Improving Yak Artificial Insemination Conception Rate and Providing Data for Informed Decision-making for Improving Farm Sustainability

View the project report

Commodities

• Animals: bovine, yaks

Practices

• Animal Production: genetics, livestock breeding

Conception Rate Improvement:

1. Extender

In this grant we will test three extenders: two of which have the same basic components as the successful extender used at the National Research Center on Yak in India (NRCYI). We will test these extenders using the increased number of sperm to improve conception rates determined in the 2021 Producer Grant using the following process for each of the extenders.

• Semen will be collected from three yak bulls and evaluated in terms of concentration (sperm/ml), motility and morphology. 
• Note: Ten days prior to the semen collection date ten yak cows will be synchronized so that they come into estrus on the date of the collection. 
• The collected semen will be extended using the particular extender to both protect the sperm and have the desired number of sperm per insemination (which may require two straws). Ten straws worth of extended semen will not be frozen but maintained for insemination within two hours. The remaining extended semen will be frozen following the timing provided by the NRCYI. 
• Ten yak cows will be inseminated at what is believed to be the best time for insemination as referenced from the time of CIDR removal. 
• The remaining semen will be tested for post thaw viability 
• Just over thirty days after the ten yaks are bred with fresh semen they will be checked for pregnancy by blood test and ultrasound. 
• If the results are positive (at least 40%) then ten yak cows will be sequenced and bred with the frozen semen to check pregnancy. 
• The yaks bred with the frozen semen will be pregnancy test and if the results are at least 30% the extender will be used in a second trial. 

2. Freezing Process

The freezing process we have used is very low technology.  The extended semen is first cooled in semen straws for a minimum of three hours in a laboratory refrigerator and then loaded on a freezing tray and slowly lowered “by hand” in a styrofoam container containing liquid nitrogen. The rate of freezing is based on information provided by the NRCYI. We do this using a digital thermometer on the straw tray and a timer so we know when to lower the tray, how much time to achieve the next temperature and how long to remain at that temperature.

Because we cannot really improve this due to the lack of exact precision after have reviewed all of the extenders we will select the best two and have the entire process done by MultiGen Reproductive Solutions who will bring their experience and latest technology to the process. Note: This will be done twice during the grant period with the best extender being selected based on final conception rate.

3. Insemination Timing

 During the current grant we started with the beef timing protocol of inseminating 72 hours post CIDR removal. Dr. Anderson, who has become involved in the project inseminated each yak cow twice: once the evening before the 72 hours and then about six hours after the 72 hours. What he discovered was that the yak cows showed more signs of being in best form for insemination at different times so that the 72 hours was really not precise enough.

Under this Producer Grant Dr. Anderson will collect more data on each yak’s condition for insemination as a function of time from CIDR removal AND will use the Cow Manager System which predicts the time for insemination based on changes in cow behavior detected by motion sensors placed in a special eartag which then transmits the data for analysis. Using the combined data we hope to determine  a “best time for insemination” measured from time of CIDR removal. This “best time” for breeding information will be collected as we complete the 2021 grant and through each insemination of the 2023 grant period: Refining it each time as we have more data on cow condition at the time of insemination and the Cow Manager System.

Date Needed To Make Informed Solutions:

Along with demonstrated results of the Yak AI conception rate producers in the southern region need actual data about yaks and yak x beef hybrids in order to make decisions that affect their operation's

We will AI ten beef cows owned by the University of Kentucky and ten yak with yak semen at the beginning of the project using fresh extended semen. We will repeat to get 60% conception (at least 6 of each bred) . We will then monitor the forage consumption of both groups until weaning. We will also weigh the yak and cross calves at birth, weaning age and at one year of age. From weaning to one year of age the yak and yak-cross calves will be in a forage consumption and rate of growth study.  The information from breeding through raising the yakxbeef calves will generate comparative 1) growth rate and forage consumption and cost data for the yak and yak hybrid calves and 2) forage cost for the yak and beef cows during pregnancy and lactation. This information on beef calves is already available and so a side-by-side comparison can be made.

We will also look at the end product by securing yak and yak x beef meat and have it tested along with beef at the University of Kentucky for total protein, fat and moisture. Furthermore we will have four chefs evaluate the yak and yak x beef meat. The "health and taste" quality of the yak and hybrid meat is key to market sales and hence sustainability. 

We will also survey yak meat producers in the east and west who sell yak and yakxbeef to obtain pricing and demand information including the venue they use to market their meat. Is there a demand?: What it sells for?;  and "How" one sells it? are the bottom line questions that need to be answered before  changes will be considered in current farm practices - and current sustainability is risked. 

 The research done under the 2021 project was based on the years of successful work on AI done at the ICAR-National Research Centre on Yak at Dirang, India (NRCYI) Starting with information on the yak semen extender and freezing protocol used at the Centre. After several times of using the information provided by NRCYI to produce a semen extender we determined that key details in terms of extender components and the process were missing. Furthermore, some of the needed components were simply not available due to manufacturing backlogs. So what we did was to start with a extender provided by IMV Technologies which said they had used on yaks.

Since starting the 2021 project we have  learned that there are safe ways to collected yak semen using electroejaculation, that the yak bulls tolerated repetitive semen collection with no loss in fertility and that higher ambient air temperature greatly impacted  the fertility of  yak bulls. This issue has very much dictated the months we can collect semen with high enough healthy sperm concentration to use for artificial insemination. 

Our approach has been to address each unknown at a time and as a result we have been able to impregnate a yak artificially, but as noted in the previously there are key pieces to  be resolved to in order to have a valid conception rate for general use.

In the proposed solution we have outlined the different steps to be taken to improve the conception rate. The methodology underlying these steps is as follows:

• To involve  people most knowledgeable in the areas needed to be resolved. To do this we have brought in Dr. Leslie Anderson who is a specialist in AI and insemination protocols and Dr. Jeffry Lehmkuhler (UKY) who is a beef extension specialist, has studied yaks for four years including visiting the yak research facility in China and evaluating how well their research applies to yaks in North America. We will  also be working  with MultiGen Reproductive Solutions which has experienced staff and the latest technology to “fine tune” our process and importantly provide the exact freezing process specified by NYRCYI.
•  The second part of our methodology will be to test each part of the process as independently as possible  so we can isolate problems and test solutions. This is why we will be inseminating yaks with unfrozen extended semen to be see if the conception rate problem is in the extender or in the and the freezing. Every time we do this we will be inseminating ten yak cows to get an accurate estimate on the conception rate of the particular trial. 
• We will be testing our freezing process by evaluating the number of viable sperm in the unfrozen extended semen and then after it has been frozen at specific time internals determined by Dr. Anderson and Dr. Prater. At each time we will be looking at the number of viable sperm upon thaw and then two hours later as the sperm needs to be able to survive long enough to impregnate. This will give us critical information on which extender best protects the sperm through freezing and thawing. 
• The freezing process can only be improved by moving to an automated system which is why we will be working with  MultiGen Reproductive Solutions to run the entire process from collection to freezing and post freezing analysis of the extended semen. 
• In terms of optimizing the insemination timing, we are using an iterative process starting with the beef protocol of inseminating 72 hours after CIDR removal, checking the internal condition of the yaks for breeding several hours before and after the “selected insemination time”, inseminating them and then measure the conception rate. From this we adjust the insemination time forward or backward for the next insemination. This is a slow process which will be carried out over the entire grant period with each set of inseminations. To help check and refine this Dr. Anderson has installed the Cow Manager System which is used to determine insemination times in beef cattle based on changes in animal movements. Repetitive examinations at time of breeding and the Cow Manager System technology should allow us to come up with an accurate yak AI timed breeding protocol.

Our methodology for obtaining the cost and production data for yak and yak x beef hybrids up to one year of age and the meat “quality and marketing information” needed in order to make an informed decision about yaks and yak/yak-hybrid meat production will be very straight forward the using forage consumption and weight gain rate methods  Dr. Lehmkuhler has run on yaks three times at Zhi-ba Shing-ga Yaks. The pregnant and lactating yak forage consumption rate date will collected separately – with the yaks at Zhi-ba Shinga and the beef cows at the University of Kentucky farm. Once the calves are weaned the growth and consumption study all be done at Zhi-ba Shing-ga Yaks so any exposure to grass will be the same.

We will purchase sirloin meat samples from yak and yak x beef hybrid meat producers for the comparative meat quality study (yak, yakxbeef and beef). Meat from similar aged and raised animals will be purchased and analyzed at the University of Kentucky Department of Agricultures for total protein, fat and moisture. We will invite four chefs who currently work with yak meat and have them evaluate the yak and yakxbeef in terms of what they look for in their cooking and offering in their restaurant. Finally we will work with the USYAKS and IYAK yak registries to survey yak and yakxbeef producers concerning their prices, demand for their meat and the venue they use to sell it. This will be done by Dr. Lehmkuhler and Mr. Dike who has served on the Boards of both the USYAKS ad IYAK registries.