Cattlemen and veterinarians primarily use commercially licensed vaccines to immunize livestock against common diseases. These commercial products are manufactured in USDA-licensed facilities, have been shown to be relatively safe when used as directed and have demonstrated some level of efficacy in controlled studies. Once a bacteria or virus is isolated, modified and approved for use in a licensed vaccine, the vaccine may occasionally be updated with more recent strains from the field. Often vaccines continue to use the original isolates for several years without being updated.
Along with commercial vaccines, licensed autogenous vaccines can be an option to control losses due to disease. What is an “autogenous” vaccine? “Auto” means “self” and, in the case of cattle, it can be extended to mean “the herd.”
The organism used to make an autogenous bacterin is isolated from one or more diseased animals from a herd or group. A veterinarian collects tissues or swabs and submits them to a diagnostic laboratory for isolation and identification of the causative agent.
Samples may be taken from pneumonic lesions in the case of respiratory disease or from the intestinal lesions in cases of diarrhea or suspected enterotoxemia. Pinkeye lesions or conjunctiva are swabbed from eyes exhibiting pinkeye.
After isolation, the laboratory may check the bacteria for pathogenicity (disease-causing ability) using PCR or virulence-associated proteins. If the same organism is isolated from more than one animal, the isolates may be evaluated for differences.
If bacteria differ significantly, more than one isolate would then be considered for inclusion in an autogenous vaccine to broaden protection.
Autogenous vaccines are licensed products produced in a USDA-licensed facility. These products must undergo rigorous testing to demonstrate the purity and safety of each serial produced.
The primary reasons for considering an autogenous bacterin are when a commercial product is not working as expected or where there isn’t a comparative commercial vaccine available.
An example would be if Moraxella bovoculi was isolated from cases of pinkeye. Currently, there are no commercial vaccines available which contain M. bovoculi . Autogenous products can be used when there is a valid veterinary-client-patient relationship.
The veterinarian should be available in the event of adverse reactions, determine if a product was beneficial and must keep records on where the autogenous vaccines were used.
The use of isolates is restricted to 12 months from when the autogenous vaccine was initially produced or 15 months from the date of isolation. In some cases, extensions may be granted for 24 months of use.
Dr. Clint Johnson (right) of Johnson Veterinary Service in Akron, Colorado, began using an autogenous Clostridium perfringens Type A bacterin approximately 18 years ago. A large dairy that he consults for was losing adult cows to hemorrhagic bowel syndrome (HBS).
Some days the dairy would have as many as eight cows die suddenly due to HBS. Necropsy would reveal an area of bloody intestine in which C. perfringens Type A would be isolated.
Johnson had an autogenous bacterin made from the clostridium isolated from this dairy. After the dairy started vaccinating, the number of cases of HBS dropped significantly to only a few cases per year.
Since autogenous bacterins need to be updated, samples from the few cases that occur are collected. The most recent vaccine was made from a cow that was producing 100 pounds of milk one day and died the next.
She had typical intestinal lesions compatible with a diagnosis of HBS. Clostridium perfringens Type A + Beta2 toxin was isolated from this cow by the diagnostic laboratory. An updated bacterin is currently being used in this dairy.
Dr. Mike Katsampes (right) of Katsampes Veterinary Services, LLC in Milliken, Colorado, has clients who are using autogenous bacterins to help control mycoplasma mastitis. One dairy client of Katsampes’ was experiencing as many as 20 cows per month with new cases of mastitis caused by Mycoplasma bovis .
These cases were occurring in spite of using control measures to reduce the spread of this contagious pathogen. The dairy owner wanted to know if mycoplasma vaccines might help since swine operations were successfully using mycoplasma bacterins.
The client persuaded Katsampes to give autogenous bacterins a try because they had nothing to lose. An autogenous bacterin was made from the mycoplasma isolated from clinical cases of mastitis. After giving two doses of vaccine, the number of new cases of mycoplasma mastitis dropped significantly.
Katsampes still recommends control procedures such as washing the bottom half of the teat only and making sure they are fully dry before attaching the milking machine.
Mycoplasma bovis can also be a cause of bovine respiratory disease. Mycoplasma bovis isolates are not uniform, and sometimes different strains occur. Evaluating the organism’s expression of variable surface proteins is one method of differentiating strains.
Dr. Tom Edwards (right) of Midwest Feedlot Services, Inc. in Kearney, Nebraska, was frequently isolating M. bovis out of lung lesions of feedlot calves that died from respiratory disease. He submitted the isolates for DNA sequencing which indicated the isolates differed.
He had a mycoplasma bacterin made for each feedyard experiencing losses. These bacterins contained up to five M. bovis isolates.
Two doses of the autogenous bacterin were recommended – one at arrival and the second three to four weeks later. One 1,700-head feedyard’s death rate decreased from 2.9 percent to 0.2 percent.
A few years ago, a couple of his feedyards decided to discontinue the autogenous M. bovis bacterin. After they did, respiratory disease due to M. bovis increased significantly. They have since reinstated M. bovis vaccines in their receiving protocol.
Recently, Edwards has been diagnosing less mycoplasma in the feedyards he consults with. He has recommended the vaccine be discontinued in some yards and, so far, they have not seen an increase in M. bovis -caused deaths.
Autogenous vaccines can be a vital part of a disease prevention program. They fill a void left when commercial products may not be available or are not working as expected. Veterinarians are in the best possible position to decide whether autogenous products can benefit their clients. PD
Dr. Schnackel is a consulting veterinarian who lives in Fort Collins, Colorado.