The performance based selection is all the result of recording data, and lots of it! A
quick review of the maternal and carcass composite percentile calculations will give you an idea of how complete the indices are in identifying animals with balanced genetic capacity. Investing in animals with performance based selection makes
gambling on the genetics of your next purchase less of a “shot in the dark”
If you want to use selection based genetics to improve your flock then GenOvis is for you! Gamble if you must but be aware that as a buyer you have the option.
Replacement ewes are selected on their maternal traits, structural soundness , breed
character and GenOvis information. Rams are selected for breed character, structural
soundness , GenOvis carcass traits, and reproductive capacity.
The 50 day weights are adjusted for age and sex of the lamb, age of dam, type of birth, and rearing (single, twin, etc). All actual weights of lambs are adjusted to a standard age of 50 days and are also adjusted to the equivalent of a ram lamb raised as a single from a mature ewe, four or five years of age. This adjustment means that adjusted weights on all lambs in the management group can be compared directly within the management group.
• 100 day adjusted weight: The lambs weight is adjusted the same way that the 50 day
weight is but for 100 days of age.
This is the real gain from 50-100 days of age for rams, female ADG is adjusted by a small factor to compare with the ADG of the males.
The 50 day weight direct value is a measure of the lambs ability to grow from 0-50 days of age on its own genetic merit. The EPD value is an estimation of the lambs ability to pass on improved gain to its progeny.
The 100 day weight direct value is a measure of the lambs ability to grow from 50-100 days of age and the total weight at 100 days. The EPD value is a measure of the lambs ability
to pass on improved gain to its progeny.
This index has been developed to be the most complete index for the selection of terminal sire rams. Consideration is given to lamb survival, 50 day weight, loin eye depth, birth weight, gain, and fat cover in the calculation of the CARC value. The index is expressed as a percentile which means that if a ram has a CARC value of 98, then he is in the top 2% of the breed for that index or trait.
Used to improve a lambs growth rate.
Reported for the terminal breed ewes on offer, this index is used to select for maternal as well as carcass traits. This is an index that you can trust but do not underestimate the importance of management in maternal performance.
The percentile ranks the animal within its population according to its EPD values. At a glance, you will know if the animal is improver or not for the breed.
< 50%: below the average / 50%: breed average / > 50%: improver
From: Strategies for Genetic Progress: A practical Guide
Written by: GenOvis
The CARCASS Index (CARC) has been developed as a tool to be used in the selection of rams whose progeny will have improved growth and carcass qualities. It is THE MOST COMPLETE index for the purchase of terminal rams to produce market lambs. The chart outlines what factors are included in the CARC index.
Loin Eye Depth 17.5%
Gain 50-100 d 29.2%
50 d weight dir 22.8%
Birth weight dir 6.5%
Lamb survival dir 6.5%
The farther backward you can look....the farther forward you can see! WInston Churchill
Genetic selection makes planning possible
To Improve lambs' growth rate. The GAIN index has been developed to estimate growth potential without the use of carcass ultrasound information.
Lamb survival dir 10%
Birth weight dir 10%
50 d weight dir 35%
Gain 50-100 d 45%