Patience pays off when breeding for maternal traits
The Gortleigh flock was one of the first to become involved in performance recording.
Frequent runners up in the BRP Most Improved Flock Award for Dorset sheep, Gill and Richard have made the highest rates of genetic gain for maternal traits of any Dorset flock in the past ten years.
Their achievement is more remarkable as Gortleigh is also one of the leading flocks for terminal sire traits.
In recent years the maternal index for the Dorset breed has been revamped, with greater focus on prolificacy and milking ability. With members of the Poll Dorset Sire Reference Scheme (Centurion) at its heart, the Dorset breeding evaluation is a success story. The leading breeders have worked together to transform the performance of Dorset Horn and Poll Dorset sheep, with high index sheep dominating the breed’s main sale the May Fair.
Over the past ten years, Gill and Richard have recorded more than 500 lambs a year, with major increases in both the growth potential and muscling of their lamb crop. However, it is the increase in maternal traits for prolificacy and milk that stand out.
In 2014 the December lamb crop comprised 76% twins, 13% singles and 11% triplets; producing a lamb crop of 182% with relatively low levels of lamb mortality. Since the Gortleigh flock started recording, there has been a 10% increase in the proportion of the flock born as twins.
Tips for success
- Collect as much data as possible. To increase muscling, scan as many lambs as possible to derive the truest picture of their genetic merit as quickly as possible
- Take time to assess rams for maternal traits, as the accuracy of their EBVs will only increase when their daughters join the flock
- Do not be afraid to try unrecorded breeding lines, but use them carefully. Test mate them on a small cross-section of ewes in the first year
- To improve maternal performance, select rams with superior maternal EBVs
Table 2: A decade of genetic improvement for the Gortleigh Flock