1. 1 nutritional factors
1) sow diet is deficient in calcium and phosphorus. When calcium and phosphorus in the diet are insufficient, sows will use calcium and phosphorus in their bones before and after calving. Over time, it will lead to calcium and phosphorus deficiency in sows, especially high-yield sows. After 20 days of farrowing, when the lactation of sows reaches its peak, most of the conditions tend to be serious.
2) The proportion of calcium and phosphorus in feed is out of balance. The low proportion of roughage in diet or the high productivity of pigs make the proportion of calcium and phosphorus in sow's diet unbalanced, leading to paralysis.
3) The proportion of cereals and beans in concentrate is too large. Phosphorus in cereals and beans mostly exists in the form of phytate phosphorus, which is not only difficult to be absorbed by pigs, but also hinders the absorption of calcium, resulting in serious shortage of calcium and phosphorus in pig tissues and paralysis.
4) Lack of vitamin A in the diet leads to nervous system diseases, skeletal muscle paralysis and dyskinesia, first in the hind limbs and then in the forelimbs.
5) Postpartum sows consume a lot of energy and nutrients. If they are not supplemented in time, or because of single feed, lack of minerals and vitamins, and imbalance of calcium and phosphorus, rickets can be caused in sows.
6) Long-term feeding of corn, distiller's grains, bean dregs, etc. Lead to insufficient Ca content in foreign bodies, leading to paralysis.
1.2 environmental factors
1) is easy to get sick in the season with high humidity and cold climate. Due to the lack of postpartum activities, sows lie in a cold and humid barn for a long time to breastfeed, and their own resistance is poor. Coupled with the invasion of thieves and other factors, rheumatic hindlimb paralysis is prone to occur.
2) Postpartum qi and blood loss, the mother was attacked by dampness and cold, blocking the meridians and leading to paralysis.
3) Long-term captivity and insufficient outdoor exercise. With less sunshine time, the synthesis of Ca in the body decreases and the resistance decreases.
1.3 sow coefficient
1) After parturition, sows produce a large amount of milk, and blood calcium and blood sugar enter the milk and are excreted with the milk; The amount of parathyroid hormone secreted by parathyroid gland decreases, and the body's ability to utilize bone calcium decreases, which makes it impossible to maintain the blood calcium balance in the body; In addition, due to the increase of pancreatic activity after delivery, maternal blood sugar concentration decreased, leading to paralysis.
2) Gastrointestinal diseases make the digestion and absorption of the body dysfunction, making it difficult to absorb Ca.
3) The gilts were bred too early, and the bones of the limbs of primiparous sows were in the stage of growth and development, which did not reach maturity, and the calcium storage in the bones was insufficient. Postpartum milk excretes more calcium than the sum of calcium absorbed from intestine and mobilized from bones supplied by diet, and blood calcium is negatively balanced, which leads to the occurrence of this disease.
4) Sows in puerperium, especially old sows, not only suffer from calcium deficiency during pregnancy, but also accumulate calcium deficiency during pregnancy, delivery and lactation. If the litter size is large (sow 10 or more), the lactation is strong and the bone salt is degraded quickly, it is more likely to cause this disease.
5) With the growth of the fetus, the increase of fetal water oppresses the abdominal organs, reduces the gastrointestinal activity and digestive function, and also affects the calcium absorption function of the small intestine. Before delivery, the bone thinning of lumbar vertebrae and hind limbs is easy to occur, and paraplegia and fractures are easy to occur. Moreover, once giving birth, the intra-abdominal pressure suddenly drops, the internal organs are passively congested, and the blood enters the breast, causing cerebral anemia, deepening the degree of brain inhibition, and reducing the thyroid secretion function, making it impossible to maintain the balance of calcium in the body, which is easy to cause loss of consciousness and quadriplegia.
1.4 Fetal factors
When the sow gives birth, the fetus is too large, the fetal position is not correct, it is difficult to give birth, the fetus is pulled out strongly, and the obturator nerve and gluteal nerve are oppressed or damaged, resulting in paralysis.