Sheep farmers are set to benefit from major improvements in the accuracy of assessing their flocks for maternal ability thanks to an updated approach.
The new method takes both direct and maternal genetic influences on eight-week lamb weights into consideration.
It also includes environmental influences.
Research commissioned by Eblex looking at the Lleyn and Dorset breeds identified the need for a better way to assess maternal ability.
The updated approach will be rolled out to all breeds recorded by Signet Breeding Services this year.
The eight-week weight analysis looks:
- The contemporary group in which lambs are reared – incorporating their flock and year of birth, as well as their sex
- The number of lambs being reared by each ewe
- Age of the ewe
- Direct genetic influence on lamb growth rate from sire and dam – this becomes the eight-week weight EBV
- Maternal genetic influence on lamb growth rate from dam – this becomes the maternal ability EBV
- Temporary environmental influences on the lamb
- Permanent environmental influences on the dam
See also: How a Welsh hill sheep farm is using EID
Sam Boon, Eblex breeding specialist, believes the new approach and use of a maternal estimated breeding values (EBVs) will allow farmers to select ewes with superior performance in terms of their ability to influence lamb growth in early life.
“Without access to detailed lamb weight records it is very difficult to assess a ewe’s genetic merit for traits such as milk production and maternal care, and virtually impossible when selecting rams.
“The maternal ability EBV provides producers with a way to assess this commercially important trait.
“This will help them avoid the purchase of rams whose daughters are likely to express poorer levels of milk production and rear lighter lambs as a result,” he says.
The maternal ability EBV is expressed independently of prolificacy, but does take into account the number of lambs a ewe is rearing, so the maternal ability EBVs of ewes producing singles/multiples are not biased in any way.