It’s tough enough breeding cows without losing the race before the gun ever goes off – the artificial-insemination gun that is.
Producers and employees need to be careful handling semen. Sauk County Extension Agriculture Agent Katie Pfeiffer, who previously bred cows for a living, said speed is of the essence when pulling straws from a semen tank. Light, temperature change, bacteria and water all kill sperm.
“Just thinking about semen kills semen,” she quipped.
Sperm injury cannot be corrected by returning semen to liquid nitrogen.
Handling the semen tank
It all begins with proper storage and management of the liquid-nitrogen-filled semen tank, she said at a recent Artificial Insemination Certification Program. She referred to the tank as a “bachelor pad.” It’s important to keep track of the level of the liquid nitrogen in the tank. She advised storing the tank on a wooden pallet, or off concrete to prevent corrosion. Store the tank in a dry, well-ventilated space, because nitrogen displaces oxygen. Liquid nitrogen is colorless, odorless and tasteless, and may cause suffocation. It can cause frostbite; its temperature is 320 degrees below zero Fahrenheit.
It’s important to keep the neck cork tight and free of frost.
“If frost is forming on the neck and cap, your tank has probably gone bad,” Pfeiffer said. “Semen probably has been destroyed.”
Straws ¼ cubic centimeter in size are packed 20 to a container. There’s research that shows fertility appears to be better with 1/4cc straws due to better freezing/processing surfaces, Pfeiffer said.
Thawing semen
Pfeiffer said when retrieving straws from the canister, only raise the canister until the cane tops are 2 to 3 inches below the top opening of the tank. Straws should not be raised above the frost line. If it takes more than 10 seconds to retrieve a straw, she said it’s important to lower the canister back into the tank so it can re-cool for 20 to 30 seconds.
“Only pull as many straws as cows you can breed in 15 minutes,” Pfeiffer said. “When you first start, it may take you 15 minutes for one cow.”
Keep in mind that tweezers for half-cc straws might not tightly grasp 1/4cc straws. Although it’s generally recommended to use tweezers when pulling straws from inside the tank, Pfeiffer said she uses her hands because she can do it more quickly that way. But she gingerly holds only the tip of the straw and quickly deposits it in an electrically heated water-bath thawing container. An insulated, wide-mouth thermos is an option for the thawing bath.
Pfeiffer said she shakes the straw gently to remove excess liquid nitrogen still in the cotton-plug end, and immediately places it in 95-degree water to thaw for at least 45 seconds. Be sure to maintain straw temperature as close to 95 degrees as possible throughout the semen-handling process; it’s critical to check for semen-temperature fluctuations. It’s important to change the water frequently, she said, because bacteria-laden water kills semen. Pfeiffer said she’s too often seen dirty semen-thawing water on farms.
Loading the gun
Before loading the gun, Pfeiffer pre-warms the barrel by rubbing it vigorously with a paper towel a half-dozen times. She then wipes the straw dry with paper toweling after removing it from the thaw water. She prefers cutting the crimped straw end at a slight angle, as opposed to straight across. She immediately places the loaded gun down the neck of her shirt so her own body temperature maintains a constant 95-degree temperature for the semen. Cold shock to the straw after thawing is a major concern; it will cause permanent injury to semen.
Universal AI guns can accommodate both 1/4cc and 1/2cc straws. Pfeiffer said she doesn’t like O-ring insemination guns, because the O-ring has a way of being lost. Never use an O-ring gun without the O-ring. The final step is, of course, placement of the semen in the cow.
Source: Agri-View
