Suckler farmers are in the business for breeding and producing livestock and will know the importance of genetics in the success of their enterprise.
Different genes control different traits and these can be both positive and / or negative, depending on how the breeding of the animal is managed.
Myostatin is a term being mentioned more often in both commercial and pedigree cattle breeding circles.
The term often comes up in conversations with other breeders, at pedigree breeding stock sales and in artificial insemination (AI) catalogues.
Many farmers are still not overly familiar with what myostatin actually is and the role it plays in breeding herds.
The College of Agriculture Food and Rural Enterprise (CAFRE) beef and sheep adviser, Noel McNeill has recently explained what myostatin is and the impact it can have on suckler herds.
What is the myostatin gene?
The myostatin gene influences muscle development in all animals. It is significant for the management of beef-breeding animals, positively effecting muscle development and yield, leanness and tenderness of the meat.
Negative impacts include potential calving problems due to bigger calves, females with reduced pelvic area, reduced milking ability and delayed puberty, and potential respiratory problems with highly-muscled calves.
The CAFRE advisor explained that: “A normal myostatin gene will inhibit the amount of muscle produced by the body. There are myostatin gene variants in cattle that do not regulate muscle growth effectively which leads to ‘double muscling’ and other traits being displayed.”
Some variants, such as F94L, can increase muscle development without significantly effecting other traits such as calving ability and milking ability.
Some variants also found in cattle in the UK such as NT821 and Q204X are commonly known as “disruptive” and while they can increase muscle, they also negatively influence calving and maternal traits.
McNeill said: “The presence of the myostatin gene, sometimes known as ‘Double muscling’ gene, has always had a place in the commercial suckler herd, however caution should be taken.
“The prevalence of myostatin genes in the pedigree breeding herd is increasing due in part to buyer demand for bulls and heifers with more extreme conformation.
“The use of the myostatin gene can increase conformation of cattle and increase kill out percentages, however it can also lead to other issues such harder calvings, fertility and milking ability issues with females and potentially increased numbers of caesarean sections on farm.
“Animals will have two copies of a myostatin gene. The genes present can be ‘normal’, or any combination of the non-disruptive or disruptive variants.”
What are the chances of having issues with myostatin on farm?
When breeding, it is important to understand what myostatin genes the females and bulls carry. For all calves, one copy of the gene comes from the sire and one from the dam.
Animals which are homozygous (have two copies) for normal myostatin, display normal growth and female traits.
Animals which are either heterozygous (one copy) or homozygous (two copies) of a non-disruptive variant will display some level of increased muscle development with no effect on calving or maternal traits
Animals which are heterozygous for one of the disruptive variants will display increased muscling with some effect on calving and maternal traits.
Animals which are homozygous for a disruptive variant can display extreme muscling and have noticeable effects on calving and maternal traits.
“To work out the risk, we look at both male and female and work out the percentage chance of an animal carrying two copies,” the advisor explained.
Has myostatin a place in the suckler herd?
The CAFRE advisor explained that overall, “there is no doubt there is a case for having myostatin gene variants in the commercial and pedigree suckler herd, however caution must be taken and knowledge of myostatin presence in the females in the herd is very important”.
He recommended that the F94L gene “may be a safer way of using these myostatin genes with lower risk of negative outcomes”.
He advised farmers choosing bulls for their suckler herd, to “always look at the EBVs first for the bull especially for calving ease, then look at the myostatin status of these bulls to see what risk they may create on your farm”.
He said that farmers in Northern Ireland who require additional information on beef-breeding management for their farm can contact their CAFRE adviser through their local Department of Agriculture, Environment and Rural Affairs (DAERA) direct office.
