WLS Charolais Catalogue April 2024 L2

Bri 琀 sh Charolais MyOSTATIN Myosta 琀 n Guide
What is Myosta 琀 n?
Why
Myosta
Myostatin?
琀 n is a gene that in 昀 uences the produc 琀 on of proteins which control muscle
Knowing the myostatin status of your animals, will help you to select bulls with the most appropriate
myostatin development. traits for When your breeding an animal program. is iden This 琀 昀 will ed lead as having to better one calving of the ease muta and help 琀 ons with it means the everpresent
that they trend have to improve inac 琀 ve carcass genes which confirmation do not control and quality. muscle There growth are both as e 昀 advantages ec 琀 vely, this and
disadvantages can result in of increased breeding with muscle animals mass. carrying Currently the myostatin ca 琀 le, gene, there which are is 19 why known it is imperative muta 琀 ons that
you know the carrier status of your breeding animals.
of the gene and a 昀 er extensive tes 琀 ng for the nine most common varients, we have
What concluded is Myostatin? that the Bri 琀 sh Charolais ca 琀 le popula 琀 on only contains two - F94L &
Myostatin Q204X. is a gene that influences the production of proteins which control muscle development. When
an animal is identified as having one of the mutations it means that they have inactive genes which do
Why are we tes 琀 ng for Myosta 琀 n?
not control muscle growth as effectively, this can result in increased muscle mass, or “double muscling”.
Knowing the myosta 琀 n status of your animals will help you to select bulls with
Currently in cattle, there are 19 known mutations of the gene, some of these mutations are breed specific
the most appropriate myosta 琀 n traits for your breeding programme. This will lead
and within the British Charolais herd book, two prevalent variants are found – F94L & Q204X.
to be 琀 er calving ease and help with the ever-present trend to improve carcase
F94L conforma 琀 on and quality. However, it is just one tool which should be used in
Research conjunc conducted 琀 with by the Adelaide wider University informa 琀 in on Australia available concluded such as that Es the 琀 mated effect of Breeding the F94L Values mutation
on birth and growth traits was not significant but was associated with an increase in meat weight and
(EBV’s) – which predict the performance of the animal based on its back pedigree,
a reduction in fat depth. The results for the average effect of substituting a single copy of the variant
F94L accurate variant indicated measurements an increase and in silverside the performance between 5.8 of and its 7.2% herd and mates meat weight – and of your between own 5.9
and judgement 7.3%. There on was type also and a reduction pedigree. in P8 fat depth, intramuscular fat and carcass fat weight.
Calves How used are these for this genes study, inherited?
carrying 2 copies of the variant F94L marker, produced carcasses with
approximately 12 to 15% more meat and 16 to 33% less fat compared with calves with no copies of
All reproducing species have two copies of each gene – called alleles. If your
the variant F94L allele, while single carriers produced approximately 3% more meat weight, while fat
depth Charolais measured has on one live copy calves of was the myosta 9.8% lower. 琀 n variant Therefore, (one the allele) F94L variant it is classed appears as to have many
positive heterozygous, effects without if has correlated two copies negative (two effects allele) of some it is other classed myostatin as homozygous.
variants.
Q204X The table to below shows the chances of inheri 琀 ng depending on the status of the
In parents: a study published in the Oxford University Press Journal of Science on the effects of the Q204X gene
in Charolais cattle, it was shown that the Q204X mutation leads to an increase in muscle mass. This
creates 2 Homozygous a dramatic increase Parents in saleable meat yield 100% because chance of of the Homozygous improved dressing o 昀 spring percentage,
reduced carcass fatness, and fineness gof the limb bones. In this study, animals with a single copy of a
mutated allele were slightly heavier at birth.
1 Homozygous Parent
50% chance of Homozygous o 昀 spring
These 1 animals Heterozygous showed consistently Parent greater gcarcass 50% yields, chance the thighs of Heterozygous were thicker, and o the 昀 spring rib eye areas
were larger. They were also markedly leaner, with less internal fat and less fat on the 6th rib. Therefore,
the presence
1 Homozygous
of even one
Parent
copy of Q204X was shown to increase the beef value of these animals
drastically. Regarding meat quality, trained taste 100% panellists chance of indicated Heterozygous that the o meat 昀 spring of young
heterozygous 1 Non-carrier bulls was Parent more tender. gThis better tenderness can be a consequence of a reduced
collagen content and a smaller mean area of the muscle fibre section because both characteristics have
been shown to be related to muscle tenderness. 25% chance of Homozygous o 昀 spring
2 Heterozygous Parents
50% chance of Heterozygous o 昀 spring
g
Variant Double Increased Increased Increased Increased 25% chance Lower of non-carrying Breeding o 昀 spring
Name muscling muscling birth calving Meat Fat Recommendation
weight difficulty tenderness
g
g
1 Heterozygous Parent
50% chance of Heterozygous o 昀 spring
1 Non-carrier Parent
50% chance of non-carrying o 昀 spring
Q204X ✔ ✔ ✔ ✔
2 Non-carrier Parents 100% chance of non-carrying o 昀 spring
F94L ✔ ✔ ✔
Best for breeding terminal animals.
Not recommended to use a
homozygous bull on heterozygous
heifers or cows with a smaller pelvis
OK for all breeding animals
to be homozygous
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