How many cows can you get on a Boeing 747?  Try 390.  Problem:  The cargo area may require air conditioning!  Not to freshen the air, but to keep it cool!  Things really heated up while the cows where being flown over the Irish Sea.  Detection devices in the cargo hold indicated a fire.  So, the pilot was forced to emergency land the plane at Heathrow Airport.  However, after a safe landing nobody found any evidence of an actual fire.  

Wow!  390 cows on one plane!  That's one hot and heavy "mile high club"!