Measurement And Analysis Of Environmental Quality Of Stacked Cage Meat Duck House In Different Seasons

China is a big country of duck production,consumption and export.As a kind of good quality poultry meat,duck meat is deeply loved by consumers.The traditional meat duck breeding mode has the advantages of low breeding density,convenient material selection and great flexibility.However,due to the problems of large area and environmental pollution,its breeding scale is restricted.In recent years,in order to solve the above problems,a new meat duck breeding mode,cascade cage,came into being.The breeding mode not only helps to improve the land utilization per unit area,but also helps to achieve large-scale breeding,which can better meet the market demand.However,due to the intensive cultivation mode,the cage duck house is 80 m long,and the number of meat ducks in a single duck house is more than 20000.The problems such as high breeding density,uneven ventilation and duck stress are more prominent.Based on the current situation of meat duck cage,a large-scale meat duck breeding enterprise in Jiaxiang County,Jining City,Shandong Province was selected as the experimental base,and the whole growth time of four batches from hatching to slaughter in summer,autumn and winter was taken as the experimental period.The environmental quality of meat duck cage was continuously measured,and the changes and changes of environmental quality in different locations and periods were explored In order to provide suggestions for the environmental control of the new breeding mode of meat duck cage.The main research contents and results are as follows:（1）In summer,the vertical ventilation mode of fan wet curtain is mainly used in duck house.The average temperature in the house is 27.88℃,the average relative humidity is79.36%,the average wind speed is 0.76m/s,the average ammonia concentration is 1.35mg/m³,and the average carbon dioxide concentration is 1407.06mg/m³.In the vertical direction of the duck house,the average temperature and humidity of the duck cage in the middle layer were higher than those in the upper and lower layers,reaching 29.07℃and 80.05%respectively;at the age of 16-30 days after grouping,the middle and lower layers did not meet the standard requirement of 0.8m/s,which indicated that the ventilation in the middle and lower layers was poor,among which the average wind speed in the lower layer was0.71m/s,the average wind speed in the middle layer was 0.76m/s,and the average ammonia concentration in the lower layer was the highest.The average concentration of carbon dioxide in the middle layer is the highest,which is 1525.18mg/m³,of which the concentration of carbon dioxide exceeds the upper limit of 1500mg/m³.In the horizontal direction,the temperature and humidity at both ends of the duck house are higher than those in the middle,reaching 28.88℃and 79.82%respectively;except for 31-35 days old,the wind speed at L_9.3m is lower than the standard requirements of 0.5m/s-0.8m/s,which indicates that the ventilation is poor in summer;the harmful gas concentration at L_45.3m and L_63.3m at the back end of the duck house is higher,which are 1.73mg/m³and 1467.40mg/m³respectively.（2）Because the air temperature outside the house in autumn is significantly lower than that in summer,and the south and north side walls in autumn only turn on the deflector ventilation,not the wet curtain for cooling,and only turn on the wet curtain for cooling when the external temperature is higher than 30℃in the later stage of breeding,there is a big difference in the environmental quality when the longitudinal ventilation mode of fan wet curtain is adopted in the house in summer and autumn.In autumn,the average temperature,relative humidity,wind speed,ammonia concentration and carbon dioxide concentration in duck house were 20.43℃,66.65%,0.57m/s,2.06mg/m³and 2747.45mg/m³respectively.Compared with summer,the wind speed of each day and layer in autumn could not meet the requirements of the standard,and the mean wind speed of the middle layer duck cage was the smallest,which was 0.66m/s,while in summer,the wind speed of the middle and lower layers could not meet the requirements of the standard,and the lowest wind speed of the lower layer was 0.71m/s;after grouping,the mean ammonia concentration of the middle layer was the highest,which was 1.52mg/m³,which was 2.01%higher than that of the lower layer The average ammonia concentration in the lower layer was the highest,which was 1.65%higher than that in the middle layer.（3）In winter,the duck house adopts the ventilation mode of fan longitudinal ventilation and side window auxiliary air intake.In the first batch of winter experiments in 2019,the duck house uses boiler burning coal for heating,and in the second batch of winter experiments in 2020,the duck house uses air heater for heating.The environmental quality distribution of the two heating modes in winter duck house is different.The similarity lies in that the average temperature and humidity of the middle duck cage in the two batches of tests are higher than those of the upper and lower layers;the wind speed of each layer can not meet the requirements of the standard,and the average wind speed of the middle layer is the smallest;the wind speed of the middle two measuring points L_27.3mand L_45.3m is lower than that of the two measuring points L_9.3m and L_63.3m at both ends,which indicates that the ventilation effect of the middle part of the duck house is poor in winter,which is different from that of summer and autumn In season,due to the opening of the south and north side wall deflectors,the ventilation of the middle two measuring points is better,and the average wind speed is higher than that of the two measuring points at both ends;from L_27.3m to L_63.3m,the temperature is high in the front and low in the back,and the change of relative humidity is opposite.The difference is that the average temperature at L_9.3m is lower than that at L_27.3min each period of the first batch of tests in winter,which may be related to the air leakage of the shed door and the effect of heat preservation.（4）The average slaughter weight of ducks in summer was（2.88±0.07）kg,that in autumn was（3.10±0.12）kg,that in winter was（3.05±0.06）kg,and that in winter was（3.06±0.09）kg.From the statistical results,the slaughter weight of meat ducks in summer was significantly lower than that in autumn and winter,but there was no significant difference in the slaughter weight of meat ducks in autumn and winter,and there was no significant difference in the slaughter weight of two batches of experimental meat ducks in winter;from the numerical point of view,the slaughter weight of meat ducks in summer was the lowest,and that in autumn was the highest,while the relative humidity in summer was significantly negatively correlated with the slaughter weight,which indicated that there was high humidity in summer.It is not good for meat duck to gain weight.In the vertical direction,the weight of meat ducks in the middle layer duck cage is the lowest,which is consistent with the characteristics of high temperature,high humidity,poor airflow and high concentration of harmful gases.In the horizontal direction,the slaughter weight of meat ducks at L_9.3m and L_63.3m at both ends of the house in summer was lower than that at L_27.3m and L_45.3m in the middle,which was consistent with the obvious cooling effect of wet curtain ventilation at the middle and the characteristics of high temperature and high humidity at both ends of the house;the average slaughter weight of meat ducks at L_45.3m and L_63.3m at the back end of the house in autumn and winter was lower than that of L_{9.3 m} at the front end of the house and L_27.3m,which is consistent with the feature that the longitudinal ventilation mode makes the accumulation of water vapor and harmful gases at the rear end.（5）Aiming at the common problems of high temperature,high humidity,weak ventilation and high concentration of harmful gases in the middle duck cages in summer,autumn and winter,it is suggested to increase the height of the middle cage layer appropriately to improve the ventilation effect of the middle duck cages;aiming at the problems of weak ventilation at L_9.3m in summer and autumn,at L_27.3m and L_45.3m in winter,and at L_45.3m and L_63.3m after the festival in summer,autumn and winter for the problems of high humidity and high concentration of harmful gases,it is suggested to install ventilation pipes and other devices at the corresponding positions for small area ventilation,so as to increase the uniformity of airflow distribution and reduce the concentration of harmful gases;for the problem of high concentration of harmful gases in the house in winter,it is suggested to set fans for regular exhaust on the premise of ensuring the house temperature to reach the target temperature,and shorten the working time of fans In order to improve the ventilation rate in the house,the fan opening frequency should be increased.