Effect of Sampling Method on Detection of the Equine Uterine Microbiome during Estrus

Bacterial endometritis is among the most common causes of subfertility in mares. It has a major economic impact on the equine breeding industry. The sensitivity of detecting uterine microbes using culture-based methods, irrespective of the sample collection method, double-guarded endometrial swab, endometrial biopsy, or uterine low-volume lavage (LVL), is low. Therefore, equine bacterial endometritis often goes undiagnosed. Sixteen individual mares were enrolled, and an endometrial sample was obtained using each method from all mares. After trimming, quality control and decontamination, 3824 amplicon sequence variants were detected in the dataset. We found using 16S rRNA sequencing that the equine uterus harbors a distinct resident microbiome during estrus. All three sampling methods used yielded similar results in composition as well as relative abundance at phyla (Proteobacteria, Firmicutes, and Bacteroidota) and genus (Klebsiella, Mycoplasma, and Aeromonas) levels. A significant difference was found in alpha diversity (Chao1) between LVL and endometrial biopsy, suggesting that LVL is superior at detecting the low-abundant (rare) taxa. These new data could pave the way for innovative treatment methods for endometrial disease and subfertility in mares. This, in turn, could lead to more judicious antimicrobial use in the equine breeding industry.

Transcriptome Signature of Immature and In Vitro-Matured Equine Cumulus-Oocytes Complex

Maturation is a critical step in the development of an oocyte, and it is during this time that the oocyte advances to metaphase II (MII) of the meiotic cycle and acquires developmental competence to be fertilized and become an embryo. However, in vitro maturation (IVM) remains one of the limiting steps in the in vitro production of embryos (IVP), with a variable percentage of oocytes reaching the MII stage and unpredictable levels of developmental competence. Understanding the dynamics of oocyte maturation is essential for the optimization of IVM culture conditions and subsequent IVP outcomes. Thus, the aim of this study was to elucidate the transcriptome dynamics of oocyte maturation by comparing transcriptomic changes during in vitro maturation in both oocytes and their surrounding cumulus cells. Cumulus-oocyte complexes were obtained from antral follicles and divided into two groups: immature and in vitro-matured (MII). RNA was extracted separately from oocytes (OC) and cumulus cells (CC), followed by library preparation and RNA sequencing. A total of 13,918 gene transcripts were identified in OC, with 538 differentially expressed genes (DEG) between immature OC and in vitro-matured OC. In CC, 13,104 genes were expressed with 871 DEG. Gene ontology (GO) analysis showed an association between the DEGs and pathways relating to nuclear maturation in OC and GTPase activity, extracellular matrix organization, and collagen trimers in CC. Additionally, the follicle-stimulating hormone receptor gene (FSHR) and luteinizing hormone/choriogonadotropin receptor gene (LHCGR) showed differential expressions between CC-MII and immature CC samples. Overall, these results serve as a foundation to further investigate the biological pathways relevant to oocyte maturation in horses and pave the road to improve the IVP outcomes and the overall clinical management of equine assisted reproductive technologies (ART).

Embryo Pulsing: Repeated Expansion and Contraction of In Vivo and In Vitro Equine Blastocysts

Morphokinetic evaluation of embryo development has allowed the discovery of events occurring during blastulation. Here, we describe equine embryo pulsing, determined as continued expansion and contraction of both in vivo and in vitro produced blastocysts. Using time-lapse imaging, we demonstrated that pulsing starts during early blastocyst development of in vitro-produced embryos in horses. The median time for a complete contraction was 0.22h (0.08h-2h; min-max) where embryos reduced their sizes around 12.0% (median; 2.3%-27.0%) and the median time for an expansion was 3.3h (0.75-9.0h) where embryo re-expanded around 16.9% (3.2%-42.8%). We also found that pulsing can be observed in in vivo-produced embryos obtained from mares 6.5 days after ovulation and continues during the expansion of the blastocysts. Even though its exact mechanism remains unknown, studies in human IVF suggest that the pulsing of embryos is associated with embryo quality and implantation rates. Thus, further investigations regarding this event in equine in vitro production procedures are warranted. Additionally, the pulsing in the in vivo-produced embryos could explain the diverse morphology occasionally observed in the collected or shipped embryos. Future studies are necessary to understand the underlying mechanism of pulsing and its association with embryo quality and embryo transfer outcome.

Characterization of the equine placental microbial population in healthy pregnancies

In spite of controversy, recent studies present evidence that a microbiome is present in the human placenta. However, there is limited information about a potential equine placental microbiome. In the present study, we characterized the microbial population in the equine placenta (chorioallantois) of healthy prepartum (280 days of gestation, n = 6) and postpartum (immediately after foaling, 351 days of gestation, n = 11) mares, using 16S rDNA sequencing (rDNA-seq). In both groups, the majority of bacteria belonged to the phyla Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidota. The five most abundant genera were Bradyrhizobium, an unclassified Pseudonocardiaceae, Acinetobacter, Pantoea, and an unclassified Microbacteriaceae. Alpha diversity (p < 0.05) and beta diversity (p < 0.01) were significantly different between pre- and postpartum samples. Additionally, the abundance of 7 phyla and 55 genera was significantly different between pre- and postpartum samples. These differences suggest an effect of the caudal reproductive tract microbiome on the postpartum placental microbial DNA composition, since the passage of the placenta through the cervix and vagina during normal parturition had a significant influence on the composition of the bacteria found in the placenta when using 16S rDNA-seq. These data support the hypothesis that bacterial DNA is present in healthy equine placentas and opens the possibility for further exploration of the impact of the placental microbiome on fetal development and pregnancy outcome.

Dynamics of the Equine Placental DNA Methylome and Transcriptome from Mid- to Late Gestation

The placenta is a temporary organ that is essential for the survival of the fetus, with a lifelong effect on the health of both the offspring and the dam. The functions of the placenta are controlled by its dynamic gene expression during gestation. In this study, we aimed to investigate the equine placental DNA methylome as one of the fundamental mechanisms that controls the gene expression dynamic. Chorioallantois samples from four (4M), six (6M), and ten (10M) months of gestation were used to map the methylation pattern of the placenta. Globally, methylation levels increased toward the end of gestation. We identified 921 differentially methylated regions (DMRs) between 4M and 6M, 1225 DMRs between 4M and 10M, and 1026 DMRs between 6M and 10M. A total of 817 genes carried DMRs comparing 4M and 6M, 978 comparing 4M and 10M, and 804 comparing 6M and 10M. We compared the transcriptomes between the samples and found 1381 differentially expressed genes (DEGs) when comparing 4M and 6M, 1428 DEGs between 4M and 10M, and 741 DEGs between 6M and 10M. Finally, we overlapped the DEGs and genes carrying DMRs (DMRs-DEGs). Genes exhibiting (a) higher expression, low methylation and (b) low expression, high methylation at different time points were identified. The majority of these DMRs-DEGs were located in introns (48.4%), promoters (25.8%), and exons (17.7%) and were involved in changes in the extracellular matrix; regulation of epithelial cell migration; vascularization; and regulation of minerals, glucose, and metabolites, among other factors. Overall, this is the first report highlighting the dynamics in the equine placenta methylome during normal pregnancy. The findings presented serve as a foundation for future studies on the impact of abnormal methylation on the outcomes of equine pregnancies.

Slow cooling is beneficial for storage of frozen-thawed equine spermatozoa

Cooled storage of semen after thawing can expand the use of frozen semen, providing the possibility of thawing and evaluating the semen at the storage site and subsequently shipping the semen. Our objectives were (1) to examine the motility and viability of frozen-thawed semen after cooled storage and (2) to compare two cooled-storage protocols for frozen-thawed semen. The samples (n=31) were either placed immediately in a passive cooling box for 8 or 24h (CB) or placed in a refrigerator at 4°C for 30 minutes and then transferred to a passive cooling box (REF). Total and progressive motility were similar at T0 and T8-REF and at T0.5 and T8.5-REF. However, a significant reduction was observed in total motility (-8.12%) between T0 and T8-CB, and in total (-9.96%) and progressive motility (-8.52%) between T0.5 and T8.5-CB (p<0.05). A significant reduction was also observed in total and progressive motility between T0 and T24, and between T0.5 and T24.5 for both storage protocols (CB and REF). Viability was lower in T8.5-CB (-11.87%), in T8.5-REF (-9.65%), in T24.5-CB (-13.52%), and in T24.5-REF (-12.32%) compared to T0.5 (p<0.05). Our results demonstrate that sperm motility and viability decrease during cooled storage. However, storing the samples at 4°C for 30 minutes before placing the semen in a passive cooling box could mitigate the adverse effect of cooling during short-term storage (8hr). Additionally, we observed individual variation between samples indicating that this protocol might not be suitable for all stallions. Our data shows that slow cooling and storage of frozen-thawed semen is a valid alternative that allows the expansion of frozen semen in breeding programs.

Parental bias in expression and interaction of genes in the equine placenta

Most autosomal genes in the placenta show a biallelic expression pattern. However, some genes exhibit allele-specific transcription depending on the parental origin of the chromosomes on which the copy of the gene resides. Parentally expressed genes are involved in the reciprocal interaction between maternal and paternal genes, coordinating the allocation of resources between fetus and mother. One of the main challenges of studying parental-specific allelic expression (allele-specific expression [ASE]) in the placenta is the maternal cellular remnant at the fetomaternal interface. Horses (Equus caballus) have an epitheliochorial placenta in which both the endometrial epithelium and the epithelium of the chorionic villi are juxtaposed with minimal extension into the uterine mucosa, yet there is no information available on the allelic gene expression of equine chorioallantois (CA). In the current study, we present a dataset of 1,336 genes showing ASE in the equine CA (https://pouya-dini.github.io/equine-gene-db/) along with a workflow for analyzing ASE genes. We further identified 254 potentially imprinted genes among the parentally expressed genes in the equine CA and evaluated the expression pattern of these genes throughout gestation. Our gene ontology analysis implies that maternally expressed genes tend to decrease the length of gestation, while paternally expressed genes extend the length of gestation. This study provides fundamental information regarding parental gene expression during equine pregnancy, a species with a negligible amount of maternal cellular remnant in its placenta. This information will provide the basis for a better understanding of the role of parental gene expression in the placenta during gestation.

Paternally expressed retrotransposon Gag-like 1 gene, RTL1, is one of the crucial elements for placental angiogenesis in horses†

RTL1 (retrotransposon Gag-like 1) is an essential gene in the development of the human and murine placenta. Several fetal and placental abnormalities such as intrauterine growth restriction (IUGR) and hydrops conditions have been associated with altered expression of this gene. However, the function of RTL1 has not been identified. RTL1 is located on a highly conserved region in eutherian mammals. Therefore, the genetic and molecular analysis in horses could hold important implications for other species, including humans. Here, we demonstrated that RTL1 is paternally expressed and is localized within the endothelial cells of the equine (Equus caballus) chorioallantois. We developed an equine placental microvasculature primary cell culture and demonstrated that RTL1 knockdown leads to loss of the sprouting ability of these endothelial cells. We further demonstrated an association between abnormal expression of RTL1 and development of hydrallantois. Our data suggest that RTL1 may be essential for placental angiogenesis, and its abnormal expression can lead to placental insufficiency. This placental insufficiency could be the reason for IUGR and hydrops conditions reported in other species, including humans.

A retrospective study on semen quality parameters from four different Dutch horse breeds with different levels of inbreeding

A high degree of inbreeding has been reported to negatively impact semen quality in Friesian horses and Shetland ponies. Both breeds are characterized by a closed studbook, small population size, and high incidence of inbreeding. The Dutch Warmblood studbook (KWPN: Koninklijk Warmblood Paardenstamboek Nederland) is a much larger studbook with two distinct populations: the KWPN-Riding horses, managed as an 'open' studbook, and the KWPN-Harness horses, representing a much smaller subpopulation within the KWPN breed and managed as an 'almost closed' studbook. It was recently reported that the degree of inbreeding in KWPN-Harness horses has increased in recent decades due to the small gene pool; however, the degree of inbreeding is still lower than that of Friesian horses and Shetland ponies. We hypothesized that a high or rising degree of inbreeding might negatively impact semen quality. In the present study, we retrospectively compared semen quality parameters of stallions from four different breeds or types (Friesian Horses, Shetland Ponies, KWPN-Riding horses, and KWPN-Harness horses), each reported with different degrees of inbreeding. Semen concentration, and percentages of motile, morphologically normal and live spermatozoa, and the total number of morphologically normal, progressive motile spermatozoa per ejaculate (TNM) were analyzed for 2832 semen evaluations performed over a 15-year period. KWPN-Harness horses had a significantly lower sperm concentration, % motile spermatozoa and % live spermatozoa than KWPN-Riding horses but the % motile and % morphologically normal spermatozoa and TNM in both KWPN-Harness and KWPN-Riding horses were significantly higher than in Friesian horses and Shetland ponies. These results suggest a lower semen quality in KWPN-Harness than KWPN-Riding horses, potentially as a result of a higher coefficient of inbreeding. The negative trend observed in the KWPN-Harness horses may be a warning sign, and breeders or stud books should monitor the degree of inbreeding carefully to avoid a further reduction in semen quality, to the levels observed in Friesian horses and Shetland ponies.

Validation of a portable device (iSperm® ) for the assessment of stallion sperm motility and concentration

The objective of this study was to evaluate the accuracy of a novel, portable device (iSperm^® Equine for assessing concentration and motility of stallion semen). In the first experiment, semen concentration was determined by the iSperm^® Equine (Aidmics Biotechnology), Androvision^® (Minitube) and NucleoCounter^® SP-100™ (ChemoMetec). The total motility and progressive motility were determined by the iSperm^® Equine and the Androvision^® using the manufacturer's guidelines. Frozen/thawed semen samples (n = 33) at various dilutions were analysed for concentration and motility with the above-mentioned devices. There was a significant correlation between the concentrations measured with iSperm^® and NucleoCounter^® at all the measured dilutions. Moreover, <10% difference in concentrations was observed between the iSperm^® and NucleoCounter^® using the Bland-Altman test. There was also a significant correlation between iSperm^® and Androvision^® for total and progressive motility. In the second experiment, the parameters used in the Androvision^® were modified to match those of the iSperm^® . Total motility and progressive motility of frozen/thawed semen samples (n = 10) were determined, and the similarity between the Androvision^® and iSperm^® was confirmed by correlation studies and Bland-Altman test. The results of these experiments demonstrate that the iSperm^® offers a reliable and practical alternative for the semi-automated measurement of concentration and motility of stallion semen in the field. The iSperm^® enables the practitioner to obtain objective and repeatable measurements on a variety of semen types (fresh, cooled and frozen) in the field at the time of insemination and thus acquire more insight into the quantity and quality of the provided insemination doses. This mare-side diagnostic tool may help practitioners in identifying presumed subfertility problems more rapidly and act accordingly.

Effect of environmental factors and changes in the body condition score on the onset of the breeding season in mares

Several methods have been proposed to advance the onset of the breeding season in horses. Most of them are based on the exposure to an artificial lighting period combined with hormonal treatments. Mares exposed to an artificial photoperiod are most often housed indoors where the ambient temperature is often higher than the outside temperature. Mares held in barns are also exposed to different daylight intensities than horses kept outside, depending on the architecture. In the current study, we evaluated the impact of ambient temperature, daylight intensity and changes in body condition score (BCS) on the timing of first ovulation after winter anestrus in mares exposed to an artificial photoperiod. Mares (n = 211) were housed in barns with different ambient temperature and daylight exposure but with the same artificial photoperiod exposure (except for a natural photoperiod control group). Artificial photoperiod as well as an increase in BCS over the winter significantly advanced the first spring ovulation. The BCS at the start and end of the anestrus period did not have an effect on the interval to first ovulation and neither did the modest increase in ambient temperature in the barn. However, a higher light intensity during the daytime significantly advanced the first spring ovulation. The results of this study suggest that exposure to more sunlight advances the onset of the breeding season. This effect is likely mediated through the biological effect of short wavelength blue light and its impact on melatonin suppression and biological rhythms. We suggest that greater/direct exposure to the blue light component of daylight improves the response to the artificial photoperiod. The results of the present study can further assist to optimize the conditions that lead to an efficient spring transition of breeding mares.

Extraction of RNA from formalin-fixed, paraffin-embedded equine placenta

Archived formalin-fixed, paraffin-embedded (FFPE) samples represent a valuable resource for the determination of gene expression for physio/pathological conditions. In the present study, we validated a protocol for the extraction of RNA from FFPE samples collected from healthy and diseased equine placenta. The quality and quantity of the extracted RNA from the FFPE and matching RNAlater™-preserved samples and expression levels of common housekeeping genes and reference microRNAs were evaluated. Precision of the expression data was evaluated by comparing relative expression of CYP19A1 and HSD3B1 in FFPE and RNAlater™ samples. The median RNA concentration recovered from FFPE samples was 316.8 ng/mm³ of tissue (ranging between 61.6 and 917.4 ng/mm³ ), average RNA integrity number was 2.3 ± 0.9 (mean ± standard deviation), and 84% of samples had RNA fragments longer than 200 nucleotides (DV₂₀₀ ). RNA concentrations and C_T values for GAPDH, ACTB, miR-8908a and miR-369 in FFPE samples were significantly correlated (r = -0.8, -0.7, -0.4 and -0.4, respectively; p < 0.001). Expression pattern of normalized CYP19A1 and HSD3B1 in paired FFPE and RNAlater™ samples was significantly correlated (r = 0.97 for CYP19A1 and HSD3B1; p < 0.001). This study demonstrates that RNA can be extracted from FFPE equine placental tissue and used for downstream transcriptomic analysis. Similar RNA expression patterns were obtained using RNAlater™ and FFPE tissue samples.

Kinetics of the chromosome 14 microRNA cluster ortholog and its potential role during placental development in the pregnant mare

Background

The human chromosome 14 microRNA cluster (C14MC) is a conserved microRNA (miRNA) cluster across eutherian mammals, reported to play an important role in placental development. However, the expression kinetics and function of this cluster in the mammalian placenta are poorly understood. Here, we evaluated the expression kinetics of the equine C24MC, ortholog to the human C14MC, in the chorioallantoic membrane during the course of gestation.

Results

We demonstrated that C24MC-associated miRNAs presented a higher expression level during early stages of pregnancy, followed by a decline later in gestation. Evaluation of one member of C24MC (miR-409-3p) by in situ hybridization demonstrated that its cellular localization predominantly involved the chorion and allantoic epithelium and vascular endothelium. Additionally, expression of predicted target transcripts for C24MC-associated miRNAs was evaluated by RNA sequencing. Expression analysis of a subset of predicted mRNA targets showed a negative correlation with C24MC-associated miRNAs expression levels during gestation, suggesting the reciprocal control of these target transcripts by this miRNA cluster. Predicted functional analysis of these target mRNAs indicated enrichment of biological pathways related to embryonic development, endothelial cell migration and angiogenesis. Expression patterns of selected target mRNAs involved in angiogenesis were confirmed by RT-qPCR.

Conclusion

This is the first report evaluating C24MC kinetics during pregnancy. The findings presented herein suggest that the C24MC may modulate angiogenic transcriptional profiles during placental development in the horse.

Electronic supplementary material

The online version of this article (10.1186/s12864-018-5341-2) contains supplementary material, which is available to authorized users.

209 MATURATION KINETICS AFTER HOLDING EQUINE OOCYTES IN EMBRYO HOLDING MEDIUM

It has been reported that immature, equine oocytes can be maintained in meiotic arrest at 24°C. To evaluate a commercial equine embryo holding medium for storage of equine oocyte at 24°C and to determine the effect of holding on maturation kinetics, cumulus‐oocyte complexes (COC) were recovered from slaughtered mares and placed in Syngro® Embryo Holding Solution at 22–25°C for 18–20 h (OH Group) or placed directly in DMEM-F12-based in vitro maturation (IVM) conditions (D-Mat Group) at 5% CO2 in air at 38.5°C. Maturation rate (metaphase II percentage; MII%) was assessed (presence of polar body under stereomicroscope) after denudation at 22, 24, and 28 h. After assessment, the denuded oocytes that were considered immature were placed back in IVM, reassessed at 24 and 28 h, and MII% was compared with that of oocytes remaining uninterrupted in IVM for 24 and 28 h. One-way ANOVA was used to compare dependent variable in different groups using PROC ANOVA (SAS, version 9.2, SAS Institute, Cary, NC, USA). A random selection of mature oocytes from both groups were fertilised using intracytoplasmic sperm injection (ICSI). A total of 250 injected oocytes were cultured in DMEM-F12 with 10% FCS. Blastocyst rates in OH and D-mat groups were similar (7.1% v. 6.3%). At 22 h, significantly more oocytes reached the MII stage in the OH group than in the D-Mat group, but MII% was similar in both groups at 24 and 28 h (Table 1). Denuded, immature oocytes reached similar maturation rate as the undenuded oocytes in the same group. Our data suggest that oocytes can be held in Syngro® Embryo Holding Solution at 22–25°C for 18–20 h without compromising oocyte developmental competence. Overnight holding of oocytes accelerates maturation with similar maturation rate at 22, 24, and 28 h of IVM in the OH group. Denudation of immature oocytes after 22 h of IVM and returning the denuded oocytes to IVM does not affect the progression of maturation. In subsequent experiment, overnight held oocytes were fixed and stained (Hoechst 33342) and MII% was evaluated after 20, 22, and 28 h of IVM. Chromatin configuration confirmed that stored oocytes reach the MII stage at 22 h. Maturation rates were significantly lower at 20 h, suggesting that 22 h of IVM is required for stored oocytes. Table 1.Maturation rates (% in MII stage) at 22, 24, and 28 h of IVM for equine oocytes held in Syngro® Embryo Holding Medium before IVM (OH) and oocytes placed directly in IVM (D-Mat) Thanks to I. Lemahieu and P. Van Damme. Study was supported by the Special Research Fund at UGent.

Embryotransplantatie bij het paard: onmisbaar in de moderne fokkerij

Embryotransplantatie bij het paard is een voortplantingstechniek waarbij een embryo van een waardevolle donormerrie wordt uitgespoeld en overgeplant in een draagmerrie. Dit heeft tal van voordelen. Praktisch behelst deze techniek verschillende aspecten. Vooraf dient de cyclus van de draagmerrie gesynchroniseerd te worden met die van de donor. Daarna dient men op het juiste tijdstip het embryo uit de baarmoeder van de drachtige donormerrie te spoelen. Na het opzoeken en wassen van het embryo wordt het ingeplant bij de draagmerrie of receptor. Na de geboorte wordt het veulen nog geruime tijd door de receptor gezoogd. Bij het spoelen van de donormerrie wordt in ongeveer 50% van de gevallen een embryo gecollecteerd en na het overplanten van een embryo wordt uiteindelijk gemiddeld 70% van de receptormerries drachtig. Uiteraard worden deze percentages in de praktijk door verschillende factoren beïnvloed. Deze factoren hebben zowel betrekking op de donor als op de receptor.

Comparison of cell proliferation index in equine and caprine embryos using a modified BrdU incorporation assay

The measurement of cell proliferation and cell viability using 5'bromo-2'deoxy-uridine (BrdU) labelling has been described in several cell types and species. The aim of this study was to adapt this technique to equine embryos and to compare the index of DNA replication (S-phase) between equine and caprine embryos. Seventeen equine embryos were recovered at day 6.5 post-ovulation and 20 caprine embryos were recovered at day 7 after the onset of estrus. Equine embryos were incubated during 1h at 39 degrees C in PBS containing 1mM of BrdU. Embryos were then treated in 0.05% trypsin during 15 min at 39 degrees C to permeabilise the capsule, and then embryos were rinsed in PBS containing 10% of foetal calf serum. After washing, embryos were immediately fixed in 2.5% paraformaldehyde with 0.3M NaOH during 15 min at ambient temperature. The S-phase was detected by immunocytochemistry technique. In caprine embryos, BrdU was visualised by the same technique but without the trypsin treatment. The percentage of cells (+/-S.E.M.) with BrdU incorporated into newly synthesised DNA strands was significantly higher in equine embryos (74+/-1) than in caprine (38+/-2). Our results demonstrated that BrdU incorporation assay can be used in equine embryos. This assay allows the determination of the proliferation index of live cells and could be used as an additional tool for evaluating the viability of embryos. The high percentage of cells incorporating BrdU during 1h of incubation with BrdU suggests that in comparison with the caprine embryos the cellular activity of proliferation is more intense in equine embryos and suggests that the cellular cycle is shorter in equine embryos.

[Giant scrotal lymphedema caused by Milroy's disease]

OBJECTIVES

To report a new case of giant scrotal lymphedema due to Milroy's disease, its treatment and outcome.

METHODS

A 27-year-old man with generalized congenital lymphedema presented with a giant scrotal mass which interfered with his daily activities and physiological necessities. Physical examination showed a scrotal mass 40 x 40 cm in size and a normal penis. CT scan showed a homogeneous mass, thickened vaginal tunica, and bilateral hydrocele.

RESULTS

A surgical procedure was performed including mass resection (5.6 kg), and bilateral hydrocelectomy. Skin defect was covered with skin grafts.

CONCLUSIONS

Several therapeutic alternatives have been suggested for Milroy's disease with genital involvement. Nevertheless, when complications are as severe as in the present case, the only valid therapy is surgery.

Quantitative and qualitative assessment of milk production after pharmaceutical induction of lactation in the mare

The induction of lactation is performed in ruminants by steroidogenic impregnation, followed by drugs intended to increase prolactin secretion. The aim of this study was to induce lactation in barren mares and to evaluate milk production. Five treated and 5 control mares were used in June and September in year 1, and 12 mares were used in year 2. Mares were administered a vaginal pessary (500 mg altrenogest and 50 mg estradiol benzoate) for 1 week. The 2nd week, another sponge with 100 mg estradiol benzoate was administered, together with 50 mg/100 kg body weight (BW) sulpiride in oil (IM q12h). All mares were milked by hand. Drug treatment was stopped after I L was obtained. Milk production and composition and plasma prolactin concentration were measured. In year 2, the same steroid treatment was applied, but mares received sulpiride (n = 6) or domperidone (1.1 mg/kg PO q12h) (n = 6). A milking machine and oxytocin injections 1 minute before the start of milking were used. In year 1, all treated mares started milking within 1-5 days after sulpiride treatment. Mean daily milk production was 0.88 +/- 0.52 L/500 kg BW. Milk immunoglobulin G (IgG) contents increased in all mares (IgG concentration range, 14-92 g/L). Plasma prolactin increased during sulpiride treatment (range. 27.7 +/- 2.9 to 43.7 +/- 6.7 ng/mL [before] to 289.0 +/- 7.8 ng/mL during treatment, P < .001). In year 2, results were similar to those in year 1, with peak IgG concentrations ranging from 4.2 to 106.7 g/L and a larger daily milk production (3.13 +/- 0.75 with sulpiride and 3.45 +/- 0.51 L/500 kg BW with domperidone). In conclusion, lactation can be induced in mares within 2 weeks, and some mares produce good-quality colostrum.

Pure preovulatory follicular fluid promotes in vitro maturation of in vivo aspirated equine oocytes

In the mare, rates of fertilization and development are low in oocytes matured in vitro, and a closer imitation of in vivo conditions during oocyte maturation might be beneficial. The aims of the present study were, therefore, to investigate whether (1) equine oocytes can be matured in vitro in pure equine preovulatory follicular fluid, (2) priming of the follicular fluid donor with crude equine gonadotrophins (CEG) before aspiration of preovulatory follicular fluid promotes the in vitro maturation rate, (3) the in vitro maturation rate differs between oocytes aspirated during estrus and those aspirated again 8 days after the initial follicular aspiration, and (4) high follicular concentrations of meiosis activating sterols (MAS) are beneficial for in vitro maturation of equine oocytes. During estrus, 19 pony mares were treated with 25 mg CEG. After 24 h (Al) and again after 8 days (A2), all follicles >4mm were aspirated and incubated individually for 30 h in the following culture media: standard culture medium (SM), preovulatory follicular fluid collected before CEG containing low MAS concentrations (FF1), preovulatory follicular fluid collected before CEG containing high MAS concentrations (FF2) or preovulatory follicular fluid collected 35 h after administration of CEG containing low MAS concentrations (FF3). Cumulus expansion rate was significantly affected by culture medium. The overall nuclear maturation rate was significantly higher for oocytes collected at A1 (67%) than for oocytes collected at A2 (30%). For oocytes collected at A1, the maturation rates were 71% (FF1), 61% (FF2), 79% (FF3) and 56% (SM). An electrophoretic protein analysis of the culture media revealed the presence of a 200-kDa protein in FF3. The results demonstrate that (1) equine oocytes can be matured during culture in pure equine preovulatory follicular fluid, (2) preovulatory follicular fluid collected after gonadotrophin-priming seems superior in supporting in vitro maturation than standard culture medium, (3) oocytes aspirated 8 days after a previous aspiration are less competent for in vitro maturation than oocytes recovered during the initial aspiration, and (4) the regulation of meiotic resumption during in vitro culture of equine oocytes might be related to the presence of a 200-kDa protein.

Seasonality in mares

In this review, we have attempted to summarize, based on recent data obtained in our laboratory and elsewhere, our current understanding of the regulatory mechanisms of seasonality and discuss the implications with regard to treatment strategies to advance the onset of cyclic reproductive activity in the early spring.

Incidence of spontaneous ovulation in young, group-housed cats based on serum and faecal concentrations of progesterone

Cats are considered to be reflex ovulators that exhibit a luteal phase (pregnancy or pseudopregnancy) only after copulatory stimulation. In a group-housed colony of 15 1-year-old domestic queens, 23 noncopulatory, spontaneous ovulations were observed in 87% of the queens over 4.5 months based upon the detection of increased concentrations of progesterone in faeces, serum, or both. Luteal phases were detectable for periods of 3 to 5 weeks with peak progesterone concentrations averaging 21 +/- 1 ng ml-1 in serum and 1874 +/- 281 ng g-1 in faeces. Individual cats exhibited from 0 to 3 spontaneous ovulations and subsequent pseudopregnancies each. A male was added to a separate cage within the room during the last 1.5 months of the study. The incidence of ovulation per 10 day period ranged from 0% to 22% before introduction of the male and from 33% to 57% immediately after introduction of the male, suggesting a potential noncopulatory influence of the male on the incidence of spontaneous ovulation in young, group-housed cats.