Newberry R C
Agriculture Canada, Research Station, Agassiz, British Columbia, Canada.
Poult Sci. 1992 Sep;71(9):1471-9. doi: 10.3382/ps.0711471.
Two 17-wk experiments compared the effects of an increasing photoperiod treatment (INC) versus a constant photoperiod treatment (23H), and intact toes versus clipped toes, on the breast button incidence and performance of heavy tom turkeys. Under INC, the photoperiod was increased gradually from 8 to 23 h between 4 and 16 wk. Under 23H, the photoperiod remained constant at 23 h. Use of INC versus 23H resulted in a significant reduction in breast button incidence at 17 wk in both experiments (P less than .05). Toe clipping had no effect on breast button incidence. The presence of breast buttons was positively correlated with body weight at 12 wk, and area of unfeathered skin over the keel at 17 wk. In Experiment 1, the photoperiod treatments had no significant effect on 17-wk body weight or mortality, but the INC treatment had an adverse effect on feed efficiency (P less than .05). In Experiment 2, turkeys reared under INC were heavier at 17 wk (P less than .05), with similar feed efficiencies. Mortality was significantly lower on INC than 23H up to 12 wk in Experiment 2 (P less than .05). Turkeys with intact toes were .44 kg heavier than turkeys with clipped toes at 17 wk in both experiments (P less than .05) and had similar feed efficiencies. Mortality to 4 wk was lower for turkeys with intact than clipped toes in Experiment 2 (P less than .05). Increasing photoperiod treatments have potential for improving turkey performance, survival, and carcass quality.(ABSTRACT TRUNCATED AT 250 WORDS)
