New BRD research to help beef producers
February 17, 2014
Bovine Respiratory Disease costs the beef industry more than any other single disease, in death losses and treatment costs. Multiple research studies have shown that at least $500 million is spent each year on drugs and vaccines that only alleviate part of the problem.
According to Steve Carlson, DVM, PhD, a researcher at Iowa State University and one of the scientists at AeroGenics LLC, "BRD frequently occurs when calves are transported from the ranch of origin to the feedlot. This disease is observed in about 10 percent of the 3 million calves that are transported each year, and about 40 percent of those affected calves perish," he says.
"This translates into a cost of about $150 per animal across the board, in production loss, death losses, labor, vaccines and antibiotics," says Carlson. The sick and dead ones take profit away from the others. It would be nice to not have to do anything with the 90 percent that don't suffer from BRD, and just put them right into the feedlot as they arrive, and only worry about the other 10 percent. It would help to know which animals are part of that 10 percent so they can be dealt with, to minimize treatment costs and losses," says Carlson. The new company, AeroGenics, was created to help identify those 10 percent
Currently there are many research groups looking at various strategies to prevent or minimize these losses. Some studies are looking at genetic differences in cattle that appear to have resistance to BRD. Others are looking at ways to predict which ones might be vulnerable to this disease, and some studies are looking at better ways to diagnose and treat BRD.
Carlson was instrumental in research that identified the genetics involved with resistance to Salmonella and E. coli in cattle and helped develop a genetic test for the responsible gene for PSR Genetics LLC. AeroGenics LLC was created as a spinoff from PSR Genetics.
"PSR Genetics has a platform in which we can look at genetic elements, specifically single nucleotide polymorphisms (SNPs) that encode for disease resistance. We found a genotype in cattle for Salmonella and E. coli resistance, so we decided to delve into the BRD problem. The genetic aspect for BRD resistance did not pan out in our research, but this led us into another path where we found a specific protein that some cattle over-express during this disease," says Carlson.
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"In BRD the stress of shipping to the feedlot induces the over-expression of a lung protein in a certain population of cattle. This lung protein is involved in a hyper-inflammatory response that damages the lungs. So we targeted the over-expressed lung protein as a predictor for development of BRD. Currently we have a moderate amount of data but we need to do studies with more animals," he says.
"The bottom line is that some animals over-express this protein, and we can detect or predict this as they come off the truck, arriving at the feedlot. We've developed a blood-based test, and plan to convert it into an ELISA format in which a drop of blood could be taken from the animal and put into an on-farm test kit, such as the SNAP kits sold by IDEXX," says Carlson.
"There are many SNAP kits available for a number of different tests used in animal health. Another option could be a simple color change test. The animal could be tested as it arrives in the feedlot and you'd get an answer within 10 minutes whether it is susceptible to BRD or not. Then the calves could be sorted." The susceptible ones could be put in a pen by themselves and managed differently, monitored closely, or treated prophylactically with a drug that blocks the over-expressed protein and helps alleviate signs of BRD.
"There is a drug that we hope might be made available to the livestock industry after further research. It's not an antibiotic, and that's a good thing, because the FDA is really cracking down on antibiotic use in food animals. My concern is that eventually prophylactic use of antibiotics against BRD will be prohibited," says Carlson.
"Currently, drugs like Draxxon, Zuprevo and Zactran are used prophylactically, in the absence of infection, to mass-treat animals as they come into the feedlot, to help keep them from getting sick. But because there is a closely related human antibiotic called azithromycin, there is concern that anti-BRD livestock drugs will be made unavailable for prophylactic use. Thus finding non-antibiotic alternatives would be the best way to medically address BRD in the future," he says.
"There's a drug that has great potential for this purpose–an anti-inflammatory that's been used in humans for quite awhile, with a good safety profile. We envision that high risk animals could be put into a separate pen and fed this drug for a week or two in their feed. There would be no further handling of the animals to stress them; they would just be in an infirmary pen, being fed the anti-inflammatory drug," he explains.
"We have a moderate amount of data on the prognostic ELISA-based test and the anti-BRD drug. We have laboratory data and some data from feedlots, and it looks very promising. To go to the next step, we need to do more experiments on a larger scale. AeroGenics was created to continue this line of research and development. Right now we need more capital to do the research so we are looking for investors to provide capital in exchange for equity in the company," says Carlson.
The human drug will likely work very well in cattle, based on the respiratory disease it treats in humans. "It is off patent in humans now, and available to be tested, patented, and approved in cattle. It's a fairly inexpensive drug to make, so I don't think the cost would be prohibitive." It might be cheaper to treat pens of cattle with this drug, rather than having to pull out sick cattle to treat with antibiotics.
"Down the line it might be cost effective to just feed this drug to all the cattle as they arrive at the feedlot, but we don't know what the drug cost will be, after approval as an anti-BRD drug. The prognostic ELISA test that is currently being developed will probably cost about $8 per calf, or less. The $8 figure is based on the approximate wholesale price that companies like IDEXX charge veterinarians for some SNAP tests."
When dogs are tested for heartworm disease, for example, the veterinarian takes a blood sample from the dog and runs it through a SNAP kit to test for the presence of proteins related to heartworm infection. "Veterinarians can usually buy these test kits from IDEXX for about $8 each. The BRD test would be a direct sale to the cattle producer and might sell for about the same price," says Carlson.
What producers ultimately do will depend on how the economics evolve. It may be more economically feasible to use the drug on all cattle entering the feedlot. Or, it may pay to use the prognostic test, followed by administration of the drug to only those that need it. "If the drug cost will be low, feedlots may opt to feed it to all the cattle," he explains. Cost of the drug will be determined by what the drug company feels it needs to charge after doing all the rigorous safety and efficacy tests, and what they have to do to satisfy all regulatory processes.
Carlson's research has shown that the over-expression of this hyper-inflammatory lung protein is not based on genetics of the animal. "It may be due to factors in the environment of the animal that creates BRD susceptibility by making an over-abundance of this protein during transportation/stress," Carlson explains. Being able to detect this protein excess could be a valuable predictor, to know which animals need more attention to prevent BRD.
"We are looking for investors to help us finish this research. We are also working with USDA for a possible grant. We submitted a USDA grant proposal in 2013 and should know soon if we can get this funding to help maintain our research. Ultimately we think the USDA and their SBIR program will fund about half the research money required to get these products to the marketplace. Once we get funding we anticipate that the test and the drug could be available by 2018," he says.
"The target date for the drug will be out of our hands, however, and availability will be up to the drug company that we license this information to," he explains. Ultimately this research may dramatically help cattle producers lower the costs of BRD in feedlot cattle. F