ST. PAUL (AP) - The heat and humidity can be hard on anyone who works or spends a great amount of time outdoors, but it can also be tough on milk-producing cows.

Dr. Marcia Endres, from the University of Minnesota-Extension, says the higher temperatures can reduce a cow's milk production by 10 to 15 percent - or up to two gallons a day.

Endres says it takes a few days for a milk-producing cow to show symptoms of heat stress, but the effects can last much longer.

The University of Minnesota is researching ways to warn dairy farmers that a cow is beginning to experience heat stress. One experiment implants a thermometer in a cow's stomach to send an email or text alert to the farmer before heat stress has a chance to escalate.

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