For most of us, and our pets, vitamin D is produced in large enough quantities by a process of conversion within our bodies, using sustained levels of certain wavelengths of UV light. This process is an evolutionary trait found in virtually all mammals. However in certain conditions a lack of vitamin D can be produced. This occurs typically in northern latitudes during the winter when our pets are indoors all day while we work and then let out for brief periods in the evening or morning. The lack of available sunlight lowers vitamin D production and can produce ailments to varying degrees.
Given that vitamin D has direct influence over the absorption of calcium and phosphorus it has significant impact on development and maintenance of our pet's skeletal structures. Not as well known or understood is its effects on production of various enzymes that work with collagen structures in the body. These two issues lead us to consider that many of skin irritations and scratching that our pets endure starting about mid-November (in the North) may be the result of lowered vitamin D concentrations in the body. We now know that vitamin D is one treatment for psoriasis so it is not inconceivable that a sustained lowering of the vitamin's concentration could cause similar effects to a lesser degree.
The addition of vitamin D is achieved primarily through the introduction of cod liver oil into the diet. Although other marine based oils may provide higher concentrations of vitamin D in general terms the cod liver oil should be adequate. A typical dosage would be 5ml (1 tsp) for each 25 Kg (55 lbs.) of body weight per day. One caution though do not over supplement as this can cause negative reactions due to excess amounts of the vitamin.
