Effects of Reduced Age at Slaughter on Carcase Traits11 January 2013
Reducing the age of cattle at slaughter does not have a negative impact on beef carcases.
A research team of Ó. López-Campos, V. S. Baron, J. L. Aalhus and M. Juárez from Agriculture and Agri-Food Canada at the Lacombe Research Centre and A. Basarab of Alberta Agriculture and Rural Development at the Lacombe Research Centre studied the effects on age at slaughter of 224 British cross Continental crossbred steers.
The two year study, published in the Canadian Journal of Animal Science, evaluated the effect of the production system (calf-fed vs. yearling-fed) and its interaction with breed cross and hormone implant strategies, with and without ß-adrenergic agonist on carcase characteristics.
Carcases from yearling-fed steers were 32 per cent heavier (P<0.001), resulting in higher (P<0.05) dressing percentages, grade fat and rib-eye (longissimus thoracis) area (REA) (1.1, 32 and 10%, respectively).
However, despite being lighter, the estimated lean yield percentage was three per cent greater (P=0.010) in carcases from calf-fed steers.
No difference (P>0.05) was observed for marbling scores between production systems.
Use of hormonal implants increased (P<0.001) weights of live animals and carcasses (seven and nine per cent, respectively).
However, non-implanted yearling-fed steers had the lowest proportion of Canada Quality Grade A and the highest proportion of Canada Quality Grade AAA carcases (P<0.001).
Moreover, the observed increase (P=0.016) in marbling scores (up to 37 per cent) from British cross-bred steers disappeared with the use of implants.
The only effect observed on carcass traits from the use of ß-adrenergic agonists was an increase of six per cent in REA (P=0.032).
The main production system effect observed for carcass composition was a lower (P=0.008) proportion of bone in carcases from yearling-fed steers.
The use of hormonal implants increased (P<0.001) the proportion of lean and decreased (P=0.019) the proportion of fat (P<0.05).
Overall carcass composition of steers with large Continental influence (>50 per cent) had a higher proportion of lean and bone and a lower proportion of fat than carcases from 50–75 per cent British steers (P<0.001), which was also reflected in the composition of several individual primal cuts (e.g., rib, short-loin, flank, chuck and plate).
The interactions amongst production systems and the other production factors studied were minimal.
Therefore, despite expected differences in carcase size, reducing age at slaughter did not have a negative impact on Canadian beef carcase traits.
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