Potential use of natural saline pasture for grazing lambs: Effect on digestibility, growth performances, carcass and meat quality

Abstract

This study aimed to investigate the effects of a natural saline pasture on digestibility, intake, growth, carcass traits and meat quality of lambs. Forty weaned female Queue Fine de l′Ouest lambs (25.4 ± 4.33 kg) were allotted into two groups. The first group raised indoor (I) with oat straw ad libitum and the second grazed natural saline pasture (SP). Both groups were supplemented the same concentrate with 300 and 500 g for SP and I respectively, to have the same average daily gain (ADG). On the 49th day, digestibility and intake were determined on 8 lambs randomly selected from each group, using total fecal collection and Acid Insoluble Ash (AIA) marker method. After 83 days, the 16 lambs were slaughtered at 34 kg. Dry matter (DM), organic matter (OM), crude protein (CP) digestibility and metabolizable energy (ME) were higher (P < 0.001) for SP. Digestible crude protein (DCP)/ME ratio was higher (P < 0.05) for SP group. DM intake (P < 0.05) was lower for SP, while digestible crude protein intake (DCPI) and ME intake (MEI) were similar between the two groups. Water intake was higher for SP (P < 0.001). Final weight and ADG were similar between groups. Carcass dressing and high-priced joints percentages were higher for SP group. Lambs from the SP group had a higher percentage of muscle (P < 0.001) and a lower fat proportion (P < 0.01). No effect of feeding system on carcass linear measurements and on compactness indexes (P >0.05) was noted. Kidney fat decreased in favor of SP group (P < 0.01). There were no differences for fat color, whereas meat of I group had a higher lightness and yellowness than that of SP one. Meat of SP group had a higher DM, protein level (P < 0.05) and lower intramuscular fat (P < 0.01). It has higher content of Fe and Zn (P < 0.01). It could be concluded rearing lambs on saline pasture, with a moderate concentrate supplementation, allowed acceptable growth performances, leaner carcass, and higher nutritional meat quality lambs.