September 5, 2017 at 3:32 p.m.
"It is one of the most important keys to survivability and profitability," said Jim Salfer, a University of Minnesota Extension Educator. "Good reproduction results in more calves, higher milk production and more profit."
Salfer presented "Reproductive Management with Reproductive Tract Dissection" during the Dairy Producer Series on March 13 in Gaylord, Minn.
Improving reproduction in dairy herds has a definite economic value for farmers.
For example, a 21-day pregnancy rate of 16 percent will increase net return by $22.78, but if producers would improve their pregnancy rate to 26 percent, the increase in net return would instead be $146.47.
"That's quite a difference," Salfer said.
Farmers can evaluate their reproductive program. One area to look at is pregnancy rate.
According to Salfer, dairy farmers should strive for a pregnancy rate of greater than 23 percent.
"That is tough," Salfer said. "A typical pregnancy rate is 13 to 18 percent. We should strive for at least 20 percent."
There are three key areas in getting cows pregnant rapidly: the rate of insemination after the end of the voluntary waiting period (VWP), conception rate and the rate of identifying and re-inseminating of open cows.
"This is the biggest challenges we see is catching those open cows," Salfer said. "One of the biggest factors that effects these is heat detection rate."
Even if farmers are using timed A.I. programs or activity monitors, it's not guaranteed to catch all the heats.
"Farmers have to engage their brains," Salfer said. "They still have to watch for heats. There are going to be some anovular cows."
To demonstrate this, Salfer looked at the percent of cows determined to be in heat and the distribution of those cows and ovulation for activity monitors and heatmount detectors.
With the activity monitors, 71 percent of cows were determined to be in heat and 29 percent not in heat. Of those 71 percent, 95 percent were ovulating. However, of the 29 percent determined to not be in heat, 35 percent were ovulating.
The same went with the heatmount detectors. There were 66 percent determined to be in heat and 93 percent of those cows were ovulating. On the flip side, 34 percent of the cows were determined to not be in heat, but 47 percent of those cows were actually ovulating.
"This is not unusual. There are always anovular cows that don't show heats," Salfer said. "These systems are good, but they are not fool proof. That is why farmers have to still watch for heats."
Low body condition scores (BCS) contribute to an increased number of anovular cows.
"Cows with a BCS of less than 2.75 when bred are at an increased risk of being anovular," Salfer said.
Conception rate is another aspect to look at when evaluating reproductive programs.
Salfer said the goal for conception rate should be greater than 35 percent.
"I think farmers can achieve this," he said. "We want to have over half of the herd confirmed pregnant."
There are many things that effect conception rate, such as cycling status, energy balance, use of presynch, length of the VWP, herd health programs and sire fertility.
"It's something we think of right away, but it makes a difference," Salfer said.
Another is proper handling and placement of semen.
"Technicians can vary," Salfer said. "Sometimes it is not a cow problem or a heat detection problem. Farmers need to keep track of who is breeding the cow."
Getting cows pregnant can be a challenge for farmers and Salfer said that cow health could play a role in this. One disease that impacts this is mastitis.
"Early occurrence of mastitis has a profound effect on fertility. On average mastitis can increase days in milk by a month," Salfer said. "It's important to keep milk quality good, especially in fresh cows."
Cows that come down with metritis, retained placentas, ketosis and lameness also effects fertility.
"Healthy cows make a difference," Salfer said.
On the same token, Salfer said, farmers need to know when to stop breeding.
"Four breedings should be the limit for most cows," he said. "An exceptional cow may get five breedings."
In the end Salfer believes farmers have to keep working on their reproductive program.
"There is always things we can work on," he said.