Castration is the surgical removal of the two testicles. It is a routine management practice for male piglets destined for slaughter. The testicles produce sperm and the male hormone testosterone. There are two reasons to castrate a male pig:
- Behaviour and meat quality. Uncastrated male pigs called boars are known for aggression. Boars will bite, shove and jump on other pigs. Boars can also be hard for workers to handle and boar aggression can be a risk to worker safety. Castrating a male pig will reduce these behaviours.
- Some boars also produce “boar taint” or “off odours.” Boar taint does not affect food safety but it does change how meat tastes and smells. Some describe it as a “musk” or a smell similar to onions or manure. Boar taint is associated with the hormones produced naturally in uncastrated male pigs. The odour evolved to attract female pigs. Castrated male pigs called barrows do not have testicles so they cannot produce these sex hormones.
Castrating very young pigs is important for several reasons. Young pigs are nursing from a sow and they get antibodies from the sow’s milk that help them heal and fight infection. Young pigs are also small enough that one person can safely perform the procedure. Younger pigs show fewer signs of pain during castration.
What time is best to castrate male pigs?
The best time to castrate a piglet is when it is 4 to 14 days of age. Young piglets are easier to hold or restrain bleed less from surgery and have antibody protection from the sow’s colostrum and milk. Piglets can be successfully castrated when they are less than four days old; however one of the major disadvantages of castrating very young piglets is that scrotal hernias are more difficult to detect and the testicles may not have descended. Examine each piglet carefully before castrating to identify those with a scrotal hernia.
Scrotal hernia in piglets
A piglet with a scrotal hernia has a loop of intestine in its scrotum.
- Hold the piglet upright so the scrotum is down to see if the scrotum is uniform in size or hold the piglet with its head down and squeeze the back legs together to lift the testicles. If there is an enlargement in one or both halves of the scrotum the piglet probably has a hernia. Do not castrate the piglet unless you are trained to repair hernias.
- The piglet’s intestines will be forced through the incision. Sometimes the testicle is removed before a scrotal hernia is discovered. If this happens the herniation must be repaired by suturing immediately. Most scrotal hernias are genetic in origin.
- Do not keep replacement animals from any litter in which one or more piglets was herniated.
- If one or both testicles are not found the piglet may be a cryptorchid. This means that the testicle(s) failed to descend through the inguinal canal from the abdomen during development. When this condition is noticed ear notch or mark the piglet and make a record of it. Often the testicle(s) will descend to a normal position as the piglet grows. The piglet should be castrated after the testicle presents itself. If one testicle has descended at the time of castration it should be removed.
Castration procedure in piglets
There are various ways to castrate piglets. The position of the animal during surgery and the method and degree of restraint are dictated by the age and size of the animal. Use either a surgical knife or side cutter to castrate. The surgical knife can be either a #12 hooked blade or straight blade. The instrument of choice must be sharp and disinfected. If the scrotum is dirty, clean it and surrounding area with a cotton swab soaked in a mild disinfectant.
Castration Methods for One Person Using a Knife
- Hold the piglet by both hind legs with its head down.
- Push up on both testicles and make an incision through the skin toward the tail. Be sure to cut low in the scrotal sac to ensure good drainage. It does not matter if you cut through the white membrane or not.
- Pop the testicles through the incision and pull on them slightly. Pull each testicle out pressing your thumb against the pelvis of the piglet. Use of your thumb is very important to ensure the cord will break off at the point of your thumb and not from deeper inside the piglet’s body. Otherwise you may cause a hernia.
- Alternatively place the piglet’s head between your legs after you have made the incisions, grab each testicle and cut the cord close to the incision with a scraping motion. Also cut any cord or tissue protruding from the incision and spray the wound with an antiseptic.
Castration Method for One Person Using Side Cutters.
This technique is best performed on piglets between four and 10 days of age. There is little or no bleeding with this method.
- Hold the piglet between your legs with the belly outward.
- Use your index finger or whichever is comfortable to use to push up on one testicle to make it more pronounced. The resulting fold of skin is where the incision is made.
- Position disinfected side cutters about two thirds of the way into the fold and make a cut directly through the scrotal tissue (right of the midline). Make a similar incision through the scrotal tissue, but to the left of the midline.
- Pop the testicles out through the incisions by pinching your thumb and index finger together. Press very firmly with your index finger against the pelvis of the piglet in front of the scrotum and pull the testicles out with the side cutters.
- Use of your index finger is very important to ensure the cord will break off at the point of your index finger and not from deeper inside the piglet’s body. Otherwise you may cause a hernia.
- Care is taken to avoid cutting through the cords beneath the testicle.
- Remove any loose cord tissue left outside the incision. Nothing but the disinfected side cutters touches the exposed tissue.
- Spray the wound with an antiseptic.
Castration Method for Two People Using a Knife
- One person holds the piglet by the rear legs while another does the castrating.
- With one hand tighten the skin over the scrotum to help expose the testicle and the site for the incision.
- With the castration knife make two incisions about as long as the testicles near the center of each. Cut deeply enough to go through the outside body skin. It does not matter whether you cut through the white membrane (tunica vaginalis) which surrounds the testicle or not.
- Squeeze or pop the testicles through the incision. Enlarge the incision slightly at the end closest to the tail if the testicle will not pop out.
- Pull out the end of the testicle which is toward the tail at a right angle to the length of the body and cut the cord close to the incision. Do not pull straight up on the testicle. Repeat the procedure for the second testicle.
- Spray the wound with an antiseptic.
- Observe castrated animals for excess bleeding or the presence of tissue or intestines (hernia). Apply pressure to the wound for about two minutes to stop any bleeding.
- Cut off any cord that may be protruding from the incision as this may serve as a wick for infection but make sure it is not intestine.
- If intestines protrude and they are black or torn it is usually best to euthanize the piglet. If the problem was recognized promptly after the intestines came out it is possible to save the piglet.
- First gently clean the intestines with clean warm water containing a surgical disinfectant and push them back through the opening holding the piglet’s head down by its rear legs. Close up by suturing the tunica vaginalis (white membrane which surrounds the testicle). If a skilled professional is not available to suture the tunica vaginalis, simply suture the castration incision closed to allow time for a skilled surgeon to repair the hernia properly a few hours later. If a skilled surgeon is not available in a few hours the piglet should be euthanized. It is much easier to replace the intestines if the tunica vaginalis covering the testicle is not removed during castration. Administer an antibiotic after surgery.