Performance response of growing-finishing pigs to an air-cooled environment during a simulated hot weather growth period

Transcription

1 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

2 Temperature response for finishing pigs Thermoneutral Zone For pigs > 150 lbs

3 Lb Chronic Heat Impacts 280 IA-SMN Pig Liveweight at Slaughter Week of year Brumm, 2013, AACC Course Lecture Brumm 2012

4 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

5 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).

6 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

7 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).

8 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.

9 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) *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.

10 Stages Furnace 2 West Side Stages Control Room Wall fan 8 8 Wall fan 216 pigs Pit fan 1 2 Pit fan 24 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

11 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 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

12 Table 2. Activity Timeline Date Activities - Move pigs to finishing barn. Implement pre-experiment room temperature regimen. 1-5& Ear tag pigs 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 Record respiration rates on focal pigs Weigh pigs, feed weighbacks Measure water flow rates on all pens - Measure water temperature on 4 pens per room Record respiration rates on focal pigs Weigh pigs, feed weighbacks Measure water flow rates on all pens - Measure water temperature on 4 pens per room Record respiration rates on focal pigs Measure water flow rates on all pens - Measure water temperature on 4 pens per room Record respiration rates on focal pigs Weigh pigs, feed weighbacks Exp. End - Weigh pigs, feed weighbacks when pigs average 270 pounds in a room

13 Same Diets fed to both Rooms Table 3. Diet composition (% as fed) Ingredient GF1 ( lb) GF2 ( lb) GF3 ( lb) GF4 (191 mkt) Corn SBM 46.5% CP Corn DDGS DENCO ANS GF Basemix ANS GF Basemix 30% DDGS Tylan Total Calculated analysis: ME, kcal/lb Crude protein, % SID Lys, % Ca, total % P, dig %

14 Results

15 Average daily room temperatures

16 Temperature (F) 120 Average Daily Rm & Outside Temperatures Dec-14 Jan-15 Feb-15 Mar-15 Apr-15 Date warm cool OUTSIDE TEMPERATURE ( F) SETPOINT ( F) warm

17 Temperature (F) Heat Stress Temperature Strategy Date warm warm set point cool cool set point

18 Temperature (F) Heat Stress Temperature Strategy Date warm warm set point cool cool set point

19 Effect of heat stress on resting respiration rate

20 Effect of heat stress on body weight Trt: P = Time: P < Trt x Time: P = 0.003

21 Effect of heat stress on average daily gain Trt: P = Time: P < Trt x Time: P = 0.282

22 Effect of heat stress on daily feed intake

23 Effect of heat stress on gain:feed ratio

24 Effect of heat stress on backfat depth Trt: P = 0.252

25 Effect of heat stress on loin eye area Trt: P = 0.672

26 Carbon Dioxide, ppm 7000 CO 2 Average Daily Concentrations warm cool Dec-14 Jan-15 Feb-15 Mar-15 Date

27 Ammonia, ppm 35 NH 3 Average Daily Concentrations warm cool Dec-14 Jan-15 Feb-15 Mar-15 Date

28 Hydrogen Sulfide, ppb 1400 H 2 S Average Daily Concentrations warm cool Dec-14 Jan-15 Feb-15 Mar-15 Date

29 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.

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