Slide 1: Baby it's Hot in Here: Impacts of Late Gestation Heat Stress on Dam and Daughter
5/3/21 Baby it’s Hot in Here: Impacts of Late Gesta<on Heat Stress on Dam and Daughter G. E. Dahl Department of Animal Sciences Ins<tute of Food and Agricultural Sciences gdahl@ufl.edu Balchem Real Science Series 4 May 2021 Milk yield? Metabolism? Immune func<on? Placental Func<on? Late gesta(on DAM
Slide 2: Study Design: Heat Load of Dry Cows
5/3/21 Study Design: Heat Load of Dry Cows Do Amaral et al., J. Dairy Sci. 94:86–96 Heat Stress Increases Mean Rectal Temperature 39.4 Treatment Effect; P<0.05 39.2 39.0 Heat Stress 38.8 Cooling 38.6 a b 38.4 38.2 Morning Afternoon Time Do Amaral et al., J. Dairy Sci. 94:86–96 Cooling Dry Cows Incre
Slide 3: Cooling Dry Cows Increases Milk Production
Co Milk, kg/d lli er 0 5 10 15 20 25 30 35 40 45 50 W et al ol .( fe 19 Av ns on 82 en da et ) ño al -R .( ey 19 es 88 et ) al .( Ad 20 06 do in et al ) Cooled Am .( 20 ar 09 Metabolism Metabolism al et ) Epithelial Cell Epithelial Cell Heat Stressed do al Am .( 20 ar 09 al et ) al .( 20 Ta 11 o ) e
Slide 4: Cooling Increased Proliferation of Mammary Cells Prepartum
5/3/21 Cooling Increased Prolifera<on of Mammary Cells Prepartum (d-20) 4.0 * ** 3.5 3.0 Ki67 labeling, % 2.5 2.0 1.5 1.0 0.5 0.0 Epithelium Stroma Total Tao et al., J. Dairy Sci. 94:5976–5986 Heat Stress During Dry Period – No Effect on MEC Apoptosis 0.7 Epithelium 0.6 TUNEL labeling, % 0.5 0.4 0.3
Slide 5: Late Gestation Cooling
5/3/21 Late Gestation Cooling • Do I have to cool cows the entire dry period? • Do heifers need to be cooled pre- partum? Heat Stress Increases Rectal Temperature and RespiraXon Rate Fabris et al. , J. Dairy Sci. 102:5647-5656. Heat Stress at Any Time Decreases GestaXon Length and Dry Period Length
Slide 6: Heat Stress at Any Time When Dry Reduces Milk Yield
5/3/21 Heat Stress at Any Time When Dry Reduces Milk Yield P Fabris et al. , J. Dairy Sci. 102:5647-5656. Heat Stress Effects on First Calf Heifers: Cooling Decreases RR and RT Week Rela<ve to Calving Week Rela<ve to Calving Davidson et al, J. Dairy Sci. 104:2357-2368 Heat Stress Effects on First Calf
Slide 7: Heat Stress Reduces DMI Prepartum But Not Postpartum
5/3/21 Heat Stress Reduces DMI Prepartum But Not Postpartum 25 Treatment effects: Prepartum P = .03 Postpartum P = .9 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 Cooling Dry Cows In
Slide 8: Cooling Dry Cows: Effects on Acquired Immunity
5/3/21 Cooling Dry Cows Increases Lymphocyte Prolifera<on Do Amaral et al., Domest. Anim. Endo. 38:38-45 Cooling Dry Cows Effects on Acquired Immunity Do Amaral et al., J. Dairy Sci. 94:86–96 Cooling Dry Cows Increases Neutrophil Ac<on Postpartum Do Amaral et al., J. Dairy Sci. 94:86–96 8
Slide 9: Dry in COOL Months Improves Performance
5/3/21 Dry in COOL Months Improves Performance Thompson & Dahl, Prof. Anim. Sci. 28:628-631 Dry in COOL Months Improves Reproduc<ve Performance Thompson & Dahl, Prof. Anim. Sci. 28:628-631 Decreases milk yield Alters placental func<on Reduces mammary growth Reduces immune func<on Late gesta(on DAM v
Slide 10: Cooling Increases Calf Birth Weight
5/3/21 Cooling Increases Calf Birth Weight 45 Treatment effect: P < 0.01 Birth Weight, kg 40 35 30 36.7 kg 42.4 kg 25 20 Heat stress Cooling Tao et al., J. Dairy Sci. 95:7128-7136 In Utero HT Reduces Weaning Weight 90 45 P = 0.04 BW Change, Kg 40 Weaning BW, Kg 80 35 30 25 70 20 Heat stress Cooling 6
Slide 11: Why Does Cooling Affect AEA? Calf or Colostrum Effect?
5/3/21 Why Does Cooling Affect AEA? Calf or Colostrum Effect? ! Monteiro et al., J. Dairy Sci. 97:6426-6439 Experiment 1 - In utero heat stress for ~6 weeks reduces body weight and height to weaning Monteiro et al., J. Dairy Sci. 97:6426-6439 Cooling Increased Apparent Efficiency of IgG Absorption (AE
Slide 12: Experiment 2 – No Effect of Colostrum from Cooled or Heat Stressed Cows
5/3/21 Experiment 2 – No Effect of Colostrum from Cooled or Heat Stressed Cows on Calf Performance Monteiro et al., J. Dairy Sci. 97:6426-6439 RetrospecXve analysis of records of calves from 5 studies between 2007 and 2011 Monteiro et al. , J. Dairy Sci. 99:8443-8450. Heat Stress Experiments 2007 - 2
Slide 13: In Utero Heat Stress Decreases Calf Bodyweight and Survival
5/3/21 Birth Weight 48 trt: P < 0.001 gender: P = 0.002 46 Birth Weight, kg 44 42 40 44.8 kg 38 39.1 kg 36 34 Cooling Heat Stress Monteiro et al. , J. Dairy Sci. 99:8443-8450. In Utero Heat Stress Decreases Calf Bodyweight to Puberty 400 350 Cooling Heat Stress 300 Body Weight (kg) 250 trt: P < 0.05
Slide 14: In Utero Heat Stress Decreases Reproductive Performance
5/3/21 In Utero Heat Stress Decreases Reproduc<ve Performance Monteiro et al. , J. Dairy Sci. 99:8443-8450. In Utero Heat Stress Reduces Milk Production P = .03 ! Monteiro et al. , J. Dairy Sci. 99:8443-8450. In Utero Heat Stress Does Not Affect Mature Bodyweight P = .03 Monteiro et al. , J. Dairy S
Slide 15: In Utero Heat Stress Alters Lifetime Yield
5/3/21 In Utero Heat Stress Reduces Survival in Herd Laporta et al. , J. Dairy Sci. 103:7555-7568. In Utero Heat Stress Alters Lifetime Yield 1st LactaXon; 2.2 kg/d 2nd LactaXon; 2.3 kg/d 3rd LactaXon; 3.9 kg/d Laporta et al. , J. Dairy Sci. 103:7555-7568. Does it Pay to Cool Dry Cows? Ferreira et a
Slide 16: Does it Pay to Cool Dry Cows?
5/3/21 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 / $1,500 250 net present value, $ per cow per year $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 / $2,5
Slide 17: In utero heat stress induces fetal programming
5/3/21 - In utero HT induces fetal programming - Alters methyla<on pamerns in mul<ple <ssues, ages - Phenotype persists to F2 17