LAMB PRODUCTION IN THE ALPINE REGION WITH MOUNTAIN SHEEP AND THEIR CROSSBREDS WITH MERINO AND BLACKHEAD-MUTTON SHEEP

The authors analysed 96 female and 103 male lambs of the following gen otypes: Brown Mountain sheep (obB), 21 males, 16 females; F1 crossbred s White Mountain sheep x Land Merino (owB x M), 29 males, 30 females; and F1 crossbreds White Mountain sheep x Blackhead Mutton sheep (owB x S), 26 males, 28 females. The experimental animals derived from the s heep flock of the BAL Gumpenstein, Austria, where continued lambing is practised, and were born during the period December 1991 up to the en d of the year 1992. The lambs were put to fattening at 22 kg (+/- 2%) liveweight. Female and male lambs were fattened on concentrate feed an d aftermath hay up to a final weight of 35 and 42 kg (+/- 2 %), respec tively. Fattening and slaughter performance were determined for each a nimal individually. The results obtained may be summarized as follows: There is no significant difference in length of fattening period, dai ly gain in weight and feed conversion between male lambs. In crossbred s the results tend to be somewhat better. As far as female lambs are c oncerned, mainly Brown Mountain sheep reveal the poorest results, i. e . during a 72-day fattening period 193 g daily gain and 5.7 kg dry mat ter consumption for 1 kg liveweight gain. The highest carcass yield (5 0.72 %) was found in female lambs of the obB genotype. Crossbreeding w ith Land Merino and Blackhead Mutton sheep resulted mainly in modified Carcass conformation, i. e. shorter and broader legs, shorter back an d larger loin eye area. Total meat proportion in male lambs is 55 to 5 7 % and does not significantly differ between the genotypes studied, b ut crossbreds reveal the higher values. In female lambs the trend is s imilar, but altogether their values are by 1 to 1.5 % lower. Meat-to-f at ratio is 0.38 to 0.43 in male lambs and 0.42 to 0.46 in female lamb s, whereby crossbreds show the better values. Summarizing it may be st ated that in the Alpine region continued lamb production for fattening using Mountain sheep as maternal basis or as partner for crossbreedin g with a mutton breed, e.g. Blackhead Mutton sheep, is most profitable .