Gestational Monitoring and Theriogenology Procedures in HORSES

Spermiogram includes

• - Volume (mL)

• - Concentration (millions/mL)

• - Motility estimates

• - pH, color, smell

• - Morphology

Motility estimates

• - CASA vs. light microscopy

• - Motility estimates of fertility and seme extension/packaging

Sperm motility

% of moving sperm of all sperm present

Progressive motility

% of forward moving sperm all moving sperm

Total progressive motility

 % of forward moving sperm of all sperm

• - Motility x Progressive motility

Systemic disease and reproduction

• Sick, poorly cared for horses has less ability to reproduce

• Inflammatory aspects of the disease can affect reproduction

  • Cyclicity changes

  • Embryo/Fetal disease

  • Uterine quiescence

  • Spermatogenesis

Male systemic diseases

• - Thermoregulation

• - Lameness

Male thermoregulation

• Any process that causes the core body temp to be raised significantly

  • Fever, heat stress, anhidrosis

• Direct negative affect on spermatogenesis

  • Process is about 60 days in stallions

  • Affects are seen at time of disease and 2 months or more later

Male lameness and reproduction

• - #1 cause of low libido in male

• - Chronic pain

Female inflammatory mediators

• - Fever, uterine disease, stress

• - Direct actions on ovaries and uterus

• - Prostaglandins

• - Disrupts gestation

Prostaglandins with females

• - Attack CL

• - Enhance/cause uterine motility

• - Shorten luteal phase of estrous cycle

  • "conception failure", EED

Inflammatory mediators disrupt gestation in females

• Remove progesterone

• Promote uterine contractions

What is the only cell designed to live outside the body?

Sperm

Gestation range

330-365 days

• >320 days is considered viable

Non-Primary Dependent Corpus luteum species

• Physiologic changes for progesterone production

• - Day 0-60 --> Primary CL

• - Day 40-120 --> secondary CL's

• - Day 100-term --> Feto-Placental Unit

Breeding dose is

 1000 x 10^6 TPM sperm

Calculation for how much sperm/mL

([Ejaculate]x 10^6/mL) x TPM

Semen extension

• - Raw semen must also be extended with energy rich dilutants to increase longevity

• - Semen needs specific concentration ratios to have best survival

• - ([𝑥]𝑖/ [𝑥]𝑑) – 1 = Parts Extender

Simple Steroidogenesis

Cholesterol → Pregnenolone → Progesterone → testosterone → Dihydrosterosterone or Estrogens

Equine gestation

• - Range: 330-365 days

  • >320 days is considered viable

• - Non-Primary Dependent CL species

  • Physiologic changes for progesterone production

  • Day 0-60 --> Primary CL

  • Day 40-120 --> secondary CL's

  • Day 100-term --> Feto-Placental Unit

Stage 0 (Quiescence) of parturition

• - Uterus must maintain a lack of contractility despite continued growth and stretch of the smooth muscles of the uterus

• - High progesterone levels

  • Prostaglandin inhibition

  • Gap junction blockage

Stage 1 Preparatory phase of parturition

• - Stress, colicky, isolation, sweating

• - Fetus is moving and early light contractions are occurring

• - End with rupture of chorioallantois

  • "break water"

• - 30 min to 4-6 hours

• - Time to get prepped and ready

  • OB chain

  • Lube

  • Wrap tail

  • Towels

Stage 2: fetal expulsion of parturition

• - 10-30 minutes

• - If progress is not made in 5-10 minutes, check or call

  • Amniotic sac usually seen within 5 minutes of rupture

Normal presentation

Anterior, Longitudinal, dorsal-sacral, bilateral, front limbs and muzzle

Neonatal exam

• - Cleft palate, suckle reflex, dip umbilicus, meconium staining, enema

• - Give it some time, let mom and baby be horses, do not break the umbilical cord

• - Be careful, mom will want to defend her new foal

Stage 3: expulsion of fetal membranes in parturition

Should occur within 3 hours of fetal birth

Complication with expulsion or lack of expulsion of fetal membranes

• - Endotoxemia

• - Metritis

• - Laminitis

• - Subfertility

What does progesterone like to inhibit

COX 1 and COX 2

Saving and examining the fetal membranes

• - Tears and completeness

• - Red velvety appearance

• - 3 area where the "velvet" is gone normally

  • Tips of uterine horn

  • Area of cervical star

• - 1, 2, 3 guideline for foals

Fetal stress parturition endocrine events

• Fetal stress can lead to increased ACTH which can lead to increased fetal cortisol

  • - Increased ACTH

    • Fetal ACTH may already be high, but ACTH receptors of Fetal adrenal may be key

  • - Increased fetal Cortisol

    • Fetal cortisol passes into circulation and affects placental enzymatic properties

  • 
    

What do the testicles live outside the body

They need a cooler temperature.

• - having a fever is not good

Late gestation problems

• - Premature placental

• - Placentitis

• - Pre-pubic tendon rupture

• - Dystocia

EED

Early embryonic death

Premature placental separation can be associated with:

• - Placentitis

• - Fescue toxicosis

• - Idiopathic

Premature placental separation

The chorioallantois separates from the uterus early

• - Associated with poor oxygen/nutrient delivery and basic anoxia

• - Emergent condition at the time of parturition

• - "Red bag delivery"

• - Fetus suffocates within the membranes

• - Treatment - Cut them!

Different forms of placentitis

• - Ascending

• - Diffuse

Placentitis

• - #1 cause of infectious abortion

• - Infection/Inflammation of the utero-placental junction

• - Direct fetal infection

• - Inflammatory mediators cause changes in various hormones that all have negative affects on maintain gestation

Clinical signs of placentitis

• - None

• - Mammary gland enlargement

• - Premature lactation

• - Abortion

Pre-pubic tendon rupture

• - Loss of ventral abdominal support to the pelvis

• - Large breeds, high parity mares, twins and gestational issues can lead to the failure of this support

Clinical signs of pre-pubic tendon rupture

• - Thickened, edematous, ventral abdominal plaque

• - Parked out stance

• - Lame, "walks on egg shells"

Treatment of pre-pubic tendon rupture

Geared towards priority

• - Induction/abortion

• - C-section have much lower success rates

• - Mare will need help to deliver

• - Mare should not be re-bred to carry a foal

Presentation of fetus

•  Fetal spinal axis orientation to that of dam

  • - Longitudinal vs. transverse

  • - Anterior vs. posterior

Position of fetus

• Fetal dorsum relative to what part of the dam's pelvis

  • - Dorso-sacral

  • - Dorso-pubic

Posture of fetus

•  Limb description and/or deformity

  • - What limb?

  • - What joint?

  • - Unilateral left carpal flexion

Mal-disposition of fetus

A deviation from normal presentation, position, or posture

Normal foal presentation

•  Anterior, Longitudinal

  • Litter bearing species can have posterior presentation as normal

Normal foal position

• - Dorso - sacral

Normal foal posture

• - Both front feet, slightly off-set, hooves, paws, claws pointed down

• - Head(muzzle) just behind the feet

When is a foal considered viable

after 320 days of gestation

Mammary gland development/Premature lactation

• - Commonly does not occur until 2 weeks prior to expected delivery

  • Gestation ranges are so diverse this is a hard indicator

  • Maiden mares can show no development until 48 hours prior if any

• Should be considered a sign of impending abortion

Chemical restraint for vaginal delivery

• - Sedation

• - Epidural

• - General anesthesia

• - Tocolytics

Ascending placentitis

• - Bacteria moved up the repro tract

• - Typically fecal bacteria moving

Diffuse placentitis

When the mare was earlier in gestation and got an infection which showered the placenta with bacteria

Parturition prediction

• - Milk electrolytes

• - Milk calcium carbonate

• - Udder secretion pH

Milk electrolytes for predicting parturition

• Oldest method, slow method

• - Sodium and potassium inversion

• - Approximately 48 hours prior to parturition

• - Some repeatability issues

• - Not reported to work in sick mares

• - Potential for outside lab

Milk calcium carbonate for predicting parturition

• - Variety of kits that test calcium carbonate and magnesium

• - Secretion change into a more milk-like content prior to foaling

• - Kits need 1.5-3mL of sample

  • this is hard to get from a maiden mare

Udder secretion pH for predicting parturition

• - Research

  • Recent work on using udder secretion pH to predict parturition

  • Initial work used pH meters and looked for set number

  • Most recent work looked at using pH strips and change in pH

• - Tested pH on a drop or two of secretions

• - No lab equipment needed

• - Owners can do monitoring

• - Normal, normal treated, placentitis, and placentitis treated mares

• - Some mares, mostly maidens, showed no shift

• - at about the 48 mark the pH dropped from about 8 to 6

Hydrops

• Allantois and Amniosis

  • Similar pathology, differing etiology

• Excessive fluid production into one of these spaces

  • 100L or more

Clinical signs of Hydrops

• - Mid to late gestation onset

• - Large pendulous abdomen

• - Difficulty in moving

• - Can lead to Pre-pubic tendon rupture

Treatment for Hydrops

• Aimed at saving mare

  • - Fetus is almost never viable

• Remove the fluid in a controlled manner

  • - Transcervical

  • - Maintain central venous pressure

    • 2 jugular catheters

    • IV fluids, corticosteroids

Sedation for controlled vaginal delivery

Hemodynamic issues, cross placenta for fetal issues

Epidural for controlled vaginal delivery

• - No effect on myometrial contractions and abdominal press

• - Vaginal analgesia/sensitivity ergo Ferguson reflex reduced

General anesthesia for controlled vaginal delivery

• - Stop all uterine contractions, may be the only way to correct issue

• - Combined with a hoist and can use gravity to assist in the fetal mutation

• - Should only take 10-15minutes to deliver the fetus

Tocolytics for controlled vaginal delivery

Isoxuprine/Clembuterol… veterinary availability? Speed of action?

When and how much does udder secretion pH change before parturition

• - At about the 48 hours mark the pH drops from about 8 - 6

Semen extenders are used to:

increase the volume of the ejaculate when the ejaculate is to be divided into 2 or more aliquots - IDK about this answer

The #1 cause of infectious abortion in the mare is:

Placentitis

In the normal pregnant mare, lactation typically begins __________ prior to the expected delivery date.

Two weeks - IDK about this answer

Clinical signs of pre-pubic tendon rupture include all of the following except:

Premature lactation