Studies in the muscles of meat animals. IV. Comparative composition of muscles from ‘doppelender’ and normal sibling heifers

Fourteen muscles from a normal 46-week-old Friesian heifer and from its 40-week-old half-sister, which showed the pronounced muscle hypertrophy of ‘doppelender’ cattle, were analysed for moisture, hydroxyproline, sodium, potassium, total nitrogen, and intramuscular fat: the iodine number of the latter was determined. In four of the muscles sarcoplasmic, myofibrillar and stroma nitrogens were also estimated. 2. Hypertrophy was associated with a mean increase in the percentage of total nitrogen, with markedly lower percentages of hydroxyproline and of intramuscular fat, and with a decreased K/Na ratio.