Fat deposition in a double-muscled steer

Area of Science:

• Animal Science
• Beef Cattle Genetics
• Meat Science

Background:

• Double-muscled (DM) cattle are known for increased muscle mass.
• Their potential for fat deposition is often considered limited.
• Understanding fat deposition in DM breeds is crucial for carcass quality assessment.

Purpose of the Study:

• To evaluate the fat deposition potential in a homozygous double-muscled steer.
• To compare the adipose tissue characteristics of DM cattle with non-DM cattle.
• To assess the physiological normality of adipose tissue in DM animals.

Main Methods:

• A homozygous double-muscled steer was fed a high-energy ration for 18 months.
• Carcass analysis included intramuscular fat, 12th rib fat thickness, and kidney, heart, and pelvic fat percentage.
• Adipose tissue composition (lipids, fatty acids) and cellularity were analyzed.

Main Results:

• The steer's carcass showed modest intramuscular fat and 2.4 cm fat thickness at the 12th rib.
• Kidney, heart, and pelvic fat constituted approximately 3.5% of the carcass weight.
• Adipose tissue lipid and fatty acid profiles were comparable to non-DM cattle.
• Adipose cellularity was similar to non-DM cattle of comparable fatness and weight.

Conclusions:

• Homozygous double-muscled cattle can possess a significant potential for adipose development.
• Adipose tissue in DM cattle can be physiologically normal and comparable to non-DM animals.
• These findings suggest that DM genetics may not inherently preclude substantial fat deposition.