Catching Up with Dr. Reuben Mapeltoft

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Published on: June 30, 2017

The Early Days and School of Hard Knocks

Most of what I know about bovine embryo transfer, I learned by making a mistake. Matt has convinced me that I should bare my soul, so here goes.

In the early days, we were using Rusch catheters to collect embryos. They were a great improvement over Foley catheters, but they were very expensive. Because of cost, we resisted autoclaving; we simply washed and dried and rinsed with alcohol and sterile saline just before use. At an early IET meeting, Peter Elsden convinced me we should be sterilizing our catheters with ethylene oxide, which we subsequently did. That year, our pregnancy rates dropped to around 30%. We then learned that certain plastic syringes were also a problem and we were using syringes to collect embryos and hold media. We never did figure out our problem, but our pregnancy rates recovered the following year. We subsequently did a lot of work with ethylene oxide as a means of sterilizing equipment, and we found that there are a lot of ways you can kill embryos with it. I am told it also kills people.

Uli Schneider from Hanover, Germany, taught us how to cryopreserve embryos in 1980. We were using glycerol in those days and so we had to move embryos through six dilutions after thawing and before transfer. Uli had a little device with a gear mechanism that he used to aspirate very small quantities of medium, and he left it with us to use when we were moving embryos through glycerol dilutions. I was not very familiar with it, having used a 1-mL syringe and a tom cat catheter most of the time. In any case, I decided Uli knew best, and one morning I thawed a set of embryos for transfer on farm. While I was in the midst of transferring embryos from one solution to the next, something happened in the lab and my attention was distracted. When we finally had things sorted out, I looked down and couldn’t find the embryos. I had aspirated them all up into the gear mechanism in the aspiration device. It wasn’t until I had made several other mistakes like this that I decided that I had to keep unnecessary people out of the lab.

When I was first involved with this business, I often found myself in difficult situations, and instead of saying “no, we can’t do this,” I carried on. I have often referred to this as how I lost embryos.

On one occasion, I flew to Vermont to collect a cow for a colleague, and when I arrived at the farm I realized that all I had was a cow and no help or facilities. I finally ended up setting up my microscope on the milk tank. Things were not very stable, but I did find a nice morula and an unfertilized egg. Then things started to go wrong. I upset the egg dish on the milk tank and spilled its contents. I aspirated all the media I could find on the surface of the milk tank and found one structure, the unfertilized egg. On another occasion, we had to set up outside on a beef farm with no table or chairs, so we set a sheet of plywood on two straw bales. With the first cow, we recovered more than 20 excellent embryos, and I was feeling pretty good as I was collecting the second cow, which also had responded very well. Then, things went downhill. My technician came up to me and whispered, “How do I get the embryos out of the straw?” I responded, “What? We are not ready to transfer yet.” You guessed it, she wasn’t talking about loading straws. On yet another occasion, we set up a table for our microscopes in a large calving barn and used trimming chutes to restrain cows for the embryo recovery procedure. One cow went a little crazy and wrecked the trimming chute and started running around the calving barn; everyone scattered while she headed for the table with the microscopes (and embryos). This story has a happy ending; she sniffed the first microscope, turned around, and ran the other direction.

I have learned some things about nitrogen tanks in this business as well. We used to travel great distances, often late at night, as we drove from one farm to another, and the roads were frequently not very good. On one occasion, I hit a tremendous pothole as I was driving much too fast on a back road; I was lucky I didn’t hit the ditch. When I arrived at my destination I unloaded my equipment, and although it really didn’t register, I noticed that there was frost at the top of the nitrogen tank. I imagined how the nitrogen had been sloshing around on those rough roads (I actually had one tip over once). In any case, the following morning, I realized the tank was dry. There wasn’t just one collection in that tank either. I learned a very real lesson: if you see frost, get worried.

These are just a small sample of mistakes I have made over the years. However, I did learn through the school of hard knocks. I challenge others to top mine.

Reuben J. Mapletoft
Distinguished Professor Emeritus
Department of Large Animal Clinical Sciences
Western College of Veterinary Medicine
University of Saskatchewan
Saskatoon, SK S7N 5B4
Cell: (306) 222-6152
Fax: (306) 966-7159

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