Abstract
This experiment was designed to investigate the fluctuation of weekly body weight gains of growing swine from a standpoint of the time serial analysis. The animals used were 24 pigs, consisted of 6 litters (3 litters of Landrace, 2 Landrace _??_× Middle Yorkshire _??_ F1, one Middle Yorkshire _??_× Landrace _??_ F1), among which 16 pigs (4 litters) were castrated and the remaining 2 litters were intact females. After weaning, 4 pigs in each litter were selected, and were fed under the same condition until the end of the experiment. From the weaning to the slaughter, body weight of each swine was measured every 7 days for 21 weeks. 1. Fluctuations of weekly body weight gain of 20 pigs (83.3%) showed recurrent changes (recurrent swine). From an analysis of their correlograms, it was recognized that their fluctuations were periodic in 9 among 20 recurrent pigs. However, the average length of the period could not be calculated because appearances of significant γk (k=1, 2, ……, n weeks) were irregular in each individual. 2. Dressed weights and dressed carcass percentages were larger in the recurrent swine than in the non-recurrent ones, although their difference was not significant. 3. Relationships between the mean square successive differences (δ2) indicating the amplitude in the fluctuation and the total gains and the dressed weights and the dressed carcass percentages were no difinite, respectively. 4. Deviations of the fluctuation patterns within a litter were much smaller than those among litters. It is presumed that the growth pattern including its periodicity is determined mainly by genetic factors. However, further investigations are necessary to verify the concept of periodic growth in other species.
