A study of the effect of environmental lighting on growth, reproduction and behavior in turkeys (Meleagris gallopavo)
Levenick, Clifford Keith
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This study was designed to determine the effect of environmental lighting on growth, reproduction and behavior in turkeys. During the growth phase a Large White and a Medium White line of turkeys were reared on an intermittent (2L:2D) or a diurnal (12L:l2D) light regimens under white, red (650 nm) or blue (450 nm) light environments. The turkeys grew faster under blue light than under red or white light up to 16 weeks of age. However, by 24 weeks of age, the rates of gain were significantly greater under the white and red lights. Growth rates were significantly greater under the intermittent regimen as compared to the diurnal regimen for both lines and sexes. The greatest acceleration in growth rate was observed from 4 to 10 weeks of age with this advantage still evident at 24 weeks of age. There were no significant differences in feed efficiency due to regimen or color. Early mortality was highest under blue light but late mortality was greater under red and white light. Mortality was higher for the LW than MW birds. Live grades were unaffected by light regimen or color but feather condition was poorest for birds reared under white diurnal regimen. The light color and regimen had no significant effect on the histological and physiological parameters measured. However, measurements of sexual development tended to be lower in both sexes for birds reared under blue light. Turkeys growing under the blue light regimens were the most placid while those reared under the white diurnal regimen were the most nervous. In the reproductive phase, medium white turkeys from each growth phase regimen and color combination were placed into white, red and blue light pens. Mating behavior measures were higher under red and white light than under blue light. In addition, rearing of turkeys under blue lights appeared to reduce sexual behavior in Experiment 2. For most mating behavior measures, the optimum light color combination appeared to be the white growth-white reproductive light program. While all mating behavior measures were continually lower for turkeys reared under intermittent light than those reared under a diurnal regimen, these differences were not significantly different. Turkeys exhibited two types of agonistic behavior. Fights between toms and hens occurred regularly in the blue reproductive light pens and rarely in the others. The majority of the fights occurred among hens and toms reared under red light. Toms from blue growth phase pens and subsequently placed in the red reproductive light environments, exhibited a super-aggressive behavior towards any human entering those pens. Egg production and semen volume measures were significantly greater for turkeys in the red and white reproductive pens than for those under the blue light conditions. The hens in the red and white growth pens came into egg production prematurely at 27 weeks of age when maintained on an intermittent light regimen during the growth phase.
- Doctoral Dissertations