Effectiveness of a new type of sprinkler system for cooling cows in free stall barns

Transcription

1 Effectiveness of a new type of sprinkler system for cooling cows in free stall barns J. K. Bernard 1, D. R. Bray 2, N. Mullis 1, and C. Rowe 1,3 1 University of Georgia and 2 University of Florida Young Scholar Research Apprenticeship Program

2 Objective 1. To determine the effectiveness of a new type of mister system to cool lactating dairy cows in a hot-humid environment. 2. To measure water usage of the new mister system compared to a high pressure system.

3 Experimental Design Switchback design with two replicates Replicate 1: June 1-19, 2009 Replicate 2: July 14-31, lactating Holstein cows each from two lots for a total of 20 cows per replicate that were housed in a 4 row free stall barn at the University of Georgia Dairy Research Center on the Tifton Campus

4 Facilities The mister systems were used in a 4 row free stall barn fitted with 36 in fans on 20 ft centers. Fans were located over the feed alley and free stalls. Both mister systems were mounted on the face of the fans and automatically controlled by a thermostat and humidistat located on the south side of the barn over the free stalls.

5 Cow Management Cows were milked twice daily beginning at 0300 and All cows were turned outside into a grassed exercise lot at approximately 0830 each day for 30 to 45 min for estrus detection. On Wednesday each week, cows were turned out from 0830 through 1030 when bedding was added to the free stalls.

6 Treatments Two types of mister systems High pressure system (Control), approximately 180 psi Low pressure system operating on line pressure of approximately 50 psi Low pressure mister High pressure mister

7 Data collection Core body temperature was recorded continuously every 5 minutes for 3 days using a water temperature probe attached to a blank CIDR placed in the vagina of each cow.

8 Data collection Environmental conditions were continuously recorded every 15 minutes in the two lots of the free stall barn using a data logger. THI was calculated using temperature (F) and relative humidity (RH) Water usage was recorded each day using inline water meters for each system.

9 Results

10 Average Temperature-Humidity Index (THI) Wk :00 2:00 4:00 6:00 8: :00 20:00 18:00 16:00 14:00 12:00 10:00 Cows were exposed to THI which are characteristic of chronic heat stress throughout the trial.

11 Average Temperature, F Wk :00 2:00 4:00 6:00 8: :00 20:00 18:00 16:00 14:00 12:00 10:00 Ambient temperature patters are similar to that expected for June and July.

12 Average Relative Humidity, % Wk :00 2:00 4:00 6:00 8: :00 20:00 18:00 16:00 14:00 12:00 10:00 Relative humidity remained high, especially during the second period, because of frequent rain showers in the area.

13 Body Temperatures High Pressure Low Pressure F :00 2:00 4:00 6:00 8:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 Treatment P = , SE = Treatment x hour interaction, P <0.0001, SE = 0.05

14 Body temperature Body temperature was similar for both treatments. (P = , SE = 0.008) Low pressure = F High pressure = F There was an interaction of treatment and time of day P < 0.001) because cows cooled with the low pressure system were slightly warmer from 1130 through 1500 but slightly cooler from 1700 through 1800.

15 Respiration Rates Low Pressure High Pressure Treatment, P = , SE = 1.82

16 Respiration Rates Low Pressure High Pressure Rep 1 Rep 2 Interaction of treatment and replicate P = , SE = 2.54

17 gallons/day Water use Low High The low pressure system used 43% less water per day than the high pressure system

18 Summary The low pressure system was as effective as the high pressure system for cooling cows based on similar core body temperature and respiration rates. The low pressure system used 43% less water than the high pressure system

19 Shade Pavillion: Paddock

20 Shade Pavillion/Fees Bunk

21 Northern Cooler System

22 Photo:SunBelt Ag Expo.10.09