal to the nutrients she is putting out in her milk.
Most likely nutrients to be imbalanced or deficient:

  1. Essential amino acids (starting with lysine).
  2. Calcium to Phosphorus ratio (especially if using legumes).
  3. Copper and Zinc levels.

Set mares up for success through lactation by managing energy intake so that mares enter lactation in a body condition score of 5-6.
Consult our qualified Equine Nutritionist to help balance diets and adjust to problem situations.

Article By: Nicole Rambo, Ph.D.
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