Nitrogen balance of lactating West African dwarf ewe fed Mexican sunflower leaf meal based diets

Abstract

Fifteen days prior to weaning, sixteen West Af rican dwarf (WAD) ewes (Initial BW 19.13±1.53kg) on a basal diet of Panicum maximum were allotted into 4 treatment groups A, B, C and D of 4 replicates each. The mexican sunflower leaf (MSL) replaced wheat bran (WB) gravimetrically at 0, 15, 30 and 45%. Treatment A served as control. The experiment lasted for one week. Digestibility was determined using a 6-d total fecal collection. The 16 ewes were previously lambed 10 weeks before the commencement of this study and tagged to their respective treatments. Parameters measured were nitrogen intake, nitrogen balance, nitrogen apparent digestibility and nitrogen retention. Data were analyzed using descriptive statistics and ANOVA. Animals on treatment B had the highest N-intake (18.1g/d), N faecal (1.7 g/d), N absorbed (16.4 g/d) and N balance (16.3 g/d) and this was significant ( P<0.05 ). Urinary nitrogen g/d was significantly higher ( P<0.05 ) with increasing inclusion of MSLM in the ration while protein retention increased from treatment A (0% MSLM) to treatment B (15% MSLM) (89.8 – 90.3%) and subsequently decreased from treatment B (15%MSLM) to D (45% MSLM) (90.3 - 84.4%). Nitrogen balance was positively related to DM intake and N intake. The overall regression were nitrogen balance (NB) =2.50+0.067 DMI; R 2 = 0.9372, (P=0.3937) and NB= 0.75+0.9066 NI; R 2 = 0.9957, (P=0.1401). Inclusion of up to 30% MSLM in the diets of lactating ewe appeared most beneficial to sheep as it had no negative effects on nitrogen intake.