Proper semen handling vital for successful AI programs

MOSCOW, Idaho — Successful artificial insemination programs focus on proper semen handling.

“There are many factors that play a role in a successful AI program,” said Joe Dalton, professor and Extension dairy specialist at the University of Idaho. “The four things I want everyone to consider are time, temperature, hygiene and skill.”

“If we have 0.5 milliliter straws and they are thawed appropriately at 95 to 98 degrees and held at that temperature, there is no difference in sperm motility from the initial motility right after thawing for 15 minutes,” he said during a webinar hosted by Hoard’s Dairyman.

The maintenance of the semen temperature is very important.

“If we thaw the straws appropriately, but hold them for 15 minutes at 70 to 72 degrees, we get a decrease in sperm motility,” Dalton said.

“This is why we urge technicians to keep loaded AI guns close to their body, in their coveralls,” he said. “And this is why there’s been a development of many good battery pack systems to carry AI guns at the appropriate temperature.”

To thaw a semen straw, place it in 95- to 98-degree water for about 45 seconds.

“Check the card thermometers with another thermometer to make sure they’re accurate,” Dalton said.

When preparing a cow for insemination, the technician should wipe the vulva a couple of times in a downward motion.

“Then in one motion, remove the gun from your coveralls and insert it into the cow,” Dalton said. “Pay attention to details.”

Skilled technicians are able to accurately deposit the semen into the uterine body of the cow.

“We know from research there’s a 10% decrease in fertility when we deposit semen in the cervix as compared to deposition in the uterine body,” Dalton said. “Cervical deposition of semen occurs in 20% of attempted uterine body depositions.”

Multiple straws of semen can be thawed at one time as long as the process is done correctly.

“We did a study on the effect of sequential insemination number on conception rates,” Dalton said. “We saw no effect of whether we thawed four straws together on the fertility of the first, second, third or fourth cow in the sequence.”

The researchers also monitored the time from when the four straws were thawed to the completion of the fourth AI.

“That happened within 10 to 15 minutes, which is the range we want to be in,” Dalton said.

All AI technicians should determine their comfort zone, the dairy specialist said.

“Thaw no more straws that can be used in the 10- to 15-minute range,” he said. “You need to recognize how long it takes to load the guns.”

It is important to prevent straws from touching during the thawing process because if they touch that will cause damage to the sperm which results in reduced fertility.

“When thawing multiple straws, gently swirl the straws when you drop them in the water,” Dalton said. “Also use the temperature card to separate the straws in the thaw bath.”

Since sexed semen is not the same as conventional semen, dairy specialist said, it must be handled appropriately to get the return on investment.

“Sexed semen is very sensitive to semen handling errors,” Dalton said.

“We shouldn’t use the 10- to 15-minute rule for conventional semen. We need to be in the 5- to 8-minute range with sexed semen,” he said.

“That timing begins as soon as the first straw hits the thaw bath and also include the time for loading the guns and walking to the cows.”

Although semen tanks are very durable, the neck tube is fragile.

“Be careful not to drop the tank and make sure there is an appropriate stopper in the neck to stop liquid nitrogen from evaporating through the neck tube,” Dalton said.

“The spacer on the bottom of the tank allows the canisters to have a unique location where they are stored so when we move the tank the canisters don’t swing widely.”

Dairymen should monitor the liquid nitrogen levels in their semen tanks.

“Every couple of days, it’s a good idea to take a dip stick, put it in the tank, remove it and shake it in the air to get a frost line on the stick,” Dalton said.

“You want to maintain a minimum of 10 inches and your AI supplier can add liquid nitrogen to the tanks so they don’t go low.”

Sperm injury occurs at minus 110 degrees, Dalton said.

“Injury to sperm cannot be corrected by returning the semen to liquid nitrogen because sperm do not have a mechanism that allows them to repair damage to membranes,” he said.

“We always want to work below the frost line within the tank to ensure we’re able to maintain the frozen sperm at an optimal temperature,” he said. “Keep the canister below the frost line even the one you’re working with.”

When technicians use poor semen handling techniques, the straw that is removed is the least affected.

“It’s the straws we don’t remove that end up getting an additive effect,” Dalton said. “On the second, third, fourth and fifth time we miss handle semen,\, there’s an additive injury rate to sperm.”

If there is snow coming out of the tank, that means there is evaporation of liquid nitrogen and it is time for a new stopper.

“A new stopper at $10 to $80 is relatively inexpensive compared to the value of semen in the tank,” Dalton said. “There is thousands of dollars worth of semen in the tank, so it’s important to make sure you have a good stopper.”

Liquid nitrogen is dangerous and it can cause burns if not handled properly.

“Work in a safe manner,” Dalton said. “Wear gloves or use tweezers to remove semen from a tank.”