LAUSR

Context Many indices of feed efficiency for livestock have been proposed, but most are associated with differences in body composition and consequently affect meat quality. Aims This study aimed to assess meat quality and lipid profile of intramuscular fat of Texel crossbred lambs classified by residual intake and gain (RIG). Methods Seventy-seven non-castrated male Texel crossbred lambs (1/4 Pantaneira and 3/4 Texel) were assessed in a 2-year study. First year: Forty-seven lambs with initial bodyweight of 29.9 ± 5.5 kg. Second year: Thirty lambs with an initial bodyweight of 22.4 ± 3.3 kg. Lambs were confined in individual stalls for 70 days for the assessment of individual dry matter intake and average daily gain, being then slaughtered. The muscle Longissimus lumborum was removed for analyses. The RIG was obtained by: RIG = (−1 × residual feed intake) + residual gain. The data of meat quality and lipid profile from both years were grouped and analysed in a completely randomised design. Animals were classified into three RIG classes based on the s.d. of RIG variable. Efficient (n = 20) and inefficient (n = 22) animals were classified adopting ± 0.5 s.d. from RIG mean, and animals between these two groups were classified as intermediate (n = 35). Key results No significant differences were observed between RIG classes regarding instrumental characteristics and proximate composition of the Longissimus lumborum muscle. We observed no differences between RIG classes for concentrations of saturated (SFA), monounsaturated (MUFA), and polyunsaturated fatty acids (PUFA), as well as for the total sum of SFA, MUFA, and PUFA of intramuscular fat, with 40.9, 54.1, and 5.1% of total FA, respectively. The MUFA:SFA ratio, PUFA:SFA ratio, atherogenic and thrombogenic index were also not influenced by RIG classes. Conclusions There were no differences in meat quality and lipid profile of intramuscular fat between animals classified based on RIG. Implications Improvements provided by using RIG to identify efficient and faster-growing lambs could assist in reducing feed and labour investments in the production system through an early slaughter without having negative impacts on meat quality.