Association of Plasma or Liver Vitamin A Concentrations with the Occurrence of Parotid Duct Metaplasia or of Ocular Papilledema in Holstein Male Calves

In 128 calves fed fixed intakes of carotene or vitamin A, the incidence of squamous metaplasia of the parotid duct was estimated from a broken-line regression equation to be 0.6% when plasma vitamin A≥19.5 μ g/l00ml; 19.7%, at 15 μ g; 59.9%, at 10 μ g; and 93.3% at 5 μ g. Ocular papilledema of 150 calves was 3.4% when plasma vitamin A≥17.8 μ g, 15.2% at 15 μ g; 50.0% at 10 μ g, and 84.8% at 5 μ g. These estimates agreed with the percentage ocurrence of elevated cisternal cerebrospinal fluid pressure, recalculated from data in this Journal (44:1368, 1961). Incidence of squamous metaplasia (87 calves) and of papilledema (129 calves) was 0.0 when liver vitamin A≥759 and 3,890 μ g/l00g, 1.1% and 11.6% at 500 μ g, 24.2% and 33.4% at l00 μ g, and 40.5% and 44.6% at 50 μ g. These estimates compared with the percentage occurrence of elevated cisternal cerebrospinal fluid pressure recalculated from data in this Journal (47:1016, 1964) differed at the higher liver vitamin A concentrations; however, at 50 μ g, there was reasonable agreement.