Dietary Changes and Forage

By Dr. Stephen Duren, Performance Horse Nutrition and Standlee Premium Western Forage® Nutritional Consultant

Horses rely on fiber (hay, pasture, forage pellets and forage cubes) to provide most of their nutrition. Their digestive system is filled with billions of naturally occurring beneficial bacteria and protozoa. These microbes ferment plant fiber and produce energy and other useful nutrients that fuel horses. The digestive system is also home to harmful bacteria such as e. coli and salmonella. The delicate balance between beneficial and harmful bacteria can be easily disturbed. This disruption in microbial population can result in gas, acidosis, diarrhea, weight loss and even death.

One of the primary causes for disruption of the microbial population is a sudden dietary change. Rapidly changing between forage types results in a huge change in bacterial numbers and function. For example, switching forage type from timothy to alfalfa will cause unprepared bacteria to encounter forages they are not well equipped to ferment and properly digest. The simple transition from one forage type to another should occur gradually. It takes a bacterial population a full 21 days to totally adjust to a different forage source. However, a gradual introduction of a new forage type over the course of 10 to 14 days will avoid elevated gas production, prevent diarrhea and eliminate other health issues. This transition period should begin with a 25% replacement of the existing forage with the new forage type. Over the course of the next 14 days, the amount of new forage should be gradually increased while the amount of the current forage decreased.

Common causes of rapid dietary changes include:

• • Running out of their current forage
  • Mistakenly purchasing the wrong forage
  • Purchasing new forage without having enough existing forage for a smooth transition

If you have questions, please contact the nutritionists at Standlee Premium Western Forage, or consult with your veterinarian.