What causes pigs to bite their tails? How to stop it

Pig tail biting, also known as “reverse discomfort syndrome”, is a clinical manifestation of porcine stress syndrome and a non-specific stress response.So why do pigs bite their tails? How to stop them from biting?

Why do pigs bite their tails?

The causes of tail biting in pigs are very complex, and are mainly summarized in the following explanations.

1. Abnormal animal behavior: Many researchers believe that pigs have normal behaviors such as sucking and rooting. When the environment changes and these behaviors cannot be satisfied, tail biting occurs. After weaning, piglets still have a strong urge to suckle and to massage the sow's udder. When they can no longer suckle or massage, they seek other objects to suck on, such as teats, the head, the vulva, and the tail, especially the tail. Gradually, the sucking behavior turns into tail biting. Some have observed that naturally weaned piglets are about 17 weeks old, at which time the urge for sucking stimulation is particularly strong, making tail biting very easy to induce. Pigs also have a particularly strong rooting behavior. If pigs are placed in a smooth concrete pen where they cannot root, and there is no straw or other material, this behavior can induce tail biting. Some people place straw, coal cinder, etc. in the pen, or hang up iron rings for them to explore, search for food, and play with, which can prevent tail biting.

2. Internal factors: Breed genetic factors are related to tail biting. It has been observed that Large White pigs and Landrace are prone to tail biting, and soft-eared pigs are more prone to tail biting than stiff-eared pigs. Sex is related to tail biting: the incidence of tail biting in boars is 11.8%, while in sows it is 2.6%. Age and body weight are related to tail biting. It has been found that the average age of tail biting is 40.7 days, with a maximum age of 90-120 days, and body weight of about 40-50 kg.

3. External factors: The appearance of abnormal behavior is importantly related to changes in the external forage environment. Indoor temperatures that are too low or too high can both increase the possibility of tail biting. Tail biting is especially frequent at 25°C and 35°C; maintaining temperatures above 17°C and between 20-22°C can prevent tail biting.

Stocking density and group size are related to tail biting. High density and crowded pig groups are prone to tail biting. Some believe that 0.47 sq m per pig carries a greater risk of tail biting than 0.6 sq m per pig.

How to stop pigs from biting their tails?

In our farming production, tail biting in pigs occurs from time to time, and once it occurs it is difficult to stop. The following are some tips for dealing with it, for the reference of farmers.

1. The nutritional needs of pigs must be met. One of the causes of tail biting in pigs is nutritional imbalance and improper matching in the feed. Therefore, complete compound feed should be supplied according to the nutritional needs of pigs at different stages. When tail biting is found, some minerals and vitamins should be added to the feed, while ensuring adequate drinking water.

2. Grouping of pigs must be reasonable. When purchasing a large number of pigs from other places, pigs with little difference in source, body weight, constitution, coat color, temperament, etc. should be grouped together in one pen. If there are pigs with skin wounds from being bumped during transport, they should be separated and raised in time to prevent mutual tail biting caused by the smell of blood.

3. Stocking density should be appropriate. The stocking density of pigs is generally determined according to the size of the pen. The principle is that it should not be crowded, should not affect growth, and should allow normal feeding and drinking. Generally, about 10 pigs per pen is appropriate. Make it denser in winter and sparser in summer. Strictly follow 0.5-0.6 sq m of floor space per pig for pigs aged 2-3 months, and 0.6-0.8 sq m for those aged 4-6 months.

4. Finishing pigs should be castrated early. Early castration of finishing piglets can not only improve fattening performance and carcass quality, but also help avoid tail biting caused by boars and sows mounting each other when kept together.

5. The sanitary environment should be good. Pigs are very sensitive to the sanitary environment, especially in large-scale and intensive pig farms, where there must be good ventilation equipment and a complete set of equipment for temperature regulation and manure treatment, so that the pig house meets the standards of preventing heat and cooling in summer and preventing cold and keeping warm in winter.

6. Deworming should be done regularly. Throughout a pig's life, internal parasites should be removed 2-3 times regularly; that is, deworming once each at 30-40 days, 70-80 days, and 100-110 days of age; at the same time, attention should be paid to removing external parasites such as lice and mange mites. Otherwise, the impact of parasites can lead to the occurrence of tail biting.

7. Raise pigs with vicious habits separately. The occurrence of tail biting in pigs is often caused by individual aggressive pigs. Therefore, if a pig with a tail-biting vice is found in the pen, it should be promptly picked out from the group and raised separately; for pigs that are especially aggressive and bite-prone and have no separate pen, each can be given 80-100 mg of chlorpromazine and 20 ml of 20% magnesium sulfate by intramuscular injection, or 3-4 sleeping pills by drench, to keep them quiet.

8. Prevention and treatment methods. For pig groups with mild tail biting, white liquor or gasoline diluted can be sprayed on the pig group 1-2 times, which can effectively control it; for bitten pigs, the wounds should be promptly cleaned with potassium permanganate solution and coated with iodine tincture to prevent wound infection. For severe bites, antibiotics can be used for treatment.