- Dr. Jake Miller
As the fall draws to a close and the winter months set in, many of our cattle producers in the area are weaning and selling off their calves and pregnancy diagnosing their cows and heifers, commonly known as “preg checking”. For this month’s article, we would like to discuss the process of pregnancy diagnosis in not just cattle, but in other animals we see in our clinic.
Cattle have a similar gestation to humans of just over 9 months. The earliest we can determine cattle pregnancy is 21 days with a blood test. This test only tells us if the cow is pregnant or not. Around 35 days, pregnancy can be determined by palpation or ultrasound. Both methods allow us to stage length of gestion of the calf, though accuracy decreases as gestation approaches 180 days (6 months) as the fetus drops deep into the abdomen. Ultrasound between 60 and 90 days of gestation allows us to determine gender of the calf. If you want the best accuracy in staging, we recommend pregnancy diagnosing between 30 and 120 days bred.
Dogs have a relatively short gestation period of 2 months. We have 3 ways of diagnosing pregnancy in man’s best friend. The first method is a blood test that can be performed at 21 days of gestion. This blood test tells us yes or no to the pregnancy. The next method is through an ultrasound at 38 days bred. The ultrasound allows us to take measurements to estimate gestation age; as well as, helps us evaluate heart rate to determine health of the puppies. The ultrasound can give a rough estimate of how many puppies are present, though it is not our most accurate method of determining the litter count. The last method of diagnosing pregnancy is an x-ray that can be taken at 48 days gestion. This method is the most accurate with a puppy count.
Cats have a short gestation period of 2 months. We have 3 ways of diagnosing pregnancy in cats. One, is an ultrasound that can be performed 2 weeks after breeding. Two, is palpation of the abdomen 21 days after being bred. Three, kitten counts can be determined around 50 days with an x-ray.
Horses have the longest pregnancy of all the animals we routinely treat, coming in at 11 months. Ironically, they can be diagnosed pregnant the earliest of all the breeds. With an ultrasound, we can confirm pregnancy as early as 14 days, but we recommend coming in around 16 days. We check at this early stage to determine if the mare is caring twins. Mares do not do well caring twins to term, so if they can be diagnosed at this time one can be reduced if needed. By day 35, a heartbeat can be detected. Fetal sexing can be done from day 55 to 75.
Pigs’ pregnancy lasts for 3 months 3 weeks and 3 days, pretty cool huh. Pregnancy can be confirmed by failure to show estrus in 21 days, or by a trans-abdominal ultrasound 30 to 90 days post breeding.
Sheep and Goats:
Sheep and goats both have a gestation length of 5 months. Pregnancy diagnosis can be detected by a blood test 1 month post breeding. Ultrasound can be performed at 60 to 80 days of pregnancy.