Comparative Study On Environmental Parameters And Production Performance In Multi-layer Cage Duck House In Summer And Winter Seasons

The duck industry has developed the new multi-layer cage duck production system in order to improve land use efficiency and relieve the environment pollution.Previous inquiries in the duck industry revealed problems in controlling environmental factors in the multi-layer cage duck house.Problems like these may affect the growth performance of the meat duck and incur economic losses.This study aims to monitor and analyze the environmental parameters in multi-layer cage duck house in summer and winter seasons,in order to demonstrate aspects of improper control of the environmental factors and effects on production performance,and thus to provide new clues for development of better environment controlling technology.The first experiment was conducted from June to July in 2018 for the summer test,and the second from November to December for the winter test.Seven representative monitoring points(forepart,middle,back,upper,lower,south,and north)were selected in the multi-layer cage duck house(east to west in orientation)for monitoring the environmental factors,including temperature,humidity,air velocity,particulate matter,bacteria,NH3 and CO2.The main conclusions are as follows:As a result,we found that the concentrations of dust,bacteria,NH3,CO2 and water vapor increased significantly in summer(P<0.05).While the temperature in middle was higher than those in the forepart and back.The concentrations of NH3 and CO2 in the middle layer were higher comparing with those in the lower and upper layer in summer(P<0.05).The concentrations of four bacteria in the south were markedly higher than those in the north(P<0.05).The multi-layer cage duck house used the ventilation method of the lateral small windows to enter the wind in winter.The environmental factors in the vertical axis of the house showed a trend higher than the two sides(P<0.05).The concentration of NH3 and CO2 in the middle layer was significantly higher than that in the lower and upper layer(P<0.05).And in the meanwhile,the concentrations of bacteria and the temperature in the lower layer were higher comparing with those in the middle and upper layer in winter(P<0.05).The concentrations of PM10,E.Coli,Staphylococcus Aureus and total bacteria in the south were markedly higher than those in the north(P<0.05).This suggests that the environmental conditions on the south side of the duck house are worse than those on the north side.The concentrations of temperature,water vapor concentration and wind speed in summer were significantly higher than those in winter(P<0.05).While the concentrations of PM2.5,PM10,total dust,bacteria,NH3 and CO2 were significantly lower than those in winter(P<0.05).There was a significant positive correlation between dust and airborne bacteria in the house both in summer and winter.In terms of wind speed,there was no significant difference in bacterial concentration among different layers in summer(P>0.05).And the air flow field in the shed was uneven due to the cross-window wind in winter,and there were many dead corners on the north and south sides,affecting the other environmental factors.In the performances of meat duck production,the weight of duck significantly increased from the air inlet to the air outlet of the duck house(P<0.05).However,the weight of duck in the middle was significantly higher than those in the forepart and back in winter(P<0.05),and those in the lower layers higher than those in the upper and middle layers(P<0.05),and those in the north higher than those in the south(P<0.05).Those changes samed as the other environmental factors.There was a negative correlation between duck weight and NH3,CO2,water vapor concentrations and temperature in winter.It shows that these environmental factors are seriously polluted and significantly affect the performances of meat duck from the category of space in winter.Analyses of 20 batches of productions showed that ducks grown in summer took two days longer than those in winter to reach market weight(P<0.05),but had 1.99%higher of survival rate.There were no significant differences in feed-gain ratio and medication cost per duck between summer and winter seasons.In conclusion,the air quality in the multi-layer cage duck house was better in summer than that in winter,but the ventilation method in summer could still not effectively avoid heat stress and reduced the growth performance of the duck.The air flow field in the shed was uneven in winter,and there were many dead corners on the north and south sides,affecting the other environmental factors,reduced the health and survival rate of meat duck.So we need better ventilation and cooling measures to reduce heat stress and improve the growth performance of meat duck in summer.And the ventilation method in winter should be further adjusted to eliminate ventilation dead angles,reduce harmful gases and bacteria in duck house,and improve duck health and survival rate.