Comparative Studies on Production and Animal Welfare Parameters in Broiler Chickens Kept Under a Constant and a Decreasing Light Intensity Program.
Conicyt InstrumentBecas en el Extranjero – Becas Chile
AuthorAsencio Schmidt, Patricio Sebastian
Summary The aim of the present study was to examine the effects of a constant and decreasing light intensity program on production and welfare of broiler chickens. Thus, in the period from June to September 2016, a total of 69.400 Ross x Ross 308 individuals were placed successively in an environmentally controlled room in two fattening runs (control and test group) and reared under two different light intensity programs for 42 days. The light... Ver más
Summary The aim of the present study was to examine the effects of a constant and decreasing light intensity program on production and welfare of broiler chickens. Thus, in the period from June to September 2016, a total of 69.400 Ross x Ross 308 individuals were placed successively in an environmentally controlled room in two fattening runs (control and test group) and reared under two different light intensity programs for 42 days. The light intensity for the control group was set at 20 Lux as required by law. For the test group a step-down light program was applied (day 1 - 10 = 20 Lux, day 11 - 13 = 15 Lux, day 14 - 18 = 10 Lux and day 19 - 40 = 5 Lux). The duration of light and dark periods for the control and test groups was identical during fattening. Body mass (BM), feed intake (FI) and feed conversion ratio (FCR) and mortality and its causes were recorded on days 1 - 10, 11 - 18, 19 - 40 and 1 - 40. At the end of treatment, 25.113 and 26.323 birds, respectively, were processed in a commercial processing plant and the mass of carcass, prevalence of footpad dermatitis, hock burn, dermatitis on breast and scratches (scored from 1 to 3) was calculated. Data were analyzed by the statistical consulting unit STABLAB of the Institute of Statistics of the Ludwig-Maximilians-Universität München. Individuals under constant light intensity had a lower BM on days 1 - 10, 11 - 18, 19 - 40 and 1 - 40 and mass of carcass compared to those kept under step-down light intensity program. FI was higher in the test group during the entire fattening period compared to the control group. There was no consistent difference in the FCR. In the control group, an increase in total mortality over the experimental period 1 - 40 was observed, while the animals kept under a step-down light program showed a tendency to decrease in total mortality (P < 0.01). In terms of causes of mortality, death due to cardiovascular disease was significantly higher in the test group on days 11 - 18 and 19 - 40 (P < 0.01) compared to birds in the control group. On the other hand, the prevalence of leg problems shows a transient increase in the test group only on days 1 to 10 (P < 0.01). "Dead" and other causes of death were the only causes of mortality, which were significantly higher (P < 0.01) at the end of the experimental period (1 - 40). Prevalence of footpad dermatitis, hock burn and scratches level 3 show significant differences between the groups. Broilers exposed to a step-down light intensity program had higher prevalence of footpad dermatitis and hock burns. The prevalence of scratches level 1 and 2 showed no differences between groups but scratches level 3 was higher on birds under a constant light intensity. In this study the presence of skin lesions on breast was not observed in any of the groups. These results indicate that birds under a step-down light intensity program have higher BM, FI, mass of carcass and lower total mortality. However, the use of step-down light intensity was associated with an increase in the prevalence of hock burn and pododermatitis, resulting in a reduction in animal welfare. An improvement on the other hand was found for the parameters scratch level 3. In addition, it was observed that the use of step down light intensity was related to an increase in the prevalence of death due to cardiovascular disease during days 11 - 18 and 19 - 40. These findings indicate that the specific design of the light intensity program also plays an essential role as an environmental factor in intensive broiler farming over the course of the fattening phase, which has a significant impact on the production and animal welfare parameters. However, due to the low number of replications per light intensity program, the results of the present study should be treated with caution. Ver menos
InstitutionLudwig Maximilians University of Munich
ContestDoctorado en el Extranjero
Date de publicación2020