Nitrogen metabolism of gravid and nongravid female swine fed every third day.

Crossbred gilts were adapted for 40 d to a 12% crude protein corn-soybean meal gestation diet fed either as a single 1.9-kg meal every day (ED) or as an accumulated 5.7 kg meal every third day (E3D). In the first experiment the effect of meal frequency on N balance was evaluated using eight gravid gilts in a 12-d balance trial. Average N retention was greater (P less than .08) for gilts fed ED (15.32 g/d) than for those fed E3D (12.64 g/d). Daily urinary N excretion showed a quadratic effect (P less than .01) with the greatest N output occurring during the second 24-h period after the meal for gilts fed E3D. The effect of physiological state on the N metabolism response to E3D feeding was measured in a second experiment using four nongravid and four gravid gilts in a 12-d N balance experiment. Average daily N retention was greater (P less than .04) for gravid gilts fed E3D (15.04 g) than for nongravid gilts fed E3D (11.82 g). Digestibility of N and energy was not affected (P greater than .10) by feeding regimen.