We've been blood testing our cows for the last 3 or 4 years. We really liked the accuracy and the fact that it was non-invasive and we could do it ourselves. But waiting several days for results became kindof a pain in the you-know-what. Palpating was nice since you knew if they were bred or not while you had them in the chute and could sort them immediately. However, it's pretty invasive and generally risky on earlier pregnancies. (We sold a group of short bred cows at the sale, had them palpated, and all but one got called open. They should have all been 3-4 months. That kindof soured us on palpating.) Ultrasound basically combines the convenience of palpating with the non-invasiveness and accuracy of blood testing. Additionally, you don't have to wait until 90 days post-calving, you can find twins, sex the calf, detect uterine infections, and find fetuses that have died but haven't been expelled yet. And it's a whole lot faster. After talking to a lot of people about it and seeing how much interest there was, we decided that it was definitely an investment worth making. As far as training goes, I've been watching YouTube videos for months, and reading everything I can find.
It's really not that difficult if you have a firm grasp of a cow's anatomy and know what you're looking at on the screen. Knowing how to AI helps, just so you're more familiar with the inside of a cow. My husband can do it. He got his degree in English (to his credit, he is a certified AI tech).
We ended up purchasing a Repro Scan XTC with a Repro Arm.
http://www.repro-scan.com There are a lot of videos on their Media page that will blow you away if you've never seen it done before. It is 95% accurate at detecting pregnancy at 35 days. We are going to be generally waiting until 45 days on ours...if they make it that long they are a lot more likely to be safe in calf, since about 5% lose the pregnancy before they make it to 45 days. That kinda explains why it's only 95%.