Digestibility, apparent mineral absorption, and voluntary intake by horses fed alfalfa, tall fescue, and caucasian bluestem.

This study compared the nutritional value of alfalfa, tall fescue, and caucasian bluestem for horses at maintenance, revealing that alfalfa boasted a higher digestibility and nutrient absorption, although each forage had its particular advantages and deficiencies. Further research and supplementation may be necessary to meet all dietary requirements.

Research Methodology

• The study involved feeding chopped hay of Alfalfa, low-endophyte tall fescue, and caucasian bluestem to six Arabian geldings of average weight 441 kg.
• The intake and digestibility of these three types of hay were compared in a replicated Latin square experimental design to determine nutritional value for horses.

Findings

• Alfalfa proved to have higher dry matter (DM) and crude protein (CP) digestibility, a greater in vitro dry matter digestibility (IVDMD), a higher apparent absorption of Calcium (Ca), Potassium (K), and Sulfur (S), as well as voluntary intake than the grass hays.
• Caucasian bluestem, on the other hand, had higher Zinc (Zn) concentration but was comparatively lower in CP, Total non-structural Carbohydrates (TNC), Magnesium (Mg), Phosphorus (P), K, S, and Copper (Cu) concentrations than tall fescue.
• Crude protein digestibility and apparent absorption of Mg, K, and S were higher in tall fescue compared to caucasian bluestem.
• Among horses consuming alfalfa, serum concentrations of vitamin A, blood urea nitrogen (BUN), Phosphorus (P), Sulfur (S), and Copper (Cu) were higher than those fed on grass hays.
• Conversely, serum Zn was higher, and BUN was lower, in horses consuming caucasian bluestem compared with those consuming tall fescue.

Implications

• All the studied forages met the requirements for CP, Ca, Mg, K, and Iron (Fe) when provided for ad libitum intake, but were deficient in Cu for horses at maintenance.
• Though caucasian bluestem lacked in adequate CP and P levels, it was the only forage that fulfilled the Zinc (Zn) requirement for the horses.
• The study suggests that while caucasian bluestem could be a useful hay for horses, it may require supplementation of CP and P.