ANIMAL HUSBANDRY - Successful Reproduction Flashcards
What are the three main methods of breeding animals?
Natural covering
Artificial insemination
Embryo transfer
What are the roles of the vet to ensure a successful breeding season?
Routine disease prevention in the female and male
Optimise conception rates
Pregnancy diagnosis
Neonatal care
Out of the common farm animals which species has the highest conception rate?
Pig with an 85-90% conception rate
What is the conception rate for sheep?
65-80%
How does the conception rate differ between dairy and beef cattle?
The conception rate for dairy cattle is 30-50% whereas for beef cattle the conception rate is 50-65%
List six factors which can impact male fertility rates
Sexual drive towards females
Ability to mount
Intromission capabilities
Ejaculation capabilities
Sperm fertility
Pathogens or genetic mutations
What is a BSE?
Breeding Soundness Evaluation (BBSE)
What are the steps involved in a typical BSE evaluation?
General physical exam
Examination of external genitalia
Examination of internal genitalia
Semen evalualtion
Observation of libido and intromission
What are the five main things that you should look out for when examining the external male genitalia?
Persistent frenulums
Phimosis
Adhesions
Hernias
Inability to obtain or sustain erection
Give two examples of instruments that can be used for semen collection in large animals
Electro-ejaculator
Artificial vagina
What is the most essential factor that needs to be maintained when carrying out semen evaluation and why?
A temperature or around 37°C is essential for optimal sperm motility
Describe how semen evaluation should be carried out
- Dilution of the semen with normal saline
- Evaluate sperm motility (should be at least 30% motility)
- Stain the sperm with haematoxylin and eosin (H&E) stain to evaluate the morphology (should be at least 60% normal morphology)
When collecting semen for artificial insemination, what should always be added to the sample?
Extender (water and buffer)
Energy source
Antibiotic
When collecting semen for artificial insemination, if you are cooling the collected sample what should be added to it?
A protector such as egg yolk, casein or caprogen should be added if the sample is being cooled
When collecting semen for artificial insemination, if you are deep freezing the collected sample what should be added to it?
An additional protector such as glycerol should be added if the sample is being deep freezed
List five advantages of artificial insemination in large animals
- Favourable genetics
- Safer
- Can use a variety of males without the costs of actually keeping them on the farm
- Less fertility variation
- Disease control
List three disadvantages of artificial insemination in large animals
- More management required
- Increased costs (collection, processing etc.)
- Storage facilities
List three reasons castration is done in farm animals?
Breeding control
Increased docility
Changes in the meat quality (meat will have a higher fat content)
What are the three different methods of castration used in farm animals?
Surgical castration
Burdizzo
Ring castration
Why are rams often vasectomised?
Vasectomised rams can be used to increased conception rates and to bring the breeding season forward through acting as a ‘teaser’ ram to align the ewe oestrus cycles ready for when an intact, fertile ram is turned out
Why are boars that are bred for meat killed or castrated at such a young age?
Because if the boar reaches sexual maturity, pheromones can result in ‘boar taint’ where the meat has a very unpleasant taste
How could you manipulate a mares breeding season to get her to come into season earlier in the year?
Artificial lights (reduces melatonin production and shortens the winter anoestrus period)
Which diseases should be tested for during a breeding soundness exam of the mare?
Contagious equine metritis (CEM)
Equine viral arteritis (EVA)
How do you test for Contagious equine metritis (CEM) in the mare?
Take a clitoral swab
How do you test for Equine viral arteritis (EVA) in the mare?
Blood sampling
What can often happen to the vulva of aged or poor body conditioned mares?
The vulva can slip cranio-dorsally over the ischium leading to the loss of the airtight seal of the vulval cleft. This can lead to vaginal irritation, infection and even reduced fertility
What can be used to correct poor conformation of the mare vulva?
Caslicks procedure
Which hormones can be administered to induce ovulation in the mare?
Human chorionic gonadotrophin (hCG)
Gonadotrophin releasing hormone
Which hormones can be administered to synchronise a mare’s oestrus cycle?
Progesterone
Prostaglandin F2α (PGF2α)
In which breed of horse can artificial insemination and embryo transfer not be used?
Thoroughbred horses
Why are thoroughbred mares often bred within the postpartum period also known as ‘foal heat’?
Thoroughbred mares are often bred during their first oestrus cycle postpartum to improve the chances of maintaining yearly foal production
What are some of the consequences of prolonged post-mating endometritis (longer than 48 hrs)?
Reduced fertility
Affected embryonic attachment and survival
What can be used to prevent prolonged post-mating endometritis?
Reduced contamination
Post-breeding uterine lavage
How long is the gestation period in the mare?
320-365 days (approx. 11 months)
What is the most accurate method of pregnancy diagnosis in the mare?
Ultrasonography
At which days of gestation should a mare be scanned for pregnancy?
First scan at 15 days, second scan between 25-28 days and the third scan at 34 days
Why is ultrasonography so useful when scanning mares for pregnancy?
Ultrasonography allows the identification of twins very early on in the pregnancy, allowing the twin pregnancy to be rectified before there are too many complications
What is the most common cause of abortion/stillbirth in the mare?
Placental dysfunction
What are the common causes of placental dysfunction in the mare?
Premature separation of the foetus from the placenta
Twin foals
Placentitis
What should be examined while investigating abortion in the mare?
Mare, foetus and placenta should all be investigated
What is a colt?
An uncastrated male horse under four years of age
What is a stallion?
An uncastrated male horse over four years of age
What is a gelding?
A castrated male horse
Which diseases should be tested for during a breeding soundness exam of the stallion?
Contagious equine metritis (CEM)
Equine viral arteritis (EVA)
Equine infectious anaemia (EIA)
How do you test for Contagious equine metritis (CEM) in the stallion?
Urethral fossa swab
How do you test for Equine viral arteritis (EVA) and Equine infectious anaemia in the stallion?
Blood sampling
What are two signs that the stallion has ejaculated?
Tail flagging
Pulsation at the base of the penis as ejaculate passes through the urethra
What are the two fractions of ejaculate?
Gel fraction: removed by filtation and discarded
Gel-free fraction: Contains majority of speramtozoa
When performing artificial insemination of a mare what is the maximum time for the use of extended fresh semen?
Extended fresh semen should be used within 12 hours
List six reasons why a male horse would be castrated?
Breeding control
Increased docility
Testicular neoplasia
Testicular trauma
Inguinal herniation
Spermatic cordtorsion
Why are most male horses castrated at a young age (within 1-2 years)?
Castration can be done at any age but it becomes more risky with age
Why are male horses not castrated in the summer?
When a horse is castrated, the scrotal incision is left open and there is a higher risk of miasis (fly strike) in the summer
How do emasculators prevent haemorrhage in horse castration?
Emasculators crush the testicular vessels proximally and cut distally to achieve haemostasis
What method of castration can not be used on stallions but can be used on colts?
Open castration
Which complications are at higher risk following an open castration of a horse?
Haemorrhage
Profusion of tissue
Evisceration
What is the term ‘rig’ used to describe the talking about horses?
‘Rig’ is the term used to describe a cryptorchid horse that behaves like a stallion even though it has no visible testicles
What is the most common malignant skin tumour found in the horse?
Squamous cell carcinoma
Where on the horse is squamous cell carcinoma found?
Occular tissue
Genitalia
Nasal tissue
Mouth
What are some of the physical signs that a bitch is in proestrus?
Swollen vulva
Bloody discharge
What are some of the physical signs that a bitch is in oestrus?
Bloody discharge stops
Bitch will ‘stand’ for the male
Other than physical signs, what else can be used to determine which phase of oestrous a bitch is in?
Vaginal cytology
What type of cells would you see on a vaginal smear of a bitch that was in proestrus?
Erythrocytes and nucleated epithelial cells
What type of cells would you see on a vaginal smear of a bitch that was in oestrus?
Fewer erythrocytes and cornified epithelial cells
What can be used to determine the time of ovulation in the bitch?
Progesterone levels (most often used)
Luteinising hormone (LH) levels
How would you use progesterone levels to determine when a bitch is ovulating?
Carry out a progesterone ELISA every two days, when progesterone levels have reached 5ng/ml, ovulation is most likely to occur
What are the disadvantages of using luteinising hormone (LH) levels to determine when a bitch is ovulating?
Daily testing required
Expensive
Ovulation time is often missed due to the rapid LH surge
Why is the optimal conception time for the bitch 2-5 days after ovulation?
After ovulation, it takes the ova a further 48 hours to fully mature into secondary ova and become fertilisable. The ova can then survive and remain fertilisable for a further 2-3 days within the female reproductive tract
What is the most common cause of infertility in the bitch?
The most common cause of infertility in the bitch is mating at the wrong time
How long can sperm survive within the female reproductive system of the bitch?
Sperm can survive 5-7 days
What are some of the benefits of artificial insemination in dogs?
Reduced risk of disease transmission
Increased gene pool
Improved fertility
What type of insemination should fresh/chilled semen be used for in the bitch?
Fresh/chilled semen should be used for intravaginal insemination
What type of insemination should frozen semen be used for in the dog?
Frozen semen should be used for intracervical insemination
What are the four different methods of pregnancy diagnosis that can be used in the bitch?
Abdominal palpation
Ultrasonography
Radiography
Relaxin assay
At which stage of gestation can abdominal palpation be used to diagnose pregnancy in the bitch?
Abdominal palpation can be used to diagnose pregnancy from 28-35 days into gestation
At which stage of gestation can a foetal heartbeat be heard using ultrasonography in a bitch pregnancy?
A foetal heartbeat can be heard using ultrasonography from 24-28 days into gestation
What is the only method of pregnancy diagnosis in the bitch that can be used to accurately determine the number of and position of the foetuses?
Radiography
When can a relaxin assay be used to diagnose pregnancy in the bitch?
Relaxin assay can be used to diagnose pregnancy 3-4 weeks after mating has occurred
Why do all bitches have a physiological pseudopregnancy?
Pseudopregnancy is due to the long luteal phase and thus increased prolactin production seen in the bitch
What can be used to treat a prolonged pseudopregnancy in the bitch?
Prolactin inhibitors
What are the three main reasons for neutering in dogs?
Breeding control
Medical reasons
Behavioural reasons
List three reasons why a dog may not be neutered?
If the dog is being used for breeding
Risk of behavioural changes
Risks of weight gain
Why should an elective ovariohysterectomy be carried out when the bitch is in anoestrus?
To prevent a prolonged state of pseudopregnancy
What are the three main medical reasons for carrying out an ovariohysterectomy in the bitch?
Pyometra
Ovarian neoplasia
Mammary neoplasia
What are the four main medical reasons for carrying out a castration in the male dog?
Prostatic hyperplasia
Testicular neoplasia
Perineal hernia
Cysteine urolithiasis
(T/F) There is an increased risk of prostatic neoplasia in neutered males
TRUE
What is the non-surgical option used for dog castrations?
Subcutaneous Deslorin implant (GnRH antagonist)
