Effects of breed, sex, and alfalfa form in total mixed ration on fattening performance, rumen fermentation, and serum biochemistry of weaned lambs

Abstract

This study investigated the potential effects of alfalfa form in total mixed ration (TMR) on the fattening performance, ruminal fermentation characteristics, and serum biochemical parameters of weaned lambs of different breeds and sexes. A total of 40 weaned lambs (20 Romanov, 20 Hamdani; 60 days old) were distributed into eight groups in a 2 x 2 x 2 factorial arrangement, accounting for breed, sex, and feed form. Hamdani lambs had higher body weight (p < 0.05) than Romanov lambs, but Romanov lambs showed a worse feed conversion ratio (p < 0.001). Male Hamdani lambs fed alfalfa hay had the highest average daily feed intake (ADFI). A significant Breed x Sex x Alfalfa Form interaction was observed for feed conversion ratio (FCR). Hamdani lambs had higher final body weight (BW) (p < 0.05), average daily gain (ADG) (p < 0.01), and better FCR (p < 0.001) than Romanov lambs. Romanov females fed hay (RFAH) had the highest acetate levels (p < 0.001), while Hamdani males fed hay (HMAH) exhibited the lowest ammonia levels (p < 0.001). Hamdani lambs had higher rumen pH but lower butyrate than Romanov lambs (p < 0.001). Male lambs had higher pH than females (p < 0.05). Pellets (AP) increased propionate (p < 0.03) and ammonia (p < 0.001), while hay (AH) raised the acetate-to-propionate ratio (p < 0.05). The highest serum glucose (Glu) concentration was found in Romanov lambs fed with pelletized alfalfa, while the highest insulin hormone concentration was observed in males (p < 0.05). In conclusion, alfalfa in TMR impacted lamb growth, rumen fermentation, and serum biochemistry. Hamdani lambs outperformed Romanov, males showed higher performance, and feed form interactions affected metabolic parameters, emphasizing breed, sex, and feed type in feeding strategies.