Pigs cannibalism: how to prevent it!
This phenomenon not only causes economic losses but also indicates serious disruptions in housing, feeding, or management systems.
In modern pig farming, one of the most alarming and insufficiently studied problems is cannibalism among pigs. This atypical behavior manifests in biting ears, tails, or flanks, and in severe cases, even eating other animals. Tail and ear biting are considered the most common and serious of these issues. A clinical observation conducted by veterinary surgeons showed that the overall prevalence of tail and ear biting across many herds was 1.2%. No pig housing system is immune to this problem. In slatted systems, the prevalence was observed in 2% of pigs, while on straw the figure was only 0.4%.
Causes of Cannibalism
Pigs have a natural tendency to chew. They are also attracted to blood, and once biting begins, it becomes contagious. Additionally, pigs’ teeth change between 3–4 weeks and 7–8 months of age, and, as is well known, all young animals tend to chew when teething, so this can be part of piglet behavior. Ordinary oral exploration can lead to “accidental” bleeding, which may cause more serious damage. However, there is no direct link between minor tail injuries caused by exploratory behavior and full-blown aggressive biting.
The range of factors that can trigger tail biting is extremely wide — from stocking density (overcrowding or understocking), temperature fluctuations, draughts, competition for food and water, veterinary diseases, mycotoxicoses, vitamin E deficiency, to high-fat diets. The inability of some pigs to find a comfortable, draught-free lying spot is one of the main causes of tail biting on farms.
Associated diseases are a frequent cause of tail biting outbreaks. Complex pathological and physiological factors arising from systemic diseases such as pneumonia, necrosis, mycotoxicoses, exudative epidermitis, eperythrozoonosis, mycoplasmosis, mange, pox, and emaciation lead to necrotic lesions, discomfort, and aggression, with tail biting being a common consequence.
Treatment and Prevention
Failure to treat can lead to infection, which may become bacteremic and spread to the joints, causing incurable septic arthritis.
Bitten pigs must be isolated to prevent further injury. A bitten tail or ear should be treated with an antiseptic or special anti-bite sprays. Applying tar to a damaged tail minimizes further damage under isolation. A veterinarian may prescribe broad-spectrum antibiotics to prevent the spread of infection.
Alongside attempts to meet pigs’ behavioral needs, a number of measures can reduce the frequency and consequences of tail biting:
Toys. Providing toys pigs can chew or bite helps prevent animal biting. Chains, PVC pipes, rubber boots, wood, etc., should always be available. However, they should not be introduced too late, when the problem has already developed. Old car tires should not be used, as exposed steel wires can damage pigs’ mouths.
Tail docking. This is the only reliable method to prevent biting, despite EC legislation banning routine docking. It must be performed within the first seven days of life, cleanly and effectively, preferably with a thermocautery device. The length of the removed tail depends on circumstances, and in high-risk cases, very short docking is acceptable and necessary.
Nutrition. Unbalanced diets increase the likelihood of aggressive behavior. Insufficient amino acids and micronutrients for fast-growing genetics may trigger cannibalistic behavior. Feed restriction or limited access to feed slows growth and encourages aggression. Easy access to drinking water is also essential.
Ventilation. Poor ventilation, especially in late autumn and winter, can quickly trigger aggression. Poor air quality irritates pigs and is a major catalyst for aggression. Ventilation should at least remove gases and moisture.
Temperature. Once pigs reach their upper critical temperature, heat stress can provoke tail biting.
Stocking density. Overcrowding adds stress through competition for feed and water. Reducing density and evenly distributing pigs across pens is critical. Limited pen space is a common cause of tail biting.
Injuries and disease. Skin abrasions, wounds, necrotic lesions of ears and tails, or skin diseases can trigger aggression, leading to cannibalism. Injured or sick pigs are more vulnerable to attacks.
Dominance and herd hierarchy. Natural social hierarchy means stronger pigs may attack weaker ones. Sorting piglets by size reduces abnormal behavior and improves performance.
Stress and poor environment. Poor hygiene, inadequate nutrition, and nutrient deficiencies increase stress, leading to pathological behaviors like cannibalism as a result of frustration and poor adaptation.
Role of Feed Additives
Increasing dietary salt (NaCl) has long been used to prevent tail biting, though overdosing must be avoided to prevent salt poisoning.
Additional magnesium supplementation reduces stress. While stress is difficult to quantify, plasma levels of cortisol, adrenaline, and noradrenaline were used as markers. Significant reductions in catecholamine and corticosterone concentrations were observed in stressed pigs supplemented with magnesium gluconate. Similarly, magnesium aspartate lowered stress responses measured by cortisol and catecholamines. Pigs given magnesium five days before slaughter had lower plasma adrenaline levels and appeared calmer. Thus, magnesium seems to enhance pigs’ ability to cope with stress, with practical applications such as reducing cannibalism during mixing and lowering the incidence of pale, exudative meat.
Tryptophan, a serotonin precursor, has long been used to reduce aggression and manage stress in both humans and livestock. Supplementation with L-tryptophan improves growth, reduces stress hormones, and mitigates pigs’ behavioral stress responses, particularly in socially stressful environments.
Glycine is important for central nervous system activity. It acts as an inhibitory neurotransmitter, regulates metabolic processes in the CNS, reduces psycho-emotional tension, has neuroprotective, anti-stress, and sedative effects, and improves brain metabolism.
Based on advanced scientific expertise and practical experience, VITAGRO NUTRITION has developed a safe and effective solution for pigs to reduce animal stress with a calming effect that prevents abnormal behaviors linked to cannibalism. The feed additive VITAMIX ANTISTRESS helps animals cope with stressors and maintain productivity, allowing for immediate and targeted responses in situations with increased demands.
Cannibalism is a serious economic issue in pig farming. Behavioral disorders occur regardless of production system and may be exacerbated by numerous factors outlined above. Therefore, prevention is the best protection against losses associated with cannibalism.