The importance of warts in cattle
is
dependent on the purpose or use of
the cattle. For show animals, warts can be devastating if they
are
present during a competition where the animal may receive a lower grade
than an animal without warts. (4,12)
For dairy cattle, warts on their teats may interfere with milking and may result in a degree of discomfort during the milking process. This can lead to reluctance to enter the milking parlour and/or a decrease in milk volume due to stress in the animals. Ultimately, these animals may be culled from the herd earlier than their herd-mates without warts - although this is by far an insignificant problem compared to dairy cows that are culled for reasons such as lameness and poor reproductive efficiency. Beef cows with teat warts may be resistant to allowing their calf to nurse, which can result in reduced growth rates and increase incidence of mastitis.
Warts located on the genitalia or in the genital area of a cow or bull require immediate treatment for breeding animals as they may be torn or broken during the mating process. This will result in reluctance to breed, susceptibility to bacterial infection of the open wound and pain for the animal. (12)
Bovine papillomavirus is generally a benign condition; however, if the warts are caused by type IV bovine papillomavirus and located in the esophogeal groove or the esophogus they have the potential to interfere with rumen digestion of feedstuffs and normal rumen motility. This may result in health issues such as temporary rumen stasis and bloat. (4,9,12)
Bovine papillomavirus IV is also important because there is a strong association between its presence, the ingestion of a plant known as bracken fern, and the transformation of papillomavirus cells into cancerous cells which may become malignant. Bracken fern is located in areas of all provinces in Canada, and it is important to understand what it looks like and to know where your cattle are grazing or where it is you are getting your feed from. (4,12, 22)
For dairy cattle, warts on their teats may interfere with milking and may result in a degree of discomfort during the milking process. This can lead to reluctance to enter the milking parlour and/or a decrease in milk volume due to stress in the animals. Ultimately, these animals may be culled from the herd earlier than their herd-mates without warts - although this is by far an insignificant problem compared to dairy cows that are culled for reasons such as lameness and poor reproductive efficiency. Beef cows with teat warts may be resistant to allowing their calf to nurse, which can result in reduced growth rates and increase incidence of mastitis.
Warts located on the genitalia or in the genital area of a cow or bull require immediate treatment for breeding animals as they may be torn or broken during the mating process. This will result in reluctance to breed, susceptibility to bacterial infection of the open wound and pain for the animal. (12)
Bovine papillomavirus is generally a benign condition; however, if the warts are caused by type IV bovine papillomavirus and located in the esophogeal groove or the esophogus they have the potential to interfere with rumen digestion of feedstuffs and normal rumen motility. This may result in health issues such as temporary rumen stasis and bloat. (4,9,12)
Bovine papillomavirus IV is also important because there is a strong association between its presence, the ingestion of a plant known as bracken fern, and the transformation of papillomavirus cells into cancerous cells which may become malignant. Bracken fern is located in areas of all provinces in Canada, and it is important to understand what it looks like and to know where your cattle are grazing or where it is you are getting your feed from. (4,12, 22)
One further concern for the presence of bovine papillomavirus is that there is experimental evidence that the condition known as sarcoids in horses may actually be caused by bovine papillomavirus types I and II. In horses, sarcoids are a tumor that can cause esthetic and functional problems and therefore requires treatment. It is wise to keep cattle with warts away from any horses that are also on the property, just as a prevention against the possibility of sarcoid development. (6, 9, 12)
Bovine papillomavirus is generally fought off by the immune system of cattle and the warts will spontaneously disapear in about 5-6 months without any treatment, but may last for more than a year. If warts are to be treated, surgical removal is generally the best option. This may be followed by the application of liquid nitrogen to ensure that all wart tissue has been killed from the site - this is a method known as cryosurgery. There is some thought that treatment of infected individuals with bovine interferon alpha may hurry the disaperance of warts, but studies are conflicting with some researchers showing this treatment to be ineffective and to actually make the warts grow bigger, faster. It is possible to vaccinate animals with a vaccine composed of crushed-up wart material from an infected animal that has been inactivated in a formalin solution. This type of vaccine is then used on infected animals in the herd and may boost the cattle's natural immunity so that they can fight off the infection sooner. However, there is also some evidence that depending on the degree of infection, the health status of the animal, and the time from original infection that the animal's are vaccinted it is possible to actually worsen the infection instead of making it better. (8, 9, 12)
Prevention of bovine papillomavirus is often more successful and practical than treatment after an infection has occured. It is possible to vaccinate un-infected animals with a mixture of ground up wart tissue and formalin (which inactivates the virus). Success of this treatment varies widely and may be ineffective. Another option is vaccination with a commercial vaccine composed of the proteins which make up the viral capsid (or the coat of the virus). This vaccine has been successful in trials, but in order to be truly effective it must contain proteins of all the virus types as there is no cross-protection between the types. Simpler methods of prevention are to separated infected animals from normal healthy animals, and to minimize the use of equipment, feeders, waters, etc. that come into contact with both groups. (12)