Voluntary intake and digestibility of reed canarygrass and timothy hay fed to horses.

The study investigates the possible use of reed canarygrass hay as an alternative to timothy hay for horses due to a decrease in timothy hay production caused by a cereal rust mite infection. Results showed that while horses fed on timothy hay consumed more and had better nutrient digestibility, reed canarygrass hay still met the minimum nutritional requirements for horses.

Research Context and Purpose

• The research was spurred by a decrease in timothy hay production caused by a cereal rust mite (Abacarus hysterix) infection which affected various regions including the Mid-Atlantic region.
• With the decline in timothy hay production, an alternative was sought, leading to reed canarygrass hay being tested for its suitability for horses.
• The key goal of the research was to measure the voluntary intake and apparent nutrient dry matter (DM) digestibility of low-alkaloid Chiefton variety reed canarygrass hay in comparison to timothy hay.

Research Method and Procedures

• Eleven mature Thoroughbred geldings weighing 549 +/- kg and exercised daily were used in the study.
• Horses were paired based on age and body weight then randomly assigned to be fed either timothy or reed canarygrass hay over a 14-day period to measure voluntary dry matter intake (DMI), followed by a 4-day period to measure apparent DM digestibility.

Research Findings

• Both timothy and reed canarygrass hay met the minimum requirements for dietary energy (DE), crude protein (CP), Calcium (Ca), Phosphorus (P), Potassium (K), Iron (Fe), and Manganese (Mn) for horses at maintenance and averaging 550 kg of body weight.
• However, they did not meet the minimum requirements for Copper (Cu), Zinc (Zn), and Sodium (Na).
• Timothy hay was found to have lower CP concentration (14.4%) compared to reed canarygrass hay (17.1%) and a more suitable Ca:P ratio for equine nutrition.
• Horses fed timothy hay ate more during the voluntary DMI period compared to those fed on reed canarygrass hay.
• Matter digestibility was greater in horses fed timothy hay by 9.6% than those fed reed canarygrass hay.
• Timothy hay-fed horses had greater dietary matter digestibility of ADF (Acid Detergent Fibre), NDF (Neutral Detergent Fibre), sugar and Ca but lower apparent DM digestibility of CP (crude protein) and crude fat.

Conclusion

• The results of the study indicate that timothy hay was superior in terms of voluntary dry matter intake and apparent dry matter digestibility when compared to low-alkaloid reed canarygrass hay fed to horses.
• Despite this, reed canarygrass hay was found to still meet the minimum nutritional requirements for horses, making it a potential alternative should there be a decrease in timothy hay production.