Proper Semen Handling in Cold Weather
(Part One)
Transcript of Select Sires' Reproductive Moment Program
on DairyLine Radio Which Aired Nov. 10, 2005
With Ray Nebel,
Extension Specialist and Professor of Reproductive Management,
Virginia Tech
Ray, the cold winter months are beginning to set in, and this week you are talking about semen handling and how to prepare for that during the cold temperatures.
We need to maintain that semen at the temperature where it was thawed. We recommend 95 degrees Fahrenheit. The normal thawing procedure is 95 degrees for a minimum of 40 seconds. And that 40 seconds brings that semen up to that temperature. With the fall coming in, back east at least, last week it got down to 30. So we are starting to get cool temperatures, and it's more critical that we maintain that temperature on our way to inseminate that cow. If we don’t, we get into the condition known as cold shock. Cold shock damages the sperm irreversibly, and that semen then will lower the conception rate of that inseminate.
So the best way to maintain that temperature to the cow?
The thaw water is 95 degrees. The semen itself has been held in liquid nitrogen that’s minus 196 centigrade, or minus 360 Fahrenheit. So when we drop it into that water it starts thawing immediately. We want a quick go-through-crystallization, so we want to maintain the viability of that semen. Waiting that 40 seconds brings temperature inside of that straw up to 95 degrees. Now the geometry of that straw is that it's going to cool very quickly, within seconds. The other critical point is that the insemination apparatus is stainless steel, so it conducts heat very easily. We need to warm up the insemination rod before placing the semen inside the gun. Because the gun and insemination rod are stainless steel, normally we rub it briskly. I put it up to my cheek to make sure I don’t feel a difference in temperature, and then the straw is taken out of the water, completely dried, and placed in the gun. The factory seal -- not the cotton plug, but where it's sealed in the lab, the lab seal -- is then cut, and a sheath is placed over it and we normally put a paper towel to protect it, and put it within our clothing to keep it in close to our body, to keep it kind of close to our body temperature.
That’s the key then with the cold weather, is you want to make sure the stainless steel is warm?
You really want to handle the semen the same, and we really don’t want to handle it much different in the summer and winter, except in the summer you don’t normally warm up the gun, because the gun is already going to be warm. In the wintertime, in the cold temperature, the gun is the same temperature as the outside environmental temperature. So when I would go tomorrow morning to breed a cow, and pick up that stainless steel rod that’s going to be 30 degrees, I would need to warm that gun up before I slip that straw of semen inside. So you are correct that the biggest difference is that we need that gun warm and up to body temperature, because when we put that straw in it, the difference of temperature is going to be conducted almost immediately, and that’s where we cold shock the semen and damage it permanently.
We will continue this next week with Ray Nebel from Select Sires.
|
