Heat Stress Abatement in Dry Cows: Does Cooling Improve Transition Success?

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1 Heat Stress Abatement in Dry Cows: Does Cooling Improve Transition Success? Bruno Amaral, Ph.D. Dairy Nutritionist & Technical Services Vita Plus Corporation Award 1

2 Outline Introduction Effects of heat stress on dry cows Milk production and components Immunity Mammary gland cell proliferation Summary Questions Introduction Can you increase milk production in your herd without changing ingredients and cost of the ration? 2

3 Definition of Stress Tension resulting from factors that tend to alter an existent equilibrium It refers to the consequence of the failure of an organism human or other animal to respond adequately to mental, emotional, or physical demands, whether actual or imagined Stress 3

4 Stress Stress in China 4

5 Heat stress Introduction Heat Stress 5

6 Effect of Heat Stress on Lactation Adapted from Collier et al., 2006 Effects on Heat Stress Dry Cows 6

7 Heat Stress Dry Cows Florida studies Experiment 1 Experiment 2 Experiment 3 COOL HOT 2 PVC water line on 8 2 PVC solenoid + timer Feed alley Fan Air flow direction 2 PVC water line on 8 2 PVC solenoid + timer HOT COOL 7

8 Experiment 1 Calan Gates 8

9 Calan Gates Fans and Sprinklers On: 71 o F Sprinklers On for 2 min Every 5 min 9

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16 Milking Cows After calving All cows were housed in a free stall barn with cooling (fans and misters) Rectal Temperature ( C) Heat Stress Increases Rectal Temperature of Dry Cows o F o F Morning Treatment Effect; P< o F Time a o F b Heat Stress Cooling Afternoon do Amaral et al.,

17 Calf Body Weight Heat Stress: 68.3 lbs Cooling: 97.0 lbs 28.7 lbs (42%) Dry Matter Intake 17

18 Cooling Cows Prepartum Improves Milk Production in the Subsequent Lactation 3.5% FCM (Lbs/d) * * * * * * * * * * * * * * * * Week of lactation 20.5 lbs of 3.5% FCM do Amaral et al., 2009 Milk Components Variable Heat Stress Cooling P-Value Fat, % Protein, % Fat yield, lb/day Protein yield, lb/day

19 Experiment 2 Second year of experiment 1 Same set up Consecutive year Experiment 2 do Amaral et al.,

20 Calf Body Weight Heat Stress: 87.0 lbs Cooling: 98.0 lbs 12 lbs (12.6%) Dry Matter Intake DMI, % BW * Time relative to calving, d 20

21 Experiment 2 FCM 3.5% FCM,Lbs/d lbs of 3.5% FCM Week of lactation * * * * * * * * do Amaral et al., 2010 Milk Components Variable Heat Stress Cooling P-Value Fat, % Protein, % Fat yield, lb/day Protein yield, lb/day do Amaral et al.,

22 Immunity Neutrophils: A First Line of Defense Healthy animal Stress immunosuppressed Proliferation and invasion of pathogens Sources: Burton and Erskine (2003); Forsberg (2004) 22

23 Neutrophil Neutrophil Phagocytosis 23

24 Heat Stress Reduces Neutrophil Phagocytosis Phagocytosis, % Treatment by day interaction P = Time relative to calving, d do Amaral et al., 2011 * Oxidative burst, % Heat Stress Reduces Neutrophil Oxidative Burst 0 Treatment by day interaction P = Time relative to calving, d do Amaral et al., 2011 * * 24

25 Lymphocyte Type of white blood cells Innate immune system Lymphocyte Proliferation do Amaral et al.,

26 Effect of Heat Stress on IgG Response to Ovalbumin Challenge Immunoglobulin G, OD * * Time relative to calving, d do Amaral et al., 2011 Experiment 3 Same set up Third consecutive year Mammary gland investigation 26

27 Temperature and Humidity Index THI Heat Stress Cooling Time of Day (h) Rectal Temperature and Respiration Rate Vita Rectal Plus Temperature Dairy Summit ( C) Treatment effects: AM: P < , PM: P < Heat Stress Cooling 38.0 AM Time PM 27

28 Water Intake Water Intake (gallon/day/cow) Heat stress Cooling Calf Body Weight Heat Stress: 91.7 lbs Cooling: lbs 10.7 lbs (11.6%) 28

29 Dry Matter Intake DMI (Lbs/d) Treatment effects: Prepartum: P = 0.03 Postpartum: P = 0.9 Heat Stress Cooling Days Relative to Calving DMI/BW (%) Dry Matter Intake Treatment effects: Prepartum: P = 0.86 Postpartum: P = 0.69 Heat Stress Cooling Days Relative to Calving 29

30 Milk Production Milk Production (Lbs/d) lbs of milk * * ** * Treatment effect: P < 0.03 *P < 0.05, **P < 0.01 * * * * * * * * * * Heat Stress Cooling Tao et al., 2011 Weeks Relative to Calving Milk Components Variable Heat Stress Cooling P-Value Fat, % Protein, % Fat yield, lb/day Protein yield, lb/day Tao et al.,

31 Does Heat Stress Abatement in Dry Cows Improve Transition Success? Milk Production (Lbs/d) * * ** * 3.5% FCM (Lbs/d) * Weeks Relative to Calving Week of lactation * * * * * * * * * Heat Stress Cooling Experiment 3 Mammary Gland Development 31

32 Mammary Gland Biopsies Mammary Gland 32

33 Mammary Gland Epithelial cells Stroma cells Proliferation Rate (Ki67 Labeling) Alveolar Lumen Stroma cells Epithelium cells Heat Stress Cooling 33

34 Heat Stress Abatement Increased Mammary Epithelial Cell Proliferation In the Dry Period Ki67 labeling, % (% of baseline) * -20 Day Relative to Calving ** * P < 0.05 ** P < 0.01 Heat Stress Cooling Epithelium Stroma Total Milk Fall Slump 34

35 Seasonality Effects on Milk Production Milk per cow ( NASS) York Iowa New York nd Quarter- (April-June) Highest milk per cow Minnesota Michigan Wisconsin Seasonality Effects on Milk Production Milk per cow ( NASS) York Iowa New York th Quarter- (Oct. Dec.) Lowest milk per cow Minnesota Michigan Wisconsin

36 Milk Fall Slump 3.5% FCM (Lbs/d) Week of lactation Take Home Message Heat stress abatement in dry cows improves transition into lactation by Increasing mammary cell proliferation Milk production Immune function 36

37 Questions Dry cows are one of the most important group of cows at your farm. Emphasis on transition success is the key 37