Special Veterinary Pathology

SELENIUM

Source

• Soil, Water, Feed

Function

• Component of enzyme glutathione peroxiase (similar to Vitamin E) (an antioxidant)

Deficiency

Causes 

• Alkaline soils & excess of sulphate fertilisers
• ↓ Se content in plants
• Such plants fed to animals causes Se deficiency
• 0.05 ppm in animal feed – deficiency

Diseases due to Se deficiency

• Muscular dystrophy (White muscle disease)
• Atrophy of pancreas - ↓ enzymes (lipases)
• Absorption of fat and fat soluble vitamins affected
• ↓ vit. E
• Neonatal mortality
• Unthriftiness
• Chronic diarrhoea - Selenium responsive disease
• Infertility, abortion, retained placenta
• Dietetic hepatosis in swine

Chronic selenium poisoning

“ALKALI DISEASE”

• Skin & hoof affected
• Alopecia, rough hair coat (mane & tail)
• Cracks in the hoof “BOB TAIL DISEASE”
• Detachment of hoof
• Lameness

• Modification of structure of keratin due to replacement of sulphur with Se

Lesions

• Chronic venous congestion of lungs, liver
• Myocardial necrosis
• Oedema of organs
• Hepatitis; nephritis

Poultry

• Muscular dystrophy
• Exudative diathesis
• Encephalomalacia
• Responds to supplements with Se & vit. E
• Hatchability ↓ in ↓ Se

Selenium poisoning

• ↑ Se content in Soil
• Example : Astragulus & Oxytropis
• 50 – 15000 ppm Se
• Se interferes with action of sulphur containing enzymes & amino acids → Necrosis
• Se is antogonostic to sulphur

Acute poisoning

• ↑ consumption of seleniferous weeds
• GI symptoms
• Respiratory symptoms
• Myocardial failure

Cattle

“BLIND STAGGERS”

• Continuous walking
• Butting against hard objects
• Blindness
• Paralysis
• Weakness
• Respiratory failure
• Cyanosis
• Death

Lesions of Chronic venous congestion noticed