Healthy Foals: Supporting the Intestinal Microbiome

During the first several months of life, foals grow at a remarkable rate: from about 10% of their mature body weight at birth to almost 50% of their mature body weight by weaning. In order to support this growth, the foal’s gastrointestinal tract must be healthy, and this includes a population of appropriate intestinal microbes capable of adapting to significant changes in the foal’s diet.

“As foals transition from colostrum, to milk, and then to forages and concentrates, the gut microbiota must evolve to efficiently utilize the diet provided,” noted Kathleen Crandell, Ph.D., a Kentucky Equine Research nutritionist.

As recently stated by veterinarians from the University of California, Davis*, “The health of the host, or in this case the foal, is dependent upon these microbes and can be influenced by perturbations to the microbiota such as those caused by infectious diseases or antibiotic treatment.”

Because diarrhea remains a significant cause of illness and even death in foals, understanding how the intestinal microbiome becomes established and subsequently develops continues to be an important area of research. To improve knowledge of the intestinal microbiome and its effects on foal health, researchers collected fecal samples from 37 foals from birth to weaning and analyzed the fecal bacterial microbiomes.

Key findings of their study included:

• Composition of bacterial populations followed clear patterns throughout the early life of the foals in an age-dependent manner;
• As foals transitioned from milk to a diet of concentrates and forages, distinct changes in fecal microbial compositions were noted, beginning with bacteria that have the ability to metabolize milk and bacteria capable of utilizing fibrous plant material;
• Foals that developed diarrhea during the study period had recognizable differences in microbial populations; and
• Management style also appeared to affect the microbial populations as differences in fecal bacteria were identified between foals raised on different farms.

“Future efforts will gauge the effects of lesser abundant bacterial populations that could also be essential to gastrointestinal health, as well as to determine how associations between microbial population profiles and animal management practices can be used to inform strategies for improving upon the health and growth of horses overall,” concluded the researchers.

“Other ways of maximizing foal health involve ensuring mare health before and after parturition, including appropriate vaccinations, strategic deworming, and sound nutrition,” advised Crandell.

“In terms of diet, supplementing pregnant mares, nursing mares, and foals with omega-3 fatty acids supports a variety of body systems. Consider offering Kentucky Equine Research’s marine-derived fish oil supplement, EO-3,” Crandell recommended.

*De La Torre, U., J.D. Henderson, K.L. Furtado, et al. 2019. Utilizing the fecal microbiota to understand foal gut transitions from birth to weaning. PLoS One. 14(4):e0216211.