Prevalence of subclinical uterine pathologies diagnosed by biopsy and cytological and bacteriological findings in cyclic bitches.

The study was performed on 45 bitches in different cycle phases that were divided into the following groups: anoestrus (I, n=15), heat (pro-oestrus (n=7) or estrous (n=8) (II, n=15) and metestrus (III, n=15). Moreover, all experimental dogs were grouped according to their age: younger than 5 years (Y, n=35) and older than 5 years (O, n=10). The endometrial status was evaluated using cytological, bacteriological and biopsy samples obtained after ovariohysterectomy. The main uterine pathology diagnosed by biopsy was endometritis, since 40%-66% of bitches, independent of the experimental group, developed this condition. No significant differences were found among the cycle phase groups (p>0.05). By contrast, significant differences were found in the age groups; the prevalence of this pathology was higher in older bitches (p=0.0019). The general prevalence of cystic endometrial hyperplasia (CEH) and a normal endometrium (NE) was lower (6.7-26.7% vs 26.7-53.3%) in all groups, and no statistically significant differences were found between certain groups (p>0.05). The percentage of polymorphonuclear neutrophilic leukocytes (PMNs) in endometrial cytology was generally low (⟨ 2%) and did not differ significantly among the experimental groups (p=0.142). In general, a low degree of correlation was found between the diagnostic results by endometrial cytology and biopsy (Kappa Coefficient= 0.046). Positive bacteriological findings were found in approximately 50% of the bitches, independent of the cycle phase and health status of the endometrium. No correlation was found between the bacteriological and histopathological findings (p=0.883). In conclusion, uterine cytology is not a reliable diagnostic method to detect the subclinical inflammatory and degenerative uterine pathologies in cyclic bitches.

Effect of progesterone-releasing intravaginal device on reproductive performance of cows with cystic ovarian follicles after puerperium.

The aim of the study was to investigate the influence of cystic ovarian follicles (COFs) occurring after puerperium on fertility and the effect of their treatment with progesterone releasing device on reproductive performance in dairy cows. The study was carried out in 3 herds of Polish Holstein-Friesian cows under herd health program. COFs were diagnosed by ultrasound above 60 days p.p. They were defined as follicular structures with a diameter > 2.5 cm in the absence of a corpus luteum at two repeated examinations at the 14-days interval. On the day of COF diagnosis blood samples were collected to measure progesterone (P4) concentration. On the basis of the wall thickness measurement and progesterone concentration at the first examination, the COFs were differentiated into follicular and luteal cysts. The experimental group consisted of 23 animals with COF. The cows were treated with PRID Delta (Ceva Animal Health, Poland), containing 1.55 g of progesterone, for 7 days. The cows without oestrus signs within 14 days after treatment were re-examinated. If COF persisted, the cows were treated again with PRID Delta. The treatment was repeated maximum three times. Fifteen cows with ovarian cysts were left untreated and served as a control group. The cows with COF were matched to healthy cows without COF. The cows with COF had worse fertility performances compared to cows without COF. There were significant (p⟨0.05) differences in conception rates, number of services per conception and days open between these groups. Compared with non-treated cows with COF, in cows with COF treated with PRID Delta conceptions rates and number of services per conception were similar, but the days open were significantly (p⟨0.05) lower in cows treated than in non-treated (183.3 days vs. 277.6 days). There were no differences in reproductive performances between the follicular and luteal cysts in treated and non-treated cows. In conclusion, the results of our study confirm the negative impact of COF after puerperium on fertility in dairy cows. Furthermore the results indicate the usefulness of PRID Delta for the treatment of COF occurring after the puerperium regardless of cysts type.

Obstetric and newborn parameters in the Maine Coon cats.

The aim of this study was to determine several obstetric and neonatal parameters in the Maine Coon breed. The birth data of Maine Coon breeding population were collected of 52 litters from different households using a questionnaire. Significant relationships between various outcomes and the relevant predictors were assessed by multiple linear regression or logistic regression, as appropriate. The overall mean gestation length was 65.5±1.32 days. Larger litter size was associated with shorter gestation lengths (p⟨0.01). Mean litter size was 5.3±2.3 kittens. The weight of kittens born alive (overall mean 119.6±18.4 g) increased with prolonged gestation lengths (p⟨0.01) and decreased with larger litter sizes (p⟨0.01). In the analyzed group of kittens, 12.5% were stillborn. The expulsion intervals varied widely. The duration of the first stage of labour was less than 2h in 82.9% of the cats. The interval between the birth of the first and the last kitten was less than 6h in 99.3% of the cats, and it exceeded 6 h in only 2 cats. The present results can be used to develop references values and reliable assistance protocol for assessing the parturition in the Maine Coon to protect the queen and reduce perinatal losses.

Endometrial histopathology, bacteriology and cytology outcomes in mares with early embryonic death (EED): a field study.

Early embryonic death (EED) is one of the causes of infertility in the mare. We compared endometrial environment in 9 mares with EED and 13 mares in diestrus phase. Cotton swab (CS), cytobrush (CB) and uterine biopsy (B) samples were obtained for the cytological, bacteriological and histopathological examinations. In the first step we compared CS and CB methods to biopsy as a reference method, as B revealed the highest number of positive results in cytological and bacteriological examinations in both groups. In turn, we also compared cytological, bacteriological and histopathological findings between EED and control animals using the B sampling. Although the differences between these groups were not statistically significant (p≥0.05), there was a tendency to a higher prevalence of subclinical endometritis in the control group, than in the EED group (62% vs 22%). In general, positive bacteriological results were similar in both groups (62% vs 55%), whereas positive cytological results were higher in the control group (62% vs 22%; p≥0.05). In histopathological examination in EED mares endometrial degeneration was better expressed (all mares were with grades IIB and III on the Kenney-Doig scale); however, the differences between both groups were not statistically significant (p≥0.05). We could not confirm a clear difference in uterine environment between the two groups. Moreover, the uterine biopsy seemed to be the most reasonable sampling method for diagnosis of endometrial state.

Second prostaglandin F2α treatment during Ovsynch protocol does not improve fertility outcomes in dairy cows.

The objective of this study was to evaluate the effect of a second prostaglandin F2α (PGF2α) treatment during Ovsynch on luteal regression and fertility in dairy cows, compared with standard Ovsynch. The study was conducted on 111 Holstein Friesian multiparous cows on commercial dairy farm. The cows in the experimental group (n=48) received two treatments of PGF2α 24 hours apart during Ovsynch. The cows in the control group (n=63) were synchronized with standard Ovsynch. To assess the progesterone (P4) concentration blood samples were collected at the day of PGF2α treatment and at the 2nd GnRH treatment. Pregnancy was evaluated by ultrasound examination 37-40 days after timed artificial insemination (TAI) by ultrasound. Cows diagnosed pregnant were re-examined between days 70-80 after TAI. The percentage of cows with complete corpus luteum (CL) regression (P4⟨0.5 ng/ml at the time of the 2nd GnRH treatment) was 89.6 % after two PGF2α treatments and 88.9 % after one PGF2α treatment. There were no statistically significant differences (p>0.05) in the pregnancies per artificial insemination (P/AI) between the experimental and control group (P/AI). However, the pregnancy loss rate was lower in cows receiving two PGF2α treatments than in the control animals (0.0 % vs. 6.4 %; p⟨0.05). In conclusion, the second PGF2α treatment during Ovsynch protocol had no significant effect on CL regression and P/AI in dairy cows. The pregnancy losses until days 75-80 after TAI were significantly lower after two PGF2α treatments than after one PGF2α treatment.

Expression of proinflammatory cytokines IL-1ß, IL-6 and TNFα in the retained placenta of mares.

Retained fetal membranes (RFM) is a prevalent postpartum disease in mares. During parturition, various proinflammatory cytokines are released in the placenta, which further facilitates uterine contractions, expulsion of the fetus and fetal membranes. We hypothesized that an altered inflammatory response in mares results in retained fetal membranes. Samples of the endometrium and the allantochorion were collected from 15 mares with RFM and from 29 control mares within 2 h of foal delivery. Next, the mRNA expression of IL-1ß, IL-6 and TNFα proteins was analyzed by Real Time PCR and Western blot. These cytokines were also localized by immunocytochemistry. In mares with RFM, the mRNA expression of IL-1ß in the endometrium (p < 0.05) and IL-6 in the allantochorion (p < 0.0001) was higher than in mares that expelled fetal membranes physiologically. Higher expression of IL-6 in the allantochorion was confirmed by Western blot. In contrast, no changes in TNFα mRNA and protein expression were observed between the 2 groups of mares. Moreover, TNFα mRNA was barely detectable. The presence of all studied cytokine proteins in the allantochorion was confirmed by immunocytochemistry. The results suggest that the outbreak of inflammation is involved in the mechanism of placenta release in mares. Increased expression of IL-6 in the allantochorion and IL-1ß in the endometrium could reflect a local immune response which leads to the detachment of fetal membranes. The low expression of TNFα mRNA might suggest that this cytokine is not involved in the expulsion of fetal membranes. Further work is needed to determine the exact role and timing of inflammatory activation in fetal membranes during equine parturition.

Preovulatory progesterone secretion terminates the duration of reproductive behavior during heat in the bitch.

To evaluate the role of preovulatory progesterone on canine sexual behavior and the course of proestrus and estrus, seven bitches in spontaneous cycles were treated with aglepristone for temporary elimination of progesterone action. Aglepristone was administered at the dose 10 mg/kg b.m., two times 24 hours apart, beginning in early proestrus when progesterone concen- tration was ⟨0.5 ng/ml. Seven untreated bitches served as a control group. Reproductive sexual behavior (standing behavior, display vulva, tail deviation) was evaluated according to behavioral score. Cytologic, clinical and vaginoscopic examinations and progesterone measurements were used for the determination of proestrus and estrus and estimation of ovulation time. Although, a similar pattern and magnitude of sexual behavior were observed in both groups, the duration of a total reproductive behavior was significantly extended (28.71 ± 2.06 vs 17.00 ± 2.45, p ⟨0.05) in experimental group; similarly, the length of cytologic estrus (23.86 ± 3.02 vs 11.14 ± 2.41, p ⟨0.05) was prolonged in treated bitches. In contrast, ovulation rate, duration of proestrus did not differ between the groups (p >0.05). We conclude, that during the canine estrus cycle the preovulatory progesterone terminates the duration of reproductive behavior and cytologic estrus.

Effect of single treatment with cloprostenol or dinoprost on estrus and reproductive performance in anestrous dairy cows after service.

Previous studies have compared the effectiveness of dinoprost and cloprostenol in cows yielding conflicting results. The aim of our study was to evaluate the efficacy of single treatment with cloprostenol or dinoprost on estrus and reproductive performance in cows with unobserved estrus after service. The study was conducted over four years in two dairy herds of Polish Holstein Frisian cows under a herd health program with an average milk yield per cow over 9000 L. Cows (n=523) diagnosed ultrasonographically as non-pregnant and with a corpus luteum were randomly assigned to be treated with either cloprostenol (n=261) or dinoprost (n=262). The estrus detection rates after administration of cloprostenol or dinoprost were 59.4%, and 57.6%, respectively. The difference between both groups was not statistically significant (p>0.05). Distribution of observed estrus did not differ between cloprostenol and dinoprost. There were no differences (p>0.05) between cloprostenol and dinoprost in conception rate (65.2% vs. 66.2%, respectively) and pregnancy rate (57.5% vs. 54.9%, respectively). Mean days open were similar in cows of both treatments (177.5 ± 74.6 days vs. 175.8 ± 62.6 days, respectively; p>0.05). In conclusion, data from this study showed no significant differences in estrus detection rates and fertility between cows with unobserved estrus after service treated with cloprostenol or dinoprost. Both products are equally useful for the treatment of non-pregnant dairy cows with anestrus after service within a reproductive herd health program.

Incidence of clinical form of anestrus after unsuccessful service in cows in eight dairy herds in north-east of Poland.

There is no information available about the incidence of anestrus and its clinical forms after service in dairy cows in Poland. Thus, the aim of this study was to investigate the incidence of clinical forms of anoestrus after unsuccessful artificial insemination in dairy cows based on ultrasound examination. The study was carried out on 1543 Polish Holstein-Friesian cows in 8 dairy herds in north-east Poland over a three-year period. Cows were examined for pregnancy on day 35 after AI using a Honda 1500 portable ultrasound scanner equipped with a 5 MHz linear-array transducer. Cows diagnosed as pregnant were re-examined on day 45. Of the 1543 inseminated cows, 408 (26.4%) showed no estrus signs and were diagnosed not-pregnant by ultrasonography, 328 (21.3%) returned to estrus within 35 days, and 807 (52.3%) were pregnant via artificial insemination. The incidence of anestrus after service in non-pregnant cows varied among herds from 10.3% to 32.9% of cows (p0.05). Based on ultrasound examination silent heat was diagnosed in 324 (79.4%), corpus luteum pseudograviditatis in 36 (8.8%), ovarian cysts in 26 (6.4%), and ovarian afunction in 22 (5.4%) of 408 anestrous, non-pregnant cows. The results of this study showed that the incidence of anestrus after service in dairy herds in North-East Poland was high. The most prevalent clinical form of post-service anestrus was silent heat.

Selenium and vitamin E supplementation enhances the antioxidant status of spermatozoa and improves semen quality in male dogs with lowered fertility.

Studies showed a beneficial effect of supplementation with selenium (Se) and vitamin E on semen quality. The aim of the study was to investigate the effect of Se and vitamin E supplementation on the antioxidant status of spermatozoa and semen quality in dogs with lowered fertility. Ten dogs were supplemented daily with Se (6 µg/kg organic Se yeast) and vitamin E (5 mg/kg) per os for 60 days. Control group consisted of 10 males without the supplementation. Semen was collected on day 0, 30, 60 and 90. Sperm quality parameters were evaluated using CASA and a microscope. Concentrations of Se and vitamin E in blood as well as glutathione peroxidase (GSH-Px) activity and total antioxidant capacity (TAC) in the spermatozoa were determined. After 60 days of supplementation the concentration of spermatozoa, the majority of motility indicators and the percentage of normal morphology and live spermatozoa increased significantly (p < .05). An increase (p < .05) in concentration of Se and vitamin E in blood and GSH-Px-activity and TAC in the spermatozoa was detected. The study results indicate that Se and vitamin E supplementation for 60 days enhances the antioxidant status of spermatozoa and improves the quality of the semen in dogs with lowered fertility.

Specific fetometric formulas of ICC and BP for calculating the parturition date in the miniature breeds of canine.

The aim of this study was to derive the growth curves of the inner chorionic cavity and the biparietal distance in miniature dog breeds by ultrasonographic fetometry and present new specific formulas for prediction of parturition date. In this study, foetal biometry parameters were obtained using serial ultrasonographic examinations in 24 pregnant bitches of six different miniature breeds (≤5 kg). The mating time was unknown. Overall, 25 inner chorionic cavity diameter (ICC) and 22 biparietal diameter (BP) measurements were taken. The relationship between ICC or BP growth and days to parturition was analysed by linear regression. The results showed a significant relationship between days before delivery and ICC or BP. The equations derived from the growth curves can be used in practical prediction of parturition date in miniature dog breeds.

Major histocompatibility complex class I in the horse (Equus caballus) placenta during pregnancy and parturition.

BACKGROUND: Major histocompatibility protein class I (MHC-I) is believed to be expressed in the horse allantochorion only in limited areas at limited times. However, its expression has only been investigated in early pregnancy with non-quantitative techniques that cannot reliably detect small amounts of protein. OBJECTIVE: To quantify the relative expression of MHC-I in the allantochorion and endometrium during days 90-240 of pregnancy (PREG), parturition with physiological delivery of fetal membranes (PHYS), and parturition with retention of these membranes (FMR). Also, to visualize protein expression and determine whether classical or non-classical MHC-I mRNA is expressed. ANIMALS: Heavy draft horses. SETTING: PREG horses (n = 12) were sampled postmortem at a slaughterhouse. PHYS (n = 6) and FMR (n = 5) horses were sampled at farms in the vicinity of Olsztyn, Poland. METHODS: For relative quantification of MHC-I, western blotting with densitometry was used. To visualize MHC-I, immunohistochemistry was used. For mRNA identification, RT-PCR was performed. RESULTS: Although the quantity of MHC-I was lower during PREG than parturition, it was present in the allantochorion and endometrium during PREG. During parturition, MHC-I expression was upregulated in the allantochorion (PHYS vs. PREG: 2.7-times higher, 95% confidence interval, 1.3- to 5.7-times higher; FMR vs. PREG: 3.2-times higher, 95% confidence interval, 1.5- to 6.7-times higher). At parturition, staining for MHC-I was detected in the microcotyledons. Classical and non-classical MHC-I were expressed in both tissues during PREG, PHYS, and FMR. CONCLUSION: MHC-I protein is present in the horse allantochorion and endometrium for at least the first two-thirds of pregnancy and at parturition.

The effects of osaterone acetate on clinical signs and prostate volume in dogs with benign prostatic hyperplasia.

A clinical trial was performed to evaluate the therapeutic efficacy of osaterone acetate (OSA) in the treatment of benign prostatic hyperplasia (BPH) in dogs. Osaterone acetate (Ypozane, Virbac) was administered orally at a dose of 0.25 mg/kg body weight once a day for seven days to 23 dogs with BPH. During the 28-day trial, the dogs were monitored five times for their clinical signs and prostate volume. The OSA treatment promoted rapid reduction of clinical scores to 73.2% on day 7 and to 5.9% on day 28 (p⟨0.05). Osaterone acetate induced the complete clinical remission in approximately 83.0% of the dogs on day 28. The prostate volume regressed to 64.3% of the pretreatment volume after two weeks of the treatment (p⟨0.05) and to 54.7% at the end of the trial (p⟨0.05). In conclusion, OSA quickly reduced clinical signs and volume of the prostate glands in dogs with BPH.

Stenotrophomonas maltophilia isolated from prostatic fluid as an infertility factor in a male dog.

The aim of this case was to describe very rare infection of canine prostate gland with Stenotrophomonas maltophilia which had influence on male fertility. The bacterium was cultured from third fraction of the ejaculate collected by manual manipulation. The sperm concentration and motility parameters were evaluated by Hamilton-Thorne Sperm Analyser, version IVOS 12.3, sperm morphology by Diff-Quick staining and live/dead spermatozoa by eosin/nigrosin staining. After 3 weeks of treatment with targeted antibiotic, ciprofloxacin, there was no bacterial growth in prostate fluid. Semen parameters were improved after 60 days from the end of treatment, and females were successfully mated.

Equine Chorionic Gonadotropin and Human Chorionic Gonadotropin Stimulation Increase the Number of Luteinized Follicles and the Progesterone Level Compared with Cabergoline Stimulation in Anoestrus Bitches.

In this study, ovarian morphologies and blood progesterone concentrations following oestrous induction in bitches were examined. Fifty-three clinically healthy anoestrus bitches received cabergoline at a daily dose of 5 µg/kg of body weight per os for 21 days (group I) or subcutaneous equine chorionic gonadotropin at a dose of 20 IU/kg of body weight for five consecutive days with an additional 500 IU s.c. per bitch of human chorionic gonadotropin on the last day of treatment (group II). Twenty bitches that spontaneously displayed oestrous signs were left untreated and served as controls (group III). The induced oestrous rates and ovulation rates in groups I and II were 60.0% vs 64.3% and 86.7% vs 83.3%, respectively. Morphological assessments of the ovarian structures after ovariohysterectomy revealed an increase in the number of luteinized follicles and cysts in group II compared with the two other groups (p < 0.001). In contrast, the numbers of corpora lutea and follicles were similar in all groups. In accordance with the above-mentioned alteration, the progesterone concentration in the gonadotropin group (II) was increased (p < 0.001) in the periovulatory period compared with the other two groups. During the entire sampling period, the progesterone profiles in the cabergoline (I) and control (III) groups were similar and typical of normally cycling bitches. In conclusion, gonadotropin treatment is associated with an increased progesterone level during the periovulatory period that probably originates from luteinized follicles, whereas cabergoline treatment induces cycles with both physiological progesterone concentrations and ovarian morphologies.

Prevalence and etiological agents of subclinical mastitis at the end of lactation in nine dairy herds in North-East Poland.

The aim of this study was to evaluate the prevalence and etiological agents of subclinical mastitis at the end of lactation in nine dairy herds in North-East Poland. In total, 387 Polish HF were involved in the study. The diagnosis of mastitis was performed on the basis of clinical examination of the udder, macroscopic evaluation of milk, determination of somatic cell count and bacteriological examination of milk. Subclinical mastitis was found in an average of 36.7% (range from 21.0% to 53.1%) of cows and of 15.7% (range from 9.6% to 25.2%) of quarters. Coagulase negative staphylococci (CNS; 31.6% of quarters), Streptococcus (Str.) agalactiae (15.6% of quarters), Staphylococcus (Staph.) aureus (12.1% of quarters) and fungi (12.2% of quarters) were most frequently isolated from subclinical mastitis. Etiological agents of subclinical mastitis differed strongly between herds. The results of this study showed that the incidence of subclinical mastitis at the end of lactation in dairy herds in North-East Poland is high. CNS were the most frequently isolated from subclinical mastitis cases, however mastitis caused by the contagious pathogens Str. agalactiae and Staph. aureus is still a problem. The fungal infections of the mammary gland also play an important role.

Differences in extracellular matrix remodeling in the placenta of mares that retain fetal membranes and mares that deliver fetal membranes physiologically.

INTRODUCTION: In mammals, placenta separation at term may involve degradation of the extracellular matrix by matrix metalloproteinases (MMPs). The activity of MMPs is modulated by TIMPs. We hypothesized that the placentas of mares that deliver fetal membranes physiologically and those that retain fetal membranes (FMR) differ in terms of histology; mRNA expression of MMP-2 and MMP-9; protein expression of MMP-2, MMP-9, and TIMP-2; and the potential activity of both MMPs. METHODS: Placenta biopsies were taken from mares (n = 9; 4 FMR, 5 controls) immediately after foal expulsion. Retention was defined as failure to expel all fetal membranes within 3 h of expulsion. All mares were monitored for time of expulsion. The degree of allantochorial/endometrial adhesion was determined in FMR mares, and biopsies from all mares were histologically examined. mRNA expression, protein immunolocalization, protein amount and potential enzyme activity were determined with RT-PCR, immunohistochemistry, Western Blotting and zymography, respectively. RESULTS: FMR mares had strong to extremely strong allantochorial/endometrial adhesion, and significantly more connective tissue in the allantochorial villi than controls. The range of MMP-2 mRNA expression levels was more than 13 times greater in FMR mares than in controls. Protein content of both MMPs and TIMP-2 differed significantly between groups. The range of potential MMP-2 and MMP-9 activity was larger in FMR mares, and MMP-2 potential activity was 1.4 times higher in controls (P = 0.02). DISCUSSION: These results indicate differences in extracellular matrix remodeling in FMR mares and controls, and suggest dysregulation of MMP expression and activation in FMR mares.

Expression of oxytocin receptors is greatly reduced in the placenta of heavy mares with retained fetal membranes due to secondary uterine atony.

REASONS FOR PERFORMING STUDY: Fetal membrane retention can be a life-threatening condition and its incidence exceeds 50% in heavy draught mares. Although fetal membrane retention is commonly treated with repeated injections of oxytocin, based on the suggestion that it is caused mainly by secondary atony of the uterus, this treatment sometimes fails. This led us to ask if expression of oxytocin receptors differs in mares that retain fetal membranes due to secondary uterine atony. OBJECTIVES: To determine whether expression of oxytocin receptors in equine placental tissues differs when heavy draught mares expel fetal membranes or retain them because of secondary uterine atony. STUDY DESIGN: Controlled study using archived tissues. METHODS: Placental biopsies (containing the endometrium and allantochorion) were taken from 8 heavy draught mares during parturition. Four mares expelled fetal membranes shortly after foaling (control mares) and 4 mares retained them (expulsion time was >3 h from delivery). The 4 mares that retained fetal membranes had secondary atony of the uterus. The amount of oxytocin receptors was estimated by measuring the intensity of western blot bands. The presence and location of oxytocin receptors were determined by immunocytochemistry. RESULTS: Oxytocin receptor expression was nearly 50 times less intense in mares with placenta retention due to secondary atony of the uterus and immunocytochemical staining was barely visible. In the control mares, oxytocin receptors were found in both epithelial and endothelial cells of the placenta and staining was most intense where the endometrium contacts the allantochorion. CONCLUSIONS: Inadequate expression of oxytocin receptors may be a cause of uterine atony leading to fetal membrane retention.

Formation of the early canine CL and the role of prostaglandin E2 (PGE2) in regulation of its function: an in vivo approach.

The mechanisms governing corpus luteum (CL) function in domestic dogs remain not fully elucidated. The upregulated expression of cyclooxygenase 2 and prostaglandin (PG) E2 synthase (PGES) at the beginning of the canine luteal phase indicated their luteotrophic roles, and the steroidogenic activity of PGE2 in the early canine CL has been confirmed in vitro. Recently, by applying a cyclooxygenase 2 (COX2)-specific inhibitor (firocoxib [Previcox]; Merial) from the day of ovulation until the midluteal phase, the luteotrophic effects of PGs have been shown in vivo. This is a follow-up study investigating the underlying endocrine mechanisms associated with the firocoxib-mediated effects on the canine CL. Experimental groups were formed with ovariohysterectomies performed on Days 5, 10, 20, or 30 of firocoxib treatments (10 mg/kg bw/24h; TGs = treated groups). Untreated dogs served as controls. A decrease of steroidogenic acute regulatory (STAR) protein expression was observed in TGs. The expression of PGE2 synthase was significantly suppressed in TGs 5 and 10, and both PGE2 and PGF2α levels were decreased in luteal homogenates, particularly from CL in TG 5. Similarly, expression of the prolactin receptor (PRLR) was diminished in TGs 5 and 20. The expression of PGE2 receptors PTGER2 (EP2) and PTGER4 (EP4), the PG- transporter (PGT), and 15-hydroxy PG dehydrogenase (HPGD) was not affected in TGs. Our results substantiate a direct luteotrophic role of PGs in the early canine CL, i.e., by upregulating the steroidogenic machinery. Additionally, the possibility of an indirect effect on PRL function arises from the increased prolactin receptor expression in response to PGE2 treatment in canine lutein cells observed in vitro.

Progesterone level does not distinguish the different course of canine ovulation determined by ultrasonography.

The aim of this study was to compare progesterone concentrations in bitches during ovulation with a different course of follicular collapse as determined by ultrasonography. The study was conducted on 36 animals of different breeds, from 2 to 7 years old, and from 2 to 44 kg of body weight. Ultrasound examinations of ovaries were conducted in the peri-ovulatory period until ovulation was detected. Based on USG scans the animals were divided into two groups: group A with fast follicular collapse within 1 day, and group B with gradual follicular collapse within 2-3 days. Progesterone measurements were performed in both groups on the day when the beginning of ovulation was diagnosed by USG. Follicular collapse in group A was observed in 27.8% of animals (n = 10) and in group B in 72.2% (n = 26). There were no statistical differences (p < 0.05) in progesterone concentrations between groups A and B (6.68 +/- 0.92 ng/ml and 6.81 +/- 0.57 ng/ml respectively). From 31 bred bitches (natural mating or insemination) pregnancy was confirmed in 29 females (93.5%). These results provide information about the sufficient stability of progesterone concentration during ovulation regardless of the follicular collapse speed. Ultrasonography during the peri-ovulatory period combined with progesterone measurements allows progress in ovulation management.