Therio- Bovine- Assisted Reproductive Technologies (ART)

wilsbach's version from 2015-11-04 18:38

Assisted Reproductive Technologies (ART)

Question Answer
what are 4 good reasons why embryo transfer (ET) is a desirable thing to do?(1) Increased progeny from genetically superior dams (2) International trade (easier to ship an embryo) (3) dz control (4) Genetic salvage of valuable individuals
what is MOET?Multiple Ovulation & Embryo Transfer
what are ways that embryo transfer is able to allow Genetic salvage of valuable individuals?Freezing of embryos, Infertile animals
basic outline of how MOET (mult ovulation and embryo transfer)Selection of the donor cows, Super-ovulation of donor cows, Synchronization of donor and recipient, Insemination of the cows, Flushing of the embryos (surgical vs non-surgical), Evaluation of the embryos (embryo grading), Selection and preparation of recipient females, Transfer of the embryos
what factors would positively influence that a cow would be selected as a donor cow?Genetic superiority, Reproductive soundness (Healthy, cycling animals with No history of reproductive problems), No diseases, 60+ days post partum, Vaccinations current
what are two methods of Super-ovulation of donor cows? (explain a little)(1) FSH products- causes a whole lot of follicles to be selected and recruited. FSH products have a short half life and you will need BID (2x d) injections (2) eCG products- only need one injection. work simimlar to FSH
**how well should a donor and a recipients cycle line up for an embryo transfer process?NB! Close synchrony betw. Donor & recipient--> Recipient in estrus 36h before to 12h after donor
*If you have one donor cow, how many recipients do you need?8
*WHEN do you flush the embryos from the donor cow?Day 6-8 post estrus
embryo grading works on a scale up to what, and what does each grading mean? what exactly is being graded?Embryos graded as to the potential likelihood of success after transfer. Grade 1- excellent or good. Grade 2- fair. Grade 3- poor. Grade 4- dead or degenerating
Embryos are also evaluated for their stage of development- what is this scale like?stages 1-9, 1 is a unfert egg, stage 2 is 2-12 cells, stage 3 is early morula, stage 4 is morula, stage 5 is early blastocyst, stage 6 is blastocyst, stage 7 is Expanded blastocyst, stage 8 is Hatched blastocyst, stage 9 is Expanded hatched blastocyst
which stages of development of the embryo are ideal for transferring or freezing? (number and what number means)Stages 4, 5, and 6, which are: morula, early blastocyst, blastocyst (clump, clump with a little space in it, clump attached to hollow ball)
what are some reasons as to why disease transmission risks are reduced with embryo transfer?the Zona pellucida is Difficult for pathogens to penetrate/adhere, The embryo is only exposed to a very restricted environment, the embryo is super small and lacks body systems that a pathogen might be interested in.
what are some steps taken to further reduce the risks of disease transmission with embryo transfer?Washing of embryos (10x), Wash with trypsin, Antibiotics in medium, and Evaluation of embryos to ensure ZP intact & free of adherents
what does OPU stand for?ovum pick up
what is going on during OPU (ovum pick up)use a special ultrasound probe in vagina of cow to visualize. Then take a needle with suction device and stab through ovary to pick up oocytes-- getting primary follicles. (Use in vitro maturation medium to grow mature follicles, do in vitro fertilization/culture, and then implant embryos into donor cow)
what does IVF & IVP stand for?In Vitro Fertilization & In Vitro Production
explain what happens in In Vitro Fertilization & In Vitro Productiondonor cows--> OPU (ovum pick up)--> in vitro maturation--> fert with sperm--> embryo culture for 7d, collect blastocysts--> then either embryo freezing or embryo transfer--> birth of calf
when is Large Calf Syndrome usually seen?seen more often with in vitro production calves
what problems constitute Large Calf Syndrome/Large Offspring Syndrome?Increased birth weight (15%+), Developmental abnormalities with placenta, Increased incidence of abortion, Dystocia
what do they think the problem is with large calf syndrome?Thought to be a problem with culture media
explain how Sex-Sorted Semen worksX chromosomes contain 4% more DNA than Y chromosomes, so they are just slightly heavier/bigger and you can use flow cytometry to sort them (•+/- 10 million sperm /hour with 90% accuracy)