Hypovitaminosis A, otherwise known as vitamin A deficiency, is mainly a concern for ducks without access to green forage, or are receiving stale or poor quality feed. Vitamin A is fat-soluble vitamin that is essential for growth, vision, and maintaining integrity of mucous membranes (skin, inside of the mouth, eyes, tear and endocrine ducts, kidney tubules, etc.). Mucous membrane serves as a barrier that separates and protects the internal organs and body cavity from the outside environment. If ducks do not get enough vitamin A in their diet, their protective barriers become weakened, making them more susceptible to invading pathogens.
Since vitamin A is used by multiple systems throughout the duck’s body, the associated clinical signs also vary widely, depending on the system affected. For example since the duck’s oral cavity and sinus are lined by mucus membranes, if these areas aren’t receiving adequate amounts of vitamin A, then the protective lining may begin to erode, causing white plaques on the roof of the mouth or base of the tongue.
NRC (1994) recommends 1,500 IU/kg (681 IU/lb) for growing geese and ducks.
Ducks with a vitamin A deficiency have an increased susceptibility to infections, especially bumblefoot