Rickets in Sheep

Vitamin D Requirements of Sheep

“…After some time (3-4 months) the total serum calcium level will gradually drop. A fall in blood phosphate in sheep seems to be invariably associated with diminished appetite (Ewer, 1951) so that affected animals make poor weight gains. This is a factor of economic importance in hoggets, and if there is bone involvement as well, especially with stud rams, this aspect is accentuated.…”

“…When lambs were fed large quantities of both minerals, even when the animals were kept for a long period indoors and when the vitamin D in the diet provided only approximately 25 international units daily, there was normal growth and no evidence of rickets (Ewer, 1951). Thomas (1952) reports that adding 4 per cent.…”

“…The field evidence suggests that young, growing sheep in countries of low latitude may receive insufficient solar radiation during winter if, a t the same time, they receive a diet low in vitamin D. While there appears to be a special reason for a high incidence of rickets among sheep grazing certain green feeds, especially young oats, which will be discussed later, the disorder is seen amongst lambs and hoggets grazing pasture or given rations containing grain, cereal chaff or proteinrich concentrates (Ewer, 1951). It was observed by Andrews and Cunningham that, with four sheep given the basic diet and kept outside so that they were exposed for 94 days and 2 part days to 463 hours of bright sunshine (nearly 5 hours daily) one became rachitic and two others showed sub-optimal calcification of rib functions and radii epiphyses.…”