Development of AI for Yak Semen and the Potential Economic Benefits to Southern Region Yak, Small Acreage Farmers and Beef Producers

View the project final report

Commodities

• Animals: Yak

Practices

• Animal Production: genetics, livestock breeding
• Farm Business Management: new enterprise development
• Sustainable Communities: local and regional food systems, quality of life

This project started with two basic components: The development of AI for yak semen process (from collection to impregnation) and educating small acreage farmers and beef producers concerning the potential benefits of introducing yaks and AI to their operations. During the first year of the project two other important questions were identified relating to yak bull fertility: The effect of repetitive semen collections and of high ambient temperatures. Studies were conducted on each of these issues as part of the project. Also, as discussed in the mid-project report, because of our lack of response in the methods we used to provide information to farmers throughout the Southern Region, we shifted the means of educating small acreage farmers and beef producers about yaks to the development of a website (skayresearchgroup.com) making the information available on demand rather than a one-time email attachment/article they may or may not see or be interested at the time it was received; monthly interactive webinars and conferences.

As of this report we have worked with: A TRIS-glycerol-egg yolk extender described in a 2017 paper (Deori) from the ICAR-National Research Centere on Yaks at Dirang, India; a commercially available extender, Opticell, developed by IMV Technologies which they stated had been used with yaks (no results provided); and Bullxcell, an extender recommended by IMV Technologies. Also, as a check to our work, we contracted with WWW Genetics to bring a mobile unit to our collection site (Morehead State University Derrickson Agricultural Center) to extend and freeze freshly collected semen using their proprietary two step extender process. To date we have had XXX nine conceptions verified by ultra-sound, three of which aborted due to stress caused by a sudden ice storm, five healthy calves and XXX more confirmed pregnancies. Bull-cow pairs were selected using the Match-A-Yak program designed which calculates the expected coefficient of inbreeding of the offspring as defined as the expected percent of homozygous alleles. 

Dr. Philip Prater developed a semen collection protocol which includes the manual massage of the seminal vesicles and Cowper's gland followed by the use of a small bovine electro-ejaculator. As this method is easily done we abandoned the attempt to train young yak bulls for semen collection using an artificial vagina since this would be lengthy (two years) which few would undertake.

At this point in time there are two tasks that remain: To test more available extenders based on  the percent of motile post thaw sperm in order to find the one which provides the most protection against freezing; and determining the optimal time period for insemination as no two yaks respond the same when synchronized using a seven day CIDR -cisterlin-lutalyse protocol: Some will be in estrus, some just coming in and some having just been in at the protocol defined time for insemination.

1. Process to Extend and Freeze Yak Semen: The objective is to develop a system (needed materials and process) to successfully extend and freeze yak semen for insemination (post thaw semen motility of 20%) in a way that is easily duplicated and does not require expensive equipment to set up: Something a veterinarian or university agriculture could set up.

Our approach to solving how to treat yak semen, extender and freezing protocol, was based on the many years of successful work done at the ICAR-National Research Centre on Yak at Dirang, India. Dr. V. Paul at the Research Centre on Yak has provided information on the semen extender and freezing protocol for use by Dr. Harrelson.  At the beginning of the project we anticipated working with MultiGen Reproductive Solutions (MRS) to test extenders using the information: Evaluating the extenders and freezing process based on percentage of motile sperm post thaw.  This did not change the objective, rather it changed the researchers involved as Dr. Harrelson was joined by Drs. Jeff Lehmkuhler and Les Anderson from the University of Kentucky Department of  XXX and WWW Genetics would process semen using its proprietary system to compare against our process.

2. Originally we had proposed Dr. Harrelson would work with MRS to develop a protocol for inseminating yaks that can be used on a typical small farm. The complexity in this is that yaks have a short period of fertility (less than 12 hours) and often do not show any visible signs of being in estrus. Dr. Les Anderson from the University of Kentucky who joined the project is a reproduction and AI specialist: The exact person needed for this objective. Dr. Anderson along with Dr. Lehmkuhler, Beef Extension Specialist, will work on this objective.
3. Develop a method to best collect yak semen. Again with Multigen Reproductive Solutions not being able to work on this project this objective was taken over by Dr. Philip Prater who was head of the Veterinary Technician program at Morehead State University and is a reproduction specialist. The initial objective was to develop a protocol for yaks using an electro-ejaculator for semen collection and also to work on training young yak bulls to use for collecting semen using an artificial vagina. Interest in collection using an artificial vagina was based on this being the method used at the ICAR National Research Centere on Yak in India.

Early on Dr. Prater developed a semen collection process which employed internal manual massage of the seminal vesicles and Cowper’s Gland followed by the use of a small bovine electro-ejaculator which worked well with the ten yak bulls used for the project.

Since Dr. Prater’s system worked well and was easy to implement, the training of bulls which would have taken two years was abandoned realizing that the training of yak bulls for breeding with an artificial vagina would not be cost or time effective and that one would also need a yak trained to be mounted as well as having the infrastructure to do this type of semen collection in.  

4. New Objective: To answer the following issue raised by yak breeders at the November 2021 Yak Conference at Morehead State University held as part of the education component of this project: The belief that repetitive use of an electro-ejaculator on a yak bull as required in an AI program will make the bull infertile.
5. New Objective: To determine if yak bull fertility is affected by ambient temperature increases during the sixty day time period over which semen is formed.
6. The original fourth objective was for Dr. Ted Kalbfleisch to modify his “Match a Yak” software which allowed a breeder to select the bull out of a group of bulls which would produce offspring with the lowest coefficient of inbreeding (COI) for a given yak cow. The plan was to use this software to be able to look at a group of bulls to determine which bull was more of an outlier and thus would yield a lower COI and greater genetic diversity in its offspring. It turned out that the way to do this is to run every bull under consideration against all the yak cows to be bred using Match-A-Yak and then select the bull which yields the lowest average COI over the group of yaks to be bred. This was done in the project and an example from the project is provided to demonstrate its use.
7. Cooperative Extension Agent Mary McCarty, Dr. Lehmkuhler and Gregor Dike will work on the information developed for the outreach component of the project. This is described in Section C. The developed information will be reviewed by area a focus group of area beef breeders to determine the best way to present the materials to their colleagues and to several yak breeders for review. Note: Greystone Farms and Nature’s Bridge Farm are no longer raising yaks. Because of this we will ask several yak farms who are part of the monthly yak webinar series to review the materials. The reviewed (and revised) materials will be available on the com website with a notice sent through the southern region about the existence of the website in addition to its being available under a normal topical search.