Focus on Maternal Performance

The number of lambs reared and sold has a major impact on flock profitability. Selective breeding can be used to produce more productive ewes.

Maternal EBVs are not only of interest to flocks selecting female replacements but they are a vitally important part of ram selection - as these attributes can’t be assessed visually.

Which EBVs are important?

Litter size born EBV
Indicates the prolificacy of a ram’s daughters.

Interpretation:

A ram with a litter size EBV of +0.2 is predicted to produce ewe lambs that produce 0.1 (10%) more lambs than a lam with an EBV of 0.


Maternal Ability EBV (kg)
Indicates rams whose daughters will produce faster growing lambs due to their milking ability.

Interpretation:

A ram with a maternal ability EBV of +0.5 is expected to sire ewes whose progeny will be 0.25kg heavier at 8 weeks than a ram with an EBV of 0.

Using EBVs to enhance (or reduce) prolificacy is more reliable than simply selecting rams reared as singles, twins or triplets. Flock management should be reviewed if large increases in prolificacy are planned.

Maternal breeding decisions must be made with great care as these traits will be expressed in the flock for successive generations.

EBVs provide the only accurate way to assess a rams breeding potential for maternal traits.