Prevention and treatment of osteomalacia in caged laying hens

Osteomalacia of caged laying hens, also known as nutritional osteodystrophy and osteomalacia, is caused by the lack, deficiency and imbalance of calcium, phosphorus, vitamin D and other substances, resulting in decalcification of bone tissue and structural and morphological changes. The main reason is that there are bead-shaped lesions and brittle bones at the rib cartilage junction of caged laying hens, which is one of the high incidence diseases of high-yield laying hens.

Caged laying hens

1. Etiology:

In laying hens less than 30 weeks old, there is often a temporary lack of calcium caused by high egg production (more than 80%), but can not increase the high calcium diet in time. If there is not enough calcium to meet the needs of eggshell formation, the hen will use the calcium in its bones, resulting in calcium deficiency. Gastrointestinal dysfunction and chronic renal failure can affect calcium absorption. Factors such as lack of exercise and lack of sunlight in winter or early spring can also cause the disease.

Second, clinical symptoms:

The laying hens initially laid thin-shell eggs and soft eggs but the egg production decreased sharply or even stopped and the hatching rate of breeding eggs decreased significantly. Weak legs, walking, eating, weight-bearing is bow-shaped, and then the bone becomes soft, the femur is easy to crack or limp, can not stand, and finally crouching, landing with two legs or even hocks, bearing the weight with the tail, the hocks are inflexible, chest out when walking, as slow as a goose.

3. Preventive measures:

Often check whether the content and proportion of calcium and phosphorus in the diet of laying hens are reasonable, if not, it should be adjusted in time. Two weeks before laying hens, calcium and phosphorus were supplemented in time to make the blood calcium content of laying hens reach the prescribed index. One week before laying hens, ensure that the calcium content in the feed is more than 3%. After laying, with the increase of laying rate, the content of calcium and phosphorus in feed was increased, and the ratio of calcium to phosphorus was kept at 3-5 ∶ 1. During the peak laying period, appropriate amount of cod liver oil or animal oil should be added to the feed, especially in summer, and adequate vitamin An and vitamin D3 should be added in order to effectively prevent and control the rickets of laying hens.

4. Treatment measures:

1. Paralyzed laying hens are picked out for free breeding, fed with feed with calcium content twice as high as normal, and diets containing 4% calcium. After 2 weeks of feeding, if there are no more sick chickens, the calcium content in the diet will be restored to normal.

2. Each diseased chicken was injected with 1500 international units of vitamin D2 intramuscularly for 2 days, and ultraviolet radiation was used for 1 hour at about zero o'clock at night, in order to enhance the synthesis of vitamin D in laying hens and avoid rickets.