R.K. Shideler

Development of a model to study endometritis in mares

Summary Endometritis is a significant reproductive disease resulting in reduced fertility. Ovarian hormones are known to affect certain aspects of uterine defense mechanisms and this premise was used to develop a model of endometritis. Ovariectomized or reproductively intact mares were treated with dexamethasone (40mg), progesterone (150mg) or a combination of progesterone and dexamethasone to suppress uterine defense mechanisms. Mares were then inoculated intrauterinely with Streptococcus zooepidemicus . Mares were monitored for endometritis by complete reproductive evaluation on Days 3, 7, 14, 21, 35 and 49 following inoculation. All mares had significant infectious and inflammatory changes during the reproductive evaluation immediately after inoculation. These changes resolved within 14 days in mares treated with dexamethasone only. Mares treated with progesterone or a combination maintained uterine infection as long as progesterone was continued. Use of systemic progesterone throughout the experimental protocol allowed consistent development of endometritis in intact experimental mares. This established a uniform population of experimental mares for further research on the pathogenesis of and treatment for endometritis.

Relationship of endometrial biopsy and other management factors on fertility of broodmares

Summary Uterine biopsies were taken from 324 mares on two breeding farms, classified, and their relationship with other management techniques and reproductive performance evaluated. Pregnancy rates, determined by palpation, were 81.0, 74.7 and 70.3% for mares in biopsy grades 1, 2 and 3, respectively. Mares classified as grade 3 tended to become pregnant at a lower (P Pregnancy loss on Farm A (18.1%) was less (P Age of the mare and culture results did not play a significant role in biopsy grade as 64.9% of the mares classified as grade 3 were less than 13 years of age. Mares were divided into groups that were: 1) not cultured; 2) cultured and had no growth on culture plates; 3) cultured and organisms isolated but were not considered pathogenic; and 4) cultured and potential pathogens grown on culture plates. Pregnancy rates were 66.7, 79.4, 81.4 and 76.9% for mares in group 1,2,3, and 4, respectively (P Mares that had been in training conceived at a lower (P Managing mares with lights did not affect (P

Relationship of progesterone to early pregnancy loss in mares

Summary Exogenous progestins are often given to pregnant mares but many questions remain unanswered as to the relationship between concentrations of progesterone and embryo survival. Thus, embryos were collected 7 days after ovulation and transferred into either ovarian-intact recipients (I,n=15) or ovariectomized recipients which were given 100 mg progesterone (L,n=15) or 1,500 mg progesterone (H,n=15) daily. Concentrations of progesterone were determined in all mares from days 0 to 13. Recipients were examined for pregnancy with ultrasonography during days 11 through 25. Between days 28 and 100, twelve ovarian-intact, pregnant recipients were monitored for follicular and luteal changes and bled for determination of progesterone concentrations for 4 days at 2-week intervals. Twelve ovariectomized pregnant recipients were taken off injectable progesterone days 25-30 and pregnancy maintained to day 100 with an oral progestin, altrenogest. Concentrations of progesterone in these mares were determined every 3 days. Progesterone treatment had no effect on maintenance of pregnancy to day 100 or size of embryonic vesicle (P>0.05). Levels of progesterone during days 1 to 13 were 1.3 to 3.0 ng/ml, >25 ng/ml and 7 to 9 ng/ml for groups L, H and I, respectively. Concentrations of endogenous progesterone in ovariectomized pregnant mares became >1 ng/ml by day 91 of gestation indicating placental progesterone secretion. Increased concentrations of progesterone from days 60 to 100, seen in ovarian-intact, pregnant mares, were primarily due to secretions from corpora lutea. There was, in fact, a correlation between the number of 2°CL and progesterone level (r2=0.74). Initial formation of secondary CLs (2°CL) occurred from 28 to 51 days, with peak formation of 2°CL on days 55 to 70 of gestation.

Use of transvaginal ultrasound-guided puncture for elimination of equine pregnancies during days 50 to 65

Twinning is a major cause of abortion in mares. Although early management of twins is quite successful, twins that remain after 40 days are difficult to manage. This article reviews the current knowledge of the use of transvaginal ultrasound probe for elimination of twins. Several techniques are presented, as well as discussion on the best time during gestation for this technique to be used.

Intrauterine equine plasma as an endometritis therapy: Use of an endometritis model to evaluate efficacy

Summary Experimental mares with induced endometritis were used in a controlled study to evaluate the efficacy of intrauterine equine plasma therapy for endometritis. Sixteen ovariectomized mares with mild to moderate lymphocytic endometritis and 10 reproductively intact mares with moderate to severe suppurative and lymphocytic endometritis with active infection were divided into treatment and control groups. All intact mares received 150 mg progesterone daily throughout the study. Mares in the control group received no intrauterine treatment. Mares in the treatment group received 100 ml intrauterine plasma daily for 5 days. All mares were evaluated by complete reproductive evaluation 21 to 42 days after initiation of treatment. Mares in both groups improved slightly in some diagnostic tests over the duration of the study. No significant differences were observed between mares in the treatment or control groups. Intrauterine plasma, when used alone, did not alter the course of mild lymphocytic or moderate suppurative and lymphocytic endometritis.

The effect of polymer and rubber particles on arena soil characteristics

Summary Research carried out in the last 15 years seems to bear out the importance of reducing the hardness of surfaces on arenas and running tracks due to the possible relationship of soil hardness and water content to lameness in horses. The matter of dust problems has been recognized for a longer period of time with its deleterious effects on horse, rider and spectator. The objective of this study was to determine the effect of rubber particles and water-absorbing polymer granules on reducing cushion hardness (impact resistance), as well as creating conditions for more efficient use of water that is applied.The addition of rubber particles had a significant effect on decreasing soil hardness when compared to polymers alone and to control plots. None of the soil treatments or their interaction had a significant effect on increasing the soil moisture content. The addition of rubber particles contributed to the maintenance of loose cushion with resultant decrease in hardness.

Uterine hematoma in a mare

Summary An 8-year-old grey Arabian mare was presented for reproductive evaluation with a history of failing to become pregnant during two previous breeding seasons. An enlargement was identified on the right uterine horn on rectal examination which was confirmed as a fluid-filled nonechogenic mass on ultrasonography. Subsequent examination procedures and laparotomy revealed an old hematoma in the wall of the uterine horn.

Progestins in Mid- to Late-Pregnant Mares

Summary Two experiments were conducted to determine when a placental source of progestin was sufficient for maintaining pregnancy in the mare. In the first study, embryos were transferred into ovariectomized mares and pregnancy was maintained with altrenogest a Altrenogest treatment was terminated at either day 100 (n=6) or day 150 (n=6). Twelve ovarian-intact mares were assigned to a second experiment on day 100 of gestation. On day 160 of gesta- tion, these mares were assigned to one of three treatments: 1) ovariectomy on day 160 and given altrenogest to day 200 (n=4); 2) ovariectomy on day 180 and given altrenogest to day 250 (n=4); or 3) ovariectomy on day 200 and given altrenogest to day 300 (n=4). Blood samples were collected every 2 weeks from all mares in both experiments from day 100 to parturition and assayed for concentrations of pro- gestins. Pregnancy loss from day 100 to parturition was not different among groups in either experiment. Serum con- centrations ofprogestins in ovary-intact mares were greater (P

Prenatal lactation associated with twin pregnancy in the mare: A case report

Summary Two cases are presented to correlate preparturient lactation in the last trimester of pregnancy to occurrence of twinning and threatened abortion. The use of progesterone therapy to prevent abortion is discussed.

SUCCESSFUL TREATMENT OF A HORSE WITH CHRONIC, SEVERE FLEXURAL DEFORMITY OF THE DISTAL INTERPHALANGEAL JOINT: A case report

Flexural deformities of the limbs of foals and young horses are relatively common entities presented to the equine practitioner. The more common areas of involvement include the distal interphalangeal, metacarpophalangeal, and(or) carpal joint areas. They may be classified as either congenital or acquired depending on the time of first appearance. Severity of deformity is graded as Type i if the cranial hoof wall does not pass the vertical, or Type II if it passes beyond the vertical, t The purpose of this ease presentation is to review initiating factors for acquired flexural deformity of the distal interphalangeal joint and the need to utilize professional capabilities of the veterinary surgeon and farrier. The etiology of acquired flexural deformity has been generally associated with nutritional imbalances occurring during the period of accelerated growth in the young horse (3 to 12 months of age). Excess energy and imbalance of rations are considered primary factors; 2,a accelerated compensatory growth rate following a change to a high nutritional plane has also been reported as a factor in this etiology. 4 Calcium and phosphorous availability and ratio appear to be important contributions to flexural abnormalities s and may have a significant relation to feed types, regional location and the effect of dietary protein on calcium hom~;ostasis, ms,6 It has also been reported as an hypothesis that rapid growth of long