Cultural energy analysis on broilers reared in different capacity poultry houses

Data obtained from 4 different capacity houses were evaluated to analyse the cultural energy and perfor- mance of broilers. Capacities of housings were 20,000, 25,000, 30,000 and 60,000 birds per production peri- od and they were assigned as HI, HII, HIII and HIV, respectively. The study was conducted in 2005 in which there were 6 production periods of 45 days. Data collected for each period were: date of starting and finish- ing; number of chicks entered and broilers sold; live weight at slaughter; carcass weight; feed consumption for starting, growing and finishing phase; labour; medication, vaccination and disinfectant; electricity con- sumption; heating and cooling methods and amount spent; distance for transportation of feed, chicks, broil- ers, wood shaving, limestone; and other miscellaneous expenditures. Ross 308 chickens in all houses received the same commercial feed and water ad libitum. Chicks were reared under a conventional temper- ature regimen. Chicks were fed starter, grower and finisher diets according to their ages. Even though capac- ities for houses were different their stocking densities were 16.36, 16.00, 16.38 and 16.54 birds/m2 for HI, HII, HIII and HIV, respectively. For cultural energy analysis, feed, transportation, labour, machinery, electric- ity, brooding, and other inputs were calculated and corresponding energy values for each input were obtained from literature. For the analysis it was assumed that carcasses would have 18.2% protein and 15.2% fat. Total cultural energy invested in broilers in HIII was lower than that of broilers in HI (P< 0.05). Energy input per kg live weight gain and per kg carcass of HIII were lower than that of HI (P< 0.05, P< 0.01, respective- ly). The HIII had lower cultural energy ratio for protein energy output than HI (0.01). Energy efficiency (kcal input/kcal output) of HIII was better than that of HI (P< 0.01). Results of the study showed that increasing capacity of housings decreases cultural energy input up to certain capacity and indicated that increasing housing capacity without interfering with performance could be a means for energy conservation in sustain- able agriculture