Differences in composition, muscularity, muscle:bone ratio and cut dimensions between six lamb genotypes

Area of Science:

• Animal Science
• Meat Science
• Genetics and Breeding

Background:

• Understanding lamb carcass composition and meat quality is crucial for the sheep industry.
• Genotype influences growth, carcass yield, and meat characteristics, necessitating detailed studies.

Purpose of the Study:

• To evaluate the impact of sire breed and dam breed on lamb carcass measurements and composition.
• To assess genotype-specific differences in leanness, conformation, muscularity, and muscle:bone ratio.

Main Methods:

• Carcass measurements and dissection data were collected from 198 lambs across six genotypes (Poll Dorset, Texel, Border Leicester, Merino sires crossed with Border Leicester × Merino or Merino dams).
• Dorsal images were captured for EUROP conformation scoring and prediction of muscularity.
• Specific muscles from the hindleg and chump were dissected and weighed; femur length and weight were measured to calculate muscularity.

Main Results:

• Merino cryptorchid lambs were leaner than Border Leicester × Merino lambs; genotype differences in conformation were observed, with Merino lambs showing poorer EUROP scores.
• Texel (T) sire lambs had higher muscularity values and greater hindleg muscle proportion than Poll Dorset (PD) sire lambs.
• Border Leicester × Merino carcasses had the lowest muscle:bone ratio, while Texel × Merino had the highest; BL × M carcasses were fatter than several other genotypes.

Conclusions:

• Lamb genotype significantly influences carcass leanness, conformation, and muscularity, with Texel and Poll Dorset sires showing distinct performance.
• Genotype-specific differences in muscle distribution and composition are evident, impacting meat yield and quality.
• The study highlights the importance of sire selection for optimizing lamb carcass characteristics and meeting market demands.