Help cows beat the summer heat

Keep the heat off your dairy

August 18, 2014
POSTED BY: Richard Wallace | DVM, MS | Senior Veterinarian | Dairy Technical Services | Zoetis

Summer temperatures are a delight to many people. But it’s a different story for dairy cows. At just 72°F, cows can experience heat stress,1 which can reduce milk production and impair reproduction. Help keep cows comfortable, healthy and productive with a heat-stress management plan this summer.

Heat stress can be a major burden on dairies. When a cow suffers heat stress, it affects reproductive performance in many ways, including with follicular development, reduced fertility and delayed conception. The impact on fertility is long-lasting.

Just consider  each additional day open beyond 90 days post fresh can cost between $1.50 and $3.00.2 Cows under heat stress can experience an additional 45 to 60 days open past the voluntary waiting period, costing you time and money. In addition, heat-stressed dairy cows have been observed to produce 1,000 to 2,000 pounds less milk during the next lactation.3 The good news is, you can avoid those financial consequences this summer by making plans to reduce heat stress.

Make proactive cow cooling a priority going into hot summer months. The most significant net heat gain for cows occurs in the holding pen while they are waiting to be milked. Start with holding pen cooling, then focus on making cows comfortable in the parlor.

  1. Holding pen and exit lanes — Install sprinklers and fans in the holding pen and return alleys. Water troughs also should be installed in the exit lanes, as cows consume more than 30% of their daily water intake within a half-hour of milking.
  2. Availability of water — Adequate access to clean and cool water must be readily available. Cows will drink 25% to 50% more water when temperatures are 80°F to 90°F or above.
  3. Adequate air movement — Use fans and soakers to keep cows comfortable. They should be a staple on most dairies. Target air movement of 5 to 7 miles per hour and constant rewetting of cows.
  4. Resting areas — Maintaining bedding quality is important. In dry-lot herds, pens may need to be dragged twice a day. If your herd is kept outside, it is essential to provide shade to get the animals out of direct sunlight.

By managing the effect of heat on cows, you’ll keep them comfortable and improve their productivity in the summer. Work with your veterinarian to assess the herd’s reproductive status during the hot summer months. In addition, aggressive use of synchronization programs can help improve breeding success and prevent bottlenecks down the road — not only in summer but year-round.

1 Donnelly M. Economic impacts of heat stress. Available at: http://www.extension.umn.edu/agriculture/dairy/facilities/economic-impacts-of-heat-stress/. Accessed May 14, 2014.

2 Smith R.D., Oltenacu P.A., Erb H.N. The Economics of Improved Reproductive Performance. Dairy Integrated Reproductive Management. Available at: http://www.wvu.edu/~exten/infores/pubs/livepoul/dirm17.pdf. Accessed July 16, 2014.

3 Payne, M. CDQAP Ruminations: Heat Stress in Dairy Cows. California Dairy Research Foundation. September 12, 2013. Available at: http://cdrf.org/2013/09/12/heat-stress-in-dairy-cows/. Accessed July 16, 2014.

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