HealthWatch: Broodmare Diets

• Email
• Print
• Tweet

The diet you offer your gestating mare, particularly in the last trimester, can influence development of her placenta as well as the level of immunoglobulins (IgGs) in her colostrum, reports a research team from North Dakota and Texas.

Colostrum is a sticky, high-protein milk secreted by the mare during the first 24 hours following birth. It has a high concentration of antibodies, which are a foal’s first line of defense against potential infection.

Dr. Carrie Hammer, an assistant professor at North Dakota State University, and colleagues hypothesized that feeding broodmares too much or too little would negatively affect colostral quality, and that selenium supplementation could offset some of these negative effects. To test their hypothesis, they randomly placed 28 Quarter Horse mares into one of four treatment groups: pasture, pasture plus selenium, pasture plus grain, or pasture plus grain and selenium. They started selenium supplementation 110 days prior to the mare’s expected foaling date.

Key findings in this study:
Mares on pasture lost body condition during the trial, while mares fed grain maintained their body condition, but the final body condition scores in both groups remained within the normal range;

Neither selenium supplementation nor nutrition group affected foaling variables (i.e., gestation length, time from water breaking to birth, time to stand and nurse, and foal body weight, length, and height);

Mares fed supplemental selenium had decreased placental cell size;

Researchers noted no difference in placental cell number, cellular activity, expulsion time, or weight, and
they identified no difference in colostral fat, protein, or other parameters.

Mares fed grain with or without selenium had lower colostral IgG, and foals from grain-fed mares tended to have lower serum IgG levels than the foals of mares that did not receive grain. Both groups of foals were healthy.

“Overall, this data suggests that maternal diet during the last third of gestation impacts both placental efficiency and colostral IgG,” summarized Hammer. “Of course, more research is needed to determine the ramifications of these changes and their mechanisms.”

Hammer emphasized these preliminary results should not encourage horse owners to withhold grain from pregnant mares in order to increase IgG.

• Email
• Print
• Tweet