Effect of type of grain and feed processing on gastrointestinal retention times in horses.

The study examines the effect of grain type and processing method on the digestive retention times in horses. It concludes that both have an influence on passage rates and compartmental retention times, but do not affect overall retention time in the horse’s gastrointestinal tract.

Research Method

• The experiment involved four Norwegian Cold-blooded trotters, a breed of horse, each weighing approximately 500 kg.
• The horses were fed three types of grain: maize, barley, and wheat. Each grain was subjected to different processing methods: ground, pelleted, extruded, and micronized, creating a total of 12 processed grains.
• An adaptation period of five days was allowed before each horse was given 0.2 kg of Yb-mordanted grain along with their morning meal of 2 kg of hay and 1 kg of one of the processed grains.
• Fecal samples were collected at specific hour intervals after the administration of the marker dose and analyzed for Yb (Ytterbium). This element was used as a marker in the food to allow tracking through the digestion process.
• The collected data was utilized in a two-compartment nonlinear passage model to compute the retention times in various segments of the gastrointestinal tract for each grain type and processing method.

Research Findings

• Among the studied grains, maize demonstrated a longer retention time in the time-dependent compartment (presumed to be the cecum) compared to barley and wheat, implying a slower passage rate out of this compartment.
• When it came to the processing method, ground grains exhibited a longer compartmental retention time compared to the grains processed at high temperatures (extruded and micronized).
• However, regardless of the type of grain or processing method, the total mean retention time within the horse’s digestive system remained unchanged.

Conclusion

• The research concludes that while the type of grain and its processing can influence passage rates and certain compartmental retention times, they do not have a noticeable impact on the overall time the food spends in the gastrointestinal tract of the horse.
• The findings could have implications for horse diet and nutrition management, possibly optimizing the benefits derived from different grains and processing methods.