Reproductive Technologies Assisted Reproduction Technology ART Objectives Identify
Reproductive Technologies Assisted Reproduction Technology (ART)
Objectives • Identify and discuss a variety of reproductive technologies available to animal breeders. • Discuss advantages and disadvantages of each method.
Failure to breed • Incompatible mates. • Environmental conditions. • Incorrect social grouping. • One or both may be infertile. • Medical condition e. g. hormonal.
If a female animal is ovulating, what does it mean? • The female is producing and releasing eggs. Superovulation: • When a female is given extra hormones to make her produce a much larger number of eggs. • Why do you think this would be useful?
Ovulation Synchronisation • This is when animals are given hormones to ensure that they all ovulate at the same time. • Why would an animal breeder want this? • E. g a sheep farmer? • All his animals would need the same kind of care - e. g. feeding, housing, health care, record keeping. • Offspring would be timed to be born at the most advantageous time.
Ovulation Indicators • What lets a keeper/owner know if a female animal is in oestrus/ovulating? • Behaviours – ‘flirty behaviours’ e. g. females seeking males, males will also be able to detect pheromones of the females. • Females may encourage males to mate them. • Males may vocalise, perform ritualistic behaviours, become restless, lose appetite, try to escape to the female.
Assisted Reproductive Technology (ART) • Problems could be overcome with artificial or assisted methods. • Skills have been developed through use with domestic animals – usually farm animals and also humans. • Knowledge and skills developed and applied to wider range of animals.
Artificial Insemination • Involves collection of sperm from the male. • Sperm introduced to females reproductive tract in mammals/birds/reptiles via artificial means.
Semen Collection • Method of collection depends on species › Fish and some birds gently massaged › Some birds mate with special device for ‘cooperative ejaculation’ › Some domestic mammals (and some large exotic mammals) trained › Dummy/’teaser’ female and artificial vagina used with farm livestock → Some risk to handler › For larger mammals they may be sedated and electro ejaculated or massaged → Intensive and risky → Electro ejaculation involves inserting a probe or electrodes into rectum – need at least 3 people; 1 to operate electrodes, one to collect semen and one to monitor animal
Semen Collection Methods A ‘dummy’ cow A stallion using a ‘dummy’ horse • Once collected keep sperm at body temperature • Process it and can then used fresh or frozen and stored for future use › Cryopreservation: Frozen in liquid nitrogen at -196 o. C – anti-freeze used so ice crystals do not form Collecting sperm with a real cow and an artificial vagina
Sperm Analysis • Assess for health issues • Reduce unsuccessful mating • Quality of sample – volume, morphology and motility › Electro ejaculated sperm generally lower density and contaminated (urine, blood and cellular material)
Insemination • External fertilisers › Ova collected and sperm directly added • Internal fertilisers › Ensure female is receptive/in correct stage of oestrous cycle → Behavioural indicators and hormone analysis › Female trained to stand or be restrained in appropriate position or sedation/anaesthesia may be necessary › Special equipment used to insert sperm into appropriate place of female reproductive tract to increase chances of fertilisation › Monitor females hormone levels to help detect if pregnant
What are the advantages/disadvantages of AI? Don’t just think about livestock… • Reduces need for animal movement – opens up gene pool. • Maximises males reproductive efficiency – can use ejaculate more than once. • Could mean popular sires could be overused. • Can be invasive and risky. • Ethical / moral concerns?
Embryo Transfer • Removal of one or more embryos from the reproductive tract of donor female and transferring them to one or more recipient › Embryos can be produced by in vitro or in vivo fertilisation › Placement of multiple embryos carries risk of multiple fertilisations. › Can transfer to surrogate of same or different species → E. g. Przewalski’s horse to domestic horse → Many failed attempts at wild to domestic embryo transfer, often no suitable surrogate
1. A genetically viable donor cow is selected. 2. Female given hormone injections to increase ovulation rate. 3. Artificial insemination after the onset of oestrus with the semen from a genetically viable male. Flushing 4. Flushing of the uterus with a sterile solution so retrieve the embryos, usually 1 week later. 5. Collection of the embryos in the laboratory using a microscope. 6. Transferring the embryos into an inseminating rod/straw. Searching for embryos 7. Transferring the embryos to recipient surrogates or frozen. https: //youtu. be/r. Sj. Fv. F 4 -Ia. E Freezing equipment
Cloning What is it? A clone is an exact copy – all cloned organisms have cloned DNA which was copied from the original DNA of the donor Produce offspring by nuclear transfer to increase the number in a population
Production of a Dolly… Key terms 1 4 • Somatic cell: • All cells in the body except sex cells. 3 Cloning is • Nucleus: completed • Contains the DNA. It's the differences in our through a DNA that make each of us unique. process called Somatic Cell Nuclear Transfer • Transfer: • Moving an object from one place to another. 2 5 6
What do you think about cloning? • In your groups discuss your thoughts on cloning and if you agree with it? • Why do you agree/disagree with it? • Do you think it’s ok just for animals – certain types of animals or humans too? • What is a good reason? • Should it be available to all?
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