Using mycobacterium cell wall fraction to decrease equine chorionic gonadotropin after abortion.

BACKGROUND: Equine embryonic loss following the development of endometrial cups delays return to cyclicity due to the production of equine chorionic gonadotropin (eCG). Natural degradation of endometrial cups coincides with an influx of immune cells at 100-120 days of gestation, but therapeutic stimulation of reduced eCG production has been relatively unsuccessful. Recently, we observed an increase in pro-inflammatory cytokine production following the use of the immunostimulant mycobacterium cell wall fraction (MCWF). OBJECTIVES: To evaluate the efficacy of hysteroscopic-guided injection of MCWF on the accelerated decline of eCG secretion. STUDY DESIGN: In vivo experiment. METHODS: Mares were pharmacologically aborted at 40-45 days of gestation, and then divided into groups: MCWF-treated (6 mg MCWF suspended in 20 mL LRS; n = 10) and Control (20 mL LRS; n = 6). Five days after abortion, hysteroscopic-guided injection of endometrial cups was performed, with 1 mL of volume placed into each visible endometrial cup. This was repeated 7 days later. Trans-rectal ultrasonography was performed to monitor ovarian activity, and serum was obtained to assess eCG and cytokine concentrations. RESULTS: Concentrations of eCG decreased in the MCWF-treated group (p < 0.01) with a significant suppression noted as early as 14 days after onset of treatment and remained suppressed for the duration of the study. This coincided with an increase in peripheral IFN-γ (p < 0.01) and IL-1ß (p < 0.01) concentrations. Eight out of ten MCWF-treated mares (80%) developed pre-ovulatory follicles, in comparison to 2/6 controls (33%). A pre-ovulatory follicle was noted 23 ± 4 days after onset of treatment. MAIN LIMITATIONS: No pregnancy data was obtained following treatment. CONCLUSIONS: This is the first report of a treatment for the accelerated reduction of eCG following abortion. Stimulation of this process allowed mares to develop a pre-ovulatory follicle within a month of MCWF treatment onset, granting repeat attempts at breeding within the confines of a single breeding season.

Effect of day of estrus cycle at time of transvaginal follicle aspiration for oocyte recovery on rates of in vitro maturation and blastocyst production after intracytoplasmic sperm injection.

OBJECTIVE: To determine the effect of stage of estrus cycle (day after ovulation) at the time of transvaginal ultrasound-guided follicle aspiration (TVA) on parameters related to the success of in vitro equine embryo production. ANIMALS: 14 healthy mares were used; 11 completed the study and were included for analysis. PROCEDURES: Mares underwent TVA of all follicles ≥ 5 mm diameter at each of 3 timepoints: 7 days after ovulation, 14 days after ovulation, and S-DSF (subordinate to a dominant stimulated follicle), during estrus at 24 hours after gonadotropin administration. The 3 treatments were assigned to each mare in random order; mares underwent follicle growth and ovulation between treatments. Recovered oocytes were matured in vitro, subjected to intracytoplasmic sperm injection (ICSI), and cultured to the blastocyst stage in vitro. RESULTS: Total follicle numbers differed significantly between individual mares but did not differ between treatments. The number of follicles of different sizes significantly (P < 0.05) differed between treatments, with mares in the Day 7 treatment having more follicles 5 to 9 mm in diameter and fewer follicles 20 to 24 mm in diameter than mares in the other 2 treatments. After in vitro maturation culture, there were significantly more mature oocytes in the S-DSF treatment than in the other 2 treatments. There were no differences in blastocyst rate after ICSI among treatment groups. CLINICAL RELEVANCE: Timing of TVA for aspiration of S-DSFs may increase the number of mature oocytes available for ICSI. Understanding of the effects of timing of TVA will help veterinarians to maximize the efficiency of this procedure.

Relationships between blood and follicular fluid urea nitrogen concentrations and between blood urea nitrogen and embryo survival in mares.

High blood urea nitrogen (BUN) concentration is linked to low fertility in cows and ewes; however, this relationship has not been reported in mares. The study characterized the relationship between BUN and follicular fluid urea nitrogen (FUN) during follicle growth (Experiment 1) and the impact of BUN from embryo donors on the pregnancy outcome of recipient mares (Experiment 2). In experiment one, follicular fluid and blood samples were collected from mares during diestrus with growing follicles and during estrus with pre-ovulatory follicles (n = 16 and 10 mares, respectively). In experiment two, BUN concentrations of embryo donors were related to pregnancy outcome after embryo transfer. In experiment one, there was a strong positive correlation between BUN and FUN (R = 0.83; P < 0.0001), with higher BUN in mares with growing follicles than with preovulatory follicles (P = 0.004) and higher FUN in growing follicles than in preovulatory follicles (P = 0.031). In experiment two, BUN was higher in donor mares that produced unsuccessful embryos compared to donor mares that produced embryos resulting in successful pregnancies at D14 (P < 0.03). Additionally, there was an effect of age (P = 0.01) and interaction between age and lactation (P = 0.009) in donor mares for embryo survival after embryo transfer. Donor mares with unsuccessful embryos were older than donor mares with successful embryos. Therefore, these experiments showed that BUN was related to follicular fluid environment as well as to the survival of Day 7-8 embryos after transfer to recipient mares.

Leukocyte Esterase Reagent Strips for Stall-Side Diagnosis of Endometritis in Mares.

The objective of this study was to compare a commercially available leukocyte esterase strip test with endometrial cytology in diagnosing endometritis and establish a cutoff point, sensitivity, and specificity for the leukocyte esterase test (LET). Forty-six light breed mares presented for breeding management were enrolled in this study. Transrectal palpation and ultrasonography examinations were performed to determine when the mares were in estrus. Kalayjian endometrial swabs were used for culture, cytology, and the LET by using the cap to retrieve an endometrial scraping. Thirty-six mares had a negative LET. There was not a significant correlation between cytology results and culture results or between LET results and culture results. The correlation coefficient between LET and cytology was r = 0.698. The LET had a receiver operator curve area under the curve of 0.871 with a test value cutoff point, which was any result that contained trace or greater amounts. The sensitivity at this point was 77.8% and the specificity was 94.6%. The LET could be used to rule in endometritis in severe cases but is not sensitive enough to rule out endometritis.

Transrectal ultrasonographic characterization of the accessory sex glands, pelvic urethra, and ureters in normal geldings.

Transrectal ultrasound of the internal urogenital tract may be used to aid in the diagnosis of reproductive tract and urinary tract pathology in both stallions and geldings. Abnormalities of the accessory sex glands of geldings are uncommon, although prostatic masses have recently been described in adult geldings presenting with dysuria, stranguria, and/or hematuria. The purpose of this study was to describe the normal ultrasonographic features and sizes of the accessory sex glands, caudal ureters, and pelvic urethra in clinically normal geldings. Eleven healthy geldings with no history of urogenital tract pathology were evaluated by a single observer experienced in ultrasound of the stallion accessory sex glands. The ultrasonographic appearance, relative anatomic relationships and sizes of the accessory sex glands, caudal ureters, and pelvic urethra were investigated using both rectal linear array and microconvex array transducers. Summary statistics including mean, standard error, confidence intervals, and range were calculated for each structure. There were no statistically significant differences in measurements between the left and right sides of paired structures or between measurements obtained with different transducers. Fluid was present in the seminal vesicles of 7 of 9 subjects. Midline cysts of the urethra as well as bulbourethral gland and prostatic cysts were identified. The normal reference ranges defined in this study will be useful in the clinical evaluation of geldings with suspected internal urogenital tract pathology.