PSA-Processing & Products: Meat Quality

Lighting programs that provide longer daylength as a broiler ages reduce the incidence of ascites and sudden death syndrome. Birds given this type of program often have an increased incidence of carcass scratches due to increased bird activity. The turkey industry uses microwave technology to restrict claw growth and reduce carcass scratches. One concern is that the treatment may reduce bird growth rate. The objective of this study was to determine if microwave toe-treatment would reduce growth rate of chickens if used to reduce carcass scratches for broilers on an increasing photoperiod program. Two replicate trials were conducted with 728 female and 728 male broilers in each trial. Half of each sex was toe-treated using microwave energy upon delivery from the hatchery. The birds in each trial were randomly assigned to four rooms with 8 pens per room. Two rooms were given 23 h of light per day from start to finish and the other two rooms were on a lighting program with short daylength after the first three days, which increased to 23 h by day 31. Light intensity was the same for each lighting program. For half the pens, the bird’s growth rate was measured by catching and weighing each bird in the pen on day 7, 14, 24, 31. On day 38, the birds from all the pens were removed and weighed. For six pens per room, computerized bird scales were installed to continually monitor bird weight. Five birds per pen were shipped for slaughter and carcass scratches monitored. Toe-treatment reduced carcass scratches for both lighting programs of which increasing photoperiod had the higher incidence (p<0.05). Based on the traditional weighing method, toe-treatment reduced bird weight on day 14 and 31 (p<0.05). The computerized scales indicated that the toe-treated birds were lighter on day 14 and 24. For both sources of bird weight, the birds given an increasing photoperiod were lighter than those with continuous light on day 7, 14, 24 and 31 (p<0.05). On day 38, there were no lighting and toe-treatment effects (p>0.05). Collectively, the present results demonstrated that microwave toe-treatment and the increasing lighting program didn’t influence body weight of broiler chickens at market age.