Why do pigs love biting other pigs' butts?

It may be pica. This disease is one of the problems commonly encountered in @#@227@#@ production, and it occurs frequently, especially in winter and spring when light duration is insufficient and temperatures are low. Improper feeding management, an unsuitable environment, unbalanced feed nutrient supply, disease and metabolic disorders are triggers of this disease. Because of long-term pica, pigs often suffer stunted growth, weight loss and loss of appetite, causing unnecessary economic losses for pig farmers.

1. Clinical symptoms

Pigs with pica show tail biting, ear biting, rib biting, navel sucking, and especially a liking for eating chicken manure, eating urine, rooting at the ground and gnawing wooden sticks, along with phenomena such as restlessness in the pen and jumping over rails. Mutual biting and fighting is one of the more vicious forms of pica, shown as pigs being sensitive to external stimuli, behaving restlessly, having reduced appetite and a fierce gaze. At first only a few pigs bite and fight each other, then gradually more join in, mainly biting tails and in a few cases ears. The tail of the bitten pig loses hair and bleeds, and the herd then develops a depraved appetite for blood, and the harm gradually expands. Bitten pigs often lose skin and hair on the tail, which affects weight gain, and in severe cases secondary infection with osteomyelitis and abscesses may occur; if not treated promptly, it can be complicated by septicemia and so on, leading to death.

2. Causes of the disease

1) Improper management: too high a stocking density, cramped rearing space, insufficient drinking water, large differences in size and strength among pigs in the same pen, and competition for rank are triggers of pica.

2) Environmental factors: the reason the incidence is relatively high in winter and autumn may be that a dry and highly dusty environment makes pigs irritable and leads to aggressive behavior. For example, if the temperature inside the barn is too high or too low, ventilation is poor and harmful gases accumulate, the lighting in the pig house is too strong so the pigs are in an excited state and become restless, or the pigs are frightened, the weather changes abnormally, or the pig pen is damp, all of these can cause pigs to feel uncomfortable and ultimately trigger biting and other pica behaviors.

3) Individual differences: if pigs of different breeds, or pigs of the same breed with too large a difference in body weight, are kept in the same pen, then because of differences in breed and living habits, conflicts and competition for dominance lead to fighting. When individual differences are large, the phenomenon of the strong bullying the weak often appears in occupying sleeping area and competing for food.

4) Disease factors: when pigs have external parasites such as lice and mange, it can cause skin irritation and restlessness, and rubbing in the pig house leads to exudate appearing behind the ears, on the ribs and elsewhere, which attracts other pigs and induces tail biting. Internal parasite diseases of pigs, especially pig roundworm, stimulate affected pigs to attack other pigs. Hormonal stimulation in the pigs' bodies leading to emotional instability can also cause tail biting.

5) Nutritional level: when the nutritional level of the feed is lower than the feeding standard and cannot meet the nutritional needs of pig growth and development, tail biting can occur. In addition, an imbalance of various trace nutrients in the diet, such as a deficiency or imbalance of potassium, sodium, magnesium, iron, phosphorus, calcium and vitamins in the diet, can also cause this condition.

6) Natural instinct: pigs love to play and move about, and when the environment is comfortable, piglets bite other pigs' tails and imitate each other; the imitative nature of pigs is one of the reasons that pica occurs in pigs and triggers pica in a large group. At the same time, injuries such as broken skin and bleeding further trigger pigs to bite and fight each other.

3. Prevention and control measures

1. Strengthen management

(1) Reasonably arrange the pig house: individual differences among pigs in the same pen should not be too large and should be as close as possible; stocking density should not be too high. The stocking density of pigs is generally determined according to the size of the pig house, and the principle is that it should not be crowded, should not affect growth, and should allow normal feeding and drinking; make it denser in winter and sparser in summer. Ensure a rearing area of 0.8-1 sq m per finishing pig, 0.6-0.7 sq m per growing pig, and 0.3-0.5 sq m per piglet.

(2) Raise pigs with vice habits separately: the occurrence of tail biting is often caused by individual aggressive pigs. If a pig with the vice of tail biting is found in the pen, it should be picked out promptly and raised separately. Tar can be applied to the pig's tail, or liquor above 50 degrees can be sprayed on the whole body and the tip of the nose of the pig, 3-5 times a day, and generally tail biting can be controlled in 2 days. At the same time, isolate the bitten pig, and the bitten pig should promptly have its wound cleaned with potassium permanganate solution and coated with iodine tincture to prevent wound infection; in severe cases, antibiotics can be used for treatment.

(3) Avoid stress: regulate the temperature inside the pig house well, strengthen ventilation in the pig house, and avoid stress caused by factors such as draft invasion, manure contamination and foul air. Feed high-quality feed at fixed times and in fixed amounts, keep drinking water clean, provide sufficient troughs and water troughs, pay attention to hygiene, and avoid fighting over food and uneven drinking.

(4) Dock piglets' tails in time: docking piglets' tails is an effective measure to control tail biting. The best time for tail docking is around 3 days of age, and the best tool for tail docking is a 1000-watt electric soldering iron; after plugging it in and heating it red, it is best if it can burn the tail off within 2-3 seconds. Many farmers use other methods for tail docking and as a result cause infection.

(5) Distract the pigs: place toys such as chains, balls, old tires and green feed in the pig pen to distract the pigs, thereby reducing the occurrence of tail biting.

(6) Use compound feed with balanced nutrition: choose high-quality feed ingredients. If the diet is mainly corn and soybean meal, be sure to add methionine to balance the amino acids. Appropriately increase the amount of edible salt used, and it is best to use mineral trace element salt powder. Flavoring and digestion-promoting agents can also be added to the feed; adding garlic, white sugar and flavoring agents sold on the market @#@136@#@ can improve pigs' pica.