Grazing horses on teff, alfalfa and perennial ryegrass
Yield and forage nutritive value are two factors livestock owners must consider when determining which forage to utilize during the grazing season. However, little research has been done to compare different types of pasture species under rotational grazing in the Upper Midwest. Considering different pasture species offer unique advantages and disadvantages, it is important to evaluate them under grazing in order to optimize yield and forage nutritive values in livestock pastures.
As a result, varieties of three forage species, including teff (a warm-season annual grass), perennial ryegrass (a cool-season perennial grass) and alfalfa (a perennial legume) were evaluated during the 2016 grazing season in St. Paul, MN. Perennial ryegrass and alfalfa were grazed monthly from May to October (with the exception of September), while teff was grazed monthly from July to September. Alfalfa and perennial ryegrass pastures were established in 2015, while teff pastures were established on June 6, 2016.
Six adult horses grazed for approximately 6 hours a day for three consecutive days each month during the grazing season (Figure 1). Forage yield and nutritive values were evaluated prior to grazing which was initiated when perennial ryegrass and teff were between 8 and 10 inches or when alfalfa reached bud stage. Following grazing, manure was removed and any remaining forage was mowed to 3 (alfalfa) or 4 inches (perennial ryegrass and teff) and allowed to regrow.
Alfalfa had the highest yield at 6.9 tons/acre in comparison to perennial ryegrass (3.2 tons/acre) and teff (2.8 tons/acre; Table 1). However, perennial ryegrass was grazed 5 times throughout the grazing season while teff was only grazed 3 times. While these results suggest alfalfa is the most productive pasture species, the ability of alfalfa to withstand long-term grazing needs to be explored. Teff also appears to be a productive annual pasture species option.
Alfalfa also had the highest crude protein (CP) and equine digestible energy (DE), followed by perennial ryegrass and teff (Table 1). However, all species exceed the general recommendation of 12% CP for adult horses at maintenance and would meet or exceed the DE requirements for adult horses at maintenance. Both alfalfa and teff had lower nonstructural carbohydrates (NSC) values in comparison to perennial ryegrass (Table 1). Although there are no nutritional recommendations for NSC in the horse diet, researchers suggest limiting the overall diet of horses diagnosed with equine metabolic syndrome (EMS), laminitis, polysaccharide storage myopathy (PSSM), obesity and/or Pituitary Pars Intermedia Dysfunction (PPID) to ≤10-12%. Based on these guidelines, teff and alfalfa would be possible forage options for horses diagnosed with these diseases. Additionally, teff had the highest Acid Detergent Fiber (ADF) and Neutral Detergent Fiber (NDF) values while alfalfa exhibited the lowest values. Although no recommendations for NDF and ADF in the horse diet exist, most experts recommend horse-quality hay should be ≤65% NDF and ≤45% ADF.
Table 1. Yield and forage nutritive values of three forage types grazed by adult horses
|tons/acre||percent dry matter (%)||Mcal/lb|
|a-eWithin a column, means without a common superscript differ based on a Tukey test (p≤0.05).|
These results suggest teff is more suitable for horses with lower energy demands or horses prone to metabolic concerns. In comparison, alfalfa and perennial ryegrass have the capability of meeting nutritional requirements of horses with elevated nutritional needs. However, all forages meet the DE and CP requirements of adult horses at maintenance based on consuming 2.5% BW on a dry matter basis each day.