BUCKING BULL SEMEN COLLECTION-CHAMPION GENETICS PROVIDES THE FACTS

by Terry Lidral

The bucking bull industry, in large part, runs on semen straws.  The global access and the preservation of great bucking bull genetics beyond the life of the bull are vital to the business.  And the fact that breeders at all levels of the industry have the opportunity to access a wide and diverse choice of top-quality bloodlines for use in their programs keeps the industry moving forward.  Collecting, freezing and maintaining straws of quality sperm is a series of complex processes.  Craig Barton of Champion Genetics has been in the semen collection business for 23 years.  In this article, he shares his expertise on the processes and how to better the chances of success.

BST:  At what age can you successfully collect a young bull?

Champion Genetics:   As a rough rule, young bulls will start producing freezable semen at 16 to 18 months of age. Bulls tend to mature a little quicker if they are able to be with females. Every bull is an individual and some with more Brahman influence can be slower maturing. Keep in mind that bulls as young as 6 to 8 months can produce semen that will breed a herd mate but not be acceptable for freezing.

BST:  How old is too old for successful freeze quality semen collection?

Champion Genetics:  There is not a definite cut off on age.  We have seen bulls as young as 3 stop producing viable semen as well as bulls that are 13. Hormone imbalance and injury to the testes are common factors that can cause semen production to quit. Just because a bull produced freeze quality semen a year ago, doesn’t mean he still can.  And sometimes the opposite can be true.  Things can change for both the good and bad.  That’s why it is important to check bulls before every breeding season. 

BST:  What can you do to prepare a bull for semen collection?

Champion Genetics:  Nutrition is essentially important.  Bulls should be in good condition but not overly fat or on a high protein diet.  High protein feeds like cotton seed and soybean can lead to problems.  A 12% ration is very adequate.  Having your bull on a proper mineral program is also very important since trace minerals are the building blocks for all of the necessary hormones for good semen production.

BST:  When is the best time to collect a bull?

Champion Genetics:  Mother Nature tends to help a bull’s semen production to be the best in the spring. So, our rule of thumb for collection is 30 days before night time temperature exceeds 70 degrees.  But we also consider 30 days after night time temperatures drop below 70 degrees to be good as well.  Bulls coming out of active breeding should have an advantage over bulls being hauled.  Bulls in competition are under stress that can lead to a rise in abnormal cells and stale semen.  These negative qualities can prevent semen from recovering successfully from the freezing process.  In some cases, leaving a bull at the collection facility for multiple collections can help get better quality.  Although, in other cases, the stress of being at a facility can cause problems.  All bulls are individuals, and in my experience, I have seen both positive and negative effects of prolonged collection.

BST:  How is semen collected and how often?

Champion Genetics:  There are multiple ways to collect semen from a bull.   Jumping a bull with the use of an artificial vagina (AV) is the preferred and most natural method. This is done with the use of a steer as a mount animal and the donor bull is allowed to watch other bulls mount the steer.  The donor bull is aroused by the activity and will then mount and allow a collector to put on the AV.  As you can imagine, this is very challenging with some bucking bulls from the point of a collector’s safety as well as with the potential for the bull’s lack of willingness to participate.  So, while some bulls participate, most bucking bulls will not. The alternative method is stimulation of the prostrate.  For this procedure, the bull is placed in a chute, and through manual or electronic stimulation, the bull is brought to ejaculation. Both methods can achieve success and semen quality is not affected in either method. Bulls are normally collected 2 or 3 times per day and given 3 to 4 days to rest. All bulls are individuals and these intervals can be adjusted to achieve maximum production from every day to once a week.

BST:  How do we determine the number of sperm cells and quality of a sample?

Champion Genetics:  A bull’s semen concentration can vary due to when he ejaculated last and the size of his testicles.  For maximum semen production, a bull will normally need to be rested for 3 to 4 days after breeding to rebuild his maximum concentration.  Once we get a sample, we can use a couple different methods. A photometer can measure density by shining light thru a known sample and using a prescribed logarithm.  The other method is to use a hemocytometer where you actually count the number of cells in a diluted sample in a prescribed area and use a formula to determine total cells per milliliter.  The next step is evaluation of percent motility, the number of sperm that are moving, by visually looking at a sample.  Lastly, we need to find out what percent of those cells are normal. There are a multitude of abnormalities that can affect the quality of cells including tail problems and cell head problems. Most abnormalities can be very transient, meaning that the number of abnormal cells can go up and down due to many different factors.  Major causes for cell abnormality are nutrition, stress and weather.

BST: How is semen frozen?

Champion Genetics:  The concentration and quality standards of collected sperm are 65% motility and 60% normal cells. Once concentration and quality are established, the sample is extended with an egg yolk extender to the desired concentration of normally 40 million per dose.   The sample is cooled to 38 to 40 degrees and allowed to maturate for 6 to 12 hours.   Then glycerin is added as a cryoprotectant (a substance used to protect biological tissue from freezing damage), placed into ½ cc straws and labeled with the bull’s name, registration, NAAB code number, and collection date. After that is done, the semen straws are placed in nitrogen vapor for freezing.  Once they are frozen, two of the straws are pulled and evaluated.  One is evaluated after 45 seconds in a 98-degree water bath, in a manner as if you were preparing it for use, with a check for motility at a standard of 50% moving sperm.  The second straw is left in the water bath for two hours to make sure that the semen maintains standard motility and a normal cell count is done to confirm a normal cell population over 60%.

BST:  What is the quality standard for straws used in Embryo Transfer?

Champion Genetics:  There is no published standard for semen quality used in Embryo Transfer.  In transcervical super ovulation settings, there are multiple eggs to be fertilized and the level of estrogen is increased which will make it harder for semen to survive in the uterine environment.  We strive for a higher percent of motility and normal cells in the semen to improve the fertilization rate of multiple embryos.  Our standard for semen used for ET is 60% motility or greater after the 2-hour stress test and greater than 75% normal cells. The reality is that this designation does not always mean successful results are achieved.  It just helps to improve your odds. Some bulls will never be able to meet this standard and still their semen might perform adequately.  DISCAIMER: No semen is recommended for use in Embryo Transfer.  All straws collected here at Champion Genetics are only recommended for single breeding insemination.  How one decides to use it in other applications is up to the owner.    

 BST:  Do all bulls produce freezable semen?

Champion Genetics:  No, some bulls will have a productive breeding career but never produce freezable quality semen. In a natural breeding scenario, bulls don’t require as high a normal cell count as we require to be able to successfully freeze semen.  A bull will normally put billions of sperm cells into a cow in live cover.  We are limited to the amount of cells we can successfully put into a straw of semen which is somewhere around 50 million.  Bucking bulls tend to be more line bred which can cause some problems with motility and cell normalcy.  And unlike the beef and dairy bulls, bucking bulls are never selected for their breeding efficiency and semen production abilities.  We are often brought bulls that passed a Breeding Soundness Exam (BSE) by a veterinarian but the semen quality does not meet the standards necessary to put up frozen semen. There is a difference in our requirements. A BSE just confirms the bull’s ability to breed cows in natural service. If it is imperative for the bull you are purchasing to produce frozen semen for you to recoup your money, make sure to get that guarantee in writing.

BST:  How long does frozen semen maintain its quality?

Champion Genetics:  Once semen is frozen, and as long as it kept stored in liquid nitrogen, we are told that it would remain viable for 1000 years.  But since this technology has only been around for 70 or so years, we are not sure exactly how long it can be used successfully.

BST:  How is semen stored and shipped?

 Champion Genetics:  After the semen is frozen and passed its quality checks, it is placed in goblets of 5 and then put on metal canes holding 2 goblets each.  The cane is labeled with the bull’s personal code number and is then stored in a liquid nitrogen container. Storage containers can vary from holding 500 to 150,000 straws. The holding time of these tanks can vary also from 30 days to 6 months.  These tanks are considered a wet vessel allowing for the nitrogen level to be monitored by use of a measuring stick. There are many storage facilities scattered across the US and the world. You can also purchase tanks that you can keep at your location.  These tanks typically hold 500 to 1000 straws and will need to be monitored and filled with liquid nitrogen every 8 to 16 weeks depending on the holding time of each particular vessel.

 Shipping semen is done in a different type of vessel which are referred to as Dry Shippers.  They are specially designed with an absorbent material so that, when filled with liquid, they absorb the nitrogen.  Excess liquid is poured off before shipping. These tanks are designed to hold temperature for 14 to 21 days if kept in an upright position. The problem with these vessels is there is no way to monitor the remaining holding time if the tank is mishandled and left on its side.  Not being upright will shorten its duration of holding time by as much as 10 days.   Also, if the tank is dropped or roughly handled, the vacuum that allows the tank to insulate can be lost and the nitrogen will evaporate in a few hours. UPS and FedEx will only insure the shipping container, not the product inside.  Under their rules, semen is considered a “perishable product” and they will not insure it. Insurance is available through certain underwriters but only for shipments between facilities. It is up to you to secure insurance on highly valued or irreplaceable semen. Sometimes the best insurance is overnight shipments. But nothing is guaranteed.

BST:  What can I expect from a straw of semen?

 Champion Genetics:  You can expect that the semen has been properly identified, handled and has met quality standards. What your expectations are for that straw is probably a better question. You need to be realistic in your goals.  Conception rates in bucking stock are low due to many factors, another article in itself. The bucking bull industry is very unique in that straws of semen are sold, traded and moved around to different storage facilities like baseball cards.  A small percentage ever sees actual use. Frozen semen was developed to give producers the ability to insure and distribute genetics from highly valued sires at a reasonable value.

In 2006, Craig Barton and Bob Woodard purchased the custom semen department of COBA/Select Sires and formed Champion Genetics to give themselves the opportunity to work in the part of the industry they are truly passionate about.

Bob worked for COBA for 30 years performing custom collections. He is also a reproductive specialist consulting on breeding programs and protocols. Bob trains owners so they can AI their own animals.

Craig has a BS in Animal Science and worked for COBA for 23 years. The first two of these were side by side with Bob collecting. The last 21 years have been in sales and cattle evaluation working in Texas, New Mexico and Arizona.

Author: Terry Lidral

Terry Lidral is a western writer/journalist who lives in Idaho. She is the publisher and editor of the online magazine Bucking Stock Talk and the online magazine Western Living Journal. Her publishing credits include Storyteller for Real American Cowboy Magazine, writing feature articles for Humps N Horns Magazine as well as a wide variety of national and international web sites, historical magazines and news publications. She is known for her "up close and personal" profiles of celebrities and industry moguls such as NPR's Tom Bodett; PBR's Wiley Petersen and D.H. Page, PRCA's Sammy Andrews, Cindy Rosser and Julio Moreno to name a few. She has been applauded for her way of making a personal connection between her readers and her subjects. She indulges in her love of rodeo by serving as an associate board member for the Caldwell Night Rodeo. She is also an accomplished trainer and handler in dog agility. Her shelties Amelie and Milo are titled in NADAC, USDAA and AKC.