Performance response of growing-finishing pigs to an air-cooled environment during a simulated hot weather growth period Presented at MPB research committee Mtg August 25, 2015 Larry Jacobson, Lee Johnston, Brian Hetchler, Adrienne Hilbrands, & Curt Reese University of Minnesota
Temperature response for finishing pigs Thermoneutral Zone For pigs > 150 lbs
Lb Chronic Heat Impacts 280 IA-SMN Pig Liveweight at Slaughter 2010 2011 2007-2011 2012 275 270 265 260 255 250 Week of year Brumm, 2013, AACC Course Lecture Brumm 2012
Estimated annual Losses (2003) $2.4 Billion per year Beef: $370 M Dairy: $1500 M Swine: $316 M Poultry: $165 M Note: estimate does not include indirect losses
Objectives of Study This project will determine the pig performance benefits of maintaining a thermal neutral condition (avoid heat stress) in a group of grow-finish pigs compared to allowing the room environment to exceed the pig's thermal neutral zone (heat stress).
Study conducted during the winter at U of MN s WCROC in Morris Easier to add heat to barn (room) to reach heat stress temperatures than to cool barn (room) in summer to keep pigs in thermoneutral range
Experimental Design of Study Two treatments were imposed with the Control treatment housing pigs as close to their thermoneutral conditions as possible. The Heat Stress treatment housing pigs under conditions that simulate estimated heat stress conditions during a Minnesota summer. The room temperature in the Control room were changed on Monday mornings automatically by the ventilation controller starting at 70 F day and 65 F at night when pigs are brought into the room (60 lbs) and gradually lowering to 57 F (day) and 52 (night) when marketed (290 lbs).
Experimental Design of Study Room temperature settings for the Heat Stress room were changed manually on Monday and Thursday mornings to one of the following five heat stress scenarios: 82 F (Day) and 63 F (Night) 85 F (Day) and 65 F (Night) 87 F (Day) and 68 F (Night) 90 F (Day) and 69 F (Night) 95 F (Day) and 75 F (Night) Temperature changes in both rooms occurred as close to 7:00 a.m. as possible. Daytime was from 7:00 AM to 7 PM while nighttime was from 7 PM to 7 AM. Ventilation rates were managed to maintain CO 2 levels in each room to 5,000 ppm or less.
Table 1. Schedule for implementing room temperature treatments* West Finishing room (Control) East Finishing room (Heat stress) Date Day (0700 to 1900h) Night (1900 to 0700h) Day (0700 to 1900 h) Night (1900 to 0700 h) 12-17-14 75 75 75 75 12-29-14 70 65 85 65 12-31-14 70 65 82 63 1-5-15 69 64 82 63 1-7-15 69 64 82 63 1-12-15 68 63 95 75 1-15-15 68 63 87 68 1-19-15 67 62 82 63 1-22-15 67 62 87 68 1-26-15 66 61 82 63 1-29-15 66 61 95 75 2-2-15 65 60 85 65 2-5-15 65 60 95 75 2-9-15 64 59 95 75 2-12-15 64 59 87 68 2-16-15 63 58 87 68 2-19-15 63 58 95 75 2-23-15 62 57 90 69 2-26-15 62 57 87 68 3-2-15 61 56 95 75 3-5-15 61 56 82 63 3-9-15 60 55 95 75 3-12-15 60 55 87 68 3-16-15 59 54 85 65 3-19-15 59 54 90 69 3-23-15 58 53 90 69 3-26-15 58 53 95 75 3-30-15 57 52 95 75 4-2-15 57 52 90 69 *Dates indicate change in temperature settings. Settings are maintained at the indicated settings until a change is required. Settings indicate desired room temperatures not controller setpoint temperatures. Controller setpoint temperature will need to be adjusted depending if the room is in heating or cooling mode to obtain these target room temperatures. Night temperatures will be achieved by letting the room cool down gradually not by driving the temperature down at 1900h.
Stages Furnace 2 West Side Stages Control Room Wall fan 8 8 Wall fan 216 pigs Pit fan 1 2 Pit fan 24 pens @ 9 pigs/pen Wall fan 5 6 Wall fan 97.9 lbs average on 1/6/15 Wall fan 3 4 Wall fan Pit fan 1 2 Pit fan Wall fan 7 7 Wall fan 1 Furnace
East Side Furnace 1 Heat Stress Room Wall fan 7 7 Wall fan Pit fan 1 2 Pit fan 216 pigs Wall fan 3 4 Wall fan 24 pens @ 9 pigs/pen Wall fan 6 5 Wall fan 99.6 lbs average on 1/6/15 Pit fan 1 2 Pit fan Wall fan 8 8 Wall fan Water Sprinklers turned OFF 2 Furnace
Table 2. Activity Timeline Date 12-17-14 Activities - Move pigs to finishing barn. Implement pre-experiment room temperature regimen. 1-5&6-15 - Ear tag pigs 1-6-15 1-26-15 - Weigh pigs - Weigh feed in feeders - Select 8 focal pigs in each room - Begin experiment - Measure water flow rates on all pens - Measure water temperature on 4 pens per room 1-27-15 - Record respiration rates on focal pigs 2-4-15 - Weigh pigs, feed weighbacks 2-16-15 - Measure water flow rates on all pens - Measure water temperature on 4 pens per room 2-17-15 - Record respiration rates on focal pigs 3-4-15 - Weigh pigs, feed weighbacks 3-9-15 - Measure water flow rates on all pens - Measure water temperature on 4 pens per room 3-10-15 - Record respiration rates on focal pigs 3-30-15 - Measure water flow rates on all pens - Measure water temperature on 4 pens per room 3-31-15 - Record respiration rates on focal pigs 4-1-15 - Weigh pigs, feed weighbacks Exp. End - Weigh pigs, feed weighbacks when pigs average 270 pounds in a room
Same Diets fed to both Rooms Table 3. Diet composition (% as fed) Ingredient GF1 (70 110 lb) GF2 (111 150 lb) GF3 (151 190 lb) GF4 (191 mkt) Corn 50.34 57.20 62.57 66.44 SBM 46.5% CP 32.05 25.50 20.57 16.88 Corn DDGS DENCO 15.00 15.00 15.00 15.00 ANS GF Basemix 1.30 1.30 -.- -.- ANS GF Basemix 30% DDGS 1.18 0.95 1.81 1.63 Tylan 40 0.125 0.05 0.05 0.05 Total 100.00 100.00 100.00 100.00 Calculated analysis: ME, kcal/lb 1500 1505 1512 1516 Crude protein, % 23.6 21.1 19.3 17.9 SID Lys, % 1.02 0.86 0.74 0.65 Ca, total % 0.71 0.63 0.56 0.50 P, dig % 0.32 0.31 0.23 0.22
Results
Average daily room temperatures
Temperature (F) 120 Average Daily Rm & Outside Temperatures 100 80 60 40 20 0-20 Dec-14 Jan-15 Feb-15 Mar-15 Apr-15 Date warm cool OUTSIDE TEMPERATURE ( F) SETPOINT ( F) warm
Temperature (F) Heat Stress Temperature Strategy 100 95 90 85 80 75 70 65 60 Date warm warm set point cool cool set point
Temperature (F) Heat Stress Temperature Strategy 100 95 90 85 80 75 70 65 60 55 Date warm warm set point cool cool set point
Effect of heat stress on resting respiration rate
Effect of heat stress on body weight Trt: P = 0.778 Time: P < 0.001 Trt x Time: P = 0.003
Effect of heat stress on average daily gain Trt: P = 0.014 Time: P < 0.001 Trt x Time: P = 0.282
Effect of heat stress on daily feed intake
Effect of heat stress on gain:feed ratio
Effect of heat stress on backfat depth Trt: P = 0.252
Effect of heat stress on loin eye area Trt: P = 0.672
Carbon Dioxide, ppm 7000 CO 2 Average Daily Concentrations 6000 5000 4000 warm cool 3000 2000 1000 0 Dec-14 Jan-15 Feb-15 Mar-15 Date
Ammonia, ppm 35 NH 3 Average Daily Concentrations 30 25 20 warm cool 15 10 5 0 Dec-14 Jan-15 Feb-15 Mar-15 Date
Hydrogen Sulfide, ppb 1400 H 2 S Average Daily Concentrations 1200 1000 800 warm cool 600 400 200 0 Dec-14 Jan-15 Feb-15 Mar-15 Date
Brief Summary Experimental Method of doing heat stress study in winter was successful Pigs were heat stressed (higher respiration rates) but not to the degree that most pig performance metrics were impacted Suggest providing more severe heat stress scenarios (higher nighttime minimums) for future studies that reflect more recent summer temperatures in the Midwest.