Performance of crossbreds of Polish Merino dams with F1 rams: Finnsheep X Polish Merino. A. Semi-intensive fattening of ram-lambs up to 40—45 kg

The investigations were carried out to evaluate fattening ability, carcass quality and wool production of semi-intensively fattened ram lambs the progeny of F1 rams: Finnsheep (F) x Polish Merino (PM) mated to PM ewes. Two experiments were performed, on a total of 73 crossbreds and 73 purebred PM lambs. The lambs were housed together in a shed and fed farm-produced roughages, supplemented by commercially available concentrates. The crossbred lambs under semi-intensive feeding were found to have similar fattening ability as the purebreds: daily gains F x PM x PM 196 g and PM 191 g, energy consumption per 1 kg of body weight gain 26.1 and 27.0MJ, respectively. Crossbreeding did not affect slaughter value, but the commercial evaluation of live lambs was poorer in the crossbred groups. The tested crossbreds had generally better wool performance: their clean fleece weight was 1.09 kg, while that of the purebreds was 0.98 kg, rendement respectively 59.3 and 53.0 %, fibre length 6.7 and 5.4 cm, while fibre diameter was similar in the both groups