Vet Call: Health risk when purchasing cattle

By Dr. Bob Larson, DVM
Reprinted with permission from the Angus Journal.

One issue in the buying and selling of cattle that is often not considered until a problem arises is the health aspects of the transaction. While every business deal involves some risk, including health risk, the level of risk is not the same for every transaction and producers and their veterinarians have options to lessen the likelihood and/or extent of negative outcomes.

In general, the less health information that is available for a sale animal, the greater risk the purchaser is taking. In many situations, the seller does not possess specific information about the health of the cattle they are selling or the potential negative outcomes that may occur when the purchased cattle are introduced into the buyer’s herd. Because a number of negative health outcomes can follow the introduction of new cattle into a herd, the buyer needs to beware of taking greater risks than should be reasonably expected.

When purchasing cattle to introduce into an existing herd, some potential health risks include: injury during transport, the stress of transport and a new environment causing a purchased animal to break with disease leading to illness of the purchased animal or transfer of germs or parasites to the herd, the purchase of cattle that have not been exposed to the germs commonly found in the home herd leading to illness of the purchased animals, and purchasing an animal that is a persistent carrier for an infectious disease and exposing the home herd to an unfamiliar germ.

The risk of injury can be decreased though careful handling and good loading, unloading and transport equipment. Good design and maintenance as well as appropriate flooring and bedding in transport trailers. A transportation plan including considerations of length of travel, weather exposure during travel and skill of the driver to avoid excessive fatigue on the part of the cattle being moved are all considerations to reduce the risk of injury of purchased cattle.

Stressed cattle are more likely to become ill, and to shed germs and parasites that can be spread to other cattle. Even when healthy cattle are transported to a clean environment in safe transport trailers, some level of stress can be expected. This potential period of greater susceptibility to disease and greater risk of exposing other cattle to disease-causing germs is the reason veterinarians recommend cattle being added to a herd are separated (quarantined) from the current herd for a period of at least 30 days so the new cattle can become completely acclimated and can have recovered from the stress of being transported to a new environment.

Even though the purchasers of new cattle are often concerned about any germs or parasites the new cattle may bring into their current herd, an equally important risk is that newly purchased cattle may be exposed to unfamiliar germs present in the home herd –– causing the new cattle to become sick. This risk can be addressed by using a period of time after the original 30 days of complete separation from the current herd to allow limited contact of the new additions with a few cattle from the original herd. Older cows or animals that are being culled are often used for this purpose.

Finally, the risk that many veterinarians and producers consider first when protecting a herd from the risk of introducing new cattle is purchasing an apparently healthy animal that is a persistently infected carrier of a disease that is not currently a problem in the herd. There are a number of important diseases that can enter a herd by the purchase of a carrier animal. In my opinion, the diseases that fall in this category that deserve the greatest attention in many parts of the U.S. are trichomoniasis (trich) and bovine viral diarrhea (BVD). Other diseases that have persistent carriers and that may be of particular concern for some herds include: anaplasmosis, Johne’s, and bovine leukosis virus (BLV).

Because of the amount of loss that can occur and our current disease-control abilities, no herd should tolerate the import of cattle infected with trich or BVD. However, for some other diseases that have persistently infected carriers, it is not always wise to insist in imports being free of the disease-causing germs. For example, in some parts of the country where anaplasmosis is extremely common, it may be better to purchase cattle that have been exposed to the organism previously and are themselves carriers. In contrast, if you live in an area with very low anaplasmosis risk, you need to protect the home herd by purchasing cattle that are not carriers. For diseases such as Johne’s and BLV, many herds already have carrier animals, and insisting that purchased replacements be negative won’t make much impact on the current herd’s health status.

My advice is to have plans to keep any cattle potentially infected with trich or BVD out of a breeding herd and to know the status of your herd for any other infectious agents you may want to exclude. Work closely with your veterinarian to develop the best plan for your specific herd to manage the risks of brining in new cattle to your herd. In many situations, it is helpful for your veterinarian to talk to the supplier’s veterinarian so the health status of your herd and the source herd can be compared. You should have a quarantine time when you can watch herd additions closely for at least 30 days. If any of the purchased cattle show signs of illness during that 30-day period –– keep them quarantined longer so that a full 30 days passes after the last episode of illness until the new cattle are allow to have contact with your herd. At the end of the quarantine period, consider exposing the herd additions to older (possibly culls) cattle so that purchased cattle are exposed to the home-herd’s germs and parasites while you can still watch them closely.

Purchasing herd additions that meet the genetic and marketing goals for your ranch is an important part of ranch management. Managing herd additions to limit the health risks involved is an often overlooked consideration in the transaction.

Dr. Larson is a professor of production medicine with the College of Veterinary Medicine at Kansas State University, Edgar E. and Elizabeth Coleman Chair of Food Animal Production Medicine, executive director of Veterinary Medical Continuing Education, and faculty member with the Beef Cattle Institute. His area of specialization is the integration of animal health, production efficiency and economic considerations in beef cattle production. This column is reprinted and redistributed with permission from the Angus Journal.