Productive and reproductive consequences of crossbreeding Dohne Merino with Corriedale in Uruguayan sheep production systems

Abstract

Context For extensive production systems, crossbreeding may be a tool that can be used to achieve production of quality wool and meat to suit market specifications. Aims To evaluate two levels of crossbreeding of Dohne Merino (DM) sires with Corriedale (C) ewes on productive and reproductive traits of the crossbreed progeny in comparison with purebred C progeny. Methods Two studies using three genotypes – 100% C (100C), 50% DM×50% C (50DM) and 75% DM×25% C (75DM) – were carried out. In Study 1, growth, wool production and nematode resistance were evaluated (n= 1652). In wethers, carcass weight, subcutaneous tissue thickness, weight of high value cuts, meat shear force and fresh meat colour were also evaluated. Before first mating, the presence and number of corpus luteum was recorded to evaluate puberty and ovulation rate, respectively, in 380 18-month-old hoggets. In Study 2, fertility, prolificacy and lambing percentages were measured in 382 ewes. Key results Increasing the percentage of DM was associated with heavier animals (P<0.01). The heaviest fleece weight, broadest fibre diameter and longest staple length were recorded in 100C, and the lowest in 75DM (P<0.001). Crossbred animals had heavier carcasses, boneless legs and French racks than 100C (P<0.001). Subcutaneous tissue thickness GR adjusted for carcass weight was thicker in 100C, intermediate in 50DM and lowest in 75DM (P<0.001). Meat quality and nematode resistance traits were not affected by crossbreeding. Genotype affected the proportion of hoggets cyclic at first mating (P<0.05), being greater in 50DM than in C hoggets, although both proportions were similar to 75DM. Fertility was not affected (P>0.05) by genotype, whereas prolificacy and lambing percentage were greater in the animals of the 50DM vs 100C and 75DM (P<0.05). Conclusions Wool quality, animal growth, carcass weight and composition, and onset of puberty were improved by crossbreeding C ewes with DM sires. A reduction in wool production, and minor influences on prolificacy and lambing percentage were detected. Implications Crossbreeding C ewes with DM sires can benefit wool and meat production in comparison with purebred C production systems.