Performance, meat fatty acid profile and meat colour of dairy bulls finished on grazed pasture or grass silage-based diets with similar concentrate allowances

Abstract

The objective of this study was to determine the impact of grazed grass (PAS bulls) and grass silage-based (UB bulls) diets on the performance, intramuscular fatty acid composition and muscle colour of finishing dairy bulls with similar concentrate allowances, ages and carcass weights. There were no differences in gain, carcass conformation, carcass fat score or meat colour between treatments. The dressing proportion of the PAS bulls was 3% higher than that of the UB bulls (p<0.01). The Longissimus muscle (LM) of the UB bulls contained a higher proportion of 14:0 and 16:0 fatty acids and saturated fatty acids than that of the PAS bulls (p<0.05). The LM of the PAS bulls contained a higher proportion of 18:1n-7, 18:2n-6, 20:4n-6 and 20:5n-3 fatty acids and polyunsaturated fatty acids than that of the UB bulls (p<0.05). There were no differences in the 18:2 cis-9, trans-11 conjugated linoleic acid or monounsaturated fatty acid profiles between treatments.