Effect of tree leaf as supplementation on nutrient digestion and rumen fermentation pattern in sheep grazing semi-arid range of India. II

A study was conducted to evaluate the effects of supplementing with different tree leaves on nutrient digestion, rumen fermentation and blood parameters of sheep. Thirty adult Malpura rams (39.0 +/- 0.56 kg) were divided into five groups of six each. They were grazed as a single flock on a semi-arid rangeland and after the end of routine grazing period (08:00-17:00 h), first group (G1), which was not provided with any supplementation, served as control group. Second group (G2) was supplemented with 200 g of a conventional concentrate mixture per head per day, whereas third, fourth and fifth groups (G3, G4 and G5) were supplemented with approximately 200 g dry matter (DM) per day freshly cut foliage from Ailanthes excelsa, Azardirachta indica and Bauhinia racemosa, respectively. Protein content (g kg(-1) DM) in A. excelsa, A. indica and B. racemosa foliage was 197, 128 and 132, respectively. A. indica and B. racemosa foliages also contained 123.2 and 211.2 g kg(-1) DM condensed tannin (CT) with protein precipitating capacity (PPC) of 16.5 and 46.5 g kg(-1) DM. None of the tree leaves contained hydrolysable tannin (HT). Dry matter intake (DMI, g day(-1)) was 591, 766, 865, 974 and 939 in G1, G2, G3, G4 and G5, respectively. Digestible crude protein (DCP) and metabolisable energy (ME) intakes in supplemented groups G2-G5 were higher (P < 0.05) compared to control (G1). Supplementation improved digestibility of all nutrients in all groups. Rumen fermentation study indicated lower (P < 0.05) ammonia and total N in the rumen liquor collected from G5 sheep compared to the other supplemented groups. Although haemoglobin (Hb, g dl(-1)) levels showed small changes among groups, blood urea nitrogen (BUN, mg dl(-1)) was lowest in G5 compared to the other groups. Initial BW were similar among the groups. After 60 days of experimental feeding, all animals maintained their BW, except sheep in the control group (G1), which lost BW. Results indicate that for adult sheep grazing on a semi-arid range, supplementation with a concentrate mixture could be replaced by tree leaves like A. excelsa, A. indica and B. racemosa, during the lean season to maintain their BW. In addition, supplementing with tree leaves containing condensed tannin has advantages in terms of N utilization.