Heat, humidity impact milk production 17 Jul 13
ST. PAUL, Minn. (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 tells KSTP-TV 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.