
Wouldn't it be great if it worked. :) The simplest way to explain it is (I know it's stating the obvious, but it's logical)
A lady's cycle is monthly & gestation is 9 months.
A dog's cycle is 6 monthly & gestation is 9 weeks, therefore reproduction in a dog will happen (pregnancy & birth) long before the dog is next due in season. Hence making it hard to diagnose pregnancy through hormones. Also a dogs progesterone level is the same post season if she's pregnant or not.
Hope that makes sense.
Clear as mud i hear you say?
snoopy1. :)