A SIMPLIFICATION OF THE DEUTERIUM-OXIDE DILUTION TECHNIQUE USING FT-IR ANALYSIS OF PLASMA, FOR ESTIMATING PIGLET MILK INTAKE

Previous studies estimating milk intake using deuterium oxide (D2O) as a tracer have required sublimation of the sample fluid (usually plasm a) to remove solids and retrieve total water. This procedure has been simplified by directly measuring the D2O content of plasma with a Four ier transform-infrared (FT-IR) spectrometer, removing the requirement for sample sublimation. Comparisons of samples that were split and the n analysed as water of sublimation and as total plasma were performed. It was found that the direct analysis of the plasma could be achieved without a loss in fidelity of the results (sublimated v. plasma, r(2) = 0.976; n = 26). Linearity of assay standards was very high (r(2) > 0.997). The modified technique was used to determine the milk intake b y piglets from litters of 7 sows during established lactation (Days 10 -15). Water turnover (WTO) was shown to be the primary point by which differences in the piglet milk intakes were influenced. Differences in the milk composition had minimal effect on the milk intake determinat ions. Milk intake by each piglet was shown to be strongly correlated t o piglet growth (r(2) = 0.59, P < 0.01). The relationship between milk intake and piglet growth was even stronger when examined based on the data from all piglet litters (r(2) = 0.84, P < 0.01).