Influence of season and breed on serum mineral levels in sheep.

The main objective of this study was to assess the concentration of various minerals (Ca, P, Mg, Cu, Zn, Fe) in the blood of sheep, followed by biochemical analysis in order to reveal possible associations of season and breed. The study was conducted by sampling four herds: Suffolk (n=20), Merino (n=20), Lithuanian blackhead (n=20) and Charolaise (n=7). The first blood collection was conducted in April and the last one was performed in February. The highest level of Ca was estimated in Suffolk ewes, lowest (12.61%) in Merino breed; the highest Mg content was found in Lithuanian blackhead breed, lowest (5.26%) in Charolaise; highest P content was determined in Merino, lowest (24.18%) in Suffolk breed (p⟨0.05). Evalua-tion of the biochemical parameters during different seasons showed a possible environmental effect on the health of the animals. The difference among minerals content showed the highest level in Ca, Mg, Fe in the autumn, P - in the summer, Cu and Zn - in the winter. The lowest differences between seasons were observed in content of Mg (1.24-4.03% from total average of all seasons) and Ca (0.59-8.18%), the highest - in Cu (2.52-18.36 %) and Zn (4.33-24.33%) (p⟨0.05). The significance of this work is the possible use of the data in the prevention of metabolic and production diseases.

Influence of puerperal metritis on the first ovulation after calving in dairy cows.

The aim of this study was to determine how puerperal metritis influences the resumption of estrous cycle in dairy cows. The ovaries of 72 multiparous Holstein cows (38 healthy and 34 metritic - after treatment) were ultrasonographically scanned until the first ovulation postpartum and 7 days after to confirm the ovulation. All 72 cows were divided in to 4 groups: HSO (healthy with single ovulation) (n=29), MSO (metritic with single ovulation) (n=21), HDO (healthy with double ovulation) (n=9), and MDO (metritic with double ovulation) (n=13). The proportion of cows that had DO in the first ovulation postpartum was similar between M and H groups, 38.2% and 23.6%, respectively (p>0.05). There was a difference between HDO and MDO groups comparing the first dominant follicle ovulation postpartum (11.4±2.7 and 20±1 days, respectively p⟨0.05) and the diameter of the ovulatory follicles (15.3±1.9 mm and 17.3±1.7 mm, respectively p0.05). The percentage of cows that had double follicle dominance in the first follicular wave after first ovulation was higher in the M groups (33.3% (MSO) vs. 6.9% (HSO) (p⟨0.05) and (69.2% (MDO) vs. 22.2% (HDO) (p⟨0.05)). The MSO group dominant follicle diameter was bigger for cows which had one dominant follicle (p⟨0.05). It might be concluded that dairy cows after puerperal metritis need more time until the first ovulation. Also, metritic cows have a higher risk for double dominance in the first follicular wave, after the first ovulation.

Agreement of different methods for assessment of progesterone concentrations in beef cattle serum.

Progesterone (P4) is responsible for the main reproduction processes. Concentration of P4 varies widely among different determination methods, and interpretation of these values may be difficult. The objective of the current study was to assess the agreement of three different enzyme immunoassays (ELISA) in relation to radioimmunoassay (RIA) of P4 concentration assessment of beef cow serum samples. Samples were collected randomly considering high (pregnant cows) and low (non-pregnant cows) P4 concentrations. Depending on the P4 assessment method, four groups were created as follows: Group 1 - direct samples assessed by ELISA, Group 2 - extracted samples assessed by ELISA, Group 3 - samples assessed by automated ELISA, and Group 4 - samples assessed by RIA. The mean progesterone concentration was 4.50 ng/mL, 1.24 ng/mL, 4.07 ng/mL and 4.39 ng/mL from Group 1 to Group 4, respectively. The mean difference (MD) between Group 1, Group 2 and Group 3 individually compared with Group 4 was -0.10 ± 1.24 ng/mL, 3.15 ± 3.58 ng/mL and 0.33 ± 1.42 ng/mL, and the 95% confidence interval (CI) for the differences (s) was from -0.99 to 0.78 ng/mL, from 0.59 to 5.71 ng/mL, and from -0.69 to 1.34 ng/mL, respectively. The confidence interval for the lower and upper limit of the agreement ranged from -4.12 to -1.05 ng/mL and from 0.84 to 3.91 ng/mL between Group 1 and Group 4, from -8.45 to 0.42 ng/ mL and from 5.88 to 14.75 ng/mL between Group 2 and Group 4, from -4.29 to -0.76 ng/mL, and from 1.41 to 4.94 ng/mL between Group 3 and Group 4. Our findings show that the best agreement with RIA was observed for Group 1 and Group 3, while the agreement in the extraction method was least accurate.

Laboratory diagnosis of Mycoplasma infection in young cattle.

The aim of this study was to detect Mycoplasma species in the respiratory tract of 110, 310 and 510 day-old groups of cattle by serological, bacteriological and histopathological investigations. Antibodies against M. bovis were found in 75% of the 110 day-old, in 50%--of the 310 day-old and in 55%--of the 510 day-old groups of cattle. Bacteriological examination of the samples from nasal cavities revealed that Mycoplasma carriers were found in 60% of the 110 day-old group of cattle, 40% of the 310 day-old and 40% of the 510 day-old group of cattle. Using the PCR method Mycoplasma was isolated from 25% of lung samples of the 510 day-old group of cattle. Mycoplasma bovis and Mycoplasma dispar were confirmed by serological investigations. Foci of bronchointerstitial pneumonia were determined by histopathological examination in 27.5% of lung samples. Mycoplasma bovis was isolated in 72.7% of bronchointerstitial pneumonia cases. Data processing with an SPSS 13.0 statistical package led to the conclusion that Mycoplasma bovis was found more frequently in the 110 day-old group of cattle (the youngest age group in this study) rather than in the 310 and 510 day-old groups of cattle (chi2 = 6.531; p = 0.038). The results obtained led to the conclusion that serological, bacteriological and histopathological examinations are important in detecting particular animal--carriers of Mycoplasma.

Post-mortem examination of sows genital organs culled for reproductive disturbances and immunohistochemical studies on ERalpha and PR A receptors in the anoestral sows uterus.

The aim of present study was post-mortem examination of ovaries, uterus and plasma oestradiol-17beta (E2) and progesterone (P4) concentrations in the blood of sows with reproductive disturbances and the distribution of oestradiol receptor (ERalpha), as well as progesterone (PR-A) in the anoestrous sows uteri. Reproductive organs of 150 crossbred sows (Lithuanian White x Danish Landrace) culled for the reasons of reproductive disturbances, were collected in local abattoir over a period of 3 months (September-November). Organs were assessed to determine the stage of the oestrous cycle or anoestrus and their development. Blood samples were collected for E2 and P4 analysis from the jugular vein 1 h prior to slaughter. For this study uterine samples only from pathological anoestrous sows were subjected to immunohistochemical staining to assess the distribution of ERalpha and PR-A in surface epithelium, subepithelial connective tissue, glandular epithelium and myometrium. Macroscopic examination of the ovaries showed that 68.7% sows had active cycling ovaries, 26.6% sows were anoestrus, ovaries were small without CL, and 4.7% of sows had multiple follicular cysts. In anoestrous sows (n = 27) the number and intensity of the nuclear staining of ERalpha varied between different uterine tissue compartments. The highest number (>80%) and the strongest intensity (+++) of positively stained cells for ERalpha was seen in myometrium and glandular epithelium. In other uterine wall compartments the number and intensity of positively stained for ERalpha nuclei was lower (+/++). The PR-A was absent from all tissue compartments. The intensity of the nuclear staining for ERalpha varied not only between the different uterine compartments but also between the sows. The 11.1% of the sows presented ERalpha in surface epithelium, 74.1% of the sows in glandular epithelium and 63.0% of sows in the myometrium.

Effect of progesterone and oestradiol on sperm-zona binding and acrosome reaction in bovine spermatozoa after thawing.

This study was conducted assess spermatozoa binding capacity to the oocyte in the presence of 0.1 or 0.5 microg/ml progesterone (P4) or a combination of 0.5 microg/ml P4 with 0.1 microg/ml oestradiol (OE). The number of oocyte-bound spermatozoa in the presence of progesterone was significantly higher (p < 0.05 to p < 0.001) when compared with the control samples, that were incubated in the absence of P4. Spermatozoa binding to the zona pellucida (ZP) of the oocyte were concentration-dependent - significantly higher numbers of spermatozoa were bound in the presence of 0.5 microg/ml P4, when compared with that of 0.1 microg/ml P4. Oestradiol at 0.1 microg/ml concentration used impaired the effect of progesterone-mediated sperm-oocyte binding. The incidences of acrosome-reacted (AR) spermatozoa bound to the ZP - following 0, 60, 120 and 180 min. incubation in the presence and absence of 1 microg/ml progesterone was also assessed. Only at 180 min of incubation a higher (p < 0.001) incidence of the AR-spermatozoa was found in sperm-ZP complexes incubated in the presence or absence of progesterone, being 56.5 +/- 11.1 and 43.2 +/- 8.8 % respectively. In conclusion, progesterone enhances the sperm-ZP binding capacity. Progesterone affects the incidences of AR on zona-bound spermatozoa only after prolonged co-culture.

The effect of oestradiol, progesterone and heparin on bovine spermatozoa function after thawing.

The present experiment was designed to determine the effects of various biologically active substances, such as oestradiol (OE), progesterone (P4) and heparin (Hep) alone or in combination on sperm plasma membrane scrambling, capacitation and acrosome reaction (AR) of post-thaw bovine spermatozoa. Spermatozoa were incubated for 180 min in capacitation medium supplemented with (i) 1 mug/ml OE; (ii) 1 mug/ml P4; (iii) 1 mug/ml OE and 1 mug/ml P4; (iv) 1 mug/ml OE and 5 mug/ml Hep; (v) 1 mug/ml P4 and 5 mug/ml Hep; (vi) 1 mug/ml OE, 1 mug/ml P4 and 5 mug/ml Hep. At predetermined time intervals aliquots were taken to assess sperm plasma membrane scrambling, or capacitation (AR induced by lysophosphatidylcholine) in spermatozoa. The second experiment was aimed to study the effects of OE, P4 and OE/P4 as potential inducers of AR in Hep-capacitated spermatozoa. Plasma membrane scrambling was assessed by a flow cytometer, using Merocyanine staining. Acrosomal status and viability of spermatozoa were evaluated under epifluorescence microscope with Ethidium homodimer-1/peanut agglutinin fluorescein isothiocyanate staining method (EthD-1/PNA-FITC). The results show that OE, P4 and a combination of OE/P4 at concentrations used did not affect sperm viability. Heparin significantly (p < 0.001) increased sperm plasma membrane scrambling of OE and P4-treated spermatozoa. P4 significantly affected the rate of sperm capacitation (p < 0.001) and AR (p < 0.05), but OE expressed membrane-stabilizing properties (p < 0.05). It can be concluded that in frozen-thawed bovine spermatozoa OE presents plasma membrane stabilizing properties that can be abolished by Hep, but not by P4. Progesterone possesses capacitating and AR-inducing properties in frozen-thawed bovine spermatozoa that can be alleviated by OE.

Effect of exogenous progesterone on post-thaw capacitation and acrosome reaction of bovine spermatozoa.

The aim of this work was to study the effect of progesterone (P4) on capacitation and acrosome reaction (AR) of post-thaw bovine spermatozoa in vitro. Spermatozoa were incubated (0-180 min) in capacitation medium supplemented with 0, 0.1, 1.0 and 10.0 microg/ml of P4. At different time intervals aliquots were taken to determine sperm plasma membrane lipid destabilization, or capacitation (AR induced by lysophosphatidylcholine) in spermatozoa. The second experiment aimed to study the effects of P4, as potential inducer of AR in heparin-capacitated spermatozoa. The acrosomal status and viability of spermatozoa were evaluated under an epifluorescence microscope using Ethidium homodimer/peanut agglutinin fluorescein isothiocyanate staining method. Plasma membrane scrambling in spermatozoa was assessed by a flow cytometer, using merocyanine staining. The results show that P4 at the concentrations used had no negative effects on sperm viability. Progesterone significantly enhanced sperm capacitation (p < 0.001), but had no effect on plasma membrane lipid stability (p > 0.05) and did not significantly increase the AR of heparin-capacitated spermatozoa (p > 0.05). Progesterone displayed its effects in a dose-dependent manner with a maximum effect of 10 microg/ml P4 at 180 min of incubation. The results demonstrate that in cryopreserved bovine semen, P4 acts as capacitating, but not as an AR-inducing agent.

Effects of insulin administration at weaning on hormonal patterns and reproductive performance in primiparous sows.

Twelve primiparous sows were grouped into six pairs. One sow from each pair (T) received subcutaneous injections of porcine insulin as follows: pairs 1 and 2, 0.5 IU/kg at 07.00 h; pairs 3 to 6, 0.5 IU/kg at 07.00 and 15.00 h. Insulin administration was started one day before weaning and continued until the last day of post-weaning oestrus. Control sows (C) received physiological saline solution as a sham treatment. Blood samples were collected every 3 h from 09.00 to 21.00 h and, additionally, at 07.00 h during the period of insulin treatment. Additional blood samples were collected at 15-min intervals for 6 h for 2 days before and for 3 days after weaning, and for 12 h on the day of weaning (D35 of lactation). Exogenous treatment with insulin increased plasma levels of insulin (53 v 36 mU/l, P < 0.001) and decreased plasma levels of glucose (4.6 v 5.5 mmol/l, P < 0.001) in T-sows as compared to C-sows. During the treatment period, the average levels of cortisol (31 v 35 nmol/l, P < 0.001) and non-esterified fatty acids (0.13 v 0.16 mmol/l, P < 0.01) were lower in T-than in C-sows. No differences in glucagon or urea levels were observed between the two groups. Plasma levels of LH were higher in T- than in C-sows both before and during the treatment period. However, no differences in number of LH pulses/6h were found between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)