The analysis of some skeletal muscles in lambs of different genotype by the distribution frequency of muscle fibres diameter

Samples of m. gluteobiceps, m. longissimus lumborum, m. psoas major, m. sem itendinosus, m. semimembranosus, m. quadriceps femoris (m. rectus femoris) and m. triceps brachii (caput longum) of 9 male lambs 71 days old, originat ing from the ewes crossbreds between the Istrian Pramenka breed and Sardini an rams and Sardinian (S), domestic Merino-Wurtemberg (W) and East Friesian (EF) rams, were investigated by the distribution frequency of muscle fibre diameters with the shift of 0.5 mu m. The frequency distribution pointed o ut the prevalence of fibres of smaller diameter in muscles of W and EF cros sbreds having higher body weight and meatiness. The comparison between W an d EF crossbreds having similar body weight and meatiness showed that smalle r fibre diameters were prevailing in 5 muscles of EF crossbreds and 2 muscl es in W crossbreds.