Production of Corriedale sheep and F1 crosses with Milchschaf and Texel in grazing conditions

Abstract

A study was made to compare the productivity of crossbred ewes, produced by crossing Milchschaf and Texel sires with Corriedale dams, relative to purebred Corriedale ewes. The essay was made during 4 years to evaluate reproductive traits, wool production and lamb growth and carcass yield of lambs. The experimental populations consisted of about 221 breeding ewes, 55 Corriedale (C), 80 F1 cross Texel x Corriedale (F1T) and 86 F1 cross Milchschaf x Corriedale (F1M). The mating was in March/April (autumn) with Hampshire Down rams, the lambing in August/September (winter, spring), shearing in October and the slaughter of all lambs at 32 kg liveweight since December to January (summer). The ewes and their lambs were running on implanted pastures (clover/festuca) all year around. Fertility was higher in F1T than C (P _ 0.01); fecundity was higher in F1M than the others genotypes (P _ 0.01); lamb survival at 72 h was similar among breeds. N°Lambs marked/ N° ewes mated was 100.2% in F1M, 91.9% in F1T and 67.5% in C (P _ 0.01). Average daily gain of lambs from birth to 50 days (GPRE) was higher (P _ 0.01) in F1T and F1M (252.5 g/d) than in C (218.1 g/d). Lamb carcass yield (%) was higher in F1T (48.6) and F1M (47.7) than in C (46.7) (P _ 0.01). GR was higher in FIT (10.1 mm) than the others genotypes. In ewes, average greasy wool weight was 4.1±0.1 kg and diameter was 32.3 m with breed effect (P _ 0.01) (31.2 m C and 32.9 m FIM y FIT).