Nutrient intake, digestibility and nitrogen balance of two temperate and two tropical forage legume hays fed to New Zealand white rabbits

Abstract

An experiment was carried out to evaluate two temperate forage legumes (Trifolium pratense and Trifolium repens) and two tropical forage legumes (Stylosanthes guianensis and Centrosema molle) for hay intake and digestibility in the cool tropical climate of Vom, Jos, Plateau State of Nigeria. The legumes were planted in the month of June, 2016 and harvested at early-podding stage for hay. Sixteen (16) growing male New Zealand White rabbits were used for the digestibility study. The rabbits were arranged in a Completely Randomised Design and in individual cages measuring 55 cm x 39 cm x 40 cm. Nutrient contents, intake and digestibility in rabbits were determined. Crude protein content was significantly (P<0.01) higher in T. repens (18.38%) compared to T. pratense (16.50 %), whereas S. guianensis produced the least value of 13.83%. The crude fibre content of the hay was significantly higher (P<0.0I) in S. guianensis (37.29 %) compared to the other forage legumes. Dry matter intake was significantly (P<0.01) higher in rabbits fed T. repens (77.88%) compared to T. pratense (76.57%), and the lowest value of 62.97% was obtained in S. guianensis. Crude protein intake was significantly (P<0.01) higher in rabbits fed T. repens (15.05 g d^-1) compared to those fed T. pratense (12.71 g d^-1), but S. guianensis had the least value of 8.64 g d^-1. On the other hand, rabbits fed S. guianensis hay had a higher (P<0.01) crude fibre intake (23.39%). Trifolium repens was significantly (P<0.01) higher in dry matter and crude protein digestibility (64.79 and 85. 88 %), while S. guianensis had lower values of 56.89 and 71.33%, respectively. Trifolium repens also had a significantly (P<0.01) higher total nitrogen intake and retained compared to the other forage legumes. Nitrogen retained in T. repens was 2.40 g d^-1 compared to 1.87 g d^-1 in T. pretense, while S. guianensis had the lowest of 1.34 g d^-1. The temperate forage legume hays were higher in nutrient content, intake and digestibility compared to the tropical legume hays. Therefore, the forage crops may serve as better supplementary feeds for livestock feeding especially during the dry season.

Keywords: Forage legumes, nutrient intake, digestibility, tropical, temperate