Comparative efficiency of Vetmag in New Zealand blood serum trials
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During the 1994 season the Te Awamutu Animal Health Centre conducted blood serum trials on a local Waikato herd to determine the comparative efficacy of drenching with Vetmag and a common brand of Chinese-origin magnesium product. The herd selected had been found to have a low magnesium status on routine veterinary blood testing and compromised 25 dry cows of 4+ years age. Baseline serum magnesium levels were established for each animal from tail vein venipuncture samples.
The cows were then matched into pairs on the basis of age, stage of gestation and serum magnesium levels. These pairs were then randomly split into two groups of 10 and the cows randomly divided to be drenched with either Vetmag or the Chinese origin product.
The two groups were drenched daily for 26 consecutive days with blood samples from each animal being taken at 8,19, and 26 days to assess serum magnesium levels. The samples were taken at the same time of the day. All blood samples were submitted to the MAF Ruakura Animal Health Laboratory for blood serum analysis.
Fall in serum Mg levels in first week of drenching may be attributive to an inhibition of Mg in absorption by salt (NaCl) in the drench mix.
Initial dose was at manufacturers recommended dose for high level, being 30g/cow/day for Vetmag and 45g/cow/day for the Chinese origin product. On veterinary advice, the dose of each product was increased to 1.5 times the manufacturer's recommended dose at day 8.
While the magnitude of the changes in serum Mg levels are similar for both groups, this was achieved using 1/3 less Vetmag than the Chinese origin product.
June 1996
© Copyright - freely available for reprint as long as attribution is made to Independent Veterinary Supplies Ltd (NZ) as source of material.
Vetmag® is a registered trademark to, and is manufactured by, Queensland Magnesia Pty Ltd, Australia.
