The Race Horse

This Kentucky horse breeder had a filly that won every race in which she was 
entered. But as she got older she became very tempermental. He soon found 
that when he raced her in the evening, she would win handily, but when she 
raised during the day she would come in dead last. 

He consulted the top veteranarians and horse psychologists to no avail. He 
finally had to give up because it had become ... a real night mare.