Root Bulbs, G6-S Testing Labs: Goat Genetic Tests 101

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When would you need a G6-S database and G6-S testing labs? If your Nubian goats carry two copies of this gene, it can be disastrous to your breeding program. Knowledge is key when it comes to raising goats, whether you’re just getting started or you need a refresher course on keeping your herd healthy and productive. 

It’s evident that animals need good veterinary care and necessary vaccinations during their lives, but there are other factors to consider when managing their well-being, such as scheduling goat blood testing at goat testing labs that can detect and also rule out diseases.   

What about genetic testing, and why is it important? Initially, it might seem overwhelming, but thanks to the University of California, Davis, pertinent information can be obtained through their Veterinary Genetics Laboratory located at UC Davis School of Veterinary Medicine. VGL is a non-profit, self-supporting department that provides highly accurate genetic testing results and animal forensic services while also contributing to the educational and research mission of the school.   

For more information: largeanimal@vgl.ucdavis.edu Website: vgl.ucdavis.edu (530)752-3556 Facebook: UC Davis Veterinary Genetics Laboratory 

“We are committed to teaching, research, and outreach.? explains chief analyst Stefanie Oppenheim, Ph.D., “We offer our services worldwide to breeders, veterinarians, researchers, and animal enthusiasts. The tests we conduct prove parentage, verification, desired genetic traits, and reveal the presence of inherited diseases in goats and many other animals.” 

Community outreach is important at VGL, especially when there’s ample time to visit with the public about genetic testing. One event that invites lively conversation is the annual UC Davis Goat Day held on campus every January. It’s an opportunity for individuals to ask questions about the testing process, specific defects and diseases, and how they can benefit by having pertinent information on file for each of their animals.   

Nowadays, many goat owners believe in being proactive when it comes to managing their operation, realizing the importance of genetic testing. Registries are requiring parent verification by DNA, and breed improvement and selection programs require accurate pedigree information, which can assist in limiting inbreeding.   

DNA testing also helps detect genetic defects that can result in specific diseases and deficiencies in goats that range from mild and manageable conditions to severe and life-threatening situations. Passing these genetic mutations onto a herd’s offspring can cause unnecessary suffering and losses in productivity. Knowing an animal’s genetic makeup is as important as knowing it’s history, especially when purchasing and bringing new goats into the herd. 

Genetic Tests 

• Parentage/Genetic Marker Report: This DNA-based parentage test uses a microsatellite marker analysis to compare an offspring’s DNA profile to the profiles of possible sires and dams, identifying and verifying pedigree. Proof of pedigree can increase the genetic value of one’s herd by identifying kids with high breeding worth and reducing the risk of inbreeding. It’s also a way to maintain up-to-date records with full parentage on young stock. 

• Alpha-S1 Casein: One of the genes (a unit of heredity transferred from parent to offspring) affects the amount of protein and fat produced in goat’s milk. This test detects variants correlated with high and low production levels of alpha-s1 casein. This is especially important to cheese producers. High fat and protein content contribute to better coagulation properties and cheese yield. 

• Freemartin: A freemartin is a female that is born with a male twin, but as a result of merged placentas, she was exposed to masculinizing hormones. A positive test indicates that the female may be sterile. 

• G6-Sulfatase Deficiency (G6-S MPSIIID): An inherited autosomal recessive metabolic defect found specifically in certain lines of Nubian goats and related crosses. G6-S is short for N-acetylglucosamine-6-sulfatase, a naturally occurring enzyme that helps maintain connective tissues throughout the body. The G6-S gene changes the amount of enzyme produced. While carriers, which have one copy of the gene, live healthy lives, problems occur when goats receive two copies: one from each parent. Affected goats suffer from delayed motor development, growth retardation, deafness, blindness, and early death. G6-S testing labs will detect if the mutation is present in the animal and, thus, if it is susceptible to the condition and can pass it on to its offspring. Reputable breeders track testing in a G6-S database.

• Goat Scrapie Susceptibility: Scrapie is a fatal, infectious neuro-degenerative prion disease affecting the central nervous system. As a result of nerve cell damage, affected animals can show behavioral changes, followed by excessive scratching and rubbing against fences, buildings, and trees to relieve irritating itching. Other telltale signs are lack of coordination, weight loss despite normal eating habits, biting of the feet and limbs, lip-smacking, and gait abnormalities. Scrapie is believed to be spread primarily through direct contact between breeding stock and their offspring. Infected animals can seem perfectly normal, some living up to five years before the disease manifests itself, but by then, it’s too late. There’s no cure or treatment for scrapie. Tests help determine if an animal has alleles (variant forms of a gene) that make them more resistant or less susceptible to the disease. 

Questions about sending samples in for testing? VGT’s website explains the process. Gather course hair with roots from the withers, chest, rump, tail, hind leg, poll, or fetlock. Use your fingers or pliers to grasp and pull eight to 10 hairs close to the skin. Repeat until you have 20 to 30 hair strands with root bulbs. Place them in an envelope and seal with the goat’s name.   

A Good Business Practice 

“Our entire herd has either been tested, or they came from two G6S normal parents,” explains Crystal Nelsen-Hall, owner of Freckled Farm Soap Company in Goochland, Virginia. “When we began our business and started looking to buy Nubian goats in 2013, we inquired about genetic test results. Folks looked at us like we had three heads; no one seemed to know or be concerned about the matter. 

“We learned the hard way about the importance of genetic testing when we bred our does that first year to a buck at another farm. Unfortunately, without knowing that sire was a G6-S carrier. One of the wethers born that season inherited the gene mutation, living only three years before his heart gave out.  

“We knew then the defect was in our herd and had all our goats tested, discovering that four of our does were carriers.”

Crystal found G6-S testing labs that could diagnose the genetic defect.

“They are retired from breeding, and fortunately, the rest of our herd is free from this deficiency and other genetic defects and disease. We are very diligent and only purchase animals that are not carriers. It’s encouraging to see an increase in awareness and follow-through, emphasizing the importance of operating a reputable business.” 

Whether or not you own Nubians and need G6-S testing labs, staying informed about genetic testing and other health issues is important. Veterinarians, breed associations, testing laboratories, and experienced goat owners can help explain more about the merits of going the extra mile in raising healthy goats.  It’s definitely worth the effort! 

DNA Tests by Species

UC Davis Genetic Veterinary Laboratory provides genetic testing for a wide variety of animals:

• Alpacas 
• Beefalo 
• Bighorn Sheep 
• Bison  
• Camel 
• Cattle 
• Coyotes 
• Goats 
• Elk, deer 
• Equines – horses, donkeys 
• Llamas 
• Paco-Vicuna 
• Pigs 
• Sheep 
• Reindeer 
• Water Buffalo 
• Wolves 
• Yaks 
• Dogs and cats 

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Originally published in the January/February 2021 issue of Goat Journal and regularly vetted for accuracy.