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.

Production and Economic Evaluation of the Corriedale Breed and Crosses With Dohne Merino Generated During the Establishment of a Rotational Crossbreeding Scheme: Ewe Hogget Results

“…Pure C had the lowest value, but it did not significantly differ from the other genotypes, except for ½DM_½C. De Barbieri et al (2021) report that genotype ¾DM_¼C had the highest live weight, slightly ahead of ½DM_½C, but both were well above pure C. Although not in perfect agreement, De Barbieri's and our study confirm that crossing C with DM will improve growth rate and live weight. We found no significant differences among genotypes in subjectively assessed Conf.…”

“…In our case, the ratio CFW/PSLW (Table 6) for the genotype with the greatest proportion of DM (¾DM_¼C) was 5.6%, well within the above-mentioned range. By contrast, it was 7% for purebred C. The pursuit of a 5 to 6 WPP% in DM provides a plausible explanation for its lower GFW and CFW compared with other Merino strains bred without that constraint (Van der Merwe et al, 2020), or with C (De Barbieri et al, 2021). The latter study reports the upgrading of C by DM, where the reduction of fleece weight as the proportion of DM increased is evident.…”

“…We found no significant differences among genotypes in subjectively assessed Conf. However, in a thorough examination of carcass traits, De Barbieri et al (2021) found that DM crosses generally outperformed pure C. An individual sheep producer may consider that the relative physical performance of pure C and the various DM crosses is insufficient to make a decision (i.e., pure C has a higher fleece weight, but the wool it produces is of greater fibre diameter and lower value; DM crosses may be heavier than pure C but that may bring about greater nutritional needs per animal). In such cases, the calculation of gross margins can be useful because it integrates physical performance, product values, and production costs, thus allowing a comparison of genotypes in monetary units (Roa, 2012;Ceballos et al, 2021;PIRSA, 2021).…”

“…The Uruguayan Wool Secretariat (SUL, for Secretariado Uruguayo de la Lana in Spanish) has conducted studies in commercial flocks, crossing DM with C and with Australian Merino (AM) (Abella and Preve, 2009;Preve and Abella, 2010). The most thorough work on the use of DM in Uruguay has been conducted by the National Institute for Agricultural Research (INIA, for Instituto Nacional de Investigación Agropecuaria in Spanish) (De Barbieri et al, 2021), comparing C, ½DM_½C, and ¾DM_¼C. In broad terms, DM crosses with C have shown lower fibre diameter and fleece weight, greater lamb growth rate and carcass yield, and better reproductive performance in ½DM_½C.…”

Combined purebred and crossbred genetic evaluation of Columbia, Suffolk, and crossbred lamb birth and weaning weights: systematic effects and heterogeneous variances

“…Crossbreeding is an important strategy to improve the efficiency of sheep production systems, especially under extensive conditions ( Gootwine, 2020 ; de Barbieri et al., 2021 ). Lambs can benefit from crossbreeding directly or due to their dams also being crossbred ( Murphy et al., 2018 ).…”