During growth, size of intramuscular adipocytes increased in JB continuously and in HS until 18months of age (Fig. 4). The increasewas significant in JB from10 to 14 months of age (P=0.011), and in HS from 14 months to 18 months of age (P=0.006) and remained constant thereafter (Pb0.9). Comparing the breeds, JB had larger adipocytes than HS at 10 and 14months of age (P=0.04 and 0.09, respectively); in older animals, differences were not significant (PN0.24).