Equine Reproduction and Neonatal Care

Flashcards covering vocabulary from a lecture on Equine Reproduction and Neonatal Care

Equine Reproduction

To produce a live foal, successful breeding, conception, implantation, gestation, parturition, and survival of the neonatal period must occur.

Type of equine estrus cycle

seasonally polyesterous

Female and male horses reach puberty at

10 - 24 months

Frequency of equine estrus

15 - 26 days

duration of equine estrus

2-12 days (average 5-7)

Equine Breeding Data

Luteinizing Hormone

Hormone that causes the follicle on the ovary to rupture, resulting in ovulation.

Corpus Luteum

Forms from the cavity left by the ruptured follicle and produces progesterone, maintaining a uterine environment conducive to fetal development.

Female Reproductive Examination

Rectal palpation (less accurate as early follicles are inside the ovary) or Ultrasound (US)

• Ovaries, uterus, and cervix

• US can be much more accurate for the estrous cycle, diagnosing pregnancy, twins, and fetal sexing

Female Reproductive Examination

Visual exam

Vulva; vagina and cervix (need speculum and light)

Female Reproductive Examination

Uterine Culture

Most common reason for infertility in mares is a bacterial infection of the uterus and these infections are usually “silent”

Female Reproductive Examination

Endometrial biopsy

able to assess the probability mare can support a pregnancy

Prostaglandin

Hormone released from the endometrium that causes the corpus luteum to regress if the mare does not conceive.

Windsucker

• in mares and fillies is a condition that is only visible in the female gender, where the air gets sucked into the vagina due to the vulva lips not sealing the entrance of the vagina properly.

• Poor conformation also makes horses more prone to infections due to fecal matter dropping on labial folds

• Surgical correction using Caslick procedure

Caslick's Procedure

• Procedure where the dorsal 2/3 of the vulva are sutured closed to prevent wind-sucking in mares.

• Must be removed during breeding or prior to parturition

Clinical Signs of Impending Parturition in Mares

Swelling of the vulva and possible discharge, udder enlargement, waxing of teats, and changes in rectal temperature.

• Edema of the legs; plaque of edema ventral abdomen (not helpful for prediction of time of foaling)

• Udder enlarges 2-4 weeks before foaling

• Waxing of teats 24-48 hours before foaling, not all mares wax

• Vulva swells with possible discharge

• Rectal temperature – if nighttime temperature is not higher than morning temperature, foaling MAY occur within 36 hours

• Calcium level in mammary secretions can be tested; test kits available; under 400ppm unlikely to foal; over that usually foal within 48 hours; or within another 48 hours after

Stage 1 of Parturition

• Preparatory Stage

• Lasts 2-4 hours

• Restlessness, pacing, sweating-particularly neck, shoulders and flank

• Disinterest in food

Stage 2 of Parturition

• Delivery of the foal

• Lasts 20-30 minutes

• Begins with “water breaking” (8-20 Liters of fluid)

• Fetus delivered in “head-dive” position

Stage 3 of Parturition

• Should occur within 2-4 hours

• Placenta passes

• If not within 4-6 hours, considered retained and need to contact veterinarian

Dystocia

• Incidence is low compared with other large domestic species

• When it does occur, consequences often disastrous, and a live foal is not often achieved

• Most common cause is fetal malposition

• If a foal is not delivered within 20-30 minutes of water breaking, contact veterinarian – Considered an EMERGENCY

• Dystocia treated: Mutation (manual reposition fetus)/traction, Fetotomy, C-section

• C-section has high complication rate and is generally last resort

Essential Aspects of Neonatal Foal Care

• First 4-5 days of life

• 2% of all foals born alive do not survive past 48 hours

• Once delivery has occurred, the following needs must be addressed:

1. Oxygenation/pulse assessment

2. Temperature regulation

3. Care of the umbilical cord and umbilicus

4. Nutrition and nursing

5. Bonding of mare and foal

6. Passage of meconium

7. Adequacy of passive transfer of antibodies

Oxygenation

• Clear away nostrils

• Foal placed sternal with head/neck extended, body rubbed vigorously

• RR at least 60 bpm at 5 min after delivery, staying around 60-80 bpm first hour, then decline to 30-40 bpm for first few weeks of life

• If not breathing after 1 minute, resuscitation can be done

• Close one nostril and breathe into the other, watch for chest rise, and open both nostrils for exhale

• Continue rate 20-30 per minute

• Can insert a nasotracheal tube through one nostril, inflate the cuff, and ventilate with Ambu-bag

Pulse Assessment

• Should be at least 60 bpm at 5 minutes after birth

• Usually elevates >100 bpm over first hour, then declines to 75-100 bpm first week of life

• If the pulse rate or respiratory rate is less than 60 per minute at 5 minutes after birth, contact veterinarian immediately

Temperature Regulation: temp ranges between 99-101.5

• Drying the foal is the first step in warming the body

• Deep bedding and prevent drafts

• Heat lamps (no closer than 4 feet), warm water pads or bottles, and blankets can be used

Care of Umbilical Cord and Umbilicus

• Should not be cut unless necessary, usually breaks naturally when mare stands

• Do not apply traction on cord

• Umbilical stump should be dipped in 2% chlorhexidine solution 2-3 times a day for first week

Nutrition/nursing

• Should be standing and nursing within 60-180 minutes (2 hours average)

• Foals nurse every 1-2 hours (often more frequently)

• Death may occur in foals with blood glucose level less than 40 mg/dL

Bonding of mare and foal

• Allow them to spend most of their time with little interference

• Imprinting can be done in gentle manner with mare always present and close as possible

Passage of Meconium

• Meconium is from the fetus swallowing amniotic fluid

• Can be hard and difficult to pass and cause straining (tenesmus)

• Common practice to give warm water or human pediatric fleet enema

• Most pass in first 9-12 hours of life

• If not seen by 24 hours, or if colic behaviors seen, contact vet

Adequacy of Passive Transfer of Antibodies

• Should receive within first 12 hours (best absorbed first 6 hours)

• Test kits available  to check immunoglobulin G levels of foal

Physical Exam of the Neonatal Foal

Limb deformities

• Club foot

• Valgus deformity

• Flexor Tendon Laxity

• Varus deformity

Neonatal Diseases

High risk foals

• Mares with illness during pregnancy

• Dystocia

• Lactation issues with mare

• Premature or dysmature foal

• Twin foal

• Orphaned or rejected foal

• Failure of Passive Transfer

• C-section delivery

Dummy Foal (Neonatal Maladjustment Syndrome)

Term for foals with behavioral and neurological abnormalities not attributable to other disorders.

• Have difficulty standing or are unable to stand

• Have opisthotonus (severe flexion of the body)

• May be blind and disoriented

• Suffer seizures

• May be stuporous

• Some are mild cases and are much more difficult to diagnose

SCID Foals (Severe Combined Immunodeficiency)

Genetic condition in Arabian horses where foals cannot produce functioning T-cell and B-cell lymphocytes.

• Seen in Arabian and part-Arabian horses

• Inherited as an autosomal recessive mutation

• Unable to produce functioning T-cell and B-cell lymphocytes

• Illness begins to be apparent as maternal antibodies decrease (around 2 months)

• Usually foals die by 5 months of age

• DNA test available for breeders as two carriers have a 25% chance of producing a SCID foal

• Arabian Horse Association Code of Ethics requires disclosure of known carriers