Symptoms and prevention of vitamin d deficiency in chickens

Vitamin D3 affects chicken growth. Vitamin D3 can regulate the metabolism of calcium and phosphorus in the body, promote the absorption of calcium and phosphorus by the intestinal tract, and have a direct effect on the calcium precipitation and osteogenesis of bone tissue.

I. Clinical symptoms

When chicks lack vitamin D3, symptoms appear 10-11 days after hatching, usually about 1 month. The occurrence time was mainly related to the deficiency of vitamin D and calcium in the feed and the content of vitamin D and calcium in the eggs. The initial symptoms of chicks are weak legs, soft and curved beaks and claws, and unsteady and laborious walking. After landing on the hock joint, crouching rest, growth retardation or complete cessation. The bones are soft or enlarged, especially the ribs, which are significantly enlarged at the junction of the ribs and costal cartilage and form rounded nodules (moniliform swelling), scoliosis of the sternum, and depression of the sternum, making the chest smaller. The spine curves downward at the sacral and caudal levels. Long bones are brittle and easy to fracture. Other symptoms are loose feathers, tarnish and sometimes diarrhea.

Vitamin D3 deficiency in laying hens begins to show symptoms 2-3 months later. Early performance for the thin-shell eggs and soft-shell eggs increased, after the decline in egg production, and finally stopped laying. Egg hatchability decreased. Flattening of the beak, claws, and keel, bending of the keel, invagination of the sternum and vertebral junction, and inward curvature of all ribs along the thorax. In later stages, the joints swell and the hen assumes a special posture of sitting on her legs. Long bone brittle, easy to fracture. Most embryos die at 10-17 days of age.

II. Pathological changes

Chickens are characterized by chain-like changes at the junction of ribs and spine, and poor calcification of bone parts of long bones. The pathological changes of adult hens are soft and brittle bones, and small spherical protrusions on the inner side of the ribs.

III. Prevention and control measures

High-yielding hens and developing chicks should have adequate vitamin D3 added to their diets to prevent vitamin D3 deficiency. When chicks lack vitamin D, each can be fed 2-3 drops of cod liver oil, 3 times a day. Rickets chicks were fed vitamin D 2000 IU per feed. For chickens lacking vitamin D, in addition to feeding green feed high in vitamin D or adding vitamin D as needed, they should also be exposed to more sun to ensure sufficient sunshine time.