The effects of LED light flicker on turkey hen production, health, and welfare to 11 weeks of age
Date
2024-04-25
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0009-0008-1843-329X
Type
Thesis
Degree Level
Masters
Abstract
This study examined the impacts of light-emitting-diode flicker on Nicholas Select turkey hens (n=3267) to 11 weeks (wk) of age. There were three treatments: the 30 Hertz (Hz) treatment (30HZ) the 90 Hz treatment (90HZ) and the 195 Hz treatment (195HZ). Birds were randomly assigned to nine independently controlled rooms (364 birds/room at placement). Performance was evaluated through body weight (BW) at 0 days (d), 4, 8, and 11 wk of age. At 0d-4, 4-8, and 8-11 wk BW gain, feed intake (FI) and feed-to-gain ratio were examined. At 10 wk, a sample of 30 birds/room was individually weighed to examine uniformity. Mortality and culls were also collected twice daily. Video recordings were taken at 4, 8, and 10 wk for 18 hrs which were scan sampled at 20-minute intervals to determine the percentage of time (%t) birds spent performing different behaviours. At 10 wk, 20 birds/room were examined for mobility (gait score), footpad lesions, feather condition, and feather cleanliness. At 11 wk 4 birds/room were euthanized and the right eyeball was excised and measured for weight, medio-lateral diameter, dorso-ventral diameter (DV), and anterior-posterior size (AP). Heterophil-to-lymphocyte (H/L) ratios were determined using blood samples at 4, 8, and 11 wk (20 birds/room). Litter quality was examined at 11 wk. Incidences of aggressive damage on birds were monitored twice daily. For the first 7 d and at 4, 8, and 11 wk, a novel object test (NOT) was performed to examine fearfulness. Data were analyzed using Proc Mixed (SAS 9.4). Tukey’s range test was used to separate means with significance declared when P<0.05. Birds in the 30HZ weighed less than those in the 195HZ at 8 wk with those in the 90HZ intermediate (P=0.025). The birds in the 30HZ had higher BW gain from 8-11 wk compared to those in the 90HZ with those in the 195HZ intermediate (P=0.003). From 0d-4 wk and 4-8 wk, birds in the 30HZ had reduced FI (P≤0.001, 0.001, respectively). Mortality corrected feed-to-gain was improved from 8-11 and 0d-11 wk in the 30HZ compared to the 90HZ with the 195HZ intermediate (P=0.048, 0.040 respectively). Infectious mortality was reduced (P=0.049) in the 195HZ versus the 90HZ from 0d-11 wk with the 30HZ intermediate. Total mortality was reduced in the 195HZ from 0d-11 wk (P=0.024) and 0d-4 wk (P=0.005). From 4-8 wk, round heart mortality was higher in the 30HZ (P=0.040). Footpad scores of 0 were seen more frequently for birds in the 90HZ, resulting in better average footpad scores (P=0.011, 0.021, respectively). Average feather cleanliness was improved and scores of 1 were more frequent for birds in the 90HZ compared to those in the 195HZ with those in the 30HZ intermediate (P=0.021, 0.030, respectively). Flicker frequency did not affect litter quality or NOT. The DV (P=0.046) and AP (P=0.033) of birds in 30 Hz were increased compared to 195 and 90 Hz, respectively. Bird behaviour varied across treatments with no clear pattern. The %t birds spent gentle feather pecking was reduced at 4 and 8 wk in the 30HZ (P=0.040, 0.016 respectively). At 8 wk, %t wing flapping was reduced by birds in the 195HZ (P=0.004). The %t birds spent fighting (P=0.049) and aggressive pecking (P=0.022) was reduced in the 30HZ compared to the 90HZ at 8 wk with the 195HZ intermediate. Birds reduced the %t preening in the 30HZ compared to the 90HZ and 195HZ at 10 wk (P=0.034). Incidences of aggressive damage were reduced at all ages at various locations for birds in the 30HZ with the exception of damage directed towards the neck at 11 wk (P<0.001). The H/L ratio of birds in the 30HZ was reduced compared to those in the 195HZ at 11 wk with those in the 90HZ intermediate (P=0.044). Overall, visible light flicker had negative impacts on production early in a turkey’s life; however, effects were not seen by the end of the production period. Aggression was reduced under the 30HZ; however, this may not be beneficial as other behaviours indicate this may have been due to a reduction in activity. Stress also seems to be reduced, based on H/L ratios, when lamps flicker at 30 Hz, though this is likely due to the reduction in aggression rather than a direct effect of flicker.
Description
Keywords
Light flicker, turkey hen, behaviour, welfare, production, health
Citation
Degree
Master of Science (M.Sc.)
Department
Animal and Poultry Science
Program
Animal Science