The effects of metabolic substrates glucose, pyruvate, and lactate added to a skim milk-based semen extender for cooled storage of stallion sperm.

Under in vitro conditions, stallion sperm might preferentially use energy substrates that primarily undergo mitochondrial metabolism. The present study sought to determine the effects of glucose, pyruvate, lactate, or their combinations on the quality of stallion sperm subjected to cooled storage at different temperatures, when using a skim milk-based semen extender. In Experiment 1, no substrate (Control), glucose (40 mM; Glu-40), pyruvate (2 mM, 19.8 mM; Pyr-2, Pyr-19), lactate (2 mM, 19.8 mM; Lac-2, Lac-19, respectively), or their combinations (G/P/L-2 or G/P/L-19, respectively) were added to a milk-based extender and their effects were determined on motion characteristics, viability/acrosomal intactness (VAI), lipid peroxidation status (VLPP), and DNA integrity (COMPα-t) of sperm incubated for 1 h at 37 °C, or sperm stored for 24 h at either 10 or 20 °C. At any period and temperature tested, Glu-40, G/P/L-2, and G/P-L-19 resulted in similar motion characteristics (P > 0.05) but were higher than that of other treatment groups (P < 0.05). Mean VAI was highest in Glu-40 (P < 0.05). Mean VLPP was highest in G/P/L-2 and G/P/L-19 groups (P < 0.05), and mean COMPα-t was lowest in Control, Glu-40, G/P/L-2 and G/P/L-19 groups (P < 0.05). All measures of sperm quality were higher in semen stored at 10 °C than 20 °C (P < 0.05). In Experiment 2, increasing concentrations of either pyruvate or lactate (Pyr-40, Lac-40 or Pyr-80, Lac-80) were added to the extender as energy substrates and compared to glucose (40 mM), following storage for 72 h at either 10 or 20 °C. Groups Glu-40 and Pyr-40 yielded similar sperm motion characteristics and VAI, while VLPP and COMPα-t were reduced in these treatment groups, as compared to Pyr-80, Lac-40, and Lac-80 (P < 0.05). All measures of sperm quality were higher in semen stored at 10 °C vs 20 °C (P < 0.05). This study demonstrates that at storage temperatures of 10 or 20 °C, stallion sperm quality is optimized by the presence of glucose in a skim milk-based semen extender. The addition of substrates that readily support oxidative phosphorylation (i.e., pyruvate or lactate) did not improve the quality of stallion sperm over that of glucose alone and resulted in deleterious effects on sperm quality over time. These effects appeared to be associated with oxidative stress. Use of pyruvate (40 mM) as an alternative energy substrate to glucose generally yielded similar results to that of glucose when sperm were stored at 10 °C only.

Inclusion of supplemental antibiotics (amikacin - penicillin) in a commercial extender for stallion semen: Effects on sperm quality, bacterial growth, and fertility following cooled storage.

In this study, the effectiveness of supplementing INRA-96® extender (INRA-Control; original antibiotic formulation: potassium penicillin G = 38 µg/mL; gentamicin sulfate = 105 µg/mL; amphotericin B = 0.315 µg/mL) with amikacin sulfate and potassium penicillin G (AP) was determined. In Exp. 1, two sources of amikacin (INRA-AP-Sigma or INRA-AP-GoldBio) in combination with penicillin G were compared with ticarcillin/clavulanate (INRA-Tim) or no-supplemental antibiotics (INRA-Control) to examine effects on sperm quality and commensal bacterial growth. No differences were detected in semen quality among treatments after 30 min of exposure (Time 30min) or 24 h of cooled storage (Time 24 h; P > 0.05). At both time periods, commensal bacterial growth was significantly lower in Groups INRA-AP-GoldBio and INRA-AP-Sigma than in INRA-Tim or INRA-Control (P < 0.05). In Exp. 2, increasing doses of amikacin sulfate (GoldBio) plus potassium penicillin G (Sigma) - AP (AP-1000, 2000, 3000, 4000 or 5000 µg-IU/mL, respectively) were added to INRA-96® extender and their effects on sperm quality and commensal bacterial growth were evaluated at Time 30min and Time 24 h. Slight reductions in progressive motility and viability were observed at Time 30min in Groups AP-4000 and AP-5000 as compared to other treatment groups (P < 0.05); however, no differences in sperm quality were detected among treatment groups at Time 24 h (P > 0.05). At both time periods, commensal bacterial growth was significantly lower in Groups AP-3000, AP-4000 and AP-5000 than in AP-1000 and AP-2000 (P < 0.05). In Exp. 3, a breeding trial was conducted to determine the effect of adding a high dose of AP (AP-5000) to INRA-96® extender on resulting pregnancy rates of mares bred with cool-stored semen (Time 24 h). Numerical, but not statistical differences, were observed in pregnancy rates between the mares bred with INRA-Control (6/11; 55%) or INRA-AP-5000 (9/11; 82%; P > 0.05). Supplementation of INRA-96® extender with two different concentrations of AP (AP-1000 or AP-5000) was tested in two clinical cases of stallions where semen was moderately to heavily contaminated with Pseudomonas aeruginosa, or both Klebsiella pneumoniae and Pseudomonas aeruginosa. In both cases, addition of AP resulted in a considerable decrease on bacterial growth in cool-stored semen when compared to the use of the original INRA-96® extender without supplemental antibiotics. In conclusion, the addition of amikacin sulfate and potassium penicillin G to INRA-96® extender allowed for effective control of commensal bacteria without affecting sperm quality. Higher doses of amikacin and penicillin can be safely added to INRA-96® extender to improve the antibacterial activity of this extender against commensal, and potentially pathogenic bacteria, while sperm quality and fertility of cooled semen remains unaffected. Based on the results of the present study, we currently recommend that INRA-96® extender can be safely supplemented with amikacin/penicillin by using a conventional dose of 1000 µg/mL - 1000 IU/mL as a prophylactic measure in cases where contamination of the ejaculates with commensal bacteria is evident. Alternatively, a high dose (5000 µg/mL - 5000 IU/mL) can be used as a control method for potentially pathogenic bacteria.

Effects of glucose concentration in semen extender and storage temperature on stallion sperm quality following long-term cooled storage.

In Experiment 1, the effects of glucose concentration in extender (0 mM, 67 mM, 147 mM, 270 mM; G0, G67, G147, and G270, respectively) and storage temperature of extended semen (5, 10, 15 and 20 °C) were evaluated after storage for up to 5 days (T0h to T120h). For all time points tested, mean total (TMOT) and progressive (PMOT) sperm motility were lower in G0 than all other treatment groups (P < 0.05). Mean curvilinear velocity (VCL) was lower in G0 than other treatment groups at all time points tested except T0h (P < 0.05). Mean percentage of plasma membrane/acrosome intact sperm (VAI) was similar among treatments at T0h, T72h, and T120h (P > 0.05). Mean TMOT and PMOT, were lower for semen stored at 20 °C than all lower storage temperatures (P < 0.05) at all time points. In Experiment 2, semen was stored at 10 °C in extender containing no added glucose (G0) or 147 mM glucose (G147). Following storage, semen was centrifuged and resuspended in extender containing no added glucose (G0 - G0 or G147 - G0, respectively) or 147 mM of glucose (G0 - G147 or G147 - G147, respectively). Mean TMOT, PMOT, and VCL were higher in G147 than G0 at all time periods tested (P < 0.05), whereas mean VAI was similar between these treatment groups throughout the experiment (P > 0.05). Mean TMOT and PMOT were higher in G0 - G147 than G0 - G0 at T72h and T120h (P < 0.05) and mean VCL was higher in G0 - G147 than G0 - G0 for all time periods. Mean TMOT, PMOT, and VCL were higher in G147 - G147 than G147 - G0 at all time points tested (P < 0.05), whereas mean VAI was similar between these two treatment groups for each of the time points (P > 0.05). In Experiment 3, the minimum concentration of glucose required to maintain sperm quality following long-term cooled storage (T120 h) was evaluated (G0, G5, G10, G20, G40, G67, G147 mM). At T120 h, mean TMOT was lowest in G0, G5, G10, and G20 (P < 0.05), whereas mean PMOT and VCL were lower in G0, G5, G10, and G20 than in G40, G67, and G147 (P < 0.05). Mean VAI was higher in G10 than G67, but similar among G10 and other treatment groups (P > 0.05). In conclusion, the absence of added glucose in extender reduced the motion characteristics of stallion sperm during long-term storage (5 days), but VAI was not affected. The use of temperatures between 5 and 15 °C for long-term storage (5 days) best maintained sperm motility and VAI. The threshold concentration of added glucose in extender required to optimize sperm motion characteristics was 40 mM.

The effects of urine concentration, and cushion centrifugation to remove urine, on the quality of cool-stored stallion sperm.

Urine-contaminated stallion semen is a clinical problem due to a variety of causes. The effect of the level of urine contamination on the longevity of sperm quality has not been evaluated. The aim of this study was to determine the effects of urine concentration level (0%, 10%, 20%, 30%, and 40%) and cushioned centrifugation and resuspension of the sperm pellet in fresh extender, on measures of sperm quality, immediately after semen collection (T0), after 1 hour of storage at room temperature (T1), and after 24 hours of cooled storage (T24). In general, most sperm quality measures declined with increasing urine concentration starting at T0. Cushioned centrifugation (CC), but not simple dilution, generally maintained sperm quality at T24 as compared with T1. At T24, total sperm motility was higher in all urine-contaminated CC samples compared with uncentrifuged samples (P < 0.05); sperm viability was lower in CC than uncentrifuged at a urine concentration of 20%, but higher at 30% and 40% (P < 0.05); and DNA quality was decreased (higher % cells outside the main population) in all urine concentrations (P < 0.05). Immediate extension in semen extender, followed by cushioned centrifugation and resuspension of the sperm pellet in fresh extender, provided the best option for preserving sperm quality of urospermic semen.

Cervical wedge resection for treatment of pyometra secondary to transluminal cervical adhesions in six mares.

CASE DESCRIPTION: 6 mares with pyometra secondary to transluminal cervical adhesions were examined. CLINICAL FINDINGS: Reasons for hospital admission included infertility (5 mares) and acute colic (1 mare). In the 6 mares, palpation per rectum of the reproductive tract revealed uterine distention, and transrectal ultrasonography confirmed the presence of echogenic fluid accumulation within the uterus. Cervical palpation during vaginal speculum examination indicated transluminal cervical adhesions. Three mares had severe distortion of the cervix as a result of diverticula and fibrosis. All 6 mares had a diagnosis of pyometra secondary to transluminal cervical adhesions. TREATMENT AND OUTCOME: Initially, the cervical adhesions were manually broken down to establish a patent cervical lumen to accommodate a uterine lavage catheter. A sample of the uterine content was obtained for bacteriologic culture and antimicrobial susceptibility testing, and the uterus was lavaged with 0.05% povidone-iodine solution to remove the mucopurulent exudate. Once the uterus was evacuated, cervical surgery was performed in standing mares following sedation and caudal epidural anesthesia. A full-thickness wedge-shaped defect was made in the dorsolateral aspect of the cervix that created a permanent opening to the uterus. Postoperative care included applying topical medication to the cervix to reduce the recurrence of adhesion formation. All 6 mares had patent cervices and resolution of pyometra following surgery. CONCLUSIONS AND CLINICAL RELEVANCE: Cervical wedge resection enabled treatment of pyometra in mares with transluminal cervical adhesions, without the need for ovariohysterectomy.

The "dilution effect" in stallion sperm.

Dilution of semen to less than 20 × 10(6) sperm/mL has been reported to decrease sperm quality in multiple species, a phenomenon known as the semen "dilution effect." Critical evaluation of stallion semen diluted to these concentrations, however, has not been reported. This study evaluated sperm motion characteristics (percent total motility [TMOT], percent progressive motility [PMOT], curvilinear velocity [µm/s], and percent straightness) and plasma membrane integrity (percent plasma membrane intact [PMI]) in semen samples diluted to 2.5 × 10(6) sperm/mL with the addition of 0%, 7.5%, or 25% seminal plasma (groups T-2.5/0, T-2.5/7.5, and T-2.5/25, respectively), or after simple dilution to 30 × 10(6) sperm/mL (group T-30), or simple dilution to a ratio of 3:1 (extender:semen; group T-3:1SD). Evaluations were performed immediately after semen collection (T0), and after 24 and 48 hours of cooled storage (T24 and T48, respectively). The PMI and TMOT were the highest in group T-3:1SD at T0. At T24, the PMI in groups T-30, T3:1SD and T3:1/30, and T-2.5/0 were higher than that in the other groups (P < 0.05), whereas TMOT in group T-3:1SD was higher (P < 0.05) than that in all other groups except T-30. By T48, no difference was detected for PMI among groups T-3:1SD, T-30, and T-2.5/0; for TMOT among groups T-3:1SD, T-30, and T-2.5/0, and T-2.5/7.5 (P > 0.05), whereas PMOT was the highest in groups T-2.5/0 and T-2.5/7.5 (P < 0.05). These findings revealed that treatments in which semen was diluted to a concentration of 2.5 × 10(6) sperm/mL had lower initial PMI, TMOT, and PMOT, but semen quality did not decline after 24 and 48 hours of cooled storage. In this study, TMOT and PMI in dilute semen were less than those in more concentrated semen at T0. This effect, while significant, was small and less apparent after cooled storage.

Dexamethasone acutely down-regulates genes involved in steroidogenesis in stallion testes.

In rodents, livestock and primate species, a single dose of the synthetic glucocorticoid dexamethasone acutely lowers testosterone biosynthesis. To determine the mechanism of decreased testosterone biosynthesis, stallions were treated with 0.1mg/kg dexamethasone 12h prior to castration. Dexamethasone decreased serum concentrations of testosterone by 60% compared to saline-treated control stallions. Transcriptome analyses (microarrays, northern blots and quantitative PCR) of testes discovered that dexamethasone treatment decreased concentrations of glucocorticoid receptor alpha (NR3C1), alpha actinin 4 (ACTN4), luteinizing hormone receptor (LHCGR), squalene epoxidase (SQLE), 24-dehydrocholesterol reductase (DHCR24), glutathione S-transferase A3 (GSTA3) and aromatase (CYP19A1) mRNAs. Dexamethasone increased concentrations of NFkB inhibitor A (NFKBIA) mRNA in testes. SQLE, DHCR24 and GSTA3 mRNAs were predominantly expressed by Leydig cells. In man and livestock, the GSTA3 protein provides a major 3-ketosteroid isomerase activity: conversion of Δ(5)-androstenedione to Δ(4)-androstenedione, the immediate precursor of testosterone. Consistent with the decrease in GSTA3 mRNA, dexamethasone decreased the 3-ketosteroid isomerase activity in testicular extracts. In conclusion, dexamethasone acutely decreased the expression of genes involved in hormone signaling (NR3C1, ACTN4 and LHCGR), cholesterol synthesis (SQLE and DHCR24) and steroidogenesis (GSTA3 and CYP19A1) along with testosterone production. This is the first report of dexamethasone down-regulating expression of the GSTA3 gene and a very late step in testosterone biosynthesis. Elucidation of the molecular mechanisms involved may lead to new approaches to modulate androgen regulation of the physiology of humans and livestock in health and disease.

Effect of non-sperm cells removal with single-layer colloidal centrifugation on myeloperoxidase concentration in post-thaw equine semen.

Myeloperoxidase (MPO) is a pro-oxidant enzyme contained in and released by neutrophils during degranulation or after lysis. Post-thaw semen contains MPO and its concentration is associated with decreased sperm motility. Recently, MPO concentration in post-thaw semen was shown to be associated with the presence of non-sperm cells (NSC). The objective of this study was to evaluate the effect of a single-layer colloidal centrifugation before cryopreservation on NSC and MPO concentrations in equine semen. The experimental design consisted of freezing semen with or without previous centrifugation through two concentrations of single-layer colloid media. Non-sperm cells and MPO concentrations were assessed in pellet and upper layer at each step of the procedure and MPO was detected in cells by immunocytochemistry. Single-layer colloid centrifugation decreased NSC and MPO concentrations in post-thaw semen. The MPO concentration was correlated with concentration of NSC in the upper layer of the supernatant. In post-thaw semen, with or without previous single-layer colloid centrifugation, MPO concentration was correlated with concentration of NSC. Overall, neutrophils were rarely observed and NSC were mainly epithelial cells or cellular debris, as demonstrated by MPO immunocytochemistry. At all steps of the semen processing and cryopreservation, MPO immunostaining was clearly identified only on NSC. In conclusion, our study shows that NSC present in fresh semen release MPO during freezing.

Azoospermia in stallions: determining the cause.

Determining the cause of failure to ejaculate sperm can be a diagnostic dilemma. The first diagnostic step is to ascertain whether the stallion is ejaculating. If the stallion appears to ejaculate, but there is azoospermia (absence of sperm in the seminal fluid), testing alkaline phosphatase (ALP) activity in seminal plasma can determine whether testicular and epididymal fluids are present. If ALP activity is low, the possibility of either blockage to sperm outflow in the excurrent duct system or retrograde ejaculation should be pursued diagnostically. If ALP activity is high, the possibility of a testicular defect should be pursued diagnostically. In some cases (notably plugged ampullae or transient, thermally induced testicular degeneration), treatment or the passage of time may restore a stallion's fertility.

Use of a modified Vinsot technique for partial phallectomy in 11 standing horses.

CASE DESCRIPTION: 6 geldings and 5 stallions were evaluated from January 2007 through April 2009 for the following conditions requiring phallectomy: chronic paraphimosis (n = 7), squamous cell carcinoma of the penis (3), and priapism (1). CLINICAL FINDINGS: None of the 7 horses with paraphimosis was able to retract the penis. Chronicity of the paraphimosis in 6 horses ranged from 2 weeks to 2 months and was unknown in the seventh horse. Horses with paraphimosis had been medically treated without success. The horse with priapism had developed the condition secondary to acepromazine administration 2 days prior to referral and was unsuccessfully treated once by intracavernosal administration of phenylephrine and irrigation of the cavernosal tissues prior to surgery. The 3 horses with squamous cell carcinoma of the penis had had the condition for 2 years and had been treated by repeated application of a cryogen or chemotherapeutic agent to the lesions. TREATMENT AND OUTCOME: All 11 horses underwent a partial phallectomy by means of a modified Vinsot technique. Modifications to the original technique included creation of a linear urethrostomy, alteration of the location and shape of the urethrostomy, application of a latex tourniquet, concurrent castration of stallions, and use of the procedure in standing horses. The procedure was technically easy to perform, well tolerated by the horses, and cosmetically acceptable to the owners, and had minimal postoperative complications. Long-term follow-up information was obtained from owners of 10 horses a median of 454 days after surgery; 2 owners reported mild urine scalding as the only adverse effect. CONCLUSIONS AND CLINICAL RELEVANCE: The modified Vinsot technique of partial phallectomy was effective and may be useful for horses that are unsuitable candidates for general anesthesia because of medical or owner financial constraints.

Common procedures in broodmare practice: what is the evidence?

Many procedures performed as part of routine broodmare practice are based on sound clinical judgment and experience or scientific evidence; however, others are based on perceived problems and needs to address them. This article presents four procedures commonly used in broodmare practice, for which there is questionable evidence to substantiate their use.

Insemination doses: how low can we go?

This manuscript presents a brief historical review of investigations related to equine artificial insemination. The origin of recommended insemination doses for use fresh, cooled and frozen semen will be reviewed. Over 30 years ago, an insemination dose of 500 x 10(6) progressively motile sperm (PMS) was recommended to maximize pregnancy rates when mares were bred with fresh semen under less than ideal conditions. Since that time, 500 x 10(6) progressively motile sperm has been almost universally accepted as a standard insemination dose, regardless of a stallion's fertility or the refinements that have been made in mare management and semen extenders. Insemination doses for cooled-transported and frozen-thawed semen have also been extrapolated from this dose. Data from a number of studies will be presented which demonstrate the feasibility and rationale of reducing sperm numbers used to breed mares with fresh, cooled and frozen-thawed semen, including the use of deep-horn insemination techniques.

Effect of feeding a DHA-enriched nutriceutical on the quality of fresh, cooled and frozen stallion semen.

Eight stallions were used in 2 x 2 crossover study to determine if feeding a nutriceutical rich in docosahexaenoic acid (DHA) would improve semen quality. Stallions were randomly assigned to one of two treatment groups (n = 4 per group). Stallions were fed their normal diet (control) or their normal diet top-dressed with 250 g of a DHA-enriched nutriceutical. Feeding trials lasted for 14 week, after which a 14-week washout period was allowed and the treatment groups were reversed for another 14 week feeding trial. Feeding the nutriceutical resulted in a three-fold increase in semen DHA levels and 50% increase in the ratio of DHA to DPA in semen. Sperm motion characteristics in fresh semen were unaffected by treatment. After 24 h of cooled semen storage in an Equitainer, total and progressive motility did not differ between treatment groups, but sperm from stallions fed the nutriceutical exhibited higher velocity and straighter projectory (P < 0.05). After 48 h of cooled storage, increases in the percentages of sperm exhibiting total motility (P = 0.07), progressive motility (P = 0.06) and rapid motility (P = 0.04), were observed when stallions were being fed the nutriceutical. For a subset of four stallions, whose progressive sperm motility was <40% after 24 h of cooled storage when fed the control diet, feeding the nutriceutical resulted in improvements in mean progressive motility of sperm after 24 h (P = 0.10) and 48 h (P = 0.03) of storage. Feeding the nutriceutical resulted in similar improvements in motion characteristics being observed in frozen-thawed semen. While it appears that feeding the nutriceutical may improve the motion characteristics of cool-stored stallion semen, it may be most beneficial for stallions of marginal fertility whose sperm do not tolerate the rigors of cooling and storage. The nutriceutical also appeared to improve the freezability of semen. More dramatic improvements in semen quality may be observed if modifications in the main fat content of the diet are incorporated with the DHA supplement.

A Bayesian approach to prediction of stallion daily sperm output.

In equine breeding, the number of spermatozoa ejaculated is considered an important factor in fertility. Methods for predicting the number of spermatozoa have been derived from semen collection procedures. A once-daily collection period for 10 days is a standard recommendation to predict long-term daily sperm output (DSO). The first objective of this study was to determine the precision or repeatability of these DSO predictions. Semen was collected and evaluated daily during four periods for 10 days, for 15 different stallions. The analytical methods utilized hierarchal Bayesian modeling as implemented by Gibbs Sampling. The overall population model showed an initial decline in total sperm number of 1.54 billion spermatozoa per day until the observed mean change point of 4.71 days, at which time mean DSO was estimated at 5.28 billion spermatozoa per day. The hierarchal model showed standard deviations in DSO within-stallion of 0.67 billion spermatozoa per day and among-stallion of 1.86 billion spermatozoa per day. The study's second objective was to determine how testicular size affected DSO models. When the model was extended to include testicular size, the optimal prediction of DSO was that DSO = 0.79 + 0.018 x testicular size (in milliliters). Testicular size explained 36.5% of the among-stallion standard deviation in DSO, but was not significantly related to the mean number of collection-days required to reach DSO.

Pregnancy rates in mares following hysteroscopic or transrectally-guided insemination with low sperm numbers at the utero-tubal papilla.

This study was conducted to evaluate two methods for insemination of a low number of sperm in the tip of the uterine horn, and to determine whether prebreeding intrauterine treatment with prostaglandin E(2) would improve pregnancy rates. Estrus was synchronized in 36 fertile Quarter Horse and Thoroughbred broodmares. When a dominant follicle >or=33 mm diameter was present, mares were treated with 2500 units hCG intravenously and were assigned to one of four treatment groups for insemination with five million total sperm in 200 microl extender the next day as follows: (1) Group PGE-HYS (n=9): 0.25mg PGE(2) in 1 ml 0.9% NaCl solution infused into the tip of the uterine horn ipsilateral to the dominant follicle 2h prior to hysteroscopic-guided inseminate placement onto the oviductal papilla; (2) Group SAL-HYS (n=9): 1 ml 0.9% NaCl solution infused into the tip of the uterine horn ipsilateral to the dominant follicle 2h prior to hysteroscopic-guided inseminate placement onto the oviductal papilla; (3) Group PGE-PIP (n=9): 0.25mg PGE(2) in 1 ml 0.9% NaCl solution infused into the tip of the uterine horn ipsilateral to the dominant follicle 2h prior to transrectally-guided pipette placement of the inseminate into the tip of the uterine horn; and (4) Group SAL-PIP (n=9): 1 ml 0.9% NaCl solution infused into the tip of the uterine horn ipsilateral to the dominant follicle 2h prior to transrectally-guided pipette placement of inseminate into the tip of the uterine horn. Mares in estrus were evaluated daily by transrectal ultrasonography to monitor follicular status and confirm ovulation. If mares had not ovulated within 2 days of insemination, the assigned treatment was repeated. Pregnancy status was evaluated by transrectal ultrasonography 12-14 days postovulation, and pregnancy rates were compared. No interaction between prebreeding treatment (SAL:PGE) and insemination protocol (HYS:PIP) on pregnancy rates occurred (P>0.10). Pregnancy rates did not differ between mares inseminated by HYS (12/18; 67%) or PIP (10/18; 56%) (P>0.10). Pregnancy rates did not differ between mares treated prior to breeding with PGE (11/18; 61%) or SAL (11/18; 61%) (P=1.00). In summary, satisfactory pregnancy rates were obtained when a low number of sperm were either placed directly onto the oviductal papilla using hysteroscopy or placed in the tip of the uterine horn using a transrectally-guided uterine pipette. Infusion of 0.25mg PGE(2) in the tip of the uterine horn 2h prior to insemination did not improve pregnancy rates.

Evaluation of early fetal losses on four equine farms in central Kentucky: 73 cases (2001).

OBJECTIVE: To determine features of an early fetal loss (EFL) syndrome and evaluate potential risk factors for EFL in Thoroughbred broodmares on 4 farms in central Kentucky. DESIGN: Retrospective study. ANIMALS: 288 pregnant broodmares. PROCEDURE: Year-2001 breeding records for 288 Thoroughbred broodmares were examined. Early fetal loss was defined as loss of a fetus that was viable at > or = 40 days of gestation but was subsequently lost by 5 months of gestation. RESULTS: Overall 2001 EFL rate was 25% (73/288), median gestational age at time of fetal loss was 77 days, and median date of loss was May 7. Mares on 1 farm had significantly fewer fetal losses (5%) than mares on the other 3 farms (26 to 35%). Fetal losses were higher for maiden (42%) and barren (42%) mares than for foaling mares (18%). Fetal losses were greater in young than in older mares. Effects of broodmare farm, mare age, and reproductive status were all significant. Fetal losses were not associated with sire used for mating or stud farm. CONCLUSIONS AND CLINICAL RELEVANCE: Greatest risk for EFL occurred during the period from late April to May (ie, in mares bred during February through March). Higher incidence of EFL in maiden and barren mares and lower incidence of EFL on 1 farm suggest management or environmental influences may have affected outcome. Risk factors that should be investigated include environmental differences among farms and differences in management procedures used for lactating versus nonlactating mares.