This experiment aimed to investigate the possibility to raise thecarcass weight of lambs of dairy breed and produce low-fat meatby increasing the slaughter age and applying strategies to reducefeeding level. At 35d of age, 70 weaned lambs of Valle del Belicebreed were divided into 2 groups and adapted to housing in multipleboxes and experimental diets over a 10-d period. The groupsreceived ad libitum pelleted alfalfa hay and concentrates differingin the 20% inclusion of durum wheat bran (0WB, 20WB) usedto reduce cost and energy level. After 45d of experiment, bothgroups were divided into 3 subgroups; 2 of them with 15 lambswere slaughtered at 90d of age (90L), whereas the other 4 subgroupsreceived the same concentrates ad libitum (120L) orrestricted at 75% of ad libitum intake (120R) for 30d untilslaughter at 120d of age. Feed intake and live weight of lambswere regularly measured. At slaughter, carcass traits and tissuecomponents of hind leg were recorded. Longissimus dorsi (LD)meat was evaluated for pH, colour, thawing and cooking losses,WB shear force and sensory properties in triangle tests. In bothphases, 45-90d and 90-120d of age, the diet did not influence feedintake and growth of lambs fed ad libitum (90L and 120L),whereas under feed restriction the lambs fed 20WB showed areduction in weight gain than 20R lambs fed 0WB (105 vs. 170g/d, P‚â§0.05). In all production systems, the diet did not affect the carcass weight (12.6 vs. 12.4; 14.7 vs. 13.7; 15.6 vs. 14.9 kg for0WB vs. 20WB in 90L, 120R and 120L), whereas the 20WB dietreduced carcass yield of 120R lambs (52 vs. 56 %, P‚â§0.01). Thesimultaneous feed and energy restriction for 120R lambs fed20WB diet resulted in the lowest performance. The fat deposition,as perirenal and pelvic fat and adipose tissue of hing leg,increased from 90L to 120R, and to 120L lambs, regardless ofdiet. The LD traits were affected by the production system, since90L lambs showed higher water losses, and lower tenderness andred colour than older lambs. At triangle tests, the panellists perceivedsignificantly the differences due to diet for 90L and 120Rmeat, and the effect of feeding level. Thus, increasing theslaughter age of dairy breed lambs from 90 to 120 d of age lead tothe production of heavier carcasses with improvements in meatquality in terms of tenderness and reduced water losses, especiallydue to a higher but moderate fat content, also when lambswere exposed to a 75% restricted feeding.
|Numero di pagine||1|
|Stato di pubblicazione||Published - 2015|