Breeding and foal management

overview of mare reproductive cycle

• seasonally polyestrous

  • breeding is spring and summer

  • long day breeders

  • multiple ovulations per year

• Maximum foal survival occurs with birth in late spring and summer

1. Four seasons for the mare - based on daylight length

   1. winter anestrus

   2. vernal transition period

   3. physiologic breeding season

   4. autumnal transition period

2. use of lights to increase day length early in spring - vernal transition and estrus occur sooner

   1. especially helpful when breeding in the northern parts of the northern hemisphere

   2. when early foals are desired for production or racing reasons

   3. 16 hours total daylight daily- adding stall lights timed on from 6pm to midnight

3. Puberty (first ovulation) occurs between 15-24 months — second summer of life

4. estrOUs cycle is from one ovulation to the next

   1. average cycle length is 21 days

5. divided into two phases: EstrUs (follicular phase) and disestrus (luteal phase)

   1. estrus: mare is receptive to stallion during 4-7 days before ovulation

   2. diestrus: The mare is not receptive to stallion from ovulation to the beginning of the estrus phase

      1. reproductive tract prepares for pregnancy

Management of the broodmare

• breeding soundness exam

  • Early estrus

  • determines if mare is fit to breed

  • maximizes chance of pregnancy and healthy foal

• Positive identification

• complete history

• examination

  • cardiothoracic auscultation

  • lameness

  • osteoarthritis

  • temperament

  • conformation

Perineal inspection

• vulva close to vertical

• closely apposed

• no discharge, scars

• no gaping with gentle pressure on either side

Vaginal examination

• speculum exam

  • visualize vestibule, vagina, external cervical os

• direct (digital) exam

  • evaluation of tears or adhesions

  • evaluation of fibrosis or incomplete dilation

Trans-rectal palpation and ultrasound

• vagina

  • masses, air

• Cervix

  • position, cysts, masses

• uterus

  • tone, size, fluid, cysts, pregnancy

• Ovaries

  • size, shape, follicles, CL, Cysts, Masses

Foal management

Preparing for parturition

• Suitable location for foaling

  • 4-6 weeks prior to due date

  • clean, dry, protection against elements

  • 14×16 foot stall with straw over shavings

• udder cleansed with mild detergent

• wash perineal region

Prepartum changes

• Waxing of teats

  • early colostrum

  • typically 1-4 days prior to foaling

• milk secretions

  • milk changes from thin straw-colored to milky white

  • yellow-orange as colostrum forms

• Vulvar and pelvic ligament laxity

• udder enlargement

  • typically significant growth in final 2 weeks

Monitoring parturition

• sleep in barn

• video

• sound monitors

• various foal alert systems

Stages of parturition

1. Stage 1

   1. 30 minutes to 4 hours

   2. restlessness and signs of colic

   3. uterine contractions

   4. fetal repositioning

   5. Preparation of the mare

      1. clean udder

      2. tail wrapped

      3. perineal area scrubbed

      4. remove extraneous people

2. Stage 2

   1. fetus passes into birth canal

   2. mare lays down, strains in lateral recumbency

   3. 20-30 minutes for this stage

      1. steady progression

      2. maximum time - 70 minutes

   4. Rupture of the chorioallantoic membrane

      1. Extended legs

      2. nose

      3. head and shoulders

      4. followed by hips

   5. The Three P’s

      1. Presentation

         1. relationship of the long axis of the foal to the long axis of the mare (longitudinal)

      2. position

         1. relationship of the dorsum of the fetus to the maternal pelvis (dorsosacral)

      3. Posture

         1. relationship of fetal extremities to the fetal body (head resting on extended metacarpals)

3. Stage 3

   1. Delivery of the placenta/ fetal membranes

      1. 30 minutes to 3 hours

      2. tie up above mare’s hocks

   2. Beginnings of uterine involution

      1. decrease uterine size occurs within 12-24 hours

      2. uterine fluid mostly expelled by 24-48 hours

Post-partum exam of the mare

• cleanse udder

• ensure adequate milk production

• colostrum

• examine perineal area

  • ensure vulva and anus intact

  • evaluation bruising and edema

  • rectovaginal fistula

Post-partum evaluation of placenta

• lay out on clean floor

• examine inside-out and right-side-in

• Can fill with water

• Critical that entire placenta, including tips of horns, is present