Reproductive technologies Flashcards by Olivia Jones

Why do we do pregnancy diagnosis?

To identify if pregnant or not (if not rebreed or cull)
To see if foetus is viable
To see litter size
To see due date
To see foetus sex

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What is an advantages of rectal palpation?

No equipment

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What are the disadvantages of rectal palpation?

Large animals only
Misdiagnosis
Need to be 35 days in cow and 30 in horse

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When can ultrasound be done for PD in cattle?

From 28 days (1 week earlier than rectal)

Whole foetus visible by 59 days

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When can ultrasound be done in PD for sheep?

71 days (2 months)

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Why is placenta thickness measured during an ultrasound?

Check for placentitis

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Hormone assays can be used for pregnancy diagnosis. Which hormones are present?

Progesterone day 0-21
Pregnancy associated proteins
Pregnant mare serum gonadotropin
Oestrone sulphate

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How can PD be carried out in small animals?

Palpation
Ultrasound
Radiography

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What is a disadvantage of palpating for PD in SA?

Only from days 20-34

After this, no longer identifiable as individual swellings

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X-rays can be used for PD in small animals. When can this be done? What is a precaution?

After day 42 - skeletons have ossified

Don’t do in first 2 trimesters as risk for foetus development

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What are the advantages of AI?

Large genetic pool (can use overseas semen)
Known traits
Biosecurity
Controllable 
No male required

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What are the disadvantages of AI?

Oestrus detection and control
Handling
Cost?

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What diseases are bulls tested against before semen collection?

Veneral diseases

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What may be added to semen?

Antibiotics against campylobacter, leptospirosis and mycoplasma

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How many straws does 1 ejaculation give?

300

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When does ovulation occur in a cow?

12-18 hours AFTER oestrus

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What should be done to a straw before AI?

Thaw in water bath

Wipe dry as water is spermicidal

Who is able to carry out AI?

Any trained personnel

How can semen be sexed? How accurate is this? What is a problem with this?

X sperm contain more DNA So attracts more fluorescent dye
Around 85% accurate
Lowers pregnancy rates

How can pregnancy rate by AI be improved?

Insert deep in uterine

Ipsilateral to corpus luteum

What is MOET?

Multiple ovulation and embryo transfer

Why may MOET be done?

Superior genetics

Seasonal breading

What are the advantages of IVF?

Females with problems (e..g blocked oviduct) able to get pregnant
Maiden animals
No donor hormones needed
Genetic diversification - rare semen can be used on multiple females

What are the disadvantages of IVF compared to AI?

More invasive
More technical
Low pregnancy rate
Sex ratio towards male offspring

What cells can be used for nuclear cloning?

Any adult somatic cell

What is flushing in animal husbandry?

Increasing nutrient intake and BCS prior to breeding

How can litter size be controlled?

Flushing Progestogen PMSG

Twins are undesirable in cattle and horses. Which cows have a higher twin ovulation rate?

High yielding cows

What hormone can be given to sows to induce parturition? When is it given and when is birth expected?

PGF2a (can be with carbetocin) Day 114 Within 36 hours

Why may parturition be induced?

So gives birth whist supervised Dam diseased Oversized neonate

Gestation length is never definite. What influences gestation length?

Breed Male factor Gender of neonate Time of breeding (Spring longer in some species - mare/alpaca)

Why may carbetocin be given 24 hrs after PGF2a to induce parturition in sows?

Lower stillbirth rate More uniform weaning waits Lower mortality preweaning

What may cattle/sheep be given to induce parturition?

Corticosteroids (long, medium or short acting) | PGF2a

What should be considered when inducing parturition in cattle/sheep?

Calfs don't survive prior 260 Lambs don't survive prior to 138 Most consider calf vs cow

What are the advantages and disadvantages of using corticosteroids to initiate parturition?

Prepare foetus - mature lungs Widen birth canal Takes longer

What is given for misalliance in mares? When?

Fluprostenol | Day 35

What is given for misalliance in bitches? When?

Oestradiol benzoate | Day 3 and 5

What is given for misalignment in cow? When?

PGF2a | Day 6 and 150 s

What is misalignment?

Pregnancy termination

What hormones can be used to suppress reproduction?

``` Progestogens Oxytocin Testosterone (bitch) Megestrol acetate GnRH vaccine w ```