Successful Mating In The Mare Part 1 Flashcards

1
Q

Name the three ways horse breeding in mare/stallion can occur?

A

Natural (live) covering
Artificial insemination
Embryo transfer

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2
Q

What are horses bred for?

A

– Thoroughbred racing
• Natural (live) coverage only (no AI or embryo transfer)
– Purebreds e.g. Irish Draught, Shire, Dartmoor etc etc
– Sports horses
• Can be crossbred

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3
Q

Breeding occurs where?

A

• Stud farms might/might not be artificial insemination)
—Studswithstandingstallions
-Mares visit the stallion
—Boarding studs
-Broodmares and offspring
—Standingstallionsandboardingstuds
-Visiting mares and some resident broodmares

• Some native breeds
— Stallionsrunwithaherdofmares(andfoals)

• Veterinary clinics
-– Artificialinsemination

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4
Q

Veterinary responsibilities in horse breeding

A

— Routine treatment of all horses on premises
-preseason testing of resident stallions (andmares)

— Prevent any incoming spread of disease
-from visiting mares

—optimise conception rates
-determine correct time for mating/insemination
-maximise conception
-pregnancy diagnosis; re-examine uterus post covering & detect twin conception and REMOVE

—foaling duties
-neonatal care may be required

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5
Q

What are the 2 types of mares on stud farms. Describe each

A

Resident mares—>
-spend their whole time there; pregnancy+foaling+early post-partum
-may be covered on ‘foal-heat’
-certified disease free
-kept isolated from visiting mares
-treated as herd- vaccinated for specific viruses

Visiting mares—>
-arrive at stud when believed to be at start of oestrus
-either stay till pregnant or return later if not preggo
-certified disease free before arrival

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6
Q

What virus are resident mares vaccinated for?

A

Herpes virus

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7
Q

Breeding season of mares

A

Have annual rhythm of repro competency
Long day breeders
Seasonal polyoestrus- April to September
Anoestrus during winter months

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8
Q

Breeding season of thoroughbreds

A

– northern hemisphere season
• ‘official’ breeding time - 15th February to end of July
• 1st January is the official birth date of the horse (TB)
• Want foals born as close to this as possible (but not before)
– Southernhemisphere
• 1st August birth date and season September to December

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9
Q

How is early season breeding manipulated in mares

A

Photoperiod
-using artificial light to encourage early transition from anoestrus to regular oestrus cycles
-16hour light: 8hr dark from November/December
-horses need to be stabled

Hormones
-synthetic progesterone may hasten ovulator oestrus
-human hormone chorionic gonadotrophin (hCG) may hasten first ovulation of breeding season

Physical conditions
-rising plane of nutrition as go into breeding season
-Replicates spring flush of grass

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10
Q

Name the 2 diseases that are of main concern to UK in mares (although neither are found in UK yet)

A

Contagious equine metritis (CEM)

Equine viral arteritis (EVA)

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11
Q

Contagious equine metritis (CEM)
-low risk to who
-causes what

A

-of low risk to mares
-causes infertility

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12
Q

What 2 swabs are used to check whether a horse has Contagious equine metritis (CEM) or not?

A
  1. Clitoral swab- at home premises or stallion stud
  2. Endometrial swab- during oestrus at stallion stud
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13
Q

Equine viral arthritis (EVA)- how is it checked

A

Checked taking a blood sample for serology

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14
Q

What are some ways used to assess the mares repro tract

A

• External genitalia
– Perineum,vulvarseal,discharge?
• Examine cervix and vestibule – Directpalpation
– Visuallyusingaspeculum
• Clitoral swab
– Microtip–forCEM
• Sample uterus
– Swabsforcultureandendometrialcytology – Endometrialbiopsy
• Transrectal palpation and ultrasonography – Cervix,uterusandovaries
• (Endoscopy of uterus)

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15
Q

What does a poor perineal conformation consist of?
What does a poor perineal conformation allow?

A

-recessed anus
-poor vulvar seal

-allows contamination (faecal) of vagina high allows ascending infection of uterus; endometritis

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16
Q

What are the 3 barriers of external genitalia in a horse?

A

– vulval seal
– vestibulovaginal ring
– cervix

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17
Q

What is caslicks procedure & what does it consist of?

A

Procedure done on cow with poor perineal conformation

-consists of Dorsal portion of vulva being sutured shut, only ventral portion open. This reduces vaginal contamination. Can be re-opened prior to foaling

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18
Q

How long is mare oestrus cycle?
How long is oestrus?
During oestrus when does ovulation occur?

A

21-22 days
5-6 days
24-48 hours

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19
Q

Which hormone causes a primary follicle to mature and
ovulate?

A

Luteinizing hormone

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20
Q

What is teasing of a horse

A

exposing her to a stallion or androgenised gelding to determine her sexual behaviour

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21
Q

What are things a mare will do during teasing during oestrus

A
  1. Tail raise
  2. Squat, tip pelvis
  3. Urinate
  4. Evert clitoris
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22
Q

What are things a mare will do during teasing during dioestrus

A

Switch tail
Kick, Squeal
Attempt to bite/avoid stallion

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23
Q

What will be seen in an ovarian examination during oestrus in mare

A

1 larger follicles +/- soft
Follicle may start ‘pointing’ near ovulation
No corpus luteum

24
Q

What will be seen in an ovarian examination during dioestrus in mare

A

Corpus luteum has formed
Follicles variable in size

25
What will be seen in a uterine examination during oestrus in mare
- uterus relaxed during palpation -Oedematous endometrial folds
26
What will be seen in a uterine examination during dioestrus in mare
Uterus firm/toned Uniform echogenicity of US
27
What will be seen in a cervix examination during oestrus in mare
Cervix short, wide & relaxed, pink & drooping, Lumen open
28
What will be seen in a cervix examination during dioestrus in mare
Long narrow & firm cervix and pale & dry Closed lumen
29
What are the different ways a mare can be examined
Ovarian examination; ultrasound & rectal examination Uterine examination; rectal and ultrasound Cervix examination; rectal, US, visualisation with speculum & palpation (lumen palpation specifically)
30
Maximum pregnancy rates achieved when breeding at what time relative to ovulation
48hrs before to 6 hours after ovulation
31
2 ways in which ovulation can be induced
1. Human chorionic gonadotrophin (hCG) Hastens ovulation in cycling mares Has luteinizing hormone (LH) activity 2. Gonadotrophin releasing hormone (GnRH; deslorelin) When dominant follicle ≥30mm induces ovulation within 48hrs of introduction of a subcutaneous implant Stimulates release of FSH and LH from anterior pituitary gland
32
What is synchronisation of oestrus
the process of manipulating the estrus cycle that results in standing estrus (heat) in the majority of animals in a short time
33
Name the 2 ways of synchronising oestrus -administered for how long -oestrus occurs how long after injections -ovulation occurs how long after injection
1. Giving Synthetic Progestogens/progesterone Administered for 14 days Oestrus 4-7 days after treatment Ovulation occurs 7-12 days after treatment 2. Prostaglandin F-2α Mares with a mature corpus luteum – shortens luteal phase Oestrus 2-4 days after injection Ovulation occurs 7-12 days after injection
34
Why does breeding occur in post partum period?
In order for mare to foal at roughly same time next year, it should conceive in the next 25 days after giving birth otherwise foals are born later and later
35
Natural covering: in-hand breeding
Natural way of mating Mare: – Remove hind shoes if present – Appropriate restraint – bridle, +/-twitch – Tail bandage +/- hind covering boots and neck cape – Hygiene: vulva, perineum & hindlegs (warm water) Stallion – Hygiene: external genitalia cleaned with warm water • Ensure brought to stallion at optimum time – Carefulmonitoring • After 48 hours check mare has ovulated if not - recover • Aim to minimise number of matings – saveonstallionandsemenforothermares
36
Artificial insemination advantages
• One ejaculate divided into several insemination doses –increased number of mares covered • Mare can be bred to remote stallion • Prevent disease transmission (especially venereal) • Reduced uterine inflammation • May improve fertility for some stallions • Avoids breeding injuries • Can assess semen before insemination
37
Artificial insemination disadvantages
• Can be expensive • Increased skill levels required • Not all stallion’s semen can be used • Risk of human injury during semen collection • Not for Thoroughbreds
38
What does artificial insemination require?
• Requires semen collection & handling –fresh/chilled/frozen semen • Time to inseminate based on ultrasonography • Need to inseminate 6h prior to ovulation to maximise conception
39
How does artificial insemination work?
Semen collected from horse and Semen introduced into uterine body using a plastic catheter -hand inserted through vulva to guide catheter through cervix
40
Embryo transfer -what is it -advantages -disadvantages
Implant embryos from mares unable to carry a foal • Can collect multiple embryos per season from valuable mares • Can collect embryos from mares unable to carry a foal Expensive Technically demanding Not for thoroughbreds
41
Postmating endometritis What is it How long does it last
Transient uterine inflammation in mare -lasts for 24-48 hours
42
Is postmating endometritis normal?
Yes!
43
What happens if postmating endometritis lasts longer than 48hours
-can reduce mares fertility -affects embryo survival and contamination
44
How to minimise contamination during postmating
-Good hygiene -Use of AI may help some -‘Washout’ post-breeding uterine lavage- the clear out of any semen, debris and other things that could cause disease in the horse
45
Pregnancy -duration -embryo implants at what time -pregnancy rates at 1 oestrus
320-365 days (about 11 months) Embryo implants at 16 days Pregnancy rates vary from 35 to 75% at any 1 oestrus
46
What is early Pregnancy diagnosis important for? (Ultrasonography)
• Essential for management reasons – Ifneedfurtherattemptsforconception • Allows identification of twins – Wanttoavoidtwinpregnancy – Difficulttoterminatepregnancyafter40days – Early diagnosis allows the situation to be rectified • ‘pinching’ of twins (destruction of one of the embryos) • Can inject one with prostaglandin
47
Why can horses not have twins?
1 placenta of mare is rarely. Enough to feed 2 foals and so they will usually both be found dead during pregnancy
48
What are some ways of diagnosing a horse pregnancy?
—Teasing- exposing mare to a stallion or androgenised gelding to determine her sexual behaviour —Blood hormone levels; Progesterone- not reliable -equine chorionic gonadotrophin -oestrogen sulphate levels elevated after 100 days pregnancy —veterinary exam -ultrasonography & rectal palpation
49
Which diagnosis of pregnancy is most reliable
Ultrasonography—> -immediate results (15 days) (direction palpation can only occur at 40 days or so) -gives clear detection of twins
50
How many times can you scan an ultrasonography?
3 scan
51
At what time is each ultrasonography scan taken and what is checked at each scan
First scan at 15 days: – confirm pregnancy and detect twins • Second scan at 25 to 28 days: – Confirm normal development and not twins – Detect heart beat • Third scan at 34 days: – Ideally repeat at this time but often not done – Ensure still there
52
Nutritional support of pregnant mare involves…
-being kept in good body condition -gradually ^ nutrition in last 3 months
53
Pregnancy loss -when most commonly occurs -due to what
-75% by 49 days -Most losses due to placental dysfunction
54
2 causes for placental dysfunction are:
Non infectious causes—> Premature separation Twins Infectious—> Placentitis
55
Abortion -occurs when? -causes
Occurs before 300 days of gestation Causes—> – Viral(EHV-1) – Bacterial – Fungal – Non-infectious • Twins • Chromosomal abnormalities • Mare illness