Relation between cervical mucus sperm toxicity and pregnancy in cows]

Cervical secretion was collected from 99 dairy cows of the Black Pied Lowland breed at an age of 24 to 109 months with a minimum performance of 4000 kg of milk annually in spontaneous oestrus 42 days post partum at the minimum. It was demonstrated by the radioimmunological determination of progesterone in skim milk that from all the breeding cows (n = 99) the oestral secretion was collected during an optimum insemination time (x = 0.19 ng.ml-1 progesterone). Of the statistical set of 99 cows, 55 (i.e. 56.57%) got in calf and 43 (i.e. 43.43%) remained barren. As found, the conception results were not influenced by the rank of the insemination after parturition and the conception capacity of the cows was not influenced by the length of time from parturition to the respective inseminations. It was demonstrated in our investigation that the conception capacity of the cows increases as the time of sperm survival prolongs in the cervical secretion in vitro. The highest conception capacity (80%) was recorded in the cows whose cervical secretion was free of spermiotoxic action. In such cases the motility of the spermatozoa in the oestral mucus was maintained at a temperature of 38 degrees C for longer than 300 minutes. On the other hand, it was demonstrated that the conception capacity of the cows declines with shortening time of sperm survival in the cervical mucus.     

Antioxidants and lipid peroxidation levels of blood and cervical mucus in cows in relation to pregnancy

Levels of vitamins A and E, beta carotene and lipid peroxidation product (TBARS) were determined in plasma and cervical mucus of 32 cows. Red blood cell (RBC) reduced glutathione (GSH) and RBC glutathione peroxidase (GSH-Px) activity as well as vitamin C plasma levels were measured. After taking cervical mucus and blood samples the animals were inseminated artificially. Three month later pregnant (n = 20) and non pregnant (n = 12) cattle were determined. Correlations between investigated parameters and pregnancy rate were performed. In blood plasma, a significant correlation was observed between vitamin A and beta carotene (P < 0.001) as well as vitamin E (P < 0.05). There was a significant (P < 0.001) correlation in TBARS values of plasma and cervical mucus. However, none of the investigated parameters showed a significant difference between pregnant and non pregnant cows. In conclusion, we did not find any difference and correlation between pregnant and nonpregnant animals concerning the investigated antioxidants. A positive correlation was observed between lipid peroxidation levels of plasma and cervical mucus. Our work provides basic informations about antioxidative parameters under physiological conditions. Further studies should investigate possible correlation between disturbed fertility and antioxidative status of plasma and cervical mucus in clinically healthy cows.     

Relationship between certain physical properties of cervical mucus and fertility in cows

The object of the present investigation was to determine several physical properties of cervical mucus in spontaneous oestrus cows in relation to fertility. Because, it is very difficult to determine the exact time of the beginning of oestrus in cows, the aim of the present study was to investigate if physical properties of cervical mucus at the time of artificial insemination (AI) are related to conception or not. A total of 93 cows of Friesian breed were used. The animals exhibited spontaneous oestrus, without being submitted to any hormonal treatment. Samples of cervical mucus were collected 5-30 min before AI and pH, viscosity, spinnbarkeit (spinability), crystallization and penetration were measured. Pregnancy diagnosis was performed by rectal palpation 3 months later. The results obtained from cows that conceived (44 animals), compared to those obtained from cows that did not conceive (49 animals), were the following: a) viscosity had been significantly lower (p < 0.05), b) crystallization had been significantly higher (p < 0.05), and c) pH, spinnbarkeit and penetration of spermatozoa into cervical mucus did not differ. In conclusion, the best time for AI is when viscosity is below 20 mm H2O and crystallization is above 3. Viscosity and crystallization could be related to ovulation time, but this needs further investigation.     

Usefulnes of cervical mucus of cattle for pregnancy tests

A qualitative fructose test was adapted for a pregnancy test in cattle. Cervical mucus was heated 1-2 minutes in a corn syrup-water solution according to the method of Hopwood. In mucus from 320 slaughtered cows there were 8.5% false positives among 118 nonpregnant and 5.0% false negatives among 202 pregnant cows. 6 distinct positives, 3 equivocal tests, and 2 definite negatives were recorded in 11 cases of intrauterine death with pseudopregnancy. The mucus from 56 live cows produced 9.7% false positives and 12.0% false negatives. Fructose contents were determined quantitatively in 96 cervical mucus samples: 60 pregnant cows averaged 148 mg%; 36 nonpregnant 34.9 mg% (p less than .005); and pregnant in the first 5 weeks 111 mg%. This method was 90% accurate in the first 5 weeks.     

Association between physical properties of cervical mucus and ovulation rate in superovulated cows

Possible associations between certain physical properties of cervical mucus (CM) and ovulation rate were studied in 21 superovulated Holstein cows. In CM samples collected at the beginning of estrus (0 h) and in 4 h intervals for the following 24 h, the pH, the spinnbarkeit (spinability), and the crystallization value were measured. Blood samples, collected at the same time points with CM samples, were assessed for progesterone and estradiol concentrations. At 48 h the number of ovulated follicles was counted by transrectal ultrasonography and the animals were allotted into 2 groups according to the occurrence of at least one (group A, n = 16) or no (group B, n = 5) ovulations. The pH was lower (P < 0.05) at 8 h (7.00 + 0.24) in group A compared with group B (7.55 + 0.12). In group A, spinnbarkeit was significantly lower at 0 h and 20 h, and higher at 8 h and 16 h compared with group B (0 h: 2.50 + 0.82 versus 6.95 + 0.41; 20 h: 3.00 + 1.89 versus 5.38 + 0.94; 8 h: 7.00 + 0.87 versus 2.75 + 0.43; 16 h: 7.00 + 1.41 versus 4.30 + 0.71, for groups A versus B, respectively). Crystallization was significantly lower at 4 h (2.00 + 0.63) and 20 h (1.50 + 0.82) in group A compared with group B (3.13 + 0.32 at 4 h and 3.00 + 0.41 at 20 h). Progesterone at all time points, and estradiol at 16 h, 20 h, and 24 h were lower (P < 0.05) in group A than in group B. The pH, crystallization, estradiol, and progesterone differed (P < 0.05) within one group, while sbk differed within both groups.Our results imply that during the periovulatory period, steadily low progesterone concentrations trigger alterations of certain CM characteristics, while extremely high estradiol concentration could prevent the occurrence of these alterations.     

Effect of norgestomet treatment on plasminogen activator activity in the cervical mucus and the endometrium in dairy cows

The aim of this study was to determine the effect of norgestomet treatment, in the absence or the presence of a functional corpus luteum (CL), on plasminogen activators activity (PAA) in the cervical mucus and the endometrium in dairy cows. Eleven days after oestrus (Day 0 = oestrus), 38 cows were randomly assigned to one untreated control group (n = 9) and three treatment groups (S(1), S(2) and S(3)). Animals of S(1) group (n = 9) received an implantation of norgestomet on the outer surface of the ear for 8 days, simultaneous injection of oestradiol valerate 5 mg and norgestomet 3 mg, i.m., and on Day 19 an injection of ECG 500 IU, i.m. Animals of S(2) group (n = 11) received the treatment of S(1) group, plus an administration of PGF(2)alpha on Day 10 for the regression of CL. Animals of S(3) group received the treatment of S(2) group, plus two additional norgestomet implants inserted on Day 16 for 36 h. Both types of plasminogen activators [the tissue-type (t-PA) and the urokinase-type (u-PA)] were detected in the cervical mucus and the endometrium of the cows. Plasminogen activators activity in the cervical mucus was higher in control group than in S(1), S(2) and S(3) groups (P < 0.001). In contrast, endometrial PAA did not differ among groups (P > 0.05). Oestradiol-17beta concentrations on Day 21 were higher in S(2) group than in control group (P < 0.01) and S(3) group (P < 0.05). Progesterone concentrations did not differ among groups (P > 0.05). Oestradiol-17beta concentrations could positively affect cervical mucus PAA in control group (P < 0.1), but not in other groups (P > 0.05). These findings suggest that control of estrous cycle by norgestomet administration, in dairy cows, exerts a suppressive effect on plasminogen activators synthesis and/or secretion in the cervical mucus, regardless of the absence or the presence of the CL. On the contrary, endometrial PAA is not affected by norgestomet treatment.     

Review article: factors influencing the estrogen and progesterone concentration in the blood of cows in late pregnancy]

This review describes the factors influencing the estrogen und progesterone levels in late pregnant cows. The various endogenous and exogenous factors (breed, calf birth weight, sex of calf, number of fetuses, season, nutrition and stressors) influence particularly significant estrogen and progesterone concentrations in peripheral blood and may lead to high variations of hormone values between cows. The possible mechanisms of influence on the estrogen und progesterone levels are discussed.     

Changes in antiproteolytic activity in the blood and cervical mucus after superovulation stimulation]

The function of proteins, peptides, proteases and inhibitors of proteases in modulations of regulation mechanisms of gonadotrophins during the development of ovarian folicles has not been fully explained up to now. We can see difference reactions of ewes to superovulation stimulations in oestrous and anoestrous periods as shown by the variation of the antiproteolytic activity of blood plasma and cervical mucus. Trypsin is used as a model for serine protease, and trypsin inhibitory activity (TIA) was measured from the reduced rate of trypsin hydrolysis of the chromogenic substrate N-alpha-tosyl-L-arginine-4-nitroanilide (TAPA, Bartík et al., 1974). Full hydrolytic activity was determined as a change in absorbency at 405 nm = 1.0 after ten-minute incubation at 25 degrees C and pH = 8.1, and inhibition was expressed in percentage of full activity. Statistical analyses were performed by Student's t-test. Twenty-three ewes in anoestrus and twenty-eight ewes in oestrus were included in this experiment. They were of the Slovak Merino breed, two to three years old, with the mean live weight of thirty to forty kg. The ewes were treated with Ageline vaginal sponges (20 mg chlorsuperlutin/sponge) to provide for synchronization of ovarian activity, in the interval of eleven to twelve days. After removal of sponges, the ewes were stimulated for superovulation as shown in Tab. I. Heparinized blood plasma samples were stored at -25 degrees C. Low molecular TIA activities were determined in HClO4--treated blood plasma. Samples of cervical mucus were taken on cotton-wool tampons which were evaluated in 0.2 M Tris-HCl buffer, pH = 8.1. Figs. 1-6 shows TIA changes in blood plasma and cervical mucus on particular days. Fig. 7 shows the mean values of controls (I-initial) after synchronization (A) and after stimulation (S). TIA changes were different in anoestrous and oestrous periods. Differences in TIA changes in blood plasma and cervical mucus in oestrous period suggested certain local regulation mechanisms of synthesis and/or secretion of this activity in the cervix. Some values of TIA were maximum at the time of expected heat or ovulation and may be some of the factor(s) which influenced fertility of females after superovulation stimulations.     

Detection of cervical bacterial contamination in swine by two methods of swabbing in relation to artificial insemination.

Factors associated with uterine contamination during artificial insemination (AI) are not well defined. A frequently imputed risk factor is vulvar hygiene, although its role has never been assessed objectively. The aim of this study was to identify an objective marker of hygiene during AI and to assess the impact of vulvar hygiene on cervical contamination. In a herd in a depopulation-repopulation process, 68 paired sows of each parity were divided into 2 treatment groups. Before 2 sham AIs, with a 24 hour interval, control sows (CTR) had their vulva cleaned and treatment sows (TRT) had theirs soiled with feces. After the 2nd sham AI, swabbings were taken from the spirette and from the cervix. Bacterial growth was assessed by a semiquantitative method, and aerobic bacterial species identified. The discordance between the paired data was assessed by a McNemar chi-square test. No difference in gram-positive bacterial counts between the 2 groups was found using the cervical swab (P > 0.05). The presence of trace colonies of Escherichia coli were, however, more frequent in TRT (P < 0.05). The spirette showed a greater contamination for mixed flora of bacterial species such as E. coli (P < 0.001) and non-S. suis streptococci (P < 0.05) in TRT sows. A light cervical E. coli growth was more frequent when the vulva had been soiled. Bacterial flora on the spirette following AI may be used as an objective and practical indicator of vulvar hygiene during AI in sows.