J. L. Goelz, D.V.M.
International SheepLetter

While the subjects of docking and castration may seem elementary to an experienced shepherd the procedures can cause frustration for the novice sheep producer. Most shepherds have been taught by their father, a neighbor or family friend or simply do it a certain way because that "is the way we have always done it" without regard to science or logic.
The purpose of castration is to: 1) prevent unwanted pregnancy and 2) improve the meat quality of lambs. The best time to castrate lambs is around the first weeks of life. While some producers desire to castrate and tail dock immediately after the lambs are born this temptation should be avoided as immediate castration and tail docking will affect mothering and also decrease the vigor of the lamb leading to a decrease in the amount of colostrum consumed. Many producers find it advantageous to process the lambs while they are in a small group after they leave the jugs. This allows them to observe the lambs during the next few days and easily find and treat any problems.

Regardless of timing, processing should always occur in as clean an environment as possible. The pen should be well bedded, particularly the creep area. All of the types of castration and docking cause a potential for infection with knife castrating creating the greatest opportunity for infection.

Methods of castration: The first and most common method of castration is the elastrator or rubber ring method. In this method a small rubber ring is stretched over the scrotum and testicles and is released above the two testicles. The ring acts as a tourniquet and cuts off blood supply to the testicles and lower scrotum. The area beneath the ring will die and fall off in the next one to two weeks. It is important that the operator grasps both testicles and keeps them below the ring when the ring is applied. If a part or all of one testicle is above the ring it will remain functional and will result in a ram. Many producers will also use the elastrator bands to dock the tail. When an elastrator band is used you should also vaccinate the lamb with tetanus toxoid as the band creates an anaerobic environment for the Clostridia tetani organism to thrive.

Vaccination with tetanus toxoid will allow the animal to generate antibodies to the tetanus toxin and thus be protected by the end of the two-week incubation period. Many producers will also administer 1 mL of long-acting penicillin at this time for further protection.

Another method of castration is the knife or open castration technique. In this method the bottom third of the scrotum is pulled away from the lamb and cut off with a clean scalpel. The remainder of the scrotum is pushed toward the lamb and the testicles are visualized. The testicles are then grasped with clean fingers or instrument and are pulled out with steady pressure. The lambs should be monitored frequently throughout the next 24 hrs. for hemorrhage. 1 mL of penicillin injected subcutaneously is very effective in preventing infections.

The last and least popular method of castration is the burdizzo method. The burdizzo is placed on the scrotum of the lamb above the testicle, the spermatic cord is felt with your fingers and held over to the side. The handles are then squeezed shut. The device will break the spermatic cord but not the skin. The same procedure is then done to the other testicle. Care must be taken to only "crush" a small area of the scrotum and to only do one spermatic cord at a time because crushing of the entire neck of the scrotum will stop blood flow and the entire scrotum will become necrotic and fall off. If the procedure is done correctly the testicles will lose blood supply, swell, and then shrivel and degenerate. The procedure has little advantage over the elastrator band and is more difficult to perform.

Docking: The purpose of docking the tail on sheep is to prevent fecal material from collecting on the tail and hindquarters of the lamb. This fecal material keeps the wool damp and is an excellent environment for flies to lay eggs and produce maggots, commonly called "fly strike" or "screwworm". The easiest method of docking tails is to use an electric tail docker. This device resembles a vise grip with a heating element attached to one of the jaws. When the jaws close the heating element burns through the tissue of the tail and cauterizes the blood supply. This method is technically easy to do even for a rookie producer. The device is currently out of production and used ones are hard to come by. The same elastrator band that is used for castration also is a very easy and effective way to dock the tail. Four to five days later remove the dead tail below the rubber ring and give a second shot of long lasting penicillin. This will help in reducing tetanus.

Pulling the tail off will result in infections of the tail stump. Another convenient method of docking is to use an emasculator. This is a device that has a cutting blade and crushing groves that crush the vessels near the cut. When using an emasculator the cutting blade should be closest to the part of the tail that will be removed. Perhaps an easier way to remember which direction to apply the emasculator is to have the nut on the hinge in the direction of the tail portion that is to be removed. A burdizzo can also be used to crush the tail. The tail is then removed with a knife inside the jaws. The length of "dock" or tail that remains on the animal is somewhat controversial. If the cut is made closer to the lamb than the end of the caudal tail folds or closer than the second tail vertebrae you will sever some of the nerves that innervate the rectum. This can predispose the lamb to rectal prolapse.