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20 Years of Limousin genetic
progress
____________________________________________________
By: IZAAN DU
PLOOY (LRF), Adapted by DERICK LE ROUX
Genetic improvements achieved within a breeding program are
a key measure of the success of any stud breeding
enterprise. Since their introduction from France, Southern
African Limousin breeders have implemented various
strategies to enhance the genetic quality of the Limousin
breed.
This article
reviews the breed’s progress over the past 20 years, as
recorded by the Livestock Registering Federation (LRF), and
highlights potential areas for improvement that can guide
future breeding plans.
Overview
The genetic trends in the Limousin breed have demonstrated
consistent progress over the last 20 years.
The breed has
successfully maintained stable birth weights while
increasing both weaning and yearling weights. Additionally,
the genetic merit for milk production has risen by 4 kg,
which is quite significant. There has also been a notable
increase in scrotal size, while gestation lengths have
decreased — both of which are positive genetic traits.
What is genetic improvement?
Genetic improvement is achieved when the average genetic
merit of the progeny, measured by Estimated Breeding Values
(EBVs), is higher than that of the parent population or the
selected individuals.
Factors affecting genetic improvement
In a nutshell,
genetic improvement is attainable for traits that exhibit
genetic variation within a specific population and for which
appropriate selection tools, such as EBVs, exist to evaluate
animals based on their genetic potential. To foster genetic
improvements, selecting animals with superior genetics as
parents for the next generation is essential. The faster the
generation turnover, the quicker the genetic improvement can
be realised.
What Drives Genetic Improvement?
Selecting bulls is a key factor in driving genetic
improvement. Typically, fewer bulls are chosen for breeding;
therefore, the selection intensity is much higher than for
females. Additionally, reproductive technologies such as
artificial insemination (AI) and embryo transfer (ET)
enhance the rate of genetic improvement by allowing the
production of more offspring from genetically superior males
and females. Furthermore, it is essential to have a clear
breeding objective, whether at an individual herd or
national level, to effectively guide genetic improvement.
Current Limousin Genetic Trends
A
genetic trend refers to the change in the average EBVs
(e.g., WW EBV) for a population over a period of time. Each
data point represents the average EBVs for a specific trait
of the animals born in a particular year. As the EBVs of the
animals are used, environmental influences are
excluded as
much as possible. Genetic trends are, therefore, a more
accurate representation of what happened to a population on
a genetic level than a phenotypic trend. The genetic trends
for all animals (males and females) can be combined as the
environmental and other non-genetic effects are excluded.
What are potential Genetic Improvements for the next 20-50
years?
Looking ahead, potential genetic improvements are
well-placed to meet future market demands, and can include
the following:
1.
Improved Genetic Recording:
The breed should improve genetic recording for more accurate
evaluations. Its relatively low-performance recording level
must be increased to enable more significant genetic
progress.
2.
Stronger Genetic Linkage Between Herds:
Establishing better performance connections among herds will
enhance accuracy and allow for more effective selection.
3.
Focus on fertility - DTC and scrotal size.
These are critical traits influencing profit and
prerequisite to deriving a selection index.
4.
Define breeding goals.
Derive and use selection indexes to select parents based on
profit for the next generation.
5.
Focus on sufficient fat cover:
The breed needs to focus on industry-relevant animals with
sufficient fat covering
(easy-fleshing)
while maintaining high genetic merit for traits relevant to
the industry.
6.
Larger Herds for Greater Genetic Intensity:
Building larger
herds will allow for higher genetic intensity, facilitating
improved genetic advancements.
7.
Decrease in Mature Cow Weight:
Over the coming
decades, the breed can focus on reducing mature cow weight.
This will decrease upkeep while increasing genetic merit.
This must be obtained while pushing growth traits and
keeping birth weight constant.
8.
Reduced Generation Interval:
Breeders should
work on decreasing the generation interval to accelerate
genetic progress.
Ultimately, the
key to improving genetics is effectively managing cattle
within a structured breeding program. A passion for the
craft will always exceed expectations. It is essential to
remain relevant, adopt solid breeding principles, increase
genetic merit, and prioritise sound, genetically superior
breeding.
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