Animal Science Papers and Reports

The effect of growth rate and age at slaughter on dressing percentage and colour, pH48 and microstructure of longissimus dorsi muscle in Black-and-White (BW) bulls vs commercial crossbreds of BW with beef breeds

Krzysztof M³ynek, Piotr Guliٌski

Abstarc :

The study was performed on 55 young purebred Black-and-White (BW) bulls and 73 bulls being
commercial crossbreds of BW with beef cattle. Daily live weight gain from 990 to 927 g was found
related to a higher dressing percentage, ranging from 58.3% in crossbreds to 55.9% in pure BW
bulls. Meat from crossbreds showed, with no reference to slaughter age and genotype, a pH48
higher (5.79) than that found in purebred BW bulls. More intensive growth rate, regardless of age
of the bulls, led to the lighter meat colour (Hunter-L; 29.6-27.5) and saturation with red (Hunter-a;
18.7-15.3). A much greater diameter of longissimus dorsi (LD) muscle fibres was observed in meat
from older animals (35.6-56.5 ىm) as well as from those showing higher live weight gain, where the
difference in the fibre size reached 16.7 ىm. A higher growth rate also resulted in a higher content
of FTO and FTG fibres.

Key Word :
bulls / commercial crosses / fattening / growth rate / meat quality

Volume 25, Number 2, - 2007