Managing Heat Stress in the SE Dr. Stephanie H. Ward Dairy Extension Specialist North Carolina State University
Stand up! Meet two new people Ask their name and where they are from A quiz will follow
Heat stress results from: High temp High humidity No air movement Direct sunlight
Energetics Fecal Loss Urinary and Gas loss Heat Increment Production (Milk Yield) Gross Energy Digestible Energy Metabolizable Energy Net Energy Energy from feedstuffs Energy available to the cow Energy used by the cow Maintenance
Thermoneutral Zone (TNZ) TNZ is temperature where heat loss is minimized and energy can be used for production Milk yields TNZ for cows 5 to 20ºC 40 to 68ºF THI = 62
Heat Abatement
Fans Don t cool the air, move it over the cow faster Evaporative cooling Wet the cow or wet the air Use fans to cool Shade Prevent heat from direct sunlight Options for conventional and grass based dairies Heat Abatement http://hoards.com/article-12403-dry-cows-feel-the-heat-too.html http://www.milkproduction.com/library/editorial-articles/have-a-plan-for-heat-stress/
SQMI Farm Data Farm Survey Questions related to heat abatement and milk quality Season Fan availability/use criteria Evaporative cooling/use criteria Feeding and nutrition
SQMI Farm Data SCC was lowest when fans were available in housing and parlor Highest when only available in housing 400000 350000 300000 250000 200000 150000 100000 50000 0 Fan Availability Fan Availability Housing Parlor Parlor + Housing
SQMI Farm Data Criteria used to turn fans on (temperature, visual observation, or always on/off) did not affect SCC Temperature criteria did 350000 300000 250000 200000 150000 100000 50000 Temperature ON/OFF 0 Temperature <60 65 70 75 >80 OBS
SQMI Farm Data Using evaporative cooling did reduce SCC Criteria for use did not 400000 350000 300000 250000 200000 150000 100000 50000 Evaporative Cooling 0 Evaporative Cooling None Misters Soakers Other
SQMI Farm Data Temperature on/off did affect SCC 400000 Temperature ON/OFF 350000 300000 250000 200000 150000 100000 50000 0 Temperature <70 752 80 >85
Heat Abatement Mechanical heat abatement is necessary to reduce temperature non-evaporative and evaporative cooling Nutritional changes can help offset loss in production
#SquadGoals Goal #1: Maintain nutrient intake Goal #2: Encourage water intake Goal #3: Maintain BCS
Heat Stress and DMI NRC (1989) predicts: 10%* decline in DMI when AT increases from 68 to 95ºF NRC (2001) predicts: 8%* decline in DMI when AT increases from 68 to 95ºF Industry says up to 20% decrease in DMI *Based on 1300lb cow producing 60lbs FCM
Goal # 1 Maintain Nutrient Intake Increasing feed offered can help Offering more feed at PM than AM may encourage intake Remember heat increment? Offer more fiber can increase heat of digestion Change ration profile 50% Forage/50% Concentrate Use best quality forages in high producing cows Maximize digestibility of the ration
Item Goal #1 Maintain Nutrient Intake Added Hay Environment Control Low Medium High Effect DMI, lb/d Cool 51.4 48.1 45.4 41.9 L** Hot 40.3 39.2 38.4 36.1 L* Hot- adjusted 37.3 38.1 39.5 39.0 L W** Milk, lb/d Cool 71.2 71.9 69.2 63.7 L Hot 54.2 56.9 58.2 50.0 Q* Hot- adjusted 52.7 55.3 58.0 53.6 L W* Cows fed increasing NDF (Bermudagrass Hay) decreased DMI during hot and cool weather Effects disappeared when hot weather DMI were adjusted for cool weather treatment effects West et al., 1995. JDS Suppl 78(1)
Goal #1 Maintain Nutrient Intake Carbs Mixed Fats P< Energy Balance, kj/kg MBW 38 a 103 b 76 ab 0.01 Milk yield, kg/d 40.2 40.1 39.7 0.88 Milk fat, % 3.86 a 4.10 ab 4.16 b <0.01 Milk Protein, % 3.26 3.26 3.26 0.99 BHBA, mmol/l 0.63 a 0.73 b 0.76 b 0.01 SCC x 10 3 3.60 a 3.67 a 4.25 b 0.01 Addition of carbohydrates reduced NEB and BHBA concentration Also reduced milk fat Limit fat to 5-7% of diet DM Van Knegsal, et al., 2007
Goal #1 Maintain Nutrient Intake Treatment Shaded Evaporative Cooled Effect LQ HQ LQ HQ DMI, lb/d 50.0 52.7 53.6 56.2 C 3.5% FCM, lb/d 53.8 60.0 58.6 66.6 P, C Rectal Temp 102.4 101.5 Resp Rate 82 64 High quality protein can also improve milk yields during heat stress Chen, et al., 1993
Electrolytes/Minerals/Probiotics Most commonly added to water trough Boss cows? Late coming out of parlor? New products designed to be added to feed Electrolyte plus combination of probiotcs
Bovine Bluelyte (TechMix) Electrolytes/Minerals Treatment Control Bovine BlueLite SEm P< Milk Yield, kg/d 33.3 32.1 1.29 0.51 Fat, % 2.73 3.05 0.32 0.47 Protein, % 3.34 3.38 0.09 0.73 Lactose, % 4.68 4.68 0.06 0.95 SNF, % 8.90 8.95 0.10 0.73 SCS, % 1.88 1.92 0.11 0.83 No change in MY or components or SCC Did improve heat stress Reduced resp rate and rectal temp Improved MY in first 5 days of lactation
Goal #2 Encourage Water Intake
Goal #2 Encourage Water Intake Mean Minimum Temperature ( F) MY (lb/d) DMI (lb/d) 40 50 60 70 80 Gallons per day 40 42 18 20 22 24 26 60 48 22 23 25 27 29 80 54 25 27 28 30 32 100 60 28 30 32 34 35
Goal #2 Encourage Water Intake Lower temperature of water? Conflicted research Chilled water can increase DMI and MY Clean and adequate access is most important During hot months clean tanks 1x per week Keep shaded if in pasture
Goal #2 Encourage Water Intake Easy access and plenty of space In return alleys 2 ft per cow In housing 2 waters per group 4in linear water space per cow <50 ft distance Locate near housing and out of direct sunlight Reduce algae growth
SQMI Farm Data Type of ration fed Frequency of feeding/ push up
SQMI Farm Data Type of ration fed had significant effect on SCC 450000 400000 350000 300000 250000 200000 150000 100000 50000 0 Ration Type Ration Type TMR GRS
SQMI Farm Data Feeding frequency did not have an effect (P <0.15) Number of times feed pushed up per day did not have an effect 450000 400000 350000 300000 250000 200000 150000 100000 50000 0 Feeding Frequency Feeding Frequency 1x/d 2x/d 3+
SQMI Farm Data Fresh feed available after milking did reduce SCC 400000 350000 300000 250000 200000 150000 100000 50000 0 Feed Availability Feed Availability YES NO
Take Homes TMR- decreases sorting, reduces impact of HS and improved SCC Offer fresh feed- increased DMI, offering after milking reduced SCC Reduce fiber in ration leads to greater DMI Cannot sacrifice fiber needed for health rumen or milk fat Balance minerals- adding electrolytes can offset loss through increased respiration Use nutrition to work beyond what mechanical heat abatement cannot do
Would Not BePossible Without This project is supported by Agriculture & Food Research Initiative Competitive Grant no. 2013-68004-20424 from USDA National Institute of Food & Agriculture
2017 Annual Meeting Sponsors Platinum Diamond V Gold Dairy Farmers of America Silver Elanco VA State Dairymen s Association Zoetis Thanks for your support!
Grazing Supplement timing Grazing under pivot (last slide- lead in to Amanda)
Grazing Farm Data
Enzymes/DG
Enzymes/DG