Effects of three different grass silage-based total mixed rations on meat quality of finishing Holstein and Nordic Red dairy bulls

Abstract

The objective of the present experiment was to study the effects of different silage-based diets on beef quality of Holstein (HO) and Nordic Red (NR) bulls. Moderate concentrate diet (MC) included grass silage (GS), barley grain and mineral-vitamin mixture in proportions of 600:385:15 on dry matter basis while the respective proportions on low concentrate diet (LC) were 850:135:15. No concentrate diet (NC) included GS, whole-crop barley silage and mineral-vitamin mixture (685:300:15). Thirty-five HO and 30 NR bulls (21–22 bulls per feeding treatment) were randomly selected for the meat quality research. One day post-slaughter, the muscle longissimus lumborum (LL) from the right side of each carcass was cut at the level of the first lumbar vertebra. The pH value of LL muscle was highest in LC, intermediate in MC and lowest in NC diet but did not differ between the breeds. For meat lightness a significant (P < 0.05) breed × diet interaction was observed. The NR bulls had lighter meat compared to the HO bulls especially with MC, but not with LC. Meat redness and yellowness were higher in MC compared to LC or NC fed bulls (P < 0.001). The breed did not affect meat redness, but yellowness was higher in HO compared to NR bulls (P < 0.05). Drip loss was higher in LL of HO than NR bulls (P < 0.01). The diets had no effects on marbling score but it was higher in NR than HO bulls (P < 0.05). Shear force was lowest in MC but no difference was found between the LC and NC and between the breeds. No differences between the treatments were found in sensory tenderness, juiciness, and flavour. Overall, the observed diet effects on meat eating quality were minor. This demonstrated the ability of finishing dairy bulls to adapt to different feedings without major effects on meat quality.