USE OF THE FOALWATCH
AND SOFCHEK
TESTS FOR EVALUATION OF PRE-FOALING MILK CALCIUM CONTENT
AND THE APPROACHING READINESS FOR BIRTH IN THE MARE.
William B. Ley
Troubleshooting
It is not unusual for some mares to reach 100 to 175 ppm and remain at that level for several days at a time before proceeding up the scale to 200 ppm (or above). Variations occur between mares, and even within the same mare from year to year. Patience and careful monitoring on a once to twice daily schedule are a must. A dramatic rise, or significant change in value, over a 12 to 24 hour interval indicates that the mare is advancing towards her actual delivery.
Occasionally a value will drop from the previous day's sampling, this is not a cause for alarm. Repeat your dilution technique to be certain that it was accurate, and carefully draw up small increments of the diluted sample, inverting the FoalWatch chamber several times between each aspiration. Reading the scale with each repetition, and observing the color change.
Initial color of the diluted sample once the indicator dye has been added to it will vary from early in the mares testing period to later when she is closer to foaling. Early samples will appear more orange in color, later samples will appear a rose-pink to reddish purple. This is a normal variation we have observed and is not a cause for concern in accuracy of the result.
Read the FoalWatch scale at the first color change. At the transition stage, you may first note a slight greyish discoloration, or the solution in the chamber might appear to be colorless. Continue aspirating small amounts at a time, gently inverting or mixing the chamber between each aspiration, until you see a definite blue color. Then read the scale to determine the final value. If bubbles are present in the solution at this point, stand the vial upright for a few minutes and re-read the scale. There may be a slight alteration in the actual value once the bubbles have disappeared. Base your estimate of the actual value on the bubble-free reading, estimated to the nearest pre-marked line on the scale. If you have to guess at the value, 'fudge' to the higher ppm line to be safe.
from the desk of:
William B. Ley, DVM, MS
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