Effect Of Residual Feed Intake On Sheep Growth Performance,Carcass Traits And Meat Quality

With the continuous improvement of large-scale breeding,the breeding cost of meat sheep production mainly comes from the feed cost required in the feeding process.Under the same feeding conditions,the individual sheep in the same population have different feed efficiencies due to different genetic factors,and individuals with high feed utilization efficiency can consume less feed and produce more livestock products in the same time.In this study,the growth performance,carcass traits and meat quality of sheep with different residual feed intake(RFI)were compared under the same feeding conditions,which would explore the effect of RFI on sheep carcass characteristics and meat quality,and provide a theoretical basis for scientific breeding,cost reduction and efficiency improvement of meat sheep production.In this experiment,198 Suffolk sheep(♂)× lake sheep(♀)were selected as the candidate groups for single-pen feeding for 75 days,including 15 days for adaptation and 60 days for the trial period.Eight test sheep with an RFI of-0.39±0.04 were screened as the low residual feed intake group(L-RFI group),and 8 test sheep with an RFI of 0.30±0.02 were screened as the high residual feed intake group(H-RFI group).The growth performance and slaughtering performance of the two groups were measured,and the longest dorsal muscle,oyster muscle,Lin meat,milon muscle and abdominal muscles were collected,and the nutrient content,meat color index and water holding capacity were determined.The main results of the trial are as follows:(1)The average daily weight gain of sheep in the L-RFI group was significantly higher than that in the H-RFI group(P<0.01),while the average dry matter feed intake was significantly lower than that in the H-RFI group(P<0.01).(2)There were no significant differences in slaughtering performance indexes such as pre-slaughter live weight,carcass weight,slaughter rate,and net meat rate between the two groups,but the slaughter performance of sheep in the L-RFI group increased,and the GR value was significantly lower than that in the H-RFI group(P<0.05).(3)The content of dorsal longest muscle fat,oyster muscle fat,ash content and Lin meat protein content of sheep in L-RFI group was significantly lower than that in H-RFI group(P<0.05),and there were no significant differences in moisture,fat,protein and ash content of milone muscle and abdominal muscle between the two groups(P>0.05).(4)The pH of the longest dorsal muscle,oyster muscle,Lin meat,milone muscle and abdominal belly muscle of sheep in the L-RFI group was significantly higher than that of the H-RFI group(P<0.05),and there was no significant difference in the pH of the longest dorsal muscle,oyster muscle,Lin meat,milone muscle,abdominal and belly muscle pH 24 h,flesh color,dripping loss,cooking loss,hydraulic power and water loss rate between the two groups(P>0.05).In summary,under the same feeding management conditions,sheep with low residual feed intake have better growth performance and higher feed efficiency,and have a tendency to convert more feed intake into muscle,sheep with low residual feed intake convert more feed intake into lean meat,and sheep with high residual feed intake convert more into fat.Different residual feed intake had no significant effects on muscle water retention,flesh color,pH24,intramuscular fat,protein and crude ash content of sheep.