Project code: RCF-04/2017

Project objectives:

  1. Evaluate the effect of sire EBV for muscle (low versus high) and finishing diet on progeny performance, net feed efficiency and meat quality
  2. Examine the dynamics of net feed efficiency in finishing lambs
  3. Establish a central progeny test flock that will evaluate sires recorded on the current breed evaluation systems used in the UK (Signet) and Ireland (Sheep Ireland)
  4. Promote the benefits of animal recording in pedigree and commercial sheep flocks in NI and promote the use of EBVs by commercial producers when making flock breeding decisions


The use of genetics provides an important pathway for sheep producers to improve the performance of their breeding flock. Genetic improvement is also permanent and cumulative, with improvements made in one generation added to those made in previous generations. Internationally, the adoption of estimated breeding values into flock breeding programmes has been shown to increase both animal performance and the rate of genetic gain within sheep populations, leading to significant improvements in flock productivity. Economic analysis has also demonstrated that breeding programmes can prove extremely valuable despite the associated higher purchasing costs of high genetic merit rams.

The uptake of breed performance recording and the use of EBV in the NI sheep sector is relatively small in comparison to the mainland UK and the Republic of Ireland (ROI). One issue often cited by producers is the variation and inconsistency of breed evaluations provided for breeding animals when recorded on the two different breed evaluation systems currently available to producers in the UK and ROI. It seems that producers need clearer explanations as to how the EBV are generated, in order to increase their confidence in the use of EBV, regardless of the breeding evaluation system used.

Feed costs are a major cost in lamb production systems and reductions in feed requirements through genetic improvement could have a dramatic impact on both the biological and economic efficiency of lamb production systems. Research has shown 95% of the energy requirement for sheep can be met from grazed and conserved grass. However, in order to realise the cost-effective production advantages that grass- and other optional forage based systems lamb production have to offer, producers most ensure that they are making the most efficient use of their feed resources – through both good grass/forage management practices and animal selection. One way to measure feed efficiency in animal is net feed efficiency which is moderately heritable (0.32 – 0.41), which is described as the difference between an animal’s actual feed intake and expected feed requirement for maintenance of body size and stage of production. Emphasis on NFE within breeding objectives and the ability to select more feed efficient animals for breeding based on EBVs would therefore provide significant potential to improve the efficiency in which feed resources are utilised and the number of animals which can be supported nutritionally on-farm. As on big advantage of selecting animals for low NFE (more efficient) is that it is genetically and phenotypically independent of growth and body size and therefore, does not result in an increase in maintenance requirements of the breeding flock. The genetic selection of more feed efficient animals would allow producers to utilise feed resources in a more efficient and sustainable manner.

Eating quality is now regarded as one of the key aspects that influences consumer’s meat buying decisions. It is of upmost importance to the NI sheep industry that we continue to produce high quality sheep meat that meets consumer expectations and encourages repeated purchasing. Many factors throughout the supply chain influence lamb meat quality, some of which are directly linked to the animal (e.g. breed, age, sex, etc.) and others that are external to the animal (diet or management). Research has shown sires selected for extremes in breeding values for muscling or fatness will produce progeny with lower eating quality. This study aims to provide a greater understanding of the effects of sire EBV for muscle and finishing diet on progeny performance, NFE and meat quality. This will assist primary producers and processors in implementing production systems that not only optimise animal performance, and resource use but also consumer eating quality potential. This project will also provide invaluable data to both the primary producer and processor on best practice in breed selection and product quality.

This project aims to investigate the effect with high and low muscle sire EBV of Suffolk and Texel sires on lamb performance, net feed efficiency and meat quality. Sires used in the progeny the two current breed evaluation systems for sheep used in the UK (Signet) and ROI (Sheep Ireland). The project will be carried out at AFBI, Hillsborough and Loughgall over a three year period and will provide NI sheep producers with invaluable information on the performance recording and breed selection tools available at present – which will be fundamental to harnessing the potential that genetics has to offer in improving flock productivity and lamb production in NI.

Genetics and diet are both significant determinants of lamb performance and meat quality. Genetic improvement on commercial sheep farms is largely realised through the purchase of breeding males. The use of terminal sires for cross-breeding is integral to the UK sheep industry where approximately 71% of market lambs are sired by terminal sire rams (EBLEX 2012). These often come from specialised flocks (but not necessarily ‘recorded’ flocks that can provide EBVs) where specific efforts are made to achieve genetic improvement of traits which maximise the saleability of breeding males to commercial farmers (growth, conformation, carcass weight). EBVs are based on progeny performance, and thus provide producers with vital selection resource to use when making flock breeding decisions. However, at present it is estimated that only 40% of sheep holdings in the UK currently use EBVs to select new breeding sires (DEFRA 2016), thus limiting the rate of genetic improvement. Instead, many producers still select their sires based on their ‘looks’ rather than their performance data.


Project deliverables:

  1. Establishment of a CPT flock in NI to evaluate sires with high and low muscle EBVs recorded on the Signet and Sheep Ireland databases
  2. Generation of new knowledge on the effect of terminal sire EBV for muscle on progeny performance, net feed efficiency and meat quality. Quantification of improvements that can be achieved in key production traits when using rams with higher EBVs. Dissemination of these findings in scientific articles.
  3. Drive greater on-farm uptake of the use of performance recorded rams for both pedigree and commercial producers.
  4. Knowledge exchange events that will improve NI producers’ understanding of how current EBVs are generated.

See RamCompare farm walk booklet 2018 here