Instructions
Use an On-Farm Pregnancy Test Kit (Two Weeks After Breeding)
Obtain an on-farm pregnancy test kit. These might be available through your veterinarian or directly from the manufacturer. Ask your veterinarian for recommendations. Kits come with a plastic cassette into which you drop the blood or milk sample, a liquid wash that you drop into the cassette with the sample you are testing, and instructions on how to use and read the results on the kit.
Test the cow using the kit two weeks after you think she was bred. These kits are especially easy to use with dairy cattle that are already lactating. Place a drop of milk into the kit with the requisite amount of wash. Set the kit aside for however long the instructions dictate, usually forty-five minutes to a couple of hours. Read the results according to kit instructions. This usually involves a color change of some sort.
Breed cows that are not pregnant, called "open cows" within their twenty-one day fertile period.
Use Rectal Palpitation of the Cow's Uterus (Thirty Days After Breeding)
Put on an arm's length latex glove and spread some lubricant on the gloved hand. Stand close behind the cow, lift her tail and begin to insert your hand and arm into her rectum.
Feel the back of the cow's uterus, which will be in a downward position, with your inserted hand. Move your hand and arm firmly but gently. After thirty days of gestation, the fetus should be about the size of a softball and will feel like a soft, but distinctive lump under your hand.
Remove your arm and hand from the cow steadily and gently. You should now have an answer to your question of "is she or isn't she" pregnant.
How to Pregnancy Test a Cow
Pregnancy detection is integral for herd management in any livestock operation. The traditional method for determining pregnancy in cattle is rectal palpitation of the uterus. This requires skill and practice, and the risk of injury is substantial. More recently, veterinarian scientists have developed on-farm tests for bovine pregnancy. These tests are fairly quick and easy, but their efficacy is still somewhat in debate and many traditionalists prefer the old palpitation method.