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1
Q

Describe the mare estrous cycle

A

• Mares are seasonally polyestrous
 Long day breeders (April- October)
 Photoperiodic control of reproduction

2
Q

Length of mare estrous cycle

A

• Estrous cycle length: 21 days
 Length of estrus: 7 days (3 to 12 days)
– Ovulation occurs in the last 24 to 48 hours of estrus
– Dominant hormone: Estrogen (from preovulatory follicle)
– Uterine edema

3
Q

Length of mare diestrus

A

• Length of diestrus: 14–15 days
 Dominant hormone: Progesterone (causes maximal tone
uterine tone)
 Corpus luteum not palpable

4
Q

Can you palpate the CL in the mare?

A

no

5
Q

Goal of advancing the breeding season

A

Foal born earlier in the year

 Sales, futurities, racing advantage

6
Q

Techniques to advance the breeding season

A

 Shift the transition period to start earlier (same duration)
 Shorten the transition period

7
Q

Protocol to advance the breeding season for the mare

A
• Start 60 days before desired
breeding date
• Apply 16 hours of light per
day
• Intensity (10 foot-candles at
mare eye level or mare
within 8 feet of 200 watt
incandescent light bulb)
8
Q

Protocol to advance the breeding season for the stallion

A
• Stallion
• Combination light +
progesterone or light +
progesterone + GnRH or
Light + Dopamine
antagonist (sulpiride,
domperidone)
9
Q

Use of progestins to advance the season most effective when

A

• Effective in late transition

10
Q

How does progesterone advance the season?

A

• Primes the HPG axis “progesterone priming”

11
Q

Breeding Options

A

• Natural cover (mandatory in some breeds i.e.
Thoroughbred)
• Artificial insemination with cooled shipped
semen
• Artificial insemination with frozen semen
• Embryo transfer
• Oocyte transfer or intra-cytoplasmic sperm
injection

12
Q

What breed is required to do natural cover?

A

Thoroughbreds

13
Q

Types of semen to use for AI

A

 Fresh extended semen
 Cooled shipped semen
 Frozen-thawed semen

14
Q

Important considerations

A

• Check with the breed registry for
requirements / paperwork particularly if doing
AI or ET
• Ensure all stallion paperwork is in order

15
Q

• Requirements for shipping equine semen into

Washington State

A

 Current Coggins test and health certificate
 Negative EVA test from the current calendar year or
proof of vaccination
 Semen permit number issued by the USDA
 Semen evaluation paperwork

16
Q

Methods for live cover

A
• Pasture mating (high risk for mares and
stallions)
• In-hand mating (old approach)
• In-hand mating (modern approach)
 Monitor follicular growth and induce
ovulation
17
Q

• In-hand mating (old approach)

A

 Tease and breed mare every 48 hours
starting on the 3rd day of estrus
 Never go beyond 12 days of estrus

18
Q

• In-hand mating (modern approach)

A
– Limit # breeding in mares susceptible
to endometritis
– Efficient use of stallions
– Use Minimum contamination breeding
technique
19
Q

 Monitor follicular growth and induce

ovulation

A

– Breed at the time of induction of

ovulation or 24 hours later

20
Q

• Timing of insemination

A

• Cooled shipped semen: 24 hours post induction
• Frozen semen
• 2 doses: 24 and 40 hours post induction (pre and postovulation)
• 1 dose: Monitor for ovulation every 6 to 8 hours then AI
after ovulation

21
Q

Indications for induction of ovulation

A

• Fixed-time AI
• Reduces the number of
inseminations/breedings
• Synchronization of mares

22
Q

If you induce ovulation, what size must the follicle be?

A

35 mm

23
Q

criteria for the induction of ovulation

A
  • Mare in estrus
  • Follicle size
  • Uterine edema
24
Q

hCG

A
• Glycoprotein (human trophoblast)
• LH activity
• Can cause anaphylactic reactions
• Less efficacious if repeated
• Dose: 750 to 300 iu IV, most
commonly 2500 iu)
• Ovulation in 24 to 48 hours
25
Q

Deslorelin (SucroMate®)

A
• Peptide in oil-based controlled
release vehicle
• GnRH analogue
• 1.8 mg deslorelin acetate per mL
• 90% of mares ovulate in 41.9±9.4 h
26
Q

Cooled shipped semen (receiving checklist)

A
- Check integrity of shipping
container
- Check paperwork
- Check semen quality after
insemination and incubation of
an aliquot for 10 minutes at
37°C
- Minimum dose 150 million
motile normal spermatozoa
27
Q

Frozen semen (receiving checklist)

A
- Check temperature of dry
shipper
- Check paperwork
- Minimum dose 150 million
progressively motile normal
spermatozoa
28
Q

Where to place the semen for AI (cooled and frozen)

A
- Place semen in the
uterine body for cooled
semen
- Place semen deep n the
uterine horn ipsilateral to
the ovulation for frozen
semen
29
Q

24 hours after insemination you…

A
  • Check for ovulation
  • Check for accumulation of
    fluid (Persistent-Mating-
    Induced Endometritis;
    PMIE)
30
Q

Pregnancy Diagnosis - 14 days out

A
 Check for double ovulation and
twins
 Check quality of CL
 Place high risk mares on
Progesterone therapy
31
Q

Pregnancy diagnosis 25-30 days out

A

 Fetal heartbeat

32
Q

Pregnancy diagnosis 45-60 days out

A

 Fetal sexing 56 to 65 days

33
Q

post 60 days checkpoints

A

• Check at 90 –100 days (mares
with reproductive problems)
• Check at 5 months

34
Q

Management of the pregnant mare: Nutrition - first 8 months

A

• Up to 8 months, no additional nutrients
 Fetal growth: 0.2 lb/day
 Feeding: 1.5 -2% BW
 Excercise

35
Q

Management of the pregnant mare: Nutrition - last trimester

A

 Fetal growth: 1lb /day
 10th month: fetus requires the most minera;s
 The average thoroughbred mare gains 175 to 225 lbs
(average foal birthweight: 100-125 lbs)
 Feed 2.25 to 2.5% BW
 Total protein of 12-14%
 Ca/P ratio 1.2 to 1.5:1
Excessive nutrition is more common than starvation
and may lead to some placental disease

36
Q

Management of the pregnant mare: Vaccination - CORE

A
• Core vaccines (4 to 6 weeks before due date)
 Influenza
 Eastern and Western encephalitis
 Tetanus
 Rabies
 West Nile virus
37
Q

• Equine Herpesvirus 1 (EHV-1, Rhinopneumonitis) Vx

A

 Killed vaccine for prevention of abortion

 5th, 7th and 9th months of pregnancy

38
Q

• Other vaccines for management of pregnancy

A

 Botulism (8th, 9th and 10th months, 30 days before due date,
every year after)
 Rotavirus
 Streptococcus equi (strangles)

39
Q

• Deworming

A

 Check label (safe for pregnant mares)
 Ivermectin
 Monitor fecal egg count (large studfarms with visiting mares)
 Deworm 10 days before due dates

40
Q

Housing of pregnant mares

A

 Broodmares should be separated from yearlings and
training horses
 Pasture
 Foaling stalls

41
Q

Foaling management

A

• Open Caslick’s 4 to 6 weeks prior to due
date
• Check mare frequently
• Plan for colostrum supply (Frozen from
previous breeding season)
• Check udder secretion for change in
electrolyte (Ca/Mg) to predict foaling time
• Educate client about management of foaling

42
Q

Pre-foaling mammary gland secretions

A
  • Increase in calcium and magnesium
  • Increased Potassium
  • Decreased sodium
  • Inversion of Na+/K+
43
Q

Sodium/Potassium inversion

A

• Inversion
• Potassium>Sodium 24 hours
before foaling

44
Q

prefoaling milk pH

A

Decrease < 6.5

45
Q

Foaling management: Close monitoring

A

• Closed-circuit TV
• Webcam
• Electronic devices
(Foalalert®)

46
Q

Postpartum mare and foal Care

A
• Mare and placenta (see details in postpartum)
• Examination of foal at birth
 Development
 Behavior
 Congenital abnormalities
• Care of the umbilical cord stump
• Check for passive transfer of immunity
47
Q

EQUINE VENEREAL DISEASES

A
• Equine coital exanthema
• Equine Viral Arteritis
• Contagious Equine Metritis (CEM)
• Dourine
• Others: Klebsiella pneumoniae, Pseudomonas
aeruginosa
48
Q

Equine coital exanthema

A
• Equine herpes virus-3
 Species specific
 Alpha herpes virus
 Worldwide distribution
(endemic in the USA)
 Latent infections can
reactivate due to stress
49
Q

Transmission of EHV

A

 Direct contact with lesions
 Mechanical (instruments,
personnel)
 Incubation 5 to 9 days

50
Q

Clinical signs of EHV

A
• Small (2-3 mm) papules
progressing to pustules then
ulceration
• Erosions with scab
• Heal in 2 t 3 weeks
• Stallions: decreased libido
51
Q

Dx and Tx of EHV

A
  • Serology
  • Viral inclusion
  • PCR
  • No treatment
  • Do not breed until lesions heal
  • breeding hygiene
  • Carrier state is possible
52
Q

Equine Viral Arteritis (EVA)

A
  • Arteriviridae
  • Epidemiology
  • Worldwide distribution
  • Endemic in US, Standardbred population
  • Reportable disease in 40 states
  • Virus is androgen dependent
  • Stallions can be lifelong carriers
53
Q

Transmission of EVA

A
  • Main source Shedding stallions
  • Aerosol
  • Vertical
  • Fomites
  • Outbreaks have been reported recently
  • 69.5% exposed via shipped cooled semen
54
Q

Clinical Features of EVA

A
• Incubation period: 2 to 14 days
• Edema due to arteritis,
vasculitis
• Fever
• Respiratory disease
• Virus replicates in endothelial
cells and macrophages
• Abortion 8 to 30 day post
infection
• 3 to 10 months
• Foal can be born infected
55
Q

Dx of EVA

A
  • Serology (virus neutralization)

* Virus isolation (semen)

56
Q

Px of EVA

A
• Vaccination of stallions
• Vaccination of mares bred to
infected stallions
• Only breed to EVA negative
stallions
57
Q

Contagious Equine Metritis (CEM) Causative agent

A
 Taylorella equigenitalis
 Taylorella asinigenitalis
(donkeys)
 Gram negative
microaerophilic coccobacillus
58
Q

Transmission of CEM

A

 Venereal, fomite, vertical

 Carrier stallions

59
Q

Clinical Signs of CEM

A
REPORTABLE
• Stallions: no clinical signs
• Mares
• Copious gray vaginal
discharge within 24-72
hours persists for one
cycle
• Cervicitis persists longer
and positive cultures may
be obtained for as long as
6 weeks
• Endometritis, salpingitis
• Infertility
• Pregnancy loss
60
Q

CEM - Diagnosis

A
• Clinical signs
• Culture requires special
media (check with lab.)
• Serology not recommended
• PCR is now the gold
standard (University of
Kentucky)
• Test breeding (stallions for
import)
61
Q

CEM - samples mare

A

 Clitoral fossa, sinus

 Vaginal discharge

62
Q

CEM samples stallion

A
 Pre-ejaculatory fluid
 Urethral swabs
 Urethral fossa
 Semen
 Test breeding
63
Q

CEM - Treatment - stallion

A

 Daily for 5 days washing of the penis with 5%
chlorhexidine gluconate, rinse and pack with
nitrofurazone ointment, parenteral antibiotics
(penicillin) re-culture 7 days after

64
Q

CEM Treatment- mare

A

 Intrauterine: Penicillin, ampicillin
 Clean the clitoral fossa and flush clitoral sinus:
chlorhexidine gluconate 4%, pack with nitrofurazone
0.2% or silver sulfadiazine 1%
 Clitoral sinusectomy

65
Q

Dourine - causative agents

A

 Trypanosoma equiperdum

 Protozoa

66
Q

Epidemiology of dourine

A

 Venereal disease
 No vectors known
 Reportable disease (foreign
animal disease)

67
Q

• Clinical signs Dourine

A
 Slow to develop (may incubate
for 20 weeks)
 Stage 1: Genital edema,
vaginal or urethral discharge,
weight loss
 Stage 2: Fever, edema and
ulceration of external genitalia,
Cutaneous plaques (silver
dollar), Ventral edema
 Stage 3: Anemia, neurologic
disorders, paresis, death
68
Q

Dx and Tx of Dourine

A

CF test, PCR
• No treatment
• Euthanasia