I have a goat. (ok, I have several)
First year with her, took her and her daughter to a neighbors buck about 5 miles away. Hoped the older one got bred but was not sure. Fast forward about 4 months, gee, I wonder if she did get bred, she sure gained a belly and there is udder development. The younger one looked preg, but we were certain she did get bred. (just not certain about the older one.) Had a friend bump her, yep, she has kids in there. well, she never kidded that year, though she did look like she should have, milk and all.
She had kids the next two years.
Then last year we bred her and she never looked preg at all. I figured that she was just too old. Even the morning that I had three does due, she did not look preg one bit. Three hours later my step dad calls me to tell me about who is kidding, and tried to tell me the old one was kidding, and I was sure he had them confused. When I got home, yes that doe was the first to kid. The third that was due that day and looked ready to pop lasted another 4 days.
That old doe went from looking no way she was bred to kid on the ground with full udder in three hours.
I gave up trying to estimate pregnancy. I just try to mark on the calender every time I see anyone in season so that I can at least try to guess when I should stick around home.
My cow is due in 2 weeks. Yep, I should have had her preg checked. Had the bull here two months and have not seen her in season and she sure looks big and uncomfortable, and there is udder development, but well...
we'll see!