I’m writing this blog post as a half procrastination-half studying tool because I really like theriogenology and reproductive technologies (and I may have a quiz tomorrow on this stuff…). They are relatively new and there is so much advancement and growth in that field! And so much more work to be done there as well…
Here are 3 of reproductive technologies that can be used for genetic improvement.
Artificial Insemination (AI) is a reproductive technology where semen is harvested from male animals and stored in semen straws that can then be deposited into chosen females. It is used to increase male selection and can therefore potentially increase the accuracy of the Estimated Breeding Values (EBVs). Semen can be sourced from all over the world and can potentially increase the effective population size (amount of genetically unrelated animals in a population). However, using a dairy bull from the USA may not be a great choice for an AUS dairy farmer as environmental interactions may pop up! AI is not used as often in the beef industry because it is more costly and labour intensive. AI is too expensive to do on commercial sheep farms as the procedure is different, it involves surgical insemination of the females. However, sheep stud farmers may use AI as they are selling the offspring for a lot more money (thus more cost effective). The benefits of using AI in your industry include:
- Increases the accuracy of EBVs and male selection
- Allows commercial breeders to access genetic information that previously would have been too expensive (and used only at a stud level)
- Allows great genetics to be rapidly spread throughout a population (because many semen straws can be made from one male)
- Technically forms a ‘world flock/herd’ of animals
Multiple Ovulation Embryo Transfer (MOET) is used to increase female selection and can therefore potentially increase the accuracy of the EBVs. However, this is a very expensive procedure as it involves taking a superior female animal, using hormones to get her to produce more eggs and then harvesting the eggs. MOET allows the female genetics to be spread farther/faster into the population. MOET is best used in species who usually only produce one egg at a time like cows.
Inbreeding can be a big problem with MOET, so farmers need to develop a good breeding scheme/plan to avoid this. It is best to use females with good genetics and semen from males with good genetics (as opposed to fresh semen and females that harvest/flush well).
This leads to a concept which I find exciting (and ethically interesting!) which is called Juvenile In Vitro Embryo Transfer (JIVET). Since all females are born with the total number of eggs they need in life, these can technically be harvested at a very young age (juvenile). These harvested eggs can then be in vitro fertilized and develop into offspring. This reduces the generation inverval and increases selection intensity. There are current issues with this reproductive technology that have not been worked out yet—and so it is not common.
I apologize if some of the terms and concepts were a bit too confusing for some of my non-vet friends; however if you are interested in food or wool production this is a vital part of the industry. Feel free to pose any queries you might have and I’ll try my best to answer 🙂