Comparison of meat quality for pasture and grain finished lambs

Summary

The objectives of this project were to: 
 a) measure carcase traits (weight, fat - GR and C, and eye muscle width and depth) differences between lambs finished on grain versus pasture, and 
 b) produce meat samples for consumer sensory testing through taste panel assessment. Merino, first cross and second cross lambs were allocated to grass or grain finishing treatments at approximately 34kg liveweight and grown to a pre-slaughter finished weight of around 50kg liveweight. 
In summary: 
Grain fed lambs grew faster than pasture fed, particularly in Merinos, and this was partly due to a relatively dry season and limited quantities of good quality pasture. 
Dressing percentage was 4-6 units greater for grain than pasture fed lambs in all breed types. 
When breed groups were statistically adjusted for carcase weight: 
- grain fed lambs had 20% (Merinos) and 50% (Poll Dorset crosses) greater levels of GR fat than pasture fed. 
- C-site fat depth was 30% (Merinos) to 100% (Poll Dorset crosses) greater in grain compared to pasture fed groups. 
- Eye muscle area was 8% (Poll Dorset crosses) to13% (Merinos) greater in pasture than grain groups. 
These results indicate that excessive carcass fatness is more likely in grain fed lambs, particularly for terminal crosses, while pasture fed lambs may have comparatively better lean meat yield than grain fed lambs.