The myostatin gene in the EasyCare Breed
The myostatin gene in sheep denotes an increase in lean meat percentage and a reduction in fat content.
First discovered by scientists in Australia, the gene is most prevalent in the Texel breed, but luckily the EasyCare breed to some extent, also carries it.
When individual animals are tested for the gene, the results from the laboratory will signify a negative, a single copy myostatin denoted by a T+ or a Twin copy denoted as a T+T+, which is usually described as being a MYOMAX GOLD which is trademarked by Innovis and must not be used on adverts or in the market. It is a double myostatin gene carrier.
Breeders who need to improve their carcass grades in pure bred EasyCares, will find that by using a ram with a single copy myostatin, 50% of the progeny wil produce some 5% extra lean meat.
Those however, who use a ram with a twin myostatin copy will expect two advantages within their flock.
Firstly, all progeny will possess an extra 10% lean meat and 7% less fat content which means of course that lambs can be taken to extra weights before being penalised for being over fat.
The second advantage to using a double myostatin ram is that all of his progeny will carry at least one copy of the gene. This is of course a simple but effective way of introducing the myostatin gene to all replacement stock.
By persisting with a double copy ram, all the flock will carry the gene within four or five years.
It is worth emphasising that there are no disadvantages to introducing the myostatin gene. Any fear of lambing difficulties can be ignored, this is one element which we must retain at all costs and the presence of the gene has no effect on lambing ease.
One thing that is worth pointing out is that there is no connection between a myostatin carrier and growth rate and therefore it is a wise move to test only lambs which you feel are above average weights at testing time. Also only test rams without horns and who are fully fleece shedding, have sound legs, good jaw and teeth and good feet.
It goes without saying that it is absolutely vital that there is no cross contamination of blood samples as that will render the whole test a waste of time. Gloves must be used, new ones with each animal. You can also take nose swab samples to get the necessary fluid to test for the gene. You must get plenty of 'snot' on the swab.
It is worth repeating that there are no negative effects to the gene and that you can proceed with confidence of a positive outcome for carcass improvement. The percentage of O grades will decrease significantly and R3Ls with some U's will dominate the grading sheets.
If you are considering testing for myostatin it is good practice to also include request for a scrapie test as well.
All test results must be shown to the purchaser prior to sale and must go with the animal when sold.
By Huw Thomas [edited and updated by Louise Hobson]