SUMMARY 2‐Thiobarbituric acid (TBA) values of raw pork were determined by distillation and extraction methods and those of raw beef were determined by the latter method during storage at 4° and –20°C. TBA values of these tissues were low compared to values usually reported for cooked tissue from these animals in similar environments. There were significant animal differences in TBA values of beef and pork; there were significant changes in TBA values of these tissues during storage at 4°C, but changes during storage at –20°C were insignificant. pH and TBA values were inversely related. Mathematical relationships between TBA values of pork and beef during storage at 4°C. between TBA values and pH and between results obtained by the two procedures for determining TBA values of pork during storage are discussed. The extraction method is an acceptable method for determining TBA values and is easier to use than the distillation method. The TBA test has limited use for meat samples that have been frozen.

Ten women were followed serially to determine the effect of stages of reproduction on calcium and bone metabolism. The study periods were nonpregnant nonlactating, the end of each trimester of gestation, 3 mo lactation, and postweaning. Comparisons were with nonpregnant nonlactating status for each individual. Fractional calcium absorption (P < 0.0001) and concentrations of 1,25-dihydroxyvitamin D (P < 0.01) were higher in the second and third trimesters. Total urinary calcium was higher during pregnancy and lower postweaning. Parathyroid hormone (PTH) concentrations were higher only postweaning (P < 0.01). Markers of bone turnover increased at the third trimester and during lactation: serum tartrate resistant acid phosphatase and bone specific alkaline phosphatase, and urinary deoxypyridinoline (P < 0.01). Serum procollagen I carboxypeptides increased only in the third trimester (P < 0.01). Bone mineral density by single-photon absorptiometry did not differ by period. We conclude that absorption and urinary excretion of calcium increase during pregnancy whereas bone turnover increases during late pregnancy and lactation; only renal changes consistent with an increase in PTH were seen postweaning.

A rapid, indirect, in situ technique for making accurate estimates of pasture dry matter (DM) yield would be of great benefit in grazing trials to insure sound grazing management and meaningful interpretation of results. A disk meter, designed to estimate pasture DM, was constructed and evaluated on tall fescue (Festuca arundinacea Schreb.) pastures which were grazed by yearling steers. Fifty paired observations of bulk‐height readings with the disk meter and DM yields were used to establish the regression relationship between meter reading and yield. Separate calibrations were made for four different size disks. Area and diameter of disks, respectively, were 0.2 m2, 0.50 m; 0.4 m2, 0.71 m; 0.6 m2, 0.87 m; and 0.8 m2, 1.0 m. Relative to a constant weight per unit area of 5 kg/m2, actual disk weights were 1, 2, 3, and 4 kg, respectively, for the 0.2, 0.4, 0.6, and 0.8 m2 disks. Also, additional calibrations were made for the 0.2 m2 disk with weights of 2 and 3 kg. Correlation coefficients (r) for bulk‐height and DM yield ranged from 0.79 to 0.94, and all were significant at the 1% level of probability. Neither size nor weight of disks had any significant effect on residual standard deviation or r, although the heavier weights did alter the regression coefficient (b). Tall fescue pastures changed from reproductive growth in June to a vegetative phase in September, and this also affected b values. This study indicates that the disk meter can be useful for monitoring herbage‐on‐offer in grazing experiments which have a pure stand of tall fescue.