Animal Science Department


Date of this Version

January 1970


Published in Journal of Animal Science 30:382‑387. Copyright © 1970 American Society of Animal Science. Used by permission.


Thirty-two Yorkshire pigs (49 kg body weight, 108 days of age) were used to determine the effect of feeding-fasting interval on rate of body weight gain, feed utilization and carcass and organ measurements at a slaughter weight of approximately 90 kilograms. Treatments were: (1) Continuous ad libitum feeding,(2) ad libitum 1 day, fasted on alternate days, (3) ad libitum 1 day, fasted 2 days, (4) ad libitum 1 day, fasted 3 days. Average daily gain was reduced progressively as severity of the fasting-feeding interval was increased. Efficiency of feed utilization, likewise, was reduced as the severity of feed restriction increased, except in group 2(1 day ad libitum-1 day fasted) in which efficiency was not significantly different from that in group 1 (continuously ad libitum). Pigs with access to feed only part of the time were able to compensate partially for the time away from feed by consuming more feed during the time of free access to feed. Dressing percent, chilled carcass weight and backfat thickness were progressively reduced and percent lean cuts increased as proportion of fasting time increased. Weight of the empty stomach and intestines progressively increased, as a percentage of carcass weight, as proportion of fasting time increased. Pituitary and thyroid weights, as percentages of carcass weights, were drastically increased by the most severe fasting interval (group 4), although less severe fasting (groups 2 and 3) was not associated with an increase in their weights. Liver fat percentage and liver and kidney weights were not affected by treatment. Adrenal gland weight was increased by the two most severe fasting intervals and this was associated with an increase in thickness of the glomerulosa and fasciculata-reticularis. No other histological changes were noted in any tissue. Myristic and linoleic acid concentrations in both middle and outer layers of backfat decreased as proportion of fasting time increased, while stearic and oleic acid concentrations increased and palmitic remained unchanged.