High-producing dairy cows generate significant metabolic heat, making them
vulnerable to hot and humid environments. Heat stress reduces milk yield, impairs
fertility, and increases health problems, all of which negatively impact farm
profitability and animal welfare. By introducing the Slick gene, dairy cattle can
maintain higher productivity and reproductive performance under heat stress.
WHY ARE SLICK GENETICS IMPORTANT
FOR PROFITABILITY AND SUSTAINABILITY?
From a global perspective, over 40% of the human population lives in the tropics, where heat and humidity are particularly hostile to high-producing dairy taurine cattle.
Countries in these regions usually raise heat-tolerant and disease-resistant zebu cattle and their crosses with taurine cattle, but these animals are generally less productive.
As climate change intensifies, heat stress will become an even greater challenge worldwide.
Slick genetics offer a sustainable solution by reducing costs associated with cooling infrastructure, lowering water and energy use, and improving animal welfare.
In short, incorporating Slick genetics into breeding programs could enhance resilience and support food security while aligning with global sustainability goals.
The advantage of Slick genetics extends beyond dairy systems. For example, F1 Beef on Dairy calves inheriting the Slick gene are more resilient to heat challenges, reducing mortality and improving growth performance. This is especially important considering recent events such as the deaths of thousands of beef cattle in Kansas in 2022 and hundreds in Iowa in 2023, highlighting the economic and welfare risks associated with extreme heat.
WHAT IS THE
SLICK GENE
AND HOW DOES
IT IMPROVE HEAT
TOLERANCE IN
CATTLE?
The “Slick gene” refers to specific variations in the DNA sequence of the Prolactin Receptor (PRLR) gene that produce the dominant “Slick” phenotype in cattle. This phenotype is characterized by animals having very short, sleek hair, which enhances their ability to dissipate heat and maintain thermal balance under hot and humid conditions. As a result, cattle carrying the Slick gene exhibit improved heat tolerance compared to animals with normal hair coats.
To date, researchers have identified six distinct Slick variants (SLICK1–SLICK6), each representing a different mutation in the PRLR gene. These variants were originally discovered in Creole cattle breeds from the Caribbean Basin, descended from Iberian cattle introduced during the colonization of the Americas.
The most widely studied variant, SLICK1, is commonly found in Senepol cattle, a breed well adapted to tropical environments. Following its discovery, the Slick gene has been introgressed into other breeds such as Holstein through crossbreeding and backcrossing programs.
The importance of such programs lies in the fact that resilience to heat stress is a complex trait in many cattle breeds, including Holsteins. Complex traits are influenced by a large number of genetic factors, each contributing a small effect, along with environmental influences. Although genomic selection has accelerated genetic progress for traits such as milk, fat, and protein yield over the past 15 years, SLICK1 transforms heat tolerance from a complex trait into a single-gene Mendelian trait, making it easier to select for and enabling even faster progress.
How Is STgenetics® Incorporating Slick Genetics Into Their Breeding Program?
The goal of the STgenetics® breeding program related to Slick genetics is to bring Slick into the modern genetic era. As dairies capitalize on advancements in Beef on Dairy, genomics, feed conversion efficiency, and increased fat and protein production, STgenetics® aims to apply Slick genetics without compromising these genetic gain initiatives.
The application of Slick genetics in our
breeding program includes mating Slick
carriers that are not as high in production
or profit traits to the highest males or females
in the population to increase the opportunity
that the progeny will be a Slick carrier as
well as improve production traits. Over time
and multiple generations, we have established
bloodlines of females and males through
IVF technologies reducing generation
intervals to see faster gains.
Dr. Pete Hansen at the University of Florida made one of the largest steps in 2016
by bringing Slick-Gator Lone Ranger into the world. Lone Ranger has over
80 genomic tested sons and over 100 tested daughters. His contributions in
components and health traits created the genetic building blocks of many of the
pedigrees in Slick today. We still have opportunities to progress Slick genetics
to increase production and profitability traits of Slick carriers to their full potential.
The next step in Slick genetics is to create more homozygous
Slick animals to ensure that their progeny will be Slick carriers.
We currently have homozygous Slick bulls available in 4M™ semen
and will continue to progress these genetics forward with the goal
to make more heat tolerant and highly productive animals that
will contribute to sustainable food production around the globe.
HOW CAN I MANAGE
SLICK GENETICS IN MY HERD?
Genetic Visions-ST™
provides Slick testing for
females to screen your
herd for Slick carriers.
These results can be viewed in
STgenetics® STrategy™ platform
and females can be a carrier,
not a carrier or homozygous Slick.
Females can be sorted
based on Slick carrier status
to be mated to Slick bulls
in Chromosomal Mating®
to have the highest likelihood
of Slick carrier status in
progeny (see Figure 1).
A Slick marker frequency
chart can also be viewed
in STrategy™ to track
the frequency of the Slick
marker in your herd over time.
In Figure 2, the Slick marker
frequency chart indicates
that 13 females in the
customer herd were carriers
of the Slick1 marker out
of 1101 females that
were tested in 2024.
Slick genetics have
the opportunity to make a
positive impact on sustainable
food production around the
world by improving production
performance in cattle, reducing
water usage, and creating
more resilient cattle
in warm climates.
Located in Navasota, Texas, STgenetics® is making the world greener,
more sustainable and profitable. By improving herd genetics through science
and technology, we believe that the best way to predict the future is to create it,
while feeding the world with our passion for the beef and dairy industries.
The STgenetics® Integrated Approach to management combines cutting
edge genetics, innovation driven programs and gender-sorted semen to aid
farmers in improving cattle performance to feed the world while reducing
their carbon footprint.
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