1. Biotin deficiency and split trotters
Swine split hoof disease widely exists in large-scale intensive pig farms, and about 80% breeding pigs have been eliminated because of the disease, which has brought huge economic losses to pig farms. When biotin is lacking, the strength and hardness of the cuticle of hoof can't be maintained, resulting in cracking of hoof shell, transverse cracking of hoof, cracking and bleeding of foot pad, and sometimes hind leg spasm, depilation, dermatitis and other symptoms. It causes the cuticle of the hoof to become soft and easy to wear, and the pigsty ground is rough, which leads to the split of the hoof, and then the sick pig will have fissure infection and limp in severe cases. Especially when the weather turns from warm to cold in autumn to early winter, in a dry and cold climate, the occurrence of hoof inflammation is often accelerated.
2. Causes of biotin deficiency
(1) The corn/soybean meal diet is widely used, but it lacks the feed rich in biotin such as yeast, whey and fermentation by-products.
(2) The feed contains biotin antagonistic factors, such as Streptomyces antibiotic protein and some antibacterial drugs (such as sulfonamides). ) and chloromethyl ethylamine oxide (pesticide).
(3) The oxidative rancidity of feed will destroy biotin. For example, improper heat treatment and granulation of feed, improper storage, improper temperature and humidity will all lead to the loss of biotin. In addition, biotin in premix can be destroyed by trace elements such as high copper, choline chloride and minerals. The titer of biotin will also decrease or fail.
(4) The interaction between biotin and other nutritional factors also affects the absorption of biotin. For example, fat, pantothenic acid, vitamin B6, vitamin B 12 and folic acid in the diet are all related to the absorption and metabolism of biotin.
(5) Diseases or other factors affecting the digestive tract will reduce the synthesis or absorption of biotin by the small intestine.
(6) Variety improvement and growth rate, lean meat rate and feed conversion rate increase, and the increase of sow litter size every year leads to an increase in biotin demand.
3. Clinical symptoms
When sows lack biotin, their body temperature, breathing and heartbeat are normal, but their fur is rough, and they have seborrheic dermatitis, especially after the ears and ears, and some of them are anorexia. The main manifestations are split hoof and limping. Cracks and ulcers appear on the soles of the sick female pig's trotters, and some soles are cracked horizontally or even bleeding; In addition to cracked hooves, some sows will also have cracked hooves and festering hooves. Sick sow's sick hoof can only be lifted but can't touch the ground. Some front and rear limbs are sick at the same time, and the rear limbs are cracked and ulcerated.
diagnose
Mainly pay attention to the differential diagnosis with pig foot-and-mouth disease. Foot-and-mouth disease in pigs occurs frequently in autumn and winter. In severe cases, there will be symptoms similar to hoof crack, such as reluctance to walk and inability to lie on the ground. But the difference is that foot-and-mouth disease is characterized by blisters and erosion on the hoof, accompanied by systemic symptoms such as elevated body temperature, and hoof crack is the main disease. Therefore, we must strictly distinguish between these two diseases to prevent unnecessary economic losses to farmers due to misdiagnosis and mistreatment.
5. Preventive and control measures
(1) to cultivate varieties resistant to limb and hoof diseases. ① Population selection: through the selection of the firmness of pig limbs and hooves, the structure of pig limbs and hooves can be improved, and the whole body shape can be changed, thus enhancing the possibility of resistance to the disease. (2) Individual selection: Individuals who are too big, too thin limbs and hooves, too heavy supporting bones per unit area, and easy to cause limb and hoof injuries are resolutely eliminated without using seeds.
(2) Improve feed nutrition, feed a completely balanced feed, and ensure the supply of minerals and vitamins, especially biotin and linoleic acid. (1) Minerals: Ensure sufficient supply and proper proportion of calcium and phosphorus, and ensure the supply of trace elements such as zinc, copper, selenium and manganese. ② Vitamins: To meet the needs of vitamin D, adding biotin can improve the hardness of hoof shell. (3) Linoleic acid: naturally dried corn is rich in linoleic acid and is not damaged; Both expanded soybean and soybean oil contain a lot of linoleic acid, which is beneficial to the absorption of biotin. Therefore, when preparing feed for breeding pigs, it is suggested to use naturally dried corn and add soybean oil or a certain proportion of puffed soybean.
(3) Improve the torus structure, texture and management. (1) The cement floor should keep proper flatness and inclination less than 3 degrees, and the floor should be free of sharp objects and accumulated water. ② It is best to use epoxy resin leakage floor on the ground of intensive pig farms. ③ Conditional pig farms should keep pigs outdoors for a certain period of time and receive sunlight, which is beneficial to the synthesis of vitamin D. ..
(4) Improve the feed formula. Add 0. 1g/kg zinc sulfate to each kilogram of sow feed (pregnant sow feed and lactating sow feed) on the basis of premix, and keep it for 7 days. Add 0. 1.5g/kg rovicin H-2 (containing 2% biotin) to each kg sow feed. After 7 days of hoof-adding treatment, limb and hoof cleft disease was basically cured.
(5) To prevent secondary infection, a foot bath device is set at the entrance and exit of the sports ground, and 1 ~ 2ml/L formalin solution is put into the bath for disinfection. After disinfection, the pigs with or just had split hoofs were treated with zinc oxide ointment or washed with 1g/L potassium permanganate solution, dried and coated with chlortetracycline ointment, once a day 1 time; Because of secondary infection such as split hoof and grinding sole, the limbs and hoofs are red and swollen, which can be treated with penicillin and fish fat.