Direct surface wetting sprinkler system to reduce the use of evaporative cooling pads in meat chicken production: indoor thermal environment, water usage, litter moisture content, live market weights, and mortalities

Abstract

An overhead sprinkler system that directly applies water onto meat chickens in tunnel ventilated houses was evaluated and compared with a conventional evaporative cooling pad system at 2 commercial farms in south-eastern Queensland, Australia. The sprinkler system was used to reduce the use of evaporative cooling pads as the primary cooling system but not replace evaporative cooling pads altogether. The sprinkler system used low water pressure and comprised evenly spaced sprinklers and a programmable controller. Water was applied intermittently based on house temperature and a temperature program that was related to bird age. The study was conducted over 6 sequential grow-outs during a 1-year period. Air temperature, relative humidity, litter moisture content, cooling water usage, live market weight, and mortality were assessed during the study. The effect of sprinklers on these measured parameters was complicated by interactions with farm, batch, bird age, and time of day. We found that, in general, houses with combined sprinkler and evaporative cooling pad systems used less water, while having similar litter moisture content, live market weight, and mortality compared with control houses that were fitted with conventional evaporative cooling pads. When evaporative cooling was required, sprinkler houses had warmer air temperature but lower relative humidity than the control houses. Bird comfort due to the direct cooling effect of water evaporating off the birds was not directly assessed during this study but was inferred from thermal camera images and from live weight and mortality data. This was the first study in Australia involving this sprinkler system, and we suggest that the sprinkler system design and operation may require some adaptation to better suit Australian poultry house design and climatic conditions, including the need for additional sprinklers to improve coverage, lower set-point temperatures, and altering sprinkler spacing to suit ceiling baffle curtains (if fitted).

Effects of a Sprinkler and Cool Cell Combined System on Cooling Water Usage, Litter Moisture, and Indoor Environment of Broiler Houses

“…This is in agreement with findings from [ 31 ] who reported no significant effect by sprinklers on litter moisture content. However, it does not agree with research by [ 50 ] who found moisture content differed with a two-way interaction between growout × sprinklers ( p = 0.002), with slightly drier litter in the sprinkler house. A weaker relationship was also found by [ 50 ] when sprinklers were considered as a main effect ( p = 0.046), where litter moisture was slightly lower in the sprinkler houses.…”

“…However, it does not agree with research by [ 50 ] who found moisture content differed with a two-way interaction between growout × sprinklers ( p = 0.002), with slightly drier litter in the sprinkler house. A weaker relationship was also found by [ 50 ] when sprinklers were considered as a main effect ( p = 0.046), where litter moisture was slightly lower in the sprinkler houses. In the current study, we did see slightly drier litter in the sprinkler/cool cell combination house.…”

“…Water usage in the sprinkler/cool cell combination house demonstrated water savings that averaged 64% over the two summer flocks in comparison to the cool cell only house. These savings are in close agreement with [ 31 ] where savings of 67% were reported and [ 50 ] where savings of 58% were reported. The greatest water savings were observed on days when only sprinklers were in use in the combination house while evaporative cooling pads were being used in the cool cell house.…”

“…Sprinkler cooling requires a slightly warmer house temperature and an associated lower house humidity other than a standard cool cell system usually provides. This warmer, drier environment does two things: (1) it creates a situation where the bird can more effectively and efficiently cool itself through evaporative respiration, and (2) it creates an auxiliary heat release mechanism, replacing the loss of sensible heat dissipation due to hot weather [ 31 , 50 , 52 ].…”

Environmental impacts of the Australian poultry industry. 1. Chicken meat production

“…Aside from drinking water, the major consumptive use of water at the farm was for cooling. Innovations or management changes in cooling, such as combined sprinkler and evaporative cooling pads (Dunlop and McAuley 2021) may offer reductions in on-farm water consumption.…”