Heat Stress During LactaFon Depresses DMI Dry Period Heat Stress: - PDF document

8/12/19 Heat Stress During LactaFon • Depresses DMI Dry Period Heat Stress: Carryover • Reduces milk yield Effects on Dam and Daughter • Recent studies suggest addiFonal metabolic effects beyond DMI G. E. Dahl Department of Animal Sciences • Recovery dependent on duraFon InsFtute of Food and Agricultural Sciences gdahl@ufl.edu Mid-South Ruminant NutriFon Conference 6 August 2019 What about dry cows? Heat Stress Effects on Yield Linger Milk yield? Metabolism? Immune funcFon? Late gesta(on DAM vs. DAUGHTER Cow performance? ThermoregulaFon? Calf health? Calf growth? Heifer growth? ReproducFon? Tao & Dahl, J. Dairy Sci. 96:4079-4093 1

8/12/19 Study Design: Heat Stress Increases Mean Rectal Heat Load of Dry Cows Temperature 39.4 Treatment Effect; P<0.05 39.2 39.0 Heat Stress 38.8 Cooling a b 38.6 38.4 38.2 Morning Afternoon Time Do Amaral et al., J. Dairy Sci. 94:86–96 Do Amaral et al., J. Dairy Sci. 94:86–96 Cooling Dry Cows Increases Milk Cooling Dry Cows Increases Milk Heat Stressed 45 Cooled 40 Milk Production, kg/d 35 30 Milk, kg/d 25 20 15 10 5 0 1 4 7 10 13 16 19 22 25 28 31 34 37 40 Weeks in milk Tao et al., J. Dairy Sci. 94:5976–5986 2

8/12/19 Milk ProducFon Milk ProducFon Epithelial Cell Epithelial Cell Epithelial Cell Epithelial Cell X X Metabolism Number Metabolism Number Cell Growth Cell Death Cooling Increased ProliferaFon of Mammary Heat Stress During Dry Period – Cells Prepartum (d-20) No Effect on MEC Apoptosis 4.0 * 0.7 Epithelium ** 3.5 0.6 TUNEL labeling, % Ki67 labeling, % 3.0 0.5 2.5 0.4 2.0 0.3 1.5 0.2 1.0 0.1 0.5 0.0 -20 2 20 0.0 Days relative to calving Epithelium Stroma Total Tao et al., J. Dairy Sci. 94:5976–5986 Tao et al., J. Dairy Sci. 94:5976–5986 3

8/12/19 Heat Stress Increases Rectal Temperature and Respira@on Rate Dry Period Cooling Duration • Do I have to cool cows the entire dry period? • Can I just cool during the close-up phase? Fabris et al., J. Dairy Sci., 102:5647-5656 Heat Stress Decreases Gesta@on Heat Stress Imposed at Any Time in Length and Dry Period Length at Any the Dry Period Reduces Milk Yield Time P < 0.05 P < 0.05 P < 0.05 P < 0.05 P = 0.05 P = 0.05 P P < 0.05 Fabris et al., J. Dairy Sci., 102:5647-5656 Fabris et al., J. Dairy Sci., 102:5647-5656 4

8/12/19 Cooling Dry Cows Increases BW Heat Stress Reduces DMI Prepartum Prepartum, Decreases Postpartum But Not Postpartum 25 Treatment effects: Postpartum P = .9 Prepartum P = .03 20 DMI (kg/d) 15 10 � Cooling 5 ☐ Heat Stress 0 -35 -30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 35 40 Days relative to calving Tao et al., J. Dairy Sci. 94:5976–5986 Thompson et al., J. Dairy Sci. 97:7426-7436 Cooling Dry Cows Increases Effect of Lymphocyte ProliferaFon Cooling Dry Cows on Metabolic Profile Do Amaral et al., Domest. Anim. Endo. 38:38-45 Tao et al., J. Dairy Sci. 95:5035-5046 5

8/12/19 Cooling Dry Cows Cooling Dry Cows Increases Effects on Acquired Immunity Neutrophil AcFon Postpartum Do Amaral et al., J. Dairy Sci. 94:86–96 Do Amaral et al., J. Dairy Sci. 94:86–96 Dry in COOL Months Improves Dry in COOL Months Improves Performance ReproducFve Performance Thompson & Dahl, Prof. Anim. Sci. 28:628-631 Thompson & Dahl, Prof. Anim. Sci. 28:628-631 6

8/12/19 Cooling Increases Calf Birth Weight - Decreases milk yield - No prepartum metabolic effect - Reduces immune funcFon 45 Treatment effect: P < 0.01 - Compromised mammary growth Birth Weight, kg 40 Late gesta(on DAM Programming for that lacta@on vs. 35 DAUGHTER Cow performance? 30 36.7 kg 42.4 kg ThermoregulaFon? 25 Calf health? Calf growth? Heifer growth? ReproducFon? 20 Heat stress Cooling Tao et al., J. Dairy Sci. 95:7128-7136 Weaning Weight Cooling Improves Total IgG and AEA 90 45 40 BW Change, Kg P = 0.04 40 30 AEA, % Weaning BW, Kg 3,000 Heat Stress 35 20 80 30 Cooling Total IgG (mg/dl) 10 2,500 25 0 20 Heat stress Cooling 70 Heat stress Cooling 2,000 1,500 60 1,000 50 500 0 40 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728 Days of Age Heat stress Cooling Tao et al., J. Dairy Sci. 95:7128-7136 Tao et al., J. Dairy Sci. 95:7128-7136 7

8/12/19 Why Does Cooling Affect AEA? Experiment 1 Calf or Colostrum Effect? - In utero heat stress for ~6 weeks reduces body weight and height to weaning ! Monteiro et al., J. Dairy Sci. 97:6426-6439 Monteiro et al., J. Dairy Sci. 97:6426-6439 Experiment 2 – No Effect of Colostrum Cooling Increased Apparent efficiency of IgG from Cooled or Heat Stressed Cows on absorption (AEA*) Calf Performance 35 trt: P < 0.05 30 25 AEA, % 20 15 30.2 % 26.0 % 10 5 0 Cooling Heat Stress * AEA = [Serum [IgG] (g/L) * birth weight (kg) * 0.091 / IgG fed (g)] x 100 Monteiro et al., J. Dairy Sci. 97:6426-6439 8

8/12/19 Heat Stress Summary – Short Term Effects on Calves Retrospec@ve analysis of records of calves • Cooling increases weight at birth and weaning from 5 studies between 2007 and 2011 • In utero heat stress reduces apparent efficiency of IgG absorpFon, but not an effect Monteiro et al. , J. Dairy Sci . 99:8443-8450. on colostrum quality • In utero heat stress alters carbohydrate metabolism, consistent with greater fat deposiFon Birth Weight Heat Stress Experiments 2007 - 2011 trt: P < 0.001 48 gender: P = 0.002 Bulls Heifers Total 46 Birth Weight, kg Cooling 31 41 72 44 42 Heat Stress 30 44 74 40 44.8 kg 38 Total 61 85 147 39.1 kg 36 34 Cooling Heat Stress Monteiro et al. , J. Dairy Sci . 99:8443-8450. 9

8/12/19 In Utero HS Decreases Calf Survival In Utero Heat Stress Decreases Calf Bodyweight to Puberty 400 Cooling 350 Heat Stress 300 Body Weight (kg) trt: P < 0.05 250 200 150 100 P = .03 50 0 0 2 3 4 5 6 7 8 9 10 11 12 Months of Age Monteiro et al. , J. Dairy Sci . 99:8443-8450. Monteiro et al. , J. Dairy Sci . 99:8443-8450. In Utero Heat Stress Decreases In Utero Heat Stress Reduces ReproducFve Performance Milk Production P = .03 ! Monteiro et al. , J. Dairy Sci . 99:8443-8450. Monteiro et al. , J. Dairy Sci . 99:8443-8450. 10

8/12/19 In Utero Heat Stress Does Not Altered autophagy Affect Mature Bodyweight Decreased mammary growth Lower milk yield Late gesta(on DAM Programming for that lacta@on vs. DAUGHTER Programming for life EpigeneFc shils P = .03 40 45 35 Birth Weight, kg 40 Milk Production (kg) 30 35 25 20 30 36.7 kg 42.4 kg 15 Cooling 25 10 Heat Stress 5 20 Heat stress Cooling Reduced 0 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 Weeks After Calving Decreased milk yield reproducFve Lower body weight Monteiro et al. , J. Dairy Sci . 99:8443-8450. efficiency Decreased IgG absorpFon Thermoregulatory changes Does it Pay to Cool Dry Cows? Does it Pay to Cool Dry Cows? 300 $24.5 / 11 lbs / $2,500 Net Present Value, barn needs to be built $20.0 / 11 lbs / $1,500 net present value, $ per cow per year 250 $20.0 / 11 lbs / $2,500 $20.0 / 11 lbs / $3,500 200 $15.4 / 11 lbs / $2,500 $20.0 / 6.6 lbs / $2,500 150 $20.0 / 2.2 lbs / $2,500 100 50 0 -50 0 30 60 90 120 150 180 210 240 270 300 330 365 Heat stress days Ferreira et al. , J. Dairy Sci . 99:9931-9941. Ferreira et al. , J. Dairy Sci . 99:9931-9941. 11

8/12/19 Does it Pay to Cool Dry Cows? 300 Net Present Value, no barn $24.5 / 11 lbs $20.0 / 11 lbs 250 net present value, $ per cow per year $15.4 / 11 lbs $20.0 / 6.6 lbs 200 $20.0 / 2.2 lbs 150 100 50 0 -50 0 30 60 90 120 150 180 210 240 270 300 330 360 Heat stress days Ferreira et al. , J. Dairy Sci . 99:9931-9941. 12