Evaluation of post mortem magnesium concentration in bovine eye fluids as a diagnostic aid for hypomagnesaemic tetany
McCoy, M.A.; Kennedy, D.G.
Veterinary Record 135(8): 188-189
1994
ISSN/ISBN: 0042-4900 PMID: 7992479 Document Number: 427403
To determine the diagnostic usefulness of PM eye fluid magnesium analysis, blood samples and both eyes were collected from 254 adult cows after slaughter. Vitreous and aqueous humour were sampled immediately from one eye of each cow and from the remaining eyes, which were stored at 19 degrees C, at intervals of up to 64 h PM. Each eye was sampled once. Potassium concentration in aqueous and vitreous humour showed large increases from 16 h onwards indicating PM changes. Magnesium concentrations fell in vitreous humour samples during the first 16 h and thereafter did not change while in aqueous humour samples the concentration rose by 15% after 16 h and continued to rise. The correlation between plasma magnesium and vitreous and aqueous humour magnesium concentration was very poor. The results of the study which included only an small number of cows with low serum magnesium concentration suggest that the validity of using PM eye fluid magnesium concentrations as a diagnostic marker for hypomagnesaemic tetany is highly questionable.