Vitamin D – and is a Fat soluble vitamin. if the horse is on good grazing with adequate daily exposure to sunshine he is able to manufacture sufficient levels of vitamin D to meet normal maintenance requirements. Stabled and hard worked horses may require a daily dietary supply, especially during the winter months.
Specific areas of involvement – Bone structure. Joint and cartilage integrity. Absorption of calcium and phosphorus from the gut.
Signs of deficiency or excess – Bone disorders. Swollen joints. General unthriftyness and weight loss. Muscular and nervous dysfunction. Calcification of soft tissue (Lungs, heart etc.)
Major interactions – calcium , phosphorus, magnesium.