Program. Advanced heat stress management in dairy cows. phileo-lesaffre.com LESAFFRE ANIMAL CARE

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1 Advanced heat stress management in dairy cows phileo-lesaffre.com LESAFFRE ANIMAL CARE

2 HEAT STRESS AND TEMPERATURE-HUMIDITY INDEX (THI) 1,2 Heat stress can be defined as an increase in core body temperature above its normal range, due to an increase in total heat load that exceeds the capacity for heat dissipation. Temperature is not the only environmental factor affecting the severity of heat stress. The THI measures the combined effects of environmental temperature and relative humidity (RH) to ascertain heat load. Heat stress threshold: THI 68 1,2 Temperature 22 C } THI = 68 Heat stress threshold for dairy cows Humidity 50% THI and heat stress impact Temperature-Humidity Index for lactating dairy cows (1) Temperature Relative Humidity (%) F C THI = (Tdb-(0.55-(0.55RH/100))(Tdb-58) where Tdb is dry bulb temperature ( F) and RH is relative humidity C = ( F 32)/1.8 Stress Threshold: respiratory rate exceeds 60 breaths/min. Milk yield starts to decline. Reproductive failure observed. Rectal temperature exceeds 38.5 C Mild-Moderate Stress: respiratory rate exceeds 75 breaths/min. Rectal temperature exceeds 39 C Moderate-Severe Stress: respiratory rate exceeds 85 breaths/min. Rectal temperature exceeds 40 C Severe Stress: respiratory rate of breaths/min. Rectal temperature exceeds 41 C Temperature & humidity 22 C 10% 27 C 35% 35 C 40% 39 C 50% THI THI < 68 No stress 68 THI 79 Moderate stress 80 THI 89 High stress 90 THI 98 Severe stress Respiratory rate breaths/min Rectal temperature 38.5 C Respiratory rate >75 breaths/min Rectal temperature >39 C Respiratory rate >85 breaths/min Rectal temperature >40 C Respiratory rate > breaths/min Rectal temperature >41 C 2 1. Zimbelman et al., A re-evaluation of the impact of temperature humidity index (THI) and black globe humidity index (BGHI) on milk production in high producing dairy cows. Proceedings of the Southwest Nutrition Conference. 2. Zimbelman and Collier Feeding strategies for high-producing dairy cows during periods of elevated heat and humidity. Tri-State Nutrition Conference.

3 EFFECT OF HEAT STRESS ON DAIRY HERDS 3 HEAT STRESS Feed intake Behavioral changes Metabolic changes DMI Sorting Ventilation Standing Sweating Insulin secretion Acidosis risk Fat mobilization Glucose mobilization Negative energy balance Lameness risk Energy demand Glucose dependence Lactose synthesis Milk production Effect of heat stress on milk production 37.0 Milk production, kg/d THI Milk production +1 pt THI kg/cow/d THI Bernabucci et al., Metabolic & hormonal acclimation to heat stress in domesticated ruminants. The Animal Consortium. 3

4 EFFECTS OF HEAT STRESS ON RUMEN HEALTH 4 Heat stress has long been known to adversely affect rumen health: One way that cows dissipate heat is by panting, and this increases the carbon dioxide (CO 2 ) exhaled. The body needs to maintain a 20:1 bicarbonate (HCO 3 ) to CO 2 ratio for effective blood ph buffering, so the kidney secretes HCO 3 to maintain this ratio. This reduces the amount of HCO 3 that can be used in the saliva to buffer and maintain a healthy rumen ph. Panting cows also salivate excessively, and this reduces the quantity of saliva that would normally be deposited in the rumen. Reduced feed intake also reduces rumination, and therefore saliva production, in heat-stressed cows. The reduction in the amount of saliva produced and in HCO 3 levels in the saliva make the heat-stressed cow much more susceptible to subclinical and acute rumen acidosis. HEAT STRESS THI 68 Respiration rate DMI Subacute ruminal acidosis CO 2 in blood Secretion by the kidneys Salivation Metabolic heat production Milk yield Rumen ph Acidosis Milk yield 4 4. Kadzere et al., Heat stress in lactating dairy cows: a review. Livestock Production Science: 77:

5 ACTISAF : IMPROVE RUMEN FUNCTION 5 Increased milk yield Reduced risk of acidosis RUMEN REDOX POTENTIAL -50 Redox potential, mv FIBER-DIGESTING BACTERIA LACTATE-UTILIZING BACTERIA VOLATILE FATTY ACIDS LACTATE Volatile fatty acids, mm Lactate, mm MILK YIELD RUMEN PH 5. Marden et al., How does live yeast differ from sodium bicarbonate to stabilize ruminal ph in high-yielding dairy cows. J dairy Sci.:91: Significant difference (p<0.05) 5

6 IMPACT EFFECTS OF OF HEAT STRESS ON ON ENERGY RUMEN METABOLISM HEALTH 4 6 Glucose oxidation and utilization is known to produce less heat than fat oxidation (43 kcal of metabolic heat vs. 49 kcal), so heat-stressed cows mainly rely on glucose as an energy source for maintenance and milk production. Basal values for the hormone insulin, which is a potent regulator of both carbohydrate and lipid metabolism, gradually increase in heat-stressed lactating cows, stimulating glucose uptake and reducing fat mobilization. As a result, the mammary gland in heat-stressed dairy cows may not receive sufficient glucose, reducing mammary lactose production and subsequent milk yield. HEAT STRESS THI 68 Negative energy balance Milk yield NEFA (as insulin, a potent anti-lipolytic hormone) Circulating insulin Systemic glucose utilization Mammary lactose production NEFA: Non-esterified fatty acids Milk yield 6 6. Wheelock et al., Effects of heat stress on energy metabolism in lactating Holstein cows. J. Dairy Sci. 93:

7 ACTISAF : RESTORE POSITIVE ENERGY BALANCE 7 Improved thermoregulation Increased milk yield PERIPHERAL VASODILATATION a GLUCOSE AVAILABILITY Plasma niacin, μg/l Plasma glucose, mg/dl RESPIRATORY COMFORT LACTOSE SYNTHESIS b Respiration rate, breaths/min Lactose, kg/d ENERGY LOSS MILK YIELD a. Niacin (nicotinic acid) is a vitamin produced by the microorganisms in the rumen. It increases the diameter of the blood vessels, improving exchanges between the blood and surrounding tissues. b. Heat-stressed dairy cows rely primarily on glucose as a source of energy. Actisaf improves rumen efficiency and increases volatile fatty acid production in the rumen, increasing glucose synthesis by the liver. 7. Salvati et al., Response of lactating cows to live yeast supplementation in summer. J Dairy Sci.:98: Significant difference (p<0.05) 7

8 IMPACT EFFECTS OF OF HEAT STRESS ON ON ENERGY ANTIOXIDANT RUMEN METABOLISM HEALTH STATUS 4 86 It has been demonstrated in dairy cows and other animals that heat stress has a negative effect on intestinal integrity and may cause lipopolysaccharides (LPS) to enter the systemic circulation (translocation), leading to systemic inflammation. Inflammatory processes are endogenous sources of reactive oxygen species (ROS), which can reduce the immune response, and cause cell damage, fertility problems, and mastitis. The most well-known causes of oxidative stress in veterinary medicine are metabolic and inflammatory events, and environmental factors (heat stress and nutrition). Prolonged exposure to oxidative stress can interfere with physiological processes, and reduce animal performance and the quality of the end product. Balanced oxidative status Pro-oxidant system Antioxidant system Healthy animals Imbalanced oxidative status Heat stress ROS Oxidative stress Pro-oxidant system Antioxidant system Disruption of physiological processes and disease 8 8. Sordillo et al., Impact of oxidative stress on the health and immune function of dairy cattle. Veterinary Immunology and Immunopathology. 128(1-3):104-9.

9 SELSAF : IMPROVE COMFORT & ANTIOXIDANT STATUS 9 An experiment was conducted to assess the effect of Selsaf on milk production, milk quality and health status in heat-stressed dairy cows. Results demonstrated that cows that were fed Selsaf had significantly lower body temperatures and higher serum glutathione peroxidase (GPx) activity than cows that were given sodium selenite. Better antioxidant status has been proven to improve overall health and reduce serum cortisol levels. RESPIRATORY COMFORT & BODY TEMPERATURE Effect of Selsaf on respiration rate (RR) and rectal temperature (RT). STRESS HORMONE SECRETION Effect of Selsaf on cortisol concentration (COR) in the serum C RR, breaths/min C RT, C COR, ng/ml % Sodium selenite Selsaf 38.3 p = p < Sodium selenite Selsaf p = GPx ACTIVITY Effect of Selsaf on the serum activity of glutathione peroxidase (GPx). ANTIOXIDANT CAPACITY Effect of Selsaf on the serum total antioxidant capacity (TAOC). GPx, U/mL % % TAOC, U/mL Sodium selenite Selsaf p = Sodium selenite Selsaf p = Cheng J. et al. China Effects of selenium yeast on performance and health status in heat-stressed dairy cows. Internal data. 9

10 Groups No. of dairy cows Actisaf inclusion rate - 6 g/cow/d THI IMPACT EFFECTS ACTISAF OF OF : IMPROVE HEAT STRESS PRODUCTION ON ON ENERGY RUMEN DURING METABOLISM HEALTH HEAT 4 STRESS The following study examined the effects of Actisaf supplementation on milk production and feed efficiency in dairy cows during the summer season in Israel. During the 13 weeks study period, the maximum daily temperature and relative humidity averaged 31.2 ± 1.6 C and 83.6 ± 5.7%. The temperature-humidity index (THI) averaged 69.4 ± 3.5 in the morning and 79.3 ± 2.1 in the afternoon. Feed efficiency Milk yield & composition 10:1 Return On Investment DRY MATTER INTAKE: +600 g/d FEED EFFICIENCY: +50 g DMI, kg/d % 24.7 Feed efficiency, kg milk/kg DMI % p < p < 0.03 MILK YIELD: +1.5 kg/d MILK FAT: +89 g/d % Milk yield, kg/d Milk fat, g/d % p < p < Moallem et al., The effects of live yeast supplementation to dairy cows during the hot season on production, feed efficiency, and digestibility. J. Dairy Sci. 92: Significant difference (p<0.05)

11 Groups Sodium selenite Selsaf No. of dairy cows Selenium inclusion rate a 0.3 mg/kg of feed 0.3 mg/kg of feed THI SELSAF : IMPROVE MILK COMPOSITION AND QUALITY 9 An experiment was conducted to assess the effect of Selsaf on milk production, milk quality and health status in heat-stressed dairy cows. During the 8-week experiment, mean THI was 77.3 in the morning; 83.3 at midday; and 80.0 in the evening, which corresponds to high stress situation. Milk selenium concentration and somatic cell count were significantly better in the Selsaf group than the sodium selenite group. MILK COMPOSITION Effect of Selsaf on milk selenium concentration % Se (µg/l) Sodium selenite Selsaf p = MILK QUALITY Effect of Selsaf on milk somatic cell count % SCC, x 1 000/mL Sodium selenite Selsaf p = Cheng J. et al. China Effects of selenium yeast on performance and health status in heat-stressed dairy cows. Internal data. a. Dose can vary according to local regulation. 11

12 The information provided in this document is, to the best of our knowledge, true and accurate. However, products must only be used in compliance with local laws and regulations; we cannot guarantee freedom of use for every intended application or country. Actisaf-R-HS-TECH-doc.12p EN Further information on heat stress management NEW Technical guide Heat stress management in dairy cows phileo-lesaffre.com 137, rue Gabriel Péri - BP Marcq-en-Barœul - France Tel.: Fax: info@phileo.lesaffre.com 12 Find out more about heat stress management by downloading your new technical guide phileo-lesaffre.com/heat-stress/dairycows Effect of heat stress Rumen function Positive energy balance Antioxidant status Zootechnical performance Feed efficiency Milk yield Milk composition & quality Download the app to assess the effect of heat stress on your farm and calculate how you could benefit Program from using LESAFFRE ANIMAL CARE