Cooling cows efficiently with sprinklers: Physiological responses to water spray

Dairies in the United States commonly cool cattle with sprinklers mounted over the feed bunk that intermittently spray the cows' backs. These systems use potable water-an increasingly scarce resource--but there is little experimental evidence about how much is needed to cool cows or about droplet size, which is thought to affect hair coat penetration. Our objectives were to determine how sprinkler flow rate and droplet size affect physiological measures of heat load in a hot, dry climate, and to evaluate cooling effectiveness against water use. The treatments were an unsprayed control and 6 soaker nozzles that delivered four 3-min spray applications of 0.4, 1.3, or ≥ 4.5 L/min (with 2 droplet sizes within each flow rate) and resulting in 30 to 47% of spray directly wetting each cow. Data were collected from high-producing lactating Holsteins (n = 19) tested individually in ambient conditions (air temperature = 31.2 ± 3.8°C, mean ± standard deviation). Cows were restrained in headlocks for 1h and received 1 treatment/d for 3d each, with order of exposure balanced in a crossover design. When cows were not sprayed, physiological measures of heat load increased during the 1-h treatment. All measures responded rapidly to spray: skin temperature decreased during the first water application, and respiration rate and body temperature did so before the second. Droplet size had no effect on cooling, but flow rate affected several measures. At the end of 1h, 0.4 L/min resulted in lower respiration rate and skin temperature on directly sprayed body parts relative to the control but not baseline values, and body temperature increased to 0.2°C above baseline. When 1.3 or ≥ 4.5 L/min was applied, respiration rate was lower than the control and decreased relative to baseline, and body temperature stayed below baseline for at least 30 min after treatment ended. The treatment that best balanced cooling effectiveness against water usage was 1.3 L/min: although ≥ 4.5 L/min reduced respiration rate relative to baseline by 4 more breaths/min than 1.3 L/min did (-13 vs. -9 breaths/min, respectively), each additional liter of water decreased this measure by only ≤ 0.1 breaths/min (≤ 1% of the total reduction achieved using 1.3 L/min). We found similar water efficiency patterns for skin temperature and the amount of time that body temperature remained below baseline after treatment ended. Thus, when using this intermittent spray schedule in a hot, dry climate, applying at least 1.3 L/min improved cooling, but above this, additional physiological benefits were relatively minor.

Sprinkler Technology Improves Broiler Production Sustainability: From Stress Alleviation to Water Usage Conservation: A Mini Review

Global poultry production is facing several challenges including a projected increase in global demand for high quality animal proteins and the need to adapt to environmental contrasts including heat stress and the increasing pressure on natural resource (water, land, and energy) availability. Heat stress is one of the most challenging stressor to poultry production because of its strong adverse effects on welfare, production, mortality, and water usage. Most commercial poultry houses worldwide are equipped with a combination of tunnel ventilation and evaporative cooling system (pads, fogging, or low-pressure misting systems) as the status quo to overcome heat stress. Despite prior investments in these systems, critical problems continue to impede poultry production efficiency, which still declines during hot seasons. In fact, these systems tend to saturate the barn air with moisture (>70% relative humidity) which is counterproductive to the bird's own physiological ability to cool itself by hyperventilation (evaporative heat loss). The second challenge with these systems is the significant amount of water usage. This review will summarize some of the benefits of surface wetting of birds through sprinkler technology (SPRINK) that has higher efficiency to maintain birds' comfort with significantly less use of cooling water. Despite higher air temperature and lower relative humidity in the sprinkler house, the SPRINK decreased broiler body core temperature, reduced systemic and intracellular stress, preserved intracellular energy, and averaged six points better FCR compared to evaporative cooling system.

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

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

Climate change is a serious challenge to food production around the world. Sustainability and water efficiency are critical to a poultry industry faced with global production concerns including increased demands for high-quality, affordable animal protein and greater environmental pressures resulting from rising global temperatures, flock heat stress, and limits on water availability. To address these concerns, a commercial sprinkler system used in combination with a cool cell system was evaluated against a cool cell system alone for two summer flocks of heavy broilers at Mississippi State University to determine effects of sprinkler technology on cooling water usage, litter moisture, and in-house environments. Environmental data were calculated and recorded throughout the flocks. The combination house exhibited a 2.2 °C (4 °F) increase in daily maximum temperature, lower coincident relative humidity, and a 64% (62,039 L/flock) reduction in average cooling water usage over the cool cell-only house. Litter moisture for the combination house tended to be numerically lower but showed no significant difference at several time points between and across flocks. A combined sprinkler/cool cell system reduced cooling water use by 64% over two flocks compared to a cool cell alone system and decreased in-house relative humidity levels.

Effectiveness of Swirl Water Mist Nozzles for Fire Suppression

Water mist nozzles are becoming increasingly popular as water extinguishing devices in buildings, increasing people's safety during evacuation. There are questions as to whether or not they are as effective as conventional sprinkler systems. The measurement of the size distribution of the created droplets is one of the components for determining the extinguishing effectiveness of water mist nozzles. The project's goal was to look into the characteristics of the atomized stream produced by a swirl water mist nozzle. The general properties of the tested nozzle are covered in the article. The measurement technique and test stand were given. The collected data was compared to data from the literature. The results are displayed as graphs that depict the distribution of mean droplets with a quantitative volume that varies with pressure and proximity to the test nozzle. The results proved the extinguishing and cooling capabilities of hot fire gases in the water stream created by the tested nozzle.

Effects of Combined Use of Olive Mill Waste Compost and Sprinkler Irrigation on GHG Emissions and Net Ecosystem Carbon Budget under Different Tillage Systems

Traditional rice (Oryza sativa L.) production by flooding is a source of greenhouse gases (GHG), especially methane. The high consumption of water, as well as the chemical and physical degradation caused by these traditional practices in rice soils, is promoting a decrease in rice production in the Mediterranean area. The aim of this study was to monitor GHG emissions and the net ecosystem carbon balance (NECB) from rice produced with sprinkler irrigation techniques and also assess the impact of olive mill waste compost (C-OW) application and tillage on GHG emissions and the NECB. A field experiment for irrigated rice production was implemented by considering four different treatments: (1) tillage (T); (2) no tillage-direct seeding techniques (DS); (3) application of C-OW followed by tillage (TC); and (4) application of C-OW followed by direct seeding (DSC). The C-OW was only applied in the first year at a dose of 80 Mg ha^-1. GHG emissions were monitored over three years in these four treatments in order to estimate the direct (first year) and residual (third year) effects of such practices. The application of C-OW caused an increase of 1.85 times the emission of CO₂-C in the TC-DSC compared to the T-DS in the first year. It is noteworthy that the TC treatment was the only one that maintained an emission of CO₂-C that was 42% higher than T in the third year. Regardless of the treatments and year of the study, negative values for the cumulative CH₄ were found, suggesting that under sprinkler irrigation, CH₄ oxidation was the dominant process. A decrease in N₂O emissions was observed under direct seeding relative to the tillage treatments, although without significant differences. Tillage resulted in an increase in the global warming potential (GWP) of up to 31% with respect to direct seeding management in the third year, as a consequence of the greater carbon oxidation caused by intensive tillage. DS presented a positive NECB in the accumulation of C in the soil; therefore, it provided a greater ecological benefit to the environment. Thus, under Mediterranean conditions, rice production through a sprinkler irrigation system in combination with direct seeding techniques may be a sustainable alternative for rice crops, reducing their GWP and resulting in a lower carbon footprint. However, the use of C-OW as an organic amendment could increase the GHG emissions from rice fields irrigated by sprinklers, especially under tillage conditions.