Analysis on the causes of Chicken leg foot Disease

In the modern industry, the incidence of chicken leg and foot disease has increased, which has become a difficult problem that can not be ignored. At present, some chicken farms (households) lack sufficient understanding and understanding of chicken leg foot disease, and often do not pay attention to it, which can easily lead to misdiagnosis and mistreatment, resulting in unnecessary economic losses. According to the author's clinical practice for many years and the clinical experience of many colleagues, the causes and similar symptoms of common leg and foot diseases in chicken production are summarized as follows.

1 leg and foot diseases related to nutrition

1.1 Vitamin deficiency

1.1.1 Vitamin B1 deficiency chicks often have a sudden attack, with rough feathers, weak feet, sitting on the back, followed by leg, wing and neck spasm, and the diseased chickens land at hocks and tails with their heads leaning back in a "stargazing" posture. Sometimes lie on your side with your head back. Adult chickens have slow onset, unstable gait and progressive paralysis.

1.1.2 Vitamin B2 deficiency occurred frequently in 14-30-day-old chicks. The toe of the diseased chicken bends inward, especially the middle toe, and cannot stand on its legs, landing at hocks. When barely moving with hocks, often spread your wings to maintain your balance.

1.1.3 Vitamin D deficiency chicks are more likely to develop rickets, showing bone hypoplasia, especially foot bones and ribs. Common bone bending weakness, fracture, enlargement of cartilage at the end of bone and so on. The sternum of the laying hen becomes soft, the feet and wings are easily broken, and sometimes the feet are paralyzed and shaped like penguins.

1.1.4 the head of the infants with vitamin E deficiency contracted downward or twisted to one side, and some of them leaned back. The gait is unstable, sometimes rushing forward or sideways, showing a "drunken" appearance. Paroxysmal spasms and cramps in both legs, incomplete paralysis.

1.1.5 the growth of choline deficiency was slow, the tarsal joint was enlarged, the foot bent to the side, the tibia and phalangeal joint flattened, the metatarsal bone was short, thick and twisted, and fatty degeneration occurred in the liver.

1.1.6 biotin deficiency dermatitis with cracks and bleeding in the soles of the feet and crusts around the corners of the mouth. Sometimes mild bone shortening occurs.

1.1.7 nicotinic acid lacks short bones, enlarged tarsal joints, arched feet, bent legs and dermatitis.

1.2 imbalance of minerals and trace elements

1.2.1Ca, P deficiency and proportion imbalance chicks developed rickets, showing poor growth and development. The legs are weak, the gait is unstable, the leg bones become brittle and easy to break, the toes become soft and flexible, the ribs are beaded, and the sternum is S-shaped.

1.2.2 Manganese deficiency causes osteopathy, which is characterized by enlargement of the tibial-metatarsal joint, torsion or bending of the distal tibia and proximal metatarsal, and finally gastrocnemius tendon slipping off from the ankle.

1.2.3 selenium deficiency often occurs at the same time as vitamin E deficiency. The sick chicks show weakness, loose feathers, drooping wings, paralyzed legs and lying on the ground.

1.2.4 Zinc deficiency grows slowly, the tarsal joint is enlarged and the skin is scaly.

1.3 excessive protein content in high-protein diet, especially lysine, can induce the occurrence of chicken leg and foot disease. The sick chicken stands stillly, the joint is swollen and painful, the movement is difficult and limps, the serious person is paralyzed.

2 leg and foot diseases related to disease

2.1 Staphylococcal arthritis is more common in larger young and adult chickens, and sick chickens are crouching, limping, lying on the side or paralysis. The foot and wing joints are inflamed and swollen, especially the tarsal and toe joints. Sometimes there is a toe tumor and the soles of the feet are swollen.

2.2 chronic pasteurellosis is often confined to a certain part of the body, such as enlarged beard on one or both sides, mucus in the nose, swelling of sinuses, accumulation of secretions in the throat, arthritis, joint swelling, suppuration, claudication, etc.

2.3 Infectious synovitis mainly affects the synovium of tibia, metatarsal joint and foot pad. In severe cases, it can spread to the synovium of other joints, causing exudative synovitis, synovitis and tenosynovitis. It is difficult for sick chickens to walk, limp, gait "eight" or walk on stilts. The joints are swollen and deformed, and large blisters appear on the chest.

2.4 Pseudomonas aeruginosa has elevated body temperature, dyskinesia, tremors, inability to lie on the ground, swelling of tarsal joints, green skin of legs and abdomen of sick chicks, suppurative ulcers of feet and claws, forming scabs, and green pus balls can be seen when scabs are removed.

2.5 Aspergillosis chicks often show acute outbreaks with high morbidity and a mortality rate of 1% 50%. A few diseased chickens invade the brain tissue, causing ataxia, inverted horn arch, leg and foot paralysis and other neurological symptoms.

2.6 chicken mites can sometimes cause skin inflammation, proliferation and roughness. After the inflammatory exudate dries up, it forms a gray-white or grayish-yellow scab, the feet are swollen and look like coated lime, commonly known as "lime foot disease". Arthritis, phalangeal osteonecrosis and difficulty in walking can occur over a long time.

2.7 the elderly in the course of Newcastle disease sometimes have neurological symptoms, systemic muscle movement disharmony (especially leg and head muscles), head and neck tilting to one side, or backward dorsiflexion. Sometimes sick chickens have unstable gait, ataxia, circle movement, or backward; sometimes their wings are paralyzed and their hind limbs are paralyzed and unable to stand.

2.8 Marek's disease nerve type often occurs incomplete or complete paralysis, two legs before and after a split position, head and neck skew or droop. The sciatic nerve turns yellow or gray, sometimes swollen and thickened locally or diffusely.

2.9 viral arthritis is common in broilers and is characterized by arthritis, tenosynovitis and gastrocnemius rupture. The gait of the diseased chicken is slightly abnormal at the beginning, and gradually develops into lameness. It likes to sit on the hock joint and moves only when it is driven away. Tarsal joint swelling can not move, the affected limb can not be stretched, do not dare to bear weight. When the course of the disease is slightly longer, there is a typical stumbling gait, and most of the affected limbs are twisted outward and stunted. 2.10 chickens with avian infectious encephalomyelitis showed abnormal gait, bilateral dyskinesia or incomplete paralysis. Sometimes the feathers are loose, the head and neck tremble nervously, sway, move, squat or even lie down when frightened. Sometimes in the dog's sitting position, the body is supported by the hocks and tibia. With the development of the disease, the leg muscles are paralyzed, so that they can not walk, and are completely paralyzed.

2.11 toxic diseases such as salt, urea, dysentery, gas, sodium selenite and polyether anticoccidial drugs are also easy to cause neurological leg and foot diseases, which should be paid enough attention. In addition, when chickens suffer from streptococcosis and infectious bursal disease, there are sometimes symptoms such as unstable gait, lameness, head tremor or paralysis.

3 leg and foot diseases related to environmental and genetic factors

Often due to wet hardening of padding, excessive feeding density, cold at low temperature in the early stage, shock factors, rough and hard bottom of the net, and unreasonable distance between the lath, etc., the toe claws of broilers were deformed and the pads were damaged.

Bone deformations caused by genetic factors are common in purebred chickens and hybrid chickens, which may also be caused by congenital thyroid dysfunction.

In short, the cause of chicken leg and foot disease is extremely complex, which should be paid great attention to and carefully identified, especially the leg and foot disease caused by infectious diseases can only be diagnosed according to pathological autopsy changes and laboratory diagnosis.