Predicting tissue distribution and partitioning in terminal sire sheep using x-ray computed tomography

Area of Science:

• Animal Science
• Agricultural Technology
• Meat Science

Background:

• Carcass composition and fat partitioning are key indicators of meat quality and production efficiency.
• Accurate in vivo prediction methods are needed to incorporate these traits into breeding programs for terminal sire sheep.

Purpose of the Study:

• To evaluate the utility of X-ray computed tomography (CT) scanning for predicting carcass tissue distribution and fat partitioning in vivo in terminal sire sheep.
• To determine the accuracy of CT-derived measurements for predicting intramuscular fat and the proportion of carcass weight in specific regions and joints.

Main Methods:

• 160 lambs from three breeds (Charollais, Suffolk, Texel) and three genetic lines were CT scanned at seven anatomical positions.
• Carcasses were dissected to determine fat (intermuscular, subcutaneous), lean, and bone content, with chemical analysis of Longissimus Muscle (LM) fat.
• Prediction equations were developed using CT scan data to estimate tissue distribution and fat partitioning variables.

Main Results:

• CT scanning predicted intramuscular fat content with moderate accuracy (R(2) = 56.6) using data from two scans.
• Proportions of total carcass and lean weight in higher-priced joints and the leg region were predicted with moderate to high accuracy (R(2) up to 77.7).
• Body weight inclusion did not improve prediction accuracy, and breed-line-sex effects were minimal, justifying common prediction equations for terminal sire sheep.

Conclusions:

• X-ray computed tomography scanning is a viable tool for non-invasively predicting key carcass quality traits in terminal sire sheep.
• CT scanning provides opportunities to integrate tissue distribution and fat partitioning data into selection programs, enhancing meat production and processing efficiency.
• The developed prediction equations are robust across different breed-line-sex combinations within terminal sire sheep.