Topical Ganciclovir Reduces Viral Excretion in Mares With Equine Coital Exanthema

Equid alphaherpesvirus 3 (EHV-3) is the etiological agent of equine coital exanthema (ECE). Because no vaccines or antiviral therapies are available, prevention consists of clinical examination of mares and stallions before mating or semen collection and resting from breeding activities when lesions are present. However, this methodology does not identify subclinically infected animals. Ganciclovir is the most potent compound known to reduce EHV-3 replication. This study aimed to evaluate the efficacy of topical ganciclovir application to reduce EHV-3 replication in experimentally infected mares. A pilot study, after a double-blind completely randomized design, was carried out. Twenty mares were randomly divided into five groups (three treated with ganciclovir with different regimen of doses, one treated with a placebo, and one nontreated). Mares were experimentally infected with EHV-3 on day 0. Rectal temperature, clinical signs, and lesions were recorded. Daily perineal and vaginal swabs were evaluated by quantitative polymerase chain reaction for virus detection. The antibody response was assessed by a virus neutralization test in serum samples collected weekly. Mares experimentally infected with EHV-3 and treated with ganciclovir twice a day for 13 days showed reduced levels and duration of viral excretion and less severe lesions. The viral excretion period was reduced from 18 to nine days compared with the untreated groups. We concluded that ganciclovir had an antiviral effect on EHV-3 replication when topically administered in mares showing clinical signs of ECE. Further trials should be performed to optimize the dose of the antiviral for a definitive formulation.     

Effects of Topical Application of Sunflower-Seed Oil on Experimentally Induced Wounds in Horses

The objectives were to evaluate clinical and histopathological aspects of topical application of sunflower-seed oil (Helianthus annuus) on the healing process of experimentally induced wounds in lumbar and metacarpal areas of healthy horses. Six adult horses were used. Eight wounds were surgically produced on each horse: two 6.25-cm² wounds cranial to the sacrum on each side of the lumbar region and two 2.89-cm² wounds close to the proximal epiphysis of the metacarpus on the lateral aspect of each forelimb. Left side was used for macroscopic observations and right side for histopathological analysis. The experimental lesions were treated daily with sunflower-seed oil, whereas saline solution was used in control lesions. Macroscopic and histopathological analyses were performed on tissue harvested at 3, 7, 14, and 21 days. Complete healing time for all wounds was recorded. For lumbar region’s wounds, a contraction of 90.78% was recorded for those treated with oil and of 79.27% for control wounds after 21 days of treatment. For metacarpal region’s wounds, a contraction of 47.63% was recorded for wounds treated with oil and of 30.21% for control wounds. Wounds in the sunflower-seed oil treatment group had an elevation of polymorphonuclear cells, a newly formed vascular bed during the inflammatory phase, and a better alignment of collagen fibers during the remodeling phase. In conclusion, topical application of sunflower-seed oil was beneficial in the healing process of experimentally induced skin wounds in horses, with best results for treatment of lumbar wounds, making it a therapeutic option in equine wound healing.     

Effects of Repeated Embryo Collection on Embryo Recovery Rate in Fertile Mares

In mares, repeated embryo collection in successive oestrous cycles is necessary if a greater number of foals should be produced. We investigated effects of repeated embryo collection in fertile donor mares on embryo recovery rates. In addition, an influence of the individual mare and season on embryo recovery rates was studied. In nine mares, a total of 153 embryo collections were performed during 30 months (17 ± 2.2 embryo collections per mare). The overall embryo recovery rate was 64% and did not differ among mares. Between successive embryo collection procedures, recovery rate varied significantly; however, no increase or decrease in the embryo recovery rate with increasing number of successive embryo collections was seen. In three mares, ovulation ceased from November to February. In the remaining six mares, embryo production was successfully continued throughout winter and no influence of the month on embryo recovery rates was detected.     

Distribution of Eosinophils and Mast Cells in the Cervical Tissue of Non-Gravid Mares during Dioestrus

Little is known about the local cellular immune system of the equine cervix. In this study we characterize the distribution of eosinophilic granulocytes and mast cells in the cervical tissue of non-gravid mares during dioestrus. For this purpose cervices of 10 mares were histologically examined after Sirius red and Toluidine blue staining. Both cell types could be found in the lamina propria mucosae. In the tunica muscularis the two cell populations were only rarely detected. No cells could be found in the epithelium mucosae. There was a decreasing cell density from the vaginal to uterine side of the cervix (p < 0.01). Therefore, eosinophils might be a part of the local cellular immune system of the equine cervix during dioestrus, unlike in animals studied so far as cows and rats.     

Hyperleptinemia in Mares: Prevalence in Lactating Mares and Effect on Rebreeding Success

Previous research from our laboratory showed that approximately one third of obese, nonfoaling mares displayed a condition of hyperleptinemia coupled with hyperinsulinemia that resembled type 2 diabetes in humans. The current study was performed to evaluate the prevalence of the hyperleptinemic syndrome in lactating mares and its possible impact on their rebreeding success. Additionally, we investigated possible relationships between leptin levels in lactating versus nonlactating mares. In experiment 1, jugular blood samples were collected from 198 lactating mares on two occasions approximately 2 weeks apart. The mares resided on eight farms in Louisiana; breeds included Thoroughbred (n = 86), Quarter Horse (n = 71), Warmblood (n = 24), and draft-type (n = 17). Body condition scores (BCS) were measured at the time of blood sampling; plasma samples were assessed for leptin and progesterone concentrations. Reproductive and medical histories, as well as feeding regimens, were compiled on each mare. Based on our previous reports and examination of the current data, a mare was considered hyperleptinemic if her plasma samples contained greater than10 ng/mL leptin; normal was considered 6.0 ng/mL or less; mares with levels above 6.0 and 10 ng/mL or greater were classified as intermediate. Overall mean leptin concentration was 4.7 ng/mL, and average BCS was 5.5. After analysis, 24 mares were classified as hyperleptinemic (12%), 138 were classified as normal (70%), and 36 were classified as intermediate (18%). Leptin concentrations were affected by BCS (P = .08), with higher concentrations in mares with higher body condition; however, there were hyperleptinemic mares with BCS of 4 to 5.5. Feeding regimen affected leptin concentrations (P < .01), with mares on pasture full-time having the highest concentrations. There was no effect of breed, mare age, number of years the mare had been bred, number of live foals, progesterone concentrations, or last foaling date on leptin concentrations. Rebreeding success averaged 81% overall and was not affected by leptin classification. In experiment 2, nonfoaling mares kept on pasture had mean leptin concentrations of 7.0 ng/mL; 8 of 31 mares (26%) displayed hyperleptinemia. Mean leptin concentration was correlated with BCS (R² = 0.65; P < .02) but was not affected by age of the mare. It was concluded that the hyperleptinemic condition occurs in lactating broodmares, even at BCS as low as 4. The overall incidence appears to be lower in broodmares than in nonfoaling mares, likely because of their lower BCS in general and the energy demands of lactation. Hyperleptinemia did not affect rebreeding success at the end of the breeding season.     

Effects of Epinephrine,Detomidine, and Butorphanol on Assessments of Insulin Sensitivity in Mares

Sympathoadrenal stimulation may perturb results of endocrine tests performed on fractious horses. Sedation may be beneficial; however, perturbation of results may preclude useful information. Four experiments were designed to 1) determine the effects of epinephrine on insulin response to glucose (IR2G), 2) assess the effects of detomidine (DET), alone or combined with butorphanol (DET/BUT), on IR2G and glucose response to insulin (GR2I), and 3) assess the effects of BUT alone on IR2G. In Experiment 1, mares were administered saline or epinephrine (5 μg/kg BW) immediately before infusion of glucose (100 mg/kg BW). Glucose stimulated (P < .05) insulin release in controls at 5 minutes that persisted through 30 minutes; insulin was suppressed (P < .05) by epinephrine from 5 to 15 minutes, rising gradually through 30 minutes. Experiments 2 (IR2G) and 3 (GR2I) were conducted as triplicated 3 × 3 Latin squares with the following treatments: saline (SAL), DET, and DET/BUT (all administered at .01 mg/kg BW). Glucose stimulated (P < .05) insulin release that persisted through 30 minutes in SAL mares; DET and DET/BUT severely suppressed (P < .0001) the IR2G. Sedation did not affect resting glucose and had inconsistent effects on the GR2I when mares were treated with 50 mIU/kg BW recombinant human insulin. Butorphanol had no effect on IR2G. In conclusion, adrenergic agonists severely suppress the IR2G and cannot be used for sedation for this test. The use of DET did not alter the GR2I, and therefore may be useful for conducting this test in fractious horses.     

The Effects of Treatment with N-Acetyl Cysteine on Clinical Signs in Persistent Breeding-Induced Endometritis Susceptible Mares

Persistent breeding-induced endometritis (PBIE) is a major cause of infertility in mares. Endometrial inflammation that persists until embryonic descent ultimately results in early embryonic death. A poor endometrial biopsy grade (IIb or III) has been identified as a risk factor for PBIE. Intrauterine fluid accumulation (>2 cm in depth), pathologic endometrial edema, and elevated intrauterine neutrophil levels are all clinical features of PBIE. Commonly applied treatment options include uterine lavage and oxytocin therapy. N-acetyl cysteine (NAC), a mucolytic used to treat bacterial endometritis in mares, has anti-inflammatory properties and was investigated as a potential treatment for PBIE. A randomized, blinded, cross-over design clinical trial used NAC before breeding in PBIE-susceptible mares (n = 9). Intrauterine infusion of 3.3% NAC was performed 12 hours before insemination, and endometrial cytology and endometrial biopsy samples were obtained at 12 and 60 hours after insemination. Endometrial biopsies were evaluated for the degree of inflammation present. Clinical signs of endometrial edema and intrauterine fluid volumes were assessed by transrectal ultrasound at 12 and then every 24 hours after breeding. Data were analyzed using repeated measures analysis of variance and a Mann Whitney Wilcoxon Test. Treatment with NAC did not improve clinical signs in PBIE-affected mares. However, endometrial biopsies from mares treated with NAC displayed more diffuse and severe neutrophil infiltration than control cycles. Further research using a larger population of mares is required to evaluate the effects of NAC treatment on the endometrium of PBIE-susceptible mares.     

不同日粮蛋白能量水平对伊犁马产奶性能和乳成分的影响

试验采用2因子4水平饱和D-最优回归设计以研究日粮粗蛋白和消化能对伊犁马泌乳后期产奶量、乳成分的影响,通过响应曲面回归分析获得伊犁马泌乳后期适宜粗蛋白和消化能的需要量.选取年龄11～12周岁、体重410 kg±30 kg、胎次4～5胎,处于第3泌乳月的伊犁马30匹,随机分为6个试验组,每组5个重复.单栏定量饲养,分别饲以6种不同DE和CP水平的日粮,试验期60 d.试验结果显示,随着粗蛋白和消化能摄入的增加,日估计产奶量逐渐增加,其中以日粮4组（CP 1 352 g/d,DE 25.5 Mcal/d）最大,为8 156 mL/d.日粮4组的乳脂率、乳蛋白率、锌、锰在各组中最高,分别为0.99％、1.77％、1.12 μg/mL和28.96 ng/mL,而体细胞数和磷最少,分别为10.60×10^3个/mL和0.32 mg/mL.乳糖、总固体物、钙和铜含量在各组间均无显著差异（P＞0.05）.日产奶量与粗蛋白和消化能的回归关系为：日产奶量（mL/d）=-1.052 1×10^5 ＋581.678 3×DE＋116.6012×CP-0.111 0×DE×CP-0.037 2×CP^2-1.958 5×DE^2 （P＜0.05）.研究结果提示：DE和CP日摄入量影响处于泌乳后期伊犁马的产奶量和乳成分,400 kg体重伊犁马泌乳后期DE和CP的适宜需要量分别为108.05MJl/d和1 419.32g/d.     

Effects of Neodymium:Yttnum Aluminum Garnet Laser Irradiation on Endometrium and on Endometrial Cysts in Six Mares

Effects of neodymium:yttrium aluminum garnet (Nd:YAG) laser irradiation on equine endometrium were evaluated In vitro and in six mares with endometrial cysts. The Nd:YAG laser was applied to six endometrial sites, in each of five uterine specimens, with power densities of 5659 to 33,954 J/cm². Depth of tissue ablation was measured and graded on histologic sections of the tissue lesions. Power density had a significant effect on the depth of tissue ablation (p < .001). Grade 3 lesions (full-thickness ablation of the endometrium) were created with energy densities of 16,977 to 33,954 J/cm². Six mares had endometrial cysts treated by photoablation. Two of the four mares that were reproductively sound but barren, despite appropriate breeding, produced foals after treatment. One mare remained reproductively unsound after treatment, and another mare that was treated postpartum was bred successfully.     

Pharmacokinetics of Selamectin in Dogs after Topical Application

Some pharmacokinetic parameters of selamectin were determined in male (n = 5) and female (n = 5) Beagle dogs following a topical application at a dose rate of 6 mg/kg. The plasma concentration versus time data for the drug were analysed using a one-compartment model. The maximum plasma concentrations of 12.72 +/- 5.13 ng/ml for males and 22.65 +/- 11.95 ng/ml for females occurred around 5 days after administration. The area under the concentration-time curve (AUC) was 192.08 +/- 63.85 ng.day/ml for males and 370.97 +/- 146.87 ng.day/ml for females. The mean residence time was the same in males and females (12.55 days). This study reveals a sex-influence on the disposition of selamectin in the plasma of dogs, which implies that further information will be needed for correlation with efficacy studies in dogs.     

Effects of Intrauterine Devices in Mares: A Histomorphological and Immunohistochemical Evaluation of the Endometrium

Oestrous suppression by intrauterine devices (IUDs) is caused by prolongation of luteal function, but the biological mechanism is unknown. The aim of the study was to investigate mechanisms which could explain the action of IUDs. Thirty mares were age‐matched and either inseminated (AI, n = 15) or fitted with an IUD (IUD, n = 15) and subsequently divided into four groups: AI‐P, pregnant (n = 8); AI‐N, non‐pregnant (n = 7); IUD‐P, prolonged luteal phase (n = 7); and IUD‐N, normal luteal phase (n = 8). The median ages were 5.5 and 7 years in AI‐P and IUD‐P groups and 14 and 11 years in AI‐N and IUD‐N groups, respectively. On Day 15 after ovulation, an endometrial biopsy was obtained to study histomorphological and immunohistochemical expression patterns of uterine proteins (uteroferrin, UF; uterocalin, UC; uteroglobin, UG), oestrogen and progesterone receptors (ER, PR), proliferation marker Ki‐67 and content of inflammatory cells. Expression of UF was higher in IUD mares; the difference between pregnant and IUD‐P mares was significant. Mares exhibiting a prolonged luteal phase (AI‐P, IUD‐P) showed only mild angiosclerosis and lower expression of both ER and PR than mares with a normal luteal phase (AI‐N, IUD‐N). No significant differences were detected in the numbers of inflammatory cells, with the exception of macrophages, which were more numerous in AI‐P than AI‐N mares. Although inflammatory cells were not detected in IUD mares, increased UF levels may indicate chronic inflammation. Young age and normality of the endometrial blood vessels may improve the efficacy of IUDs.     

Reproductive Performance of Thoroughbred Mares in Sweden

During 1997–2001, a total of 430 Thoroughbred mares were mated by one of the two Thoroughbred stallions on a well‐managed stud farm in the central part of Sweden. On arrival, a thorough gynaecological examination of all mares was performed. An early pregnancy examination was performed on days 14 and 15 after ovulation. The overall conception rates for the two stallions were 92.2 and 88.8%, and the corresponding live foal rates were 82.6 and 75.2%, respectively. The mean number of served oestrous cycles was 1.60 per mare per conception and 1.86 per live foal. The first and second cycle conception rates are reported for different age groups, mare categories and month of mating. The age of the mares had a significant influence on the live foal rate, being lower for mares >13 years of age. Resorption and abortion occurred in higher percentages among mares >8 years of age. The highest embryonic death occurred among mares with a history of being barren, or with having resorbed or aborted foetuses during the previous season. The month of mating had no significant influence on the first cycle conception rate or the second cycle conception rate. The frequency of twinning was 10.5% and the results of manual crushing of one of the conceptuses was successful in 88.9% of all cases, according to the ultrasound scanning 2 days later.     

Evaluation of Single-Incision Laparoscopic Ovariectomy in Standing Mares

Our objective was to compare the invasiveness of single-incision laparoscopic surgery (SILS) and multiport laparoscopic surgery (MLS) for ovariectomy in 5 standing healthy adult Thoroughbred mares. First, laparoscopic ovariectomy was performed by SILS or by MLS on the right paralumbar fossa region in a standing mare. One month after surgery, ovariectomy by the other method was performed on the left side. For surgery evaluation, the surgical time, length of incision, and amount of lidocaine used were recorded and compared between SILS and MLS. Physical examination (body temperature, heart rate, and respiration rate) and hematology (number of leukocytes and hematocrit) were performed before surgery and every day for 7 days after surgery. Similarly, the degrees of swelling, heat, pain, and incisional wound healing were evaluated (grades1-4). The length of incision and amount of local anesthetic for SILS were significantly less than those for MLS. Moreover, the scores for swelling, heat, and pain in the SILS group tended to be lower than those in the MLS group for several days after surgery. We concluded that SILS was less invasive than MLS and is therefore useful for ovariectomy in mares.