Prevention and treatment of vitamin A deficiency in visually impaired sheep

Sheep

1. Etiology:

Because of the lack of vitamin An in the diet, it is easy to see the disease in sheep when they are not fed for a long time. Under normal circumstances, vitamin A can be stored in the body. When the content of the feed is low, the storage part can be transferred to supply the needs. However, in the event of long-term drought, snow or lack of green feed, the vitamin A stored in the body is exhausted, so if the sheep have poor eyesight, it can be considered to be due to vitamin deficiency.

Second, symptoms:

When sheep lack vitamin A, the synthesis of rhodopsin in the retina is blocked, which affects the perception of weak light stimulation in the retina, resulting in night blindness. Sheep with vitamin A deficiency show photophobia, poor vision and even complete blindness. Corneal thickening, conjunctival cell atrophy, glandular epithelium can decline, so can not keep the eye conjunctiva moist, and show dry eyes. As the secretion of the glandular epithelium decreases and cannot dissolve the invading microorganisms, it aggravates the process of conjunctival inflammation and corneal malacia, and sometimes the changes can involve the deep layer of the cornea.

3. Diagnosis:

According to the history of long-term lack of green feed and vitamin A supplementation, a preliminary diagnosis can be made combined with night blindness, dry eyes, skin keratosis and scales, ataxia, reproductive damage and other clinical manifestations. The analysis of the contents of vitamin An and carotene in plasma and liver provides a basis for the diagnosis of the disease. Conjunctival smear examination of the increase in the number of keratinized epithelial cells has auxiliary diagnostic value.

Fourth, prevention and control:

1. Pay attention to improving the feeding conditions. Vitamin A content must be taken into account when matching diets; carotene should be supplied daily of 0.1 to 0.4 mg / kg body weight.

2. Special attention should be paid to the supply of green fodder for pregnant sheep, and hay, silage or carrots should be supplemented in winter.

3. Sick sheep with vitamin A deficiency should be immediately treated with vitamin A preparation at a dose of 10 to 20 times the daily requirement.