Delivered through Sheep Genetics, LAMBPLAN is the national genetic evaluation
services for the Aust sheep industry. It provides a common genetic language in the
form of Australian Sheep Breeding Values (ASBVs) to stud and commercial sheep
What is an Australian Sheep Breeding Value (ASBV)?
An ASBV is an estimate of the genetic potential a sheep will pass on to its progeny. ASBVs are available for a range of economically important traits and are designed to be used in conjunction with visual selection. The appearance and performance of an animal is a combination of its genes and the environment in which it is raised (eg the amount and quality of feed, single or twin birth type). ASBVs account for these environmental effects, allowing the comparison of sheep based on the genes they will pass on to their progeny. It is important to remember when selecting sheep you are choosing the genes, not the environment.
Live Weight ASBV Definitions
BWT: Birth Weight (kg) – Rams with higher BWT ASBVs will produce lambs which are heavier at birth.
WT: Weight (kg) – Rams with more positive WT ASBVs produce progeny that grow quicker and are heavier at a certain age. WT ASBVs are reported at weaning (WWT), post weaning (PWT), yearling (YWT), hogget (HWT) and adult (AWT) ages.
These ASBVs estimate the genetic difference between animals in live weight at a given age.
Carcase ASBV Definitions
FAT: Fat Depth (mm) – Rams with more negative FAT ASBVs produce progeny that are leaner. FAT is reported at post weaning (PFAT), yearling (YFAT) and hogget (HFAT) ages.
FAT ASBVs estimates the genetic difference between animals in GR fat depth.
EMD: Eye Muscle Depth (mm) – Rams with more positive ASBVs for EMD will produce progeny that have more muscle, independent of weight, and a higher lean meat yield. EMD is reported at post weaning (PEMD), yearling (YEMD) and hogget (HEMD) ages.
EMD ASBVs estimate the genetic difference between animals in eye muscle depth at the C site.
Gestation Length (GL) ASBV Definition
GL: Gestation Length ASBV provides an estimate of the genetic difference between animals in gestation length. It is important that GL ASBVs are used to optimise performance for this trait at moderately short values as both very long and very short gestation lengths will have a negative effect on lamb survival.
Lambing Ease (LE DIR) ASBV Definition
LE DIR: Lambing Ease ASBVs are estimates of genetic differences in the ability of a sire’s lambs to be born unassisted. LE DIR is reported as the percentage difference in unassisted lambings. Higher, more positive, LE DIR ASBVs are more favourable.
Though many large studies have consistently shown birth weight to be the most important genetic factor influencing lambing ease, there are also other aspects that need to be considered. For example, lamb shape, pelvic area and lambing “will” all play a role in lambing ease.
Lambing Ease (LE DIR) ASBVs are calculated using lambing ease scores recorded at birth. As they are a direct score, they combine all of the factors affecting lambing ease.
At Spring Valley we CIDR ewes for yard mating and Artificial Insemination (AI). We record the conception date and the birth date. This gives us the information required to determine Gestation Length of our sires.
Lambing Ease is recorded on all lambs born: unassisted, early pull, hard pull or abnormal presentation (breech etc).
Live weights are recorded on all lambs at birth, weaning, post weaning and yearling.
Fat score and muscle scanning is done on all lambs at post weaning (5 months).
See our time line for photos and more information on what we do at Spring Valley. For more on Lambplan visit the web site: