Effect of feeding system on growth and carcass characteristics of Churra Tensina light lambs

Abstract

Forty-eight single male lambs were used to evaluate the effect of feeding systems on carcass characteristics and fat depots of Churra Tensina light lambs. Four treatments were studied: GR, lambs and ewes were continuously grazing, no concentrate was available to them and lambs were unweaned; GR+S, as the previous one, but additionally lambs had free access to concentrate; DRL−GRE, lambs remained indoors with free access to concentrate and ewes grazed during 8 h a day, thereafter remaining with lambs; DRL, lambs and ewes were kept always in confinement, ewes had free access to dry unifeed and lambs to concentrate. In DRL−GRE and DRL lambs were weaned at 45 days old. When lambs reached 22–24 kg of live-weight they were slaughtered. Feeding system had effect on growth rates ( p < 0.05), age ( p < 0.001) and live-weight at slaughter ( p < 0.01), carcass weight ( p < 0.001), dressing percentage ( p < 0.001), fatness thickness ( p < 0.01) as well as on the subjective classification parameters, as carcass conformation score ( p < 0.001), fatness degree ( p < 0.01) and KKCF score ( p < 0.01), having the GR lambs lower values than the rest of treatments. Nevertheless, carcasses from grazing animals were classified within the normal ranges for Ternasco commercial category similar to drylot systems. Treatment had effect on pelvic ( p < 0.01) and carcass compactness ( p < 0.001) being GR carcasses less well conformed. Feeding system affected the total body fat depots ( p < 0.01), presenting GR the lowest amount. In all treatments, carcass fat depot was greater than internal fat depots (abdominal, pelvic and renal) ( p < 0.05). Grazing treatments (GR and GR+S) presented higher proportion of anterior-rib and lower proportion of breast in relation to indoor lambs (DRL−GRE and DRL). The feeding system did not affect the proportion of first category of commercial meat. It was concluded that light lamb carcass characteristics were slightly affected by the feeding systems, being carcasses from grazing lambs classified within the normal ranges for Ternasco commercial category, similarly to drylot systems. The small differences among the products of different feeding systems had no commercial constraint in the light lamb meat market.