This month I checked another state off the list as I traveled to Columbus, Ohio for a work trip. We were there for a “Think Tank” meeting with some of the best reproductive physiologists in the academic world of cattle in the U.S. Along with this meeting, we had the opportunity to tour the Select Sires bull stud facilities near Plain City to learn more about their bull semen collection and processing facilities.
Select Sires is one of the largest cattle semen collection and distribution companies in the country. This semen is used in breeding programs across the globe for Artificial Insemination in both beef and dairy cattle herds. Most bulls used for semen collection are dairy bulls which produce much more semen than beef bulls on average.
Advantages of Artificial Insemination
Artificial Insemination in cattle has huge advantages in disease control and access to a pool of high-quality genetics. Reproductive diseases are a big concern for affecting semen quality and successful pregnancies in cattle. 6 diseases the bulls are tested for before collection are Brucellosis, Tuberculosis, Leptospirosis, Trichomoniasis, Campylobacteriosis, and Bovine Viral Diarrhea Virus. Vaccinations do exist for some of these reproductive diseases, but the best bet for elimination is testing for the diseases and preventing their spread by eliminating infected animals from the herd.
Genetic Selection and Progress
The bulls with a company like Select Sires go through a strenuous testing period starting at a very young age. The first cut for bulls happens at birth based on genetic lines. Do the bull’s genetics fit the direction of the desired traits in breeding herds? From a pool of 100 bulls, only a few may make the final cut for a high-volume semen collection. At around 1 year of age, bulls are collected for a young sire test. Several cows will be bred to the bulls and their offspring will be used to estimate the genetic value of the bulls. The bulls that graduate in the full program may then be used to collect semen for larger marketing.
At this point bulls may be 4-5 years of age, so time span is obviously a huge obstacle when predicting what genetics will be in demand by breeding herds years down the road. Bull semen companies like Select Sires are beginning to utilize genomic testing to narrow their bull selection pool, selecting bulls with higher genetic value at a younger age. The use of genetic testing is expanding in the industry and increases our ability to make quicker genetic progress.
Bull Semen Collection and Processing
The semen collection process is relatively simple and has been narrowed down to a science by these companies. Bulls are collected with an artificial vagina 2-4 times per week and as many as eight. An average ejaculate may contain 1 billion sperm which are then diluted with an extender (made from a base of whole milk or egg yolk) and stored in 1/2cc straws for freezing. An average Holstein bull can produce 80,000 to 110,000 straws of semen annually. Each year, Select Sires produces 1,962 gallons of processed semen.
Prior to freezing the semen collection is checked for abnormalities of motility (forward movement) and morphology (normal shape, size, formation). A healthy sperm travels 12 feet per hour. In a relative size that’s equivalent to a car traveling 37-41 mph.
The semen straws are then stored frozen in liquid nitrogen (-320*F) where the metabolic activity of sperm comes to a halt. Select Sires uses over 500,000 gallons of liquid nitrogen annually and can process up to 75,000 straws per day.
Sex-Sorted Bull Semen
I also had the opportunity to tour their facilities where sperm are sorted to produce sexed semen. Sperm carrying X- or Y- chromosomes have a different amount of genetic material and can be sorted to produce male or female semen samples. This is most commonly used in dairy herds looking to produce more heifer calves. The fertility of sexed semen is lower and the cost is higher, so the use of sexed semen is not as frequent as non-sorted.
Companies like Select Sires, Genex, ABS, and numerous others contribute a great deal of information and technology to the cattle industry. Their money contributed to academic research allows us to investigate better management of reproduction in cattle, improving efficiency and genetic progress within herds across the country.
It’s all a pretty cool segment of cattle production, but this comes from a confessed cattle agnerd, so what do I know? Now if I can just get my cows to text me when they’re in heat…
Do you have any questions about semen collection of bulls or use of artificial insemination in cattle?
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