Farmers call it a “preg check.” Veterinarians call it “pregnancy diagnosis.” Either way, knowing a cow is with calf becomes step one for making money in a dairy herd.
Scott Poock, DVM and University of Missouri Extension veterinarian, held one of seven stops at “Focus on Repro Dairy Day.” The event drew 120 dairy producers from across Missouri. The educational day was June 1 at the MU Foremost Dairy Center west of Columbia.
“I love finding that a cow is pregnant,” Poock said. “But the way I make you the most money is when I find your open (nonpregnant) cows.”
Learning of a pregnancy early saves the most money. Nonpregnant cows are nonworking cows. “They need to be re-inseminated as quickly as possible,” Poock said.
Poock reviewed recent progress in preg checks. The old way was to do nothing after breeding the cow but wait nine months to see if a calf was born.
A lot of progress has been made in this vital management tool, Poock said. The first progress was in palpation, when the vet put on a plastic sleeve and reached in to find a developing calf.
“A problem with palpation is that you can’t tell if a calf is alive or dead,” he said.
“The use of ultrasound machines makes it possible to see a video image of the fetus. That shows much more. Very early you can see the beating heart. A bit later in gestation you see if it is a heifer or a bull.”
Ultrasound allows earlier diagnosis, as soon as 30 days after breeding.
Poock cautioned that early detections should be followed with another check. “Up to 15 percent of early pregnancies are lost to natural causes.”
Rapid progress has been made in ultrasound devices. Original models were huge and were moved on a cart.
The most recent model can be worn on a belt. Instead of looking at a video monitor, Poock sees the calf through “reality goggles.” A handheld device connected by Wi-Fi can be viewed by the nearby farmer or student.
With ultrasound, accurate estimates can be made on the calf’s age in days. That gives a predicted calving date.
The most recent diagnosis tool is a chemical test. A milk or blood sample is tested by applying a drop into a test kit. The blood sample must be sent to a lab. The milk sample can be tested on the farm.
For now, those tests cost the most, ranging from $2.50 to $4.
Poock said when he was in private practice 10 years ago he could palpate 150 cows in an hour and a half. ”Since I charged by the hour, that would cost about a dollar a cow.” He added, “The farmer had to have the cows lined up and ready to go when I arrived.”
Whichever way, it’s important to know early whether a cow is pregnant, Poock said. “Open cows should be re-bred as soon as possible. We want to minimize long lactations where the cow gets fat and not producing well.”