Equine Reproduction

LESSON FOUR

Broodmare Management

In this lesson we continue to discuss the broodmare and examine some of the modern techniques used on the breeding farm to make for a more efficient program.

Assignment: Read Chapter 4 – Breeding Soundness Examination in the mare.

The following outline will help you follow your reading assignment and also contains pertinent information regarding the proper management of the broodmare.

I. Obtain Reproductive History of Mare

II. Review Physical Condition of Mare

III. Internal Reproductive Exam

A. Rectal Palpation (this course does not teach “hands-on”, but broodmare managers must know what reproduction specialists are determining)

1. Palpate ovary size, shape, and function (follicles, CL); check for cysts.

2. Palpation of both uterus and cervix.

a. Tone of uterus, size, comparison of the horns, any abnormalities.

b. Cervix – open or closed?

B. Ultrasonography (Chapter 5 – Manual of Equine Reproduction)

1. Rectal exam with ultrasound probe in palpating hand.

2. Can examine ovaries, uterus, cervix, early pregnancy (14 to 16 days).

C. Vaginal speculum exam

1. Status of the cervix.

a. Open, relaxed, edematous (swollen), and moist – estrus.

b. Closed and dry – Pregnancy or diestrus or anestrus.

2. Determination of Urine pooling in vaginal vault

a. Usually in older mares.

b. Some urine is not excreted to the outside, but splashes back and pools in the vagina (responsible for infertility).

c. Candidates for surgical correction to prevent problem.

D. Uterine fiber optic exam

Not routine. Only done for examinations of the internal structures of the uterus for diagnostic purposes.

E. Uterine Culture

1. Use of a sterile swab that is introduced into the uterus and a swab sample is taken from the uterus.

a. Sample is sent to laboratory to attempt to grow microorganism (bacteria) on gel agar plates, identify the microorganisms, and determine susceptibility to antibiotics.

Common Pathogenic bacteria isolated:

a. E. coli

b. Beta-hemolytic streptococcus

c. Klebsiella pneumoniae

d. Pseudomonas

2. Care must be taken the swab is not contaminated with outside microorganisms, resulting in a false positive for an infection.

3. Positive results should be followed with a biopsy

F. Uterine Biopsy

1. Use of a biopsy instrument to get a small sample of uterine tissue.

2. Microscopic exam of this tissue by a pathologist.

3. Biopsy classified in 4 basic categories (1986 Kenney and Doig Grading System)

Grade I: normal endometrium or mild, focal inflammation or fibrosis = > 80% chance of conceiving and maintaining until term.

Grade IIA: mild - moderate inflammation and/or multifocal fibrosis with 1-3 layers of fibroblasts surrounding glands or < 2 fibrotic nests per 5 mm linear field = 50-80% chance of conceiving and maintaining until term.

Grade IIB: moderate inflammation and/or multifocal - diffuse fibrosis with 4 or more layers of fibroblasts surrounding glands or 2-4 fibrotic nests per 5 mm linear field = 10-50% of conceiving and maintaining until term.

Grade III: severe inflammation and/or diffuse fibrosis with 5 or more fibrotic nests per 5 mm linear field = < 10% chance of conceiving and maintaining until term.

Practical Farm Practices with Broodmare Management

I. Pregnant Mares

A. Carry through foaling and determine status at foal heat for rebreeding.

1. Foal heat is 9 days post foaling

a. If uterine involution is good at this stage, the mare is healthy, consider breeding. (Refer to Chapter 3, pg. 29 - Manual of Reproduction)

b. Heat after 9 day heat is 28 -30 days from foaling. Conception rates are higher if mare is bred at this time.

II. Barren mares (did not conceive or aborted last breeding season)

A. Begin in the latter fall to examine these mares and clear up any infections, urine pooling, poor vulvar conformation (caslicks) or other problems.

B. Consider putting these mares under lights (16 hours of light per day from the first part of December through February.

III. Maiden mares

A. Examine at the beginning of breeding season for normality of reproductive tract.

1. Open hymen if necessary.

2. Open caslicks if necessary.

3. Use light to go through transition phase of cycle on these mares as well (same as barren mares).

IV. Management concerns in the broodmare during the breeding season (this includes all mares to be bred and undergoing an estrous cycle).

A. Irregular Cycles

1. Mares going through the transition phase (were not put under lights).

a. Put on REGUMATE for 14 days. When they are taken off, some may begin cycling normally.

b. Transition phase mares can be very difficult. May just have to wait out the transition phase.

2. Persistent heat

a. Normally caused by transition phase.

b. An excessively long fertile heat can be ended by using Human Corionic gonadotropin (HCG). This will normally cause ovulation within 24 - 48 hours.

3. Prolonged diestrus (persistent corpus leteum)

a. The CL continues to produce progesterone and possibly the prostaglandin level of the mare is not high enough to cause luteolysis.

b. Injection of prostaglandin product (lutalyse) will destroy the CL and the mare will show estrus within 2 to 3 days. This will be a fertile heat.

c. Early embryonic death may cause a prolonged diestrus. Prostaglandin would also be used in this case.

d. BE SURE THE MARE IS NOT PREGNANT BEFORE ADMINISTERING PROSTAGLANDIN

4. Silent Heat

a. Detected when records indicate the mare should be in heat (9-day heat, or 16 to 18 days since last heat and mare is not pregnant.

1. Palpation to determine if mare is showing physical evidence of heat (estrus) is pregnant or possibly has a persistent CL.

2. Silent heat normally seen in mares with first foals and over protective dams.

3. Rectal palpation to determine breedability, follicle, artificial insemination, or tranquilization and live cover. Allow mare to visualize foal during the breeding process. Take extra time to tease and reassure the mare and her foal will be okay.

5. Anestrus during breeding season (mare stops cycling)

a. MAKE SURE IT IS NOT PREGNANCY THAT IS CAUSING ANESTRUS.

b. The occasional mare that foals will stop cycling for no reason. These mares appear to be every other year mares. They usually continue to show this characteristic throughout their lifetime.

c. Early embryonic death in mares cause many to fail to come back into regular cycling. Prostaglandin will usually work to bring them back in if it is not more than 45 days since the mare was bred.

d. Stallion like behavior in the mare

e. Normally caused by granulosa cell tumor on the ovary.

V. Granulosa cell tumors produce testosterone. These mares are infertile until the tumorous ovary is removed. Can normally be diagnosed by behavior signs and palpation of ovary (these tumorous ovaries can become very large).

VI. Endometritis - (uterine infections). This subject is covered under infertility in the mare. (Lesson 5)

Assignment

1. List at least 10 things you would want to know about the broodmare’s reproductive history.

2. Describe a healthy broodmare’s estrous cycle – giving average length of each stage.

3. During the general non-reproductive examination of the broodmare what would you review?

4. Describe what a uterine biopsy is and what can be learned from such a procedure.

5. In what ways is rectal palpation used in the mare (what can be learned by this procedure)?

6. In what ways is reproductive ultrasonography used in the mare (what can be learned by this procedure)?

Please send reports to jsales@horsecoursesonline.com Students may send essays individually or in one document. Be sure to check spelling. Do not copy and paste answers – reports must be in your own words.

There is no quiz for this lesson.