Effects of alfalfa hay supplementation level and grain source (barley and corn) on performance, blood metabolites and skeletal growth characteristics of suckling Farahani lambs

Forty eight 10-d old Farahani neonatal lambs (6.8 ± 1.8 kg of body weight) were allocated (n = 12 lambs per treatment; 6 males and 6 females) in a randomized completely block design with 2 × 2 factorial arrangement including the factors of alfalfa hay (AH) supplementation level (low, 10%; or high, 30% on DM basis) and grain source (corn vs. barley). Hence, treatments were: (1) barley grain (BG) with 10 % of AH; (2) BG with 30 % of AH; (3) corn grain (CG) with 10 % of AH; and (4) CG with 30 % of AH. All lambs had ad libitum access to water and starter feed throughout the experiment. Further, no interaction was detected between forage supplementation level and grain source for starter intake, average daily gain (ADG) and feed efficiency. Lambs fed low level of AH had greater betahydroxy butyrate (BHB) concentration in serum on d 30 and 60 of the study (P < 0.01 and P = 0.02, respectively). Lambs received barley-based starters had greater blood urea nitrogen concentrations than corn-based diets on d 60 of the study. Treatments had no effect on skeletal growth characteristics of sucking lambs on d 30 and 60, however, high level of AH supplementation decreased (P < 0.01) hip width compared with low AH inclusion. In general, results showed that AH supplementation at high level could decrease growth performance; however, grain source had no effect on suckling lambs performance.