Nursing Mares on Pasture May Not Need Grain
Broodmares that are nursing a foal are “eating for two,” or maybe even “eating for three” if they have been successfully rebred. Mares in early pregnancy don’t actually have an increased energy requirement related to development of the fetus, but the production of milk does require a higher dietary energy level than when mares are not lactating.
It is a common practice to provide grain to these nursing mares, but at least one study indicates this energy boost may not be necessary for broodmares on lush pasture. Recent research conducted in France showed that lactating saddle horse mares on good-quality pasture didn’t need to be fed grain to maintain their weight or their foals’ growth.
In the study, 16 riding horse broodmares and their nursing foals were turned out on pasture. The mares were divided into two groups, with one group receiving a daily quantity of barley feed sufficient to provide 60% of energy requirements for lactation. The remaining mares received no concentrated feeds.
All the mares were experimentally infected with roundworms to investigate their ability to fight off infection with the different nutritional inputs. The mares and foals were all weighed regularly, and their body condition scores and parasite loads were recorded throughout the study.
All mares spent an average of 15 hours grazing each day. However, mares that did not receive grain ingested 12% more grass during the entire study period than mares in the grain-fed group. Both groups of broodmares maintained their weight relatively well, and there was no difference by dietary treatment in the mares’ ability to fight off parasite infection. Foals in both groups had similar growth curves for height and weight.
Results of this study suggest that access to good-quality pasture allows nursing mares to meet their energy requirements by grazing without supplementary grain intakes. Broodmares with fewer hours on pasture or those grazing poor-quality forage might not maintain this level of nutrition. Managers of mares and foals should weigh and measure mares and foals on a frequent basis, and should consider modifying their feeding program if mares lose weight or foals do not show a steady growth plane.
If mares can maintain their weight on high-quality forage while lactating, they should be fed a well-formulated ration balancer or vitamin and mineral supplement to ensure that all vital nutrients are consumed. I.R. Pellet, a vitamin and mineral supplement from Kentucky Equine Research (KER), is an appropriate product.
Kentucky Equine Research Staff