Semen Division & Collection

Bovine Semen Division

Semen Collection
REI began as a custom semen collection facility in 1978 and has been working to improve the process ever since. REI has been a member of National Association of Animal Breeders (NAAB) and Certified Semen Services (CSS) since 1980. REI pairs experienced staff members with innovative technologies to increase efficiency and to collect, process and freeze quality semen faster.

REI is flexible in that your bull can be here for as long, or as short as you wish. REI offers one-day collections where the bull can be brought in, collected and sent home on the same day. Bulls with large orders to fill can be housed in-clinic and collected twice a week until the order is complete. Every bull that enters the facility, one-day or extended stay, will be subjected to health tests at the owner’s expense and can be screened in-clinic upon arrival, or prior to entry with your veterinarian. Required testing for all bulls entering our facilities include: Brucellosis, Tuberculosis, Leptospirosis, BVD, Trichomoniasis and Camphylobacteriosis. Click here to download Health Test Requirements.

Bulls left in-clinic are housed individually in pens that have been designed and built for the safety and comfort of both the bull and the REI employees. The collection arena is centrally located between the pens and processing lab, maximizing efficiency. Additionally, the collection arena is large enough for both the bull and collector to work safely and comfortably. The flooring is also designed so the bull will have good footing during collection, minimizing the chance for injury.

When bringing an animal for semen collection, please bring a copy of your animal’s registration paper, the test results from your veterinarian (if you are using your personal veterinarian) and the completed bull contract which can be found on the website. To save time when checking in, please have the contract completed upon arrival.

If in-clinic is not an option for you or your operation, semen collection is available on-farm and no health tests are required for this but additional fees for travel and set up will apply.

Preparing your bull for collection
To optimize the production and quality of the frozen sample, it is a good idea to have your bull “cleaned out” prior to collection day. The best method for “clean out” is to turn bull out with cows for at least a week, and pull him off cows for a minimum of 5 days prior to appointment. This allows all dead cells to be flushed out and initiates the production of active, good quality cells to be stored for collection.

Sexed Semen
For our customers who want to incorporate sexed semen into their operation, we have partnered with Sexing Technologies in Navasota, Texas. Sexing Technologies offers both AI and ET and custom sexed semen doses. Prior to collection we will need to know what gender you want, or both, and what dosage (AI or ET) you want.

CSS Certified Facility
REI is a Certified Semen Service facility as defined by the National Association of Animal Breeders. All bulls will undergo testing for Brucellosis, Tuberculosis, Leptospirosis, BVD, Trichomoniasis, and Camphylobacteriosis. Bulls participating in the CSS program are housed at REI for a minimum of 60 days before CSS quality semen can be collected. However, semen collected during the 60-day quarantine period can be collected and used for domestic use. A bull qualified for the minimum CSS requirements does not qualify them for export.

Export Semen
REI works with USDA/APHIS and their standards to export semen across the world. Bulls that are being collected for quality export semen will undergo the same tests required for CSS plus any additional tests that may be required by the importing country. The length of time the bull will be in clinic depends on the protocol set by the importing country. For more information on this service please contact our main office.

Goat Collection

Goats can be collected any day, but to maximize efficiency we synchronize our does twice a month and schedule most collections on those days. We try to find dates that work best for all involved. If our next collection date does not work for you we can schedule you for the following month. If neither of those works for you, there are other options. One option is to bring your own doe in heat to collect from. The second option is to electro ejaculate your buck. If electro ejaculation is used please be assured that we take all necessary precautions to ensure the safety of your animal.

We have built a brand new small Ruminant facility to board and perform all services. Bucks can now stay for an extended period of time for collection. If you are interested in boarding please call to make a reservation.

At the time of collection we typically dilute semen to 100 million sperm cells per straw. If you desire a different dosage rate, please let us know prior to collection so the dilution rate can be adjusted accordingly, additional fees may apply. Semen is typically frozen in 0.5 cc straws, but 0.25 cc straws are available upon request. Once semen is collected and diluted, we are not able to adjust the dilution rate.

Sheep Collection

We can electro ejaculate rams and normally dilute semen to 70 million sperm cells per straw. If you desire a higher dosage for use in ET work, please let us know prior to collection so that we can adjust the dilution rate. Once semen is collected and diluted, we are not able to adjust the dilution rate. Ram collections can be scheduled at any time. AV collection is also available for rams. At the time of scheduling appointments, ask about our ewe synchronization availability.

Deer Collection

All deer collections are performed on-farm. It is the owner’s responsibility to sedate the buck before the collection process starts. Once the animal is stabilized, semen will be collected through electro ejaculation. Fresh semen will be brought back to our facility to undergo packaging, freezing, and evaluation. Semen is diluted to 70 million sperm cells per 0.5 cc straw. One straw equals one breeding dose. Once semen is packaged it can be stored at our facility or shipped back to the owner.

Equine Collection

We do not collect stallions at our facility, however we provide processing, 0.5 cc straw packaging, freezing and evaluation, and storage. Typically four straws are recommended as an adequate breeding dose. If you are in need of semen collection services we have partnered with Benchmark Animal Hospital in Perkins, OK. Benchmark Animal Hospital has the ability to house and collect, as well as provide other breeding services. For more information please visit their website:

Dog Collection

REI not only provides semen collection and other reproduction services to livestock, we also provide these services for canines as well. We have partnered with Benchmark Animal Hospital out of Perkins, OK to provide you with the highest quality canine reproductive services. Services provided by REI include semen collection, preservation, post mortem collection, consignment sales, storage and shipping. Benchmark Animal Hospital is able to provide the progesterone testing, artificial insemination and other veterinary services. For more information about Benchmark Animal Hospital click here.

Post Mortem Testicle Recovery

  • Testicles should be harvested from the animal as soon as possible after death. The testicles should be left inside the scrotum if possible.
  • The testicles should be allowed to cool slowly. The most critical aspect to the testicle collection is to cool them slowly as to avoid temperature shock.
  • If you are within 30 miles of Stillwater, Oklahoma, call Reproduction Enterprises, Inc. as soon as possible for delivery.
  • If you are shipping the cooler, please do so as soon as possible for overnight delivery. Do not ship on a Friday or Saturday. The specimens are safe in a refrigerator over the weekend (after slow cooling in the box) until able to ship. Call REI on the day of the shipment with date and time the shipment will arrive.

Instructions for Post-Mortem
The following is a step by step procedure of how testicles should be harvested, taking special care not to remove any important male anatomy.

  1. Skin the animal from a hanging position except do not remove any of the scrotum, penis, or rectum. It is acceptable to leave hair on these parts.
  2. Using a scalpel or knife, open the body cavity cranial to the point of attachment of the penis and cut down to the ribs. Use a knife or saw and split apart the rib cage allowing the intestines to fall.
  3. Using your hand, pull the large and small intestines down vertically revealing the bladder and the caudal part of the large intestine.
  4. Use two pieces of string to tie off the large intestine 2 inches apart. This can be done 2-3 inches below the bladder. Cut between the two pieces of string. Allow the cranial part of the large intestine to fall. Use the tip of the knife and poke a hole in the bladder and allow it to drain. DO NOT REMOVE THE BLADDER!
  5. Locate a point in the spine 2-3 joints cranial to the pelvis and separate the cranial and caudal parts of the carcass.
  6. Remove the left and right legs by cutting along the muscle layers and dislodge the hip socket. What should be left is the pelvic bone with some muscles, the drained bladder, the penis/ scrotum, the last 6 inches of the large intestine, and the inner contents of the pelvis.
  7. The testicles, still in the scrotum, should be placed in a plastic bag and sealed.
  8. Pack the testicles (still in the scrotum, all in the plastic bag) in a styrofoam box/post mortem recovery shipper in the following manner:
    1) Cold packs on the bottom.
    2) Next put crumpled paper on top of the cold packs.
    3) Place the plastic bag containing the testicles on the crumpled paper.
    4) Add more crumpled paper to the top of the plastic bag.
    5) Put in more cold packs
    6) Close and seal box.
    7) See diagram above for additional help.

Contracts & Health Requirements

All bulls entering REI must have completed the following tests:


Test Sample




Intradermal Tuberculin Test


Blood Serum

Buffered Brucella Antigen test card – RAP – and CF


Blood Serum

Micro-Agglutination Lysis Test for 5 Serotypes


Blood Serum

Antigen Capture ELISA


Preputial Smegma

Microscopic exam of Cultured Sample


Preputial Smegma

Cultured Test of Sample

*Consistent with USDA NAAB and CSS Uniform Methods and Rules.

View & Download Contracts

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