By: EC Intern, Shelby Glessner
As breeding season nears, it is time to consider creating a nutritional plan for our broodmares. This begins with making sure the mare is in good nutritional condition at the time of breeding and continuing through the lactation period.
Body Condition Prior to Breeding
Research shows that having mares at a slightly higher body condition score at the time of breeding, somewhere from 5 to 6.5, is ideal. Maintaining the body condition score throughout the mare’s pregnancy becomes especially important approaching the time of lactation, as her weight will almost certainly drop due to dramatically increased energy demands. Bear in mind that obesity is still bad for the mare’s health, but likely would not be too much of a problem regarding foaling specifically. A mare that is thin at the time of breeding is a much bigger risk, as this decreases conception rates and increases the chance that she may lose the foal.
In other livestock species, a practice known as “flushing” is used which steadily increases the nutritional plane provided to an animal for a short period after breeding, then drops feeding back to a maintenance level. Veterinarians who are familiar with other species may be tempted to apply this concept to horses, but it should not be done. While it does work for other species with differently functioning reproductive systems, it will be detrimental to the horse.
During the early stages of pregnancy, we can treat a broodmare as if she were a horse at maintenance. Demands on the mare’s body do not significantly increase until later during gestation. In these first five months or so, our biggest concern should be ensuring she is provided with proper vitamins and minerals. Use of a mineral block or a hay balancer is appropriate.
Most growth of the fetus and weight gain of the mare will occur in the second trimester of the pregnancy. As her energy requirement begins to increase as well, this poses some issues for the mare. At this point we should be concerned about gut fill: it may be uncomfortable for her to eat a large amount of hay, especially while carrying the growing foal. Adding a grain or increasing her grain ration will give her more bang for her buck.
Around the first month of lactation, the energy demand on the mare is at its highest. During this time, it is crucial that the mare is provided with a high enough energy intake to meet her new requirements (nearly double that of a maintenance horse!) and that she receives an appropriate balance of minerals to encourage proper development of the foal. Pasture access is a huge advantage during this time, as it will help keep gut fill problems to a minimum and should naturally provide her with a good vitamin and mineral assortment.
“Ministry of Agriculture, Food and Rural Affairs.” Flushing The Ewe Flock: Is It Beneficial?, www.omafra.gov.on.ca/english/livestock/sheep/facts/02-055.htm.
Parker, Rick. Equine Science. Fourth ed., Cengage, 2013.
Shelby Glessner is a senior student at Michigan State University studying Animal Science and the equine industry. She spent an academic year working with renowned researcher Dr. Stephanie Valberg in the Equine Neuromuscular Diagnostic Lab at MSU’s College of Veterinary Medicine and has undertaken extensive science and equine related coursework. Passionate about education, she hopes to pursue a career advocating for research-based practices in animal agriculture.