| Abstrakt: |
Two experiments involving 288 pigs were conducted to determine the effects of short-term feed restriction during the growing period on average daily gain (ADG), average daily feed consumption, feed required/unit of gain (F/G), age at 100 kg and average backfat depth at 100 kg. Pigs were fed 100, 85 or 70% of ad libitum consumption for 2- or 4-wk periods in Exp. 1 and 100 or 85% for 2- or 4-wk periods in Exp. 2, and then allowed ad libitum consumption during the postrestriction period to 100 kg body weight. During the restriction period, ADG was reduced by feed restriction, but F/G was not affected. In the postrestriction period, daily feed consumption was similar for all treatments, while ADG tended to be higher for previously restricted than for control pigs, and pigs fed 85% ad libitum tended to gain faster than those fed 70%. In Exp. 1, pigs restricted to 85% for 4 wk gained 8% faster than control pigs and F/G was reduced by 5.6% after ad libitum consumption was resumed. For the total test period (including restriction), ADG was not affected by treatment in either experiment. In Exp. 1, restricted pigs consumed less feed (P<.07) and were more efficient (P<.07) than control pigs. The same trend was present in Exp. 2. Data from Exp. 1 and 2 for control treatments and those restricted to 85% of ad libitum for 2- or 4-wk were pooled and analyzed. During the postrestriction period, previously restricted pigs had higher ADG (P<.05) and were more efficient (P<.02) than control pigs, but intake was not affected. Pigs restricted for 4 wk were more efficient (P<.05) and tended to grow faster than pigs restricted for 2 wk. For the total test period, no significant differences were present for ADG, age at 100 kg or backfat thickness, but restricted pigs consumed less feed (P<.10) and were more efficient (P<.07). Pigs restricted for 4 wk had lower F/G than those restricted for 2 wk, but did not differ in ADG or daily feed consumption. Results show that short-term feed restriction results in subsequent compensatory response in ADG and F/G, and not in daily feed consumption, suggesting that restriction causes more efficient digestion or utilization of nutrients after ad libitum consumption resumes. |
