“No animal is perfect; every animal has multiple genetic defects in it. So do we, all of us have them,” Matt McClure of ABS Global stated during the Undesirable Genetic Factors and Genomics’ Role in Discovery panel discussion, held during the Council on Dairy Cattle Breeding (CDCB) annual meeting on Oct. 4 in Madison, Wisconsin.
Moderated by Neal Smith of the American Jersey Cattle Association, the panel included Spencer Hackett of Melarry Farms, Matt McClure of ABS Global, JR Tait Jr. of Neogen, Paul VanRaden of the USDA Animal Genomics and Improvement Laboratory (AGIL) and George Wiggans, who was brought out of retirement from the Council on Dairy Cattle Breeding (CDCB) to offer his expertise.
Smith began with the emphasis that reporting at the producer level is the key to discovering undesirable genetic factors in dairy cattle. Verifying requires genomic testing.
“We have tremendous potential for future discovery and management,” Smith said. While the breed associations and bull studs are doing a great job of managing this information, reporting at the producer level is crucial.
VanRaden reminded the attendees of the basics of haplotypes. The haplotypes that are causing trouble are those from when the sire and dam provide the same stretch of DNA, and they find a defect that can lead to the embryo being lost or defects that are consequential to the breeder.
“After the discovery of the haplotype, the next step is to find the point of mutation in the haplotype that caused trouble. Then we can provide that to the laboratories so that they can develop gene tests to more accurately track the problem,” VanRaden noted. Genomic testing has enabled scientists to look at the DNA and pinpoint undesirable genetics.
Wiggans, a retired technical advisor from the CDCB, said the goal is to identify animals that appear to have the haplotype that causes a reduction in fertility. Because of genomics, we can be alerted to issues early, which has been of great value in recent history. He also noted the advancement of testing with genomics, and what we can glean from this data is breathtaking.
McClure, a lead geneticist at ABS Global, emphasized the effort that ABS Global has made to genomic test every animal and report those results.
“Most of them are unknown – they are too rare that we can’t select for them – but once we know the animal’s genetic defects, we can use that in our mating system to help decrease the risk of genetic defects while maximizing genetic potential,” McClure said.
He also noted that an animal is not excluded from the company’s breeding program just because it has a genetic defect.
“We look at the severity of the defect, we look at the frequency of it and its genetic potential and decide how to use the animal,” McClure said.
ABS also has a role in supporting research by donating data from cattle that express defects. They have also done in-house research and published it for others to use in their genetic-mating decisions.
Tait, from research and development at Neogen, discussed the advantages of densities in genomic testing. Genomic nominations to the CDCB are 65,000 tests.
“It increases the resolution of what people can look at, roughly 10 to 15 times, so it gives them more opportunity,” Tait said.
Hackett, of Melarry Farms, milks 150 cows on his dairy in central Minnesota, and he said he believes dairy producers are at the forefront of data collection. He said that seeing these undesirable characteristics in the field gives producers an opportunity to get a test done and make new discoveries.
“My grandfather always said, ‘Keep working with the best you’ve got, don’t force it to the top, let it come to the top,’” Hackett said. “What I’ve learned with the carrier part of it is that I do not shy away from them. I just learn how to manage them because some of those families seem to have a lot of other really desirable traits. I think some of the progress in getting these animals identified early as carriers has helped us as producers not line them up one on top of the other, sire on dam, which ends up leading to a higher rate of abortions. I also think having this information available to us has really helped us along with fertility and health trait selections.”
Hackett feels that, as a producer, he is at the forefront of information, and it is very important to collect data as it is observed. He noted his wife, as their primary calf feeder, has been able to observe the haplotypes in the calves before they are even tested. He said the ease of getting the cattle sampled and tested has provided the opportunity to discover new haplotypes.
Hackett related a pre-genomic testing story about a mating that resulted in 15 calves, of which seven were born deformed or dead. They sent a deceased calf to a university for research and to find the common denominator in that mating that would cause the abnormalities.
“It would be so much easier today to grab a tissue sample and collaborate two or three things that maybe we see in Minnesota, and now somebody in Texas might be seeing it, and somebody in another country might be seeing it,” Hackett noted. “Maybe some of these samples could be sent in and labeled as research to try to compile some of this data that we’re looking for and get in front of this undesirable trait before it has a chance to impact the mating of the most productive animal for our dairy producers.”
Having worked on several peculiar cases of defects, McClure emphasized the importance of reporting any defects to your local vet or the breed association.
“If it’s not reported to anyone, we can’t help the farmer,” McClure said.
Because of research developments, Tait said several conditions have direct tests that can be done.
“Getting lots of animals genotyped with the direct test is a very strong way to understand and manage it,” Tait said. He emphasized that the direct gene test is a powerful tool to help increase productivity and improve fertility.
VanRaden noted that gene tests are much more accurate than haplotype tests.
“Two animals can inherit the same haplotype from ancestors, but during one of the generations a mutation occurs, which causes the defect,” VanRaden said. “So, some of the families have the normal version, and other ones have the defective version, and that’s a case where gene tests are much more accurate than haplotype tests.”
Misinformation can be very damaging to the industry, and when Holstein muscle weakness presented itself in the breed, breeders wanted answers quickly.
“We are all on the first page of this,” Hackett said. “These guys trying to do the research haven’t had a whole lot of time ahead of us, and we are trying to be 99.9 percent accurate with the information for the producer to make decisions and move forward. We are going to have to give the CDCB a little time to develop an accurate test.”
Questions from the crowd included the topic of gene editing and whether we should be using it or not.
“Yes, we could use gene editing for genetic defects, but we have other tools that are quicker and more effective,” McClure said.
VanRaden pointed out that, while in some cases crossbreeding may not be a popular thought, there are some good things that have come from it. He pointed to the slick gene mutation that is now being expressed in Holsteins.
“There are other things that one breed has that the others don’t, which may be worth transferring,” VanRaden said. "You have a little bit of a risk of transferring something unexpected, but you have a very high benefit of transferring the thing that you really want. And that gets back to gene editing. There’s more than one way to move the useful genes around, and we should use all the tools we have.”
