Lambing ease breeding values for the Combined LAMBPLAN analysis will be released in March 2026.
There are four key enhancements made for the lambing ease module for Combined LAMBPLAN:
The lambing ease model in Combined LAMBPLAN will move to a 5-trait model including assessment of lambing ease of singles and multiples separately, as well as birth weight, dead at births, and gestation length. While the model will assess lambing ease of singles and multiples separately, there will still be a single ASBV produced to describe the animal’s genetic merit for lambing ease. There will also be a universal maternal effect fit across litter size.
The direct and maternal genetic merit will continue be reported for lambing ease and gestation length like the current Terminal and Maternal analyses, however the ASBVs will be named slightly different. Direct traits describe how genes inherited by the lamb will impact the lamb directly, where maternal traits describe the maternal genetic difference between animals for such trait. Lambing ease and gestational length will be reported as LE and MLE, and GL and MGL for direct and maternal genetic differences, respectively.
Genetic parameters are used within the evaluation to account our understanding of the underlying genetic factors influencing how an animal performs. The lambing ease genetic parameters were reviewed for Combined LAMBPLAN to reflect the larger dataset used and remain similar to those used in the current Terminal and Maternal analyses. There were no significant differences in genetic parameter estimates within breeds in the Combined LAMBLAN analysis, so a universal set of genetic parameters will be applied. Maternal effects will be used for lambing ease in Combined LAMBPLAN.
Genetic groups are used in the Sheep Genetics evaluations to help describe breed and population structure of animals with missing pedigree. The genetic groups in Combined LAMBPLAN will be at a genomic breed structure level (were previously at a flock level).