Understanding Myostatin in the suckler herd

Date published: 29 October 2024

Many genes control traits that can be both positive and/or negative depending on how the breeding of the animal is managed.

The importance of Myostatin is being discussed more frequently in the breeding of the suckler herd in Northern Ireland. This may be at pedigree breeding stock sales, AI catalogues or speaking to semen companies. But do you know what myostatin is?

What exactly is the myostatin gene?

The Myostatin gene influences muscle development in all animals. It is very 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.

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.

Noel states that, “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.

Has myostatin a place in the suckler herd?

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. The F94L gene may be a safer way of using these myostatin genes with lower risk of negative outcomes. When choosing bulls for your suckler herd be sure 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.

If you require additional information on beef breeding management for your farm, please contact your CAFRE Adviser through the local DAERA Direct office.