Ultrasounds are not the only tool to determine pregnancy!
The preg-tone is a tool used that hears the presence of amniotic fluid in the female 40-50 days after breeding.
I have been using the preg-tone for 15 years to confirm pregnancy in my herd. It is most accurate 45-50 days after breeding up until a couple months before delivery. Swine breeders have been using this for years as quick, easy, a cost effective way of determining a positive. I HAVE NEVER HAD A FALSE POSITIVE and very few false negatives (only if I have tried to do it too early). Other users claim 97-100% accuracy.
The process in simple. Vegetable oil is used as a conductor on a wand that is pressed lightly to your females tummy. It gives off a steady beep if amniotic fluid is detected. That's it! Usually can be done in 1-2 minutes!
All you need to do is have your female penned or preferably in some kind of chute where she cannot cush.