Effect Of Different Rearing Systems For Broilers On Housing Environment And Welfare

In order to comprehensively assess and compare different broiler rearing systems for broilers, the effect of two different flooring systems (litter and netting) on broiler housing environment, welfare, and performance was evaluated in this paper. The environmental conditions, gaseous concentrations, and ventilation rate were recorded continuously using a portable monitoring unit (PMU) installed on-site. Temperature, relative humidity (RH), concentrations of ammonia and carbon dioxide, and ventilation were monitored continuously during a 6-week growout with four flocks over four different seasons from May to December, 2014. Gaseous concentrations were analyzed for 5min every 30min and temperature and RH were recorded every 5min by sensors. Broiler welfare parameters and production performances including huddling, panting, plumage cleanliness, footpad dermatitis, hock burn, breast blister, gait score, avoid distance, live weight, body weight gain, feed conversion rate and mortality rate were assessed in this study. The results are as follows:(1)For different seasons:average concentrations of ammonia was highest in winter, lower in spring, summer and autumn in litter bedded house. Spring and winter had higher ammonia concentration than summer and autumn in netting type house (P<0.05). Carbon dioxide, temperature, RH and ventilation of both floor systems were the same in each season. Concentrations of carbon dioxide was higher in winter than spring and autumn due to limited ventilation to conserve energy while it was lowest in summer (P<0.05). The indoor temperatures of spring and summer were higher than the other seasons (P<0.05). RHs of summer in the two houses were highest, followed by spring, autumn and winter (P<0.05). Ventilation rate ranks were summer, spring, autumn and winter from high to low (P< 0.05).(2) For different flooring systems under same season:the concentrations of ammonia in the netting type house was higher than that in the litter bedded house in each season (P<0.05). There was no significant difference on carbon dioxide, temperature, and ventilation rate between litter and netting houses (P>0.05). The RH in litter bedded house wras significantly higher in winter (P<0.05). Ammonia and RH had significant difference between two houses in the process of brooding throughout the year(P<0.05).(3) Different rearing systems had impacts on broiler welfare. from. There was no significant difference on the huddling and panting behavior of broilers between the two different rearing systems (P>0.05). Netting system was better than the litter system on plumage cleanliness (P<0.05). There were more footpad dermatitis incidences in the litter bedded house than the netting house and the difference was significantly in 5 and 6-week of age (P<0.05). Hock burn, gait score and avoid distance test were not significantly different between netting type and litter bedded houses, but the walking ability of the broilers under netting type was weaker than that in litter bedded in weeks 5 and 6 (5th week,P=0.0644; 6th week, P=0.0525).(4) There was no significant difference in broiler performance including body weight, body weight gain, feed conversion rate and mortality rate between litter bedded system and netting-type system in every week(P>0.05).