Pelvic dimensions and occurrence of dystocia in Black-and-White and Holstein-Friesian heifers.

The Black-and-White (BW) breed, which until recently had dominated in Europe, was replaced by the Holstein-Friesian (HF) breed. As a result, the incidence of dystocia has increased. Dystocia occurs most frequently in heifers, and it is associated with high calf weight and/or too narrow pelvic openings in heifers. The aim of this study was to evaluate retrospectively the effects of pelvic dimensions and rump angle on calving ease in two cattle breeds. The research was carried out in four barns where BW and HF cattle were used. The course of parturition was evaluated in 317 heifers (BW, n=169; HF, n=148) based on direct observations. Calves were weighed, external and internal pelvic measurements were performed (using the Rice pelvimeter), and rump angle was determined in heifers. Based on the course of parturition, heifers of both breeds were divided into easy calving (EC) and difficult calving (DC) groups. The frequency of DC was 24.3% in HF heifers and 13.1% in BW heifers. In comparison with DC heifers, EC heifers had a larger pelvic area, in particular the internal dimensions of the bony pelvis, and a higher rump angle. In comparison with BW heifers, HF heifers had a smaller rump angle, a narrower pelvis and a lower ratio of pelvic area to calf weight. High dystocia rates in HF heifers could result from a relatively large fetus size and a less preferable pelvic size and rump angle. High variation in the internal pelvic dimensions in HF heifers indicates that the incidence of dystocia can be reduced through selection for a larger pelvic size and the optimal rump angle.

Effect of repeated low doses of GnRH analogue (buserelin) on fertility performance of dairy cows with anovulation type I.

The aim of this study was to evaluate the fertility response of dairy cows with anovulation type I on repeated low doses of GnRH agonist buserelin. The study was conducted on 83 anovulatory and 60 cyclic Polish Holstein Friesian cows. Anovulation type I was defined as small ovaries with follicles of ≤ 5 mm in diameter and without corpus luteum on two examinations in a 7-10 day interval between 50-60 days after parturition. Cows from the experimental group (n=58) received 0.4 µg of buserelin i.m. once a day for 5 consecutive days. Cows from the negative control group (n = 25) received saline. Sixty cyclic cows receiving no treatment served as positive controls. Intervals from calving to estrus and from calving to conception, pregnancy rate 30-35 days and 260 days after AI, and pregnancy loss were calculated. The anovulatory cows had a substantially prolonged calving to conception interval, decreased pregnancy rate and increased pregnancy loss and culling rate compared to cyclic herd mates. The average calving to conception interval was significantly (p⟨0.05) shorter in treated cows compared to non-treated anovulatory cows (153.7 days vs 209.3 days). In conclusion, repeated low doses of GnRH analogue buserelin led to a significant shortening of calving to conception interval. More clinical trials are needed to determine the practical usefulness of this method for the treatment of anovulation type I in dairy cows.

Effect of repeated low doses of GnRH on follicular development and ovulation in anovulatory dairy cows with follicle growth to emergence size.

The aim of the study was to evaluate the effect of repeated low doses of GnRH agonist buserelin once a day for 5 days on follicle development and ovulation in anovulatory dairy cows with follicles growth only to emergence. The study was conducted on 71 anovulatory Polish Holstein Friesian cows. Anovulation with growth of follicles to emergence was defined as small ovaries with follicles of ≤ 5 mm in diameter and without corpus luteum on two examinations in a 7-10 day interval between 50-60 days after parturition. Cows were allocated to one of two group. Cows from group 1 (n = 58) received 0.4 µg of buserelin (Receptal, MSD, Poland) i.m. once a day for 5 days. Control cows from group 2 (n = 13) received saline. Ovarian structures were monitored weekly after the end of treatment by ultrasound for 4 weeks. The diameter of ovarian follicles on the ovaries was measured and recorded. Occurrence of ovulation was determined by the presence of corpus luteum. Overall, ovulation occurred in 46.6% (27/58) of cows treated with repeated doses of GnRH, while no corpus luteum was observed in the control group during the study period. There were significantly (p⟨0.05) more follicles 6-9 mm in diameter and 10-20 mm in diameter in cows treated with GnRH than in control cows. In conclusion, repeated low doses of GnRH analogue buserelin once a day for 5 days stimulate the development of ovarian follicles in anovulatory dairy cows with small ovarian follicles and led to ovulation in 46.6% of cows during 4 weeks after the end of the treatment.

Effect of an integrated veterinary herd health program on fertility performance and incidence of reproductive disorders in five dairy herds.

The study was carried out in 5 dairy herds of Polish Holstein-Friesian cows. The average milk yield was about 9000 kg per year. For each herd, the following fertility parameters were calculated at the start of the program and 4 years later: first- service conception rate, services per conception, length of inter-calving period and culling rate due to infertility. The incidence of silent heat, ovarian cysts, ovarian afunction, retained placenta and clinical endometritis was also recorded. Four years after implementation of the program, the average first-service conception rate increased from 43.2% to 51.2%. In three herds the differences were statistically significant (p⟨0.05). There was also a decrease in the number of services per pregnancy and in the culling rate due to infertility. Fertility performance was maintained in two herds. The average incidence of silent heat decreased from 38.1% to 29.7% and the difference was statistically significant (p⟨0.05) in three herds. There was no significant reduction in incidence of other reproductive disorders during the 4 years except for clinical endometritis in one herd. The average milk yield increased from 9300 kg to 9530 kg milk per cow per year. In conclusion, the results indicate that the implementation of the integrated veterinary herd health program improved or maintained fertility performance despite an increase in milk yield.

Comparison of efficacy of Ovsynch protocol to single PGF2α administration in treatment of individual dairy cows with post-service subestrus.

The aim of this study was to evaluate the efficacy of the Ovsynch protocol in the treatment of post-service subestrus in individual dairy cows compared to a single administration of PGF2α. The study was performed on 517 Polish Friesian Holstein cows with post-service anestrus over four years in 3 dairy herds under a herd health program. Cows (n=240) diagnosed ultrasonographically as non-pregnant and with a mature corpus were treated with a single PGF2α administration and inseminated at detected estrus. Cows without corpus (n=277) were treated with the Ovsynch protocol. The estrus detection rate after PGF2α administration, percentages of cows pregnant after the treatment and at day 260, intervals from parturition to treatment and from treatment to conception and pregnancy loss rates were calculated. The overall percentage of cows pregnant after treatment did not differ between animals treated with the Ovsynch protocol and with PGF2α (38.9% vs. 42.5%; p>0.05). In herd A the percentage of cows pregnant after treatment was significantly lower (p⟨0.05) for the Ovsynch group than for the PGF2α group (30.2% vs. 61.2%). In contrast, in herd C the percentage of cows pregnant after treatment was significantly higher (p⟨0.05) in the Ovsych group than in the PGF2α group (39.6% vs. 28.8%). The overall estrus detection rate after administration of PGF2α was 59.6%. However, it was significantly lower (p⟨0.05) in herd C (44.7%) than in herds A (79.6%) and B (76.3%). The overall pregnancy loss rate ranged from 5.1% to 13.3% and did not differ significantly between herds and treatment groups (p>0.05). In conclusion, Ovsynch protocol can be a useful alternative for treatment of post-service suboestrus in individual cows in dairy herds with insufficient oestrus detection.

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.

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.

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.

In vitro cow uterine response to Escherichia coli, leukotrienes and cytokines.

The aim was to determine the dynamic profile of interactions between Escherichia coli (E. coli) and the actions of leukotrienes (LTs) and TNF and INFγ (cytokines) in the uterus in vitro. Uterine explants (N=6) were incubated for 2, 12 and 24h either as E. coli-treated (106CFU) or non-treated and/or with: LTB4 and C4 (10-6M, for both LTs), LTs receptors antagonists (aLTR; 10-6M) and/or cytokines (each 10ng/ml). Toll Like Receptor 4 (TLR4) mRNA expression increased in explants incubated with E. coli, cytokines and LTs after 2 and 12h and aLTR inhibited the effect of LTs in explants incubated with E. coli (P<0.05). IL-6 mRNA expression was up-regulated in E.coli-treated explants with cytokines after 2h and cytokines with LTs after 12h (P<0.05). E. coli increased prostaglandin (PG)E2 output after all examined time points, and PGF2α and IL-6 levels in E.coli-treated explants after 12 and 24h with cytokines, with LTs (P<0.05). aLTR inhibited LT stimulating action on PGs and IL-6 output in explants incubated with E. coli after 12 and 24h (P<0.05). LTs modify and enhance experimentally induced infection: TLR4 and IL-6 mRNA expression, IL-6 and PGs secretion, and cytokines participate in this process.

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.

Fertility after fetotomy: a clinical study focusing on heavy draft mares.

Although fetotomy is recommended for all mares when the fetus is dead and difficult to extract, little has been written about fetotomy and heavy draft mares. This lack includes indications for fetotomy in heavy draft mares, differences in treatment and prognosis of heavy mares kept by farmers of low socioeconomic status, and how this procedure affects the mare's further fertility. The literature on mares, in general, also differs on the survival rate of mares that undergo fetotomy, the prevalence of postpartum complications, and further fertility. To answer these questions, we reviewed the medical records of 102 mares that underwent fetotomy, mostly heavy draft mares (n=93). Head malposture (62.7 per cent) was the most common fetal maldisposition, which required fetotomy in all cases. The survival rate was 84.3 per cent (n=86). The most common postpartum complications were endometritis puerperalis (32.5 per cent) and retained placenta (27.9 per cent). 61 mares (70.9 per cent) both showed foal heat and cycled regularly in the first season after fetotomy. Out of 45 mares that were bred in the first season, 14 became pregnant (31.1 per cent). Survival rate and further fertility were reduced by delayed requests for veterinary assistance due to the difficult economic situation of the owners. Fetotomy is the method of choice for serious maldispositions, especially head malpostures, because in contrast with cesarean sections, it has a higher survival rate and allows the mare to return to breeding in the same season.

Distribution of CD14+ macrophages, CD4+, CD8+ lymphocytes and mRNA expression of inducible nitric oxide synthase in the endometrium of repeat breeding cows.

The expression of CD14+ macrophages, CD4+, CD8+ lymphocytes and mRNA of inducible nitric oxide synthase (iNOS) was investigated in the endometrium of repeat breeders with subclinical endometritis [experimental group (EXP), n = 10] and healthy [control group (CTRL), n = 10] cows. The cows were selected on the basis of repeat breeding (3 unsuccessful inseminations), clinical and cytological examinations (> 10% polymorphonuclear neutrophils in uterine smears obtained by cytobrush). From all the cows endometrial biopsies were collected and the presence of CD14+, CD4+ and CD8+ cells in the endometrium was evaluated immunohistochemically using semi quantitative counting method. The mRNA expression of iNOS was determined using reverse transcription-PCR. In general, there were no significant differences between EXP and CTRL groups in the expression of CD4+ and CD8 + lymphocytes in all endometrial structures. In contrast, we observed a higher number of CD14+ macrophages in repeat breeding group compared to the control cows, however, this difference was slightly pronounced. CD14+ cells were detectable only in the stratum compactum and stratum spongiosum. The statistically significant (p < or = 0.05) higher expression of iNOS mRNA was measured in the cows with subclinical endometritis compared to the healthy animals. Our results suggest that the increased expression of CD14+ macrophages and iNOS mRNA may be associated with embryonal mortality in repeat breeding cows with subclinical endometritis.

Reproductive performance of cows with subclinical endometritis diagnosed by different cytological thresholds in the postpartum period.

OBJECTIVE: To determine the impact of cytologically determined endometritis (CE) diagnosed according to three different cytological thresholds in the 4th and 6th week postpartum (p. p.) on the subsequent reproductive performance in dairy cows. MATERIAL AND METHODS: Dairy cows (n = 222) were clinically examined in the 4th week (Exam I) and in the 6th week (Exam II) p. p. and endometrium samples were collected for cytological examination using the cytobrush method. Three cytological thresholds (percent of polymorphonuclear leucocytes to epithelial cells) were used for categorization of cows: 1) > 18% at Exam I and > 10% at Exam II; 2) > 8% at Exams I and II; 3) > 5% at Exams I and II. The animals were categorized as endometritis positive (CE+) or negative (CE-) according to all cytological thresholds at Exams I and II. For all six experimental groups the following reproductive parameters were calculated: first insemination pregnancy rate, number of services per conception, intercalving period, and total pregnancy rate on day 300 p. p. RESULTS: According to different thresholds prevalence of CE ranged from 48.0% to 65.9% at Exam I and from 26.0% to 34.7% at Exam II. The first insemination pregnancy rate was statistically lower in all CE positive groups at Exam I. Number of inseminations per conception was higher (p < 0.05) in each CE positive cows with exception of group CE+ at Exam II. Intercalving periods were longer in CE cows, and significant (p < 0.05) difference was found for groups ICE+ and ICE- at Exam I. Overall pregnancy rates were similar in cytologically determined endometritis and control cows. CONCLUSION AND CLINICAL RELEVANCE: Impaired fertility at herd level may concern only particular reproductive indices. It seems that each herd with subclinical endometritis needs to be evaluated and managed individually, according to the different housing, feeding, and environmental conditions. The first of three thresholds used to cytologically diagnose endometritis seems to be the most reliable when applied in the 4th week p. p.

Prevalence of subclinical endometritis in repeat breeding cows and mRNA expression of tumor necrosis factor alpha and inducible nitric oxide synthase in the endometrium of repeat breeding cows with and without subclinical endometritis.

Information on the prevalence of subclinical endometritis and its mechanism in repeat breeding cows is very limited. The aims of this study were: a) to evaluate the incidence of this disorder with cytobrush cytology b) to analyze mRNA expression of tumor necrosis factor alpha (TNFalpha) and inducible nitric oxide synthase (iNOS) in endometrial biopsy samples collected from repeat breeding cows with and without subclinical endometritis. Two experiments were carried out. In experiment 1,112 (12.4%) repeat breeding cows (inseminated at least 3 times and not pregnant) were selected out of 902 cows from 8 dairy herds. Cytobrush cytology was performed on these cows, using the threshold of 10% PMNs in uterine smears. The results showed that 45 out of the 112 cows (40.2%) were diagnosed as having subclinical endometritis. In experiment 2, uterine biopsy samples were taken from repeat breeding cows with subclinical endometritis (n = 10) and without this disorder (n = 10). Using reverse transcription-PCR, the mRNA expression of TNFalpha and iNOS was determined. A statistically significant increase in expression of both substances was measured in the group of cows with subclinical endometritis (p <0.05). These results provide evidence for a high prevalence of subclinical endometritis in repeat breeding cows as well as the involvement of TNFalpha and iNOS pathways in the regulation of this pathological condition.

The diagnosis and prevalence of subclinical endometritis in cows evaluated by different cytologic thresholds.

The aims of our study were to determine (1) how the prevalence of cytologically determined subclinical endometritis varies when using three different cytological threshold ratios to categorize cows as either with or without endometritis, (2) how the number of animals categorized as having endometritis changes from the fourth to the sixth wk postpartum when using each threshold, (3) how subclinical endometritis influences the number of days open, and (4) how the results of cytological and bacterial examinations correlate. To answer these questions, 222 clinically healthy cows in two herds were examined in the fourth (Exam 1) and the sixth wk (Exam 2) postpartum, when endometrial surface scrapings for bacteriologic and cytologic examination were collected by cytobrush from their uterine horns. After each examination, all cows were categorized using three different thresholds: (1) > 18% polymorphonuclear leucocytes in Exam 1 and > 10% in Exam 2, (2) > 8% in both exams, and (3) > 5% in both exams. It was found that: (1) The number of cows categorized as having endometritis increased as the threshold was lowered, and ranged from 18.9% to 75.4% according to herd, time of examination, and the threshold used; (2) with all three thresholds and in both herds, the number of cows categorized as having endometritis in Exam 1 was approximately double that in Exam 2; whereas depending on the herd and the threshold used, 6.1% to 17.0% of the cows that were negative in the first exam were positive in the second, and 7.4% to 33.3% were positive in both exams; (3) cows were open for a significantly greater number of days if categorized as having endometritis with the first threshold in Exam 1 (mean ± SEM 151.5 ± 9.5 vs. 115.9 ± 7.8; P < 0.01), or with either the first or the second threshold in Exam 2 (mean ± SEM 155.0 ± 15.0 vs. 125.1 ± 6.6; P < 0.05); and (4) the most common bacteria were Streptococcus acidominimus and Escherichia coli, and the correlation between cytologic and bacteriologic findings was low (Φ = 0.08 to 0.17 for different tested thresholds). Subclinical endometritis seems to be associated more with the postpartum recovery of the endometrium than with bacterial infection.

Late embryonic and foetal losses in eight dairy herds in north-east Poland.

The information about the occurrence of embryonic and fetal losses in dairy herds in Poland is limited. Thus, the objective of this study was to assess the pregnancy loss between days 30 and 45 (late embryonic mortality) and between days 45 and 260 after artificial insemination (AI) (foetal loss). The study was carried out in 8 dairy herds in north-east Poland. In total 954 cows were examined for pregnancy on day 30 after AI using an ultrasound scanner. Cows diagnosed pregnant were re-examined on day 45 and 260 after AI using transrectal palpation. The pregnancy rate on day 30 after AI was 62.0%, after re-examination on day 45 after AI the pregnancy rate was 56.4%. The late embryonic loss rate was on an average 9.1%. The occurrence of late embryonic mortality differed not significantly (p > 0.05) among herds and ranged from 13.1% to 19.3%. The pregnancy rate on day 260 after AI was 53.5%. The average foetal loss after day 45 of pregnancy was 5.0%, ranged between herds from 0 to 9.2% (p > 0.05) and was significantly lower than embryonic loss rate (p < 0.05). The study revealed that in 8 dairy herds in north-east Poland the overall pregnancy loss between days 30 and 260 averaged 13.7% and therefore it is an important factor affecting economic efficiency of dairy production. The foetal loss was less prevalent than the late embryonic loss. Future strategies to minimizing late embryonic loss are needed.

Concentrations of oestrogens in blood plasma and seminal plasma of boars during the postpuberal period.

Concentrations of oestrogens in the blood plasma and seminal plasma of mature boars are high. However, little is known about their concentrations after reaching sexual maturity. The aim of this study was to determine the concentration of oestrogens in blood plasma and seminal plasma of boars during the postpuberal period. Free and conjugated oestrone and oestradiol-17beta were determined by radioimmunoassay in blood from the testicular vein and artery, and peripheral circulation as well as in seminal plasma collected from 18 Polish Landrace boars. The animals were divided into three groups (n = 6) according to age (8, 12 and 16 months, respectively). Oestrone was predominant free and conjugated oestrogen. The highest values of oestrogens were measured in the testicular vein (p < or = 0.05). The concentrations of oestrogens in seminal plasma did not differ from those found in the peripheral circulation. An age-dependent increase in levels of all four oestrogens (p < or = 0.05) was observed. This can be associated with biochemical maturation of the reproductive system during the postpuberal period.

Oestrogens in faeces as an indicator of the foeto-placental unit function in mares.

Total of 30 pregnant mares were used in this study: 17 Thoroughbred and 13 Primitive Polish Horse. The concentration of total unconjugated oestrogens was determined by radioimmunoassay in faecal samples obtained every second week after mating until delivery or interruption of pregnancy. Concentration of oestrogens in pregnant healthy mares ranged from 40 to 200 ng/g and showed typical profiles for pregnancy. In 5 of 30 mares (16.6%) of either breed abortions and cases of embryonic death occurred. Abortions were preceded by sharp or gradual decrease in oestrogen concentration, whereas prior to embryonic death no elevation of the level of these hormones was noted. The present data suggest that determination of faecal oestrogens may serve as an indicator of the foeto-placental unit function during either the physiological or pathological pregnancy.