Breeding is both an art and a science. Artists like what they do; they focus their attention and their natural skills to produce exceptional results.

The science of breeding means knowing the facts about heat detection and semen thawing and placement. It means you don’t take shortcuts, don’t do your own thing, and do work according to protocols.

I’d like to clarify the art and science components of breeding to help you get one more additional cow pregnant each day that you breed.

Art:

Science: Very precise! You need to know that all injections MUST be administered exactly as specified by the particular OvSynch protocol selected by your owner and veterinarian.

Failure to inject an animal with the proper hormone – at the correct dose, in the muscle, on the precise day and hour – will result in not getting the animal pregnant when you do breed her. If done correctly all the time, you will get that one more new pregnancy.

Visual
You may be using tail striping as part of the heat detection program on your dairy. Tail striping is a two-step process: First, “read” the tail stripe applied previously for signs of heat; then reapply the crayon tail stripe again.

Reading the cow for signs of heat includes asking these questions: Is the tail stripe partially, somewhat or totally rubbed off? Is there mucus or dirt on the cow’s back? Is there mucus or blood on the tail? Is the vulva swollen and pink, or normal and dry?

Art: Extremely important! You must be very focused on looking for subtle secondary signs of heat on every cow you evaluate. Draw upon your experience and your cowmanship to make judgments about whether the cow is in heat or not.

Science: Very important! Recognize that individual cows can show different degrees of signs of heat (number of mounts per hour and number of hours exhibiting estrus activity). Regardless of how strong or weak the signs are, all have the same chance of becoming pregnant (strength of heat sign does not impact conception rate).

Sperm are alive, but immobilized by the special semen processing techniques used by your A.I. company when packaging semen in the straws stored in your tank. Thawing regenerates sperm mobility and vitality. But the thawing process must be done correctly to avoid injury to sperm as they move from the frozen, immobilized state to the motile, highly fertile state.

During thawing, solid ice changes to crystals, which move back and forth until these finally change to liquid. At this crystal-forming stage, sperm cells can be damaged or destroyed as the crystals move to the liquid state. 

Each A.I. company specifies thawing times and temperatures (usually a waterbath at 96ºF or 35.5ºC for more than 30 seconds) to minimize sperm damage and maximize fertility.

Art: Important. The better you can manipulate the cane and straws within the tank to select and move straws into the waterbath, the better. Train yourself to become efficient to:
• Raise the cane only as high as necessary (low in the tank neck) to select the particular straw needed.
• Identify the bull number needed.
• Transfer up to three straws from the tank to the waterbath as quickly as possible.
• Have everything organized: a record, guns, sheath straw-cutter and paper towels.

Science: Important. Thawing is an exact process and should be done according to a precise, step-by-step procedure:
• Check waterbath temperature.
• Maintain straws in the waterbath for the required time.
• Dry off the straw with a paper towel. (Blot dry.)
• Put the straw into the gun.
• Cut off the tip of the straw.
• Place the sheath over the straw and gun; lock it in place.
• Keep the gun next to your body or in the insulated carrying case until you get to the cow to breed.

There are two semen placement techniques: 1) Deposit all semen in the uterine body; 2) Deposit half of the semen deep into each of the two uterine horns. Sperm cells are propelled up the uterine horns, then pass through several inches of oviducts and meet the egg at the tip of these ducts, where the new pregnancy is formed. 

While there are thousands of sperm cells in each straw of semen and while it takes only one sperm cell to unite with the egg to create a new pregnancy, failure to place semen correctly impedes sperm movement and results in low conception rates.

Art: Very important! Regardless of which location you use to deposit semen, you must be able to manipulate the reproductive tract with finesse. It takes practice to develop this skill efficiently and with no trauma to the rectum.

The variation in conception rates that exists between different inseminators is generally due to their ability to manipulate the cervix and uterus.

Science: Very important! Regardless of site selection, 50 percent of the sperm cells must travel up each uterine horn. If you body-breed, locate this “spot” (smaller than a penny) just ahead of the last cervical ring with your index finger. Then touch the pipette to your finger.

Elevate your finger and deliver the entire contents of semen to that “spot” without allowing the gun to move forward or back while pushing in on the plunger during the 10-second delivery time. If you horn-breed, be certain to deliver 50 percent of the semen (mark the plunger on your gun) deep into each horn.

The science of A.I. breeding has improved dramatically over the past five years; you can continue to learn the science by reading and asking questions. Developing the art of breeding is an individual commitment to practice, focus and developing the attitude to always want to do better.

Use both to help you get one more additional cow pregnant each day that you breed.  EL

	Dr. Tom Fuhrmann MVZ President, Dairy Works This e-mail address is being protected from spambots. You need JavaScript enabled to view it