Reproductive technologies Flashcards
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
What is an advantages of rectal palpation?
No equipment
What are the disadvantages of rectal palpation?
Large animals only
Misdiagnosis
Need to be 35 days in cow and 30 in horse
When can ultrasound be done for PD in cattle?
From 28 days (1 week earlier than rectal)
Whole foetus visible by 59 days
When can ultrasound be done in PD for sheep?
71 days (2 months)
Why is placenta thickness measured during an ultrasound?
Check for placentitis
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
How can PD be carried out in small animals?
Palpation
Ultrasound
Radiography
What is a disadvantage of palpating for PD in SA?
Only from days 20-34
After this, no longer identifiable as individual swellings
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
What are the advantages of AI?
Large genetic pool (can use overseas semen) Known traits Biosecurity Controllable No male required
What are the disadvantages of AI?
Oestrus detection and control
Handling
Cost?
What diseases are bulls tested against before semen collection?
TB
Veneral diseases
What may be added to semen?
Antibiotics against campylobacter, leptospirosis and mycoplasma
How many straws does 1 ejaculation give?
300
When does ovulation occur in a cow?
12-18 hours AFTER oestrus
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
