The aim of this study was to compare markers of semen quality, sperm membrane damage, and the seminal plasma antioxidant activity in warmblood stallions with and without sport workload stress. Four stallions were used for breeding only (control) and four both for breeding and competition in jumping. Semen samples were collected at 14-day intervals (from June to August) from each stallion (5 ejaculates per stallion). Immediately after sperm collection, a conventional examination of the ejaculate was processed. Catalytic activities of enzymes aspartate aminotransferase, alanin aminotransferase, glutathione peroxidase, superoxide dismutase and indicator of lipoperoxidation - F2(alpha) isoprostanes were measured in samples of seminal plasma. Contrary to basic semen quality indicators, the values of seminal plasma pH, aspartate aminotransferase and alanin aminotransferase were significantly (P < 0.05) impaired in the physically stressed stallions. Also, the level of F2(alpha) and the activity of superoxide dismutase were significantly (P < 0.05) increased by stress. The antioxidant activities of superoxide dismutase and glutathion peroxidase increased during the monitored period and reflected changes in F2(alpha) isoprostane concentration. We can conclude that even the conventional basic sperm indicators stay within the reference ranges of the biochemical indicators of seminal plasma such as pH or AST/ALT activity may be negatively influenced by sport workload stress. Increased concentrations of F2 alpha isoprostanes indicate that lipoperoxidation can be a mechanism of cell membrane destabilization, which is counteracted by an increase of antioxidant enzyme activities. This is the first report of oxidative stress symptoms in normospermic equine semen in relation to stallion sport workload.

Differences in follicular development and repeatability of follicular growth pattern among Czech Fleckvieh (n = 20) and Holstein (n = 23) heifers were investigated. Follicular dynamics was evaluated by daily sonographic scanning during three interovulatory intervals. The mean duration of the interovulatory interval was 20.66 +/- 0.32 days, no differences between breeds were observed. The proportion of the non-alterna-ting pattern was nearly the same as that of the alternating pattern (54% and 46%, respectively). The majority of IOIs <= 21 days were of the 2-wave pattern (71%) whereas only 29% of them were of the 3-wave pattern. Conversely, the majority of IOIs = 22 days were of the 3-wave pattern (84%), whereas only 16% were of the 2-wave pattern. Differences could be observed in the Czech Fleckvieh heifers. Comparing 2- and 3-wave interovulatory intervals, 44.2% of the heifers exhibited 3 waves and 55.8% of the heifers exhibited 2 waves of follicular growth. The ratio of 3- to 2-wave heifers was about the same in the Holstein breed; in Czech Fleckvieh 2-wave cycles slightly dominated (11/12, 8/12; respectively). In Holstein heifers, the first follicular wave occurred 0.92 +/- 0.15 days after ovulation in 2-wave interovulatory intervals, and the emergence of the first wave in 2-wave Czech Fleckvieh heifers appeared later (P < 0.05), 1.83 +/- 0.3 days after ovulation. The maximal size reached by the dominant follicles in all animals and in the Czech Fleckvieh differed in the first and in the second wave of 2-wave cycles (P < 0.05). In 3-wave interovulatory intervals the dominant follicles in the second wave differed (P < 0.05) from the mean diameters of the first and the third wave in the Czech Fleckvieh. The ovulatory follicles were significantly (P < 0.05) smaller in 2-wave than in 3-wave interovulatory intervals among all animals and between the Holstein and Czech Fleckvieh heifers. In conclusion, we found a similar pattern of ovarian follicular dynamics in Czech Fleckvieh and Holstein heifers kept under identical nutritional and environmental conditions. Whether the significant difference in the emergence of the 1(st) follicular wave in 2-wave IOIs between C and H heifers is of real biological significance is ambiguous.

The intake of zearalenone or genistein can interfere with estrogenic signalization in an organism, and these compounds can influence the state and the function of the genitals. This study investigates the possible enhanced effects of simultaneous exposure of boar sperm to both these compounds on sperm motility. The boar sperm samples were incubated in the presence of zearalenone (Zea1 = I,mu M; Zea2 = 2 mu M), genistein (Gen1 = 1 mu M; Gen2 = 2 mu M), or a zearalenone and genistein combination (ZeaGen1 = 0,5,mu M Zea + 0,5 mu M Gen; ZeaGen2 = 1 mu M Zea + 1 mu M Gen) at 38 degrees C. Sperm motility was evaluated after 4 minutes and after 4 hours of incubation. There was a significant stimulative effect of genistein in 2 mu M concentration after 4 minutes of incubation. On the contrary, the combination of zearalenone and genistein significantly decreased sperm motility in both concentrations (1 mu M, 2 mu M) after 4 hours of incubation. Genistein in 1 mu M concentration and zearalenone in 1 mu M, 2 mu M concentration had no effect on sperm motility. In conclusion, genistein can stimulate sperm motility; on the contrary, the genistein and zearalenone combination influenced sperm motility clearly negatively. The simultaneous presence of zearalenone and genistein can lead to enhanced effects than similar doses of these individual compounds.

Phytoestrogens can act as endogenous estrogens due to their binding activity to estrogen receptors (ER). The most widely investigated phytoestrogen is genistein, but differences in the potential of individual phytoestrogens do exist. The aim of the study was to verrify a hypothesis, that biochanin A, another phytoestrogen, influences meiotic maturation of pig oocytes in a manner analogous to data published on genistein or estradiol. We monitored effects on the nuclear maturation and the expansion of cumular cells during meiotic maturation in vitro. The oocytes were cultured 24 hours to the metaphase I stage. Five concentrations of biochanin A in the culture medium (0, 20, 30, 40, 50 pg/ml) were tested. Biochanin A inhibited both the nuclear maturation as well as the expansion of cumular cells of pig oocytes, depending on the dose. The cumular expansion process seems to be even more sensitive than nuclear maturation. When the highest concentration used increased presence of abnormal oocytes (20%) was found. The changes in nuclear maturation induced by biochanin A were more pronounced than in data published on comparable concentrations of genistein, the phytoestrogen with higher binding ability to ER.

As one step of cryopreservation, the choice packaging system can affect quality of insemination dose after thawing. Straw size varies quite considerably in volumes as well as in diameters. In Czech Republic are used in commercial practice 0,5 ml straws and 6 ml aluminium tubes. The objective of this study was to determine, whether the larger volume of the aluminium tubes, and, therefore, a potentially worse course of freezing, substantially influence the quality of the semen after thawing.Ejaculates from five stallions of dfferent breed, age and exploatation were compared. The diluted semen was packed into 0,5ml straws and into the aluminium tubes. The straws were thawed at 37 degrees C for 30 seconds, the aluminium tubes were thawed at 50 degrees C for 45 sec. The motility of the each sample spermatozoa was tested after thawing and after 6, 12, and 24 hours of storage at 4-5 degrees C. The differences obtained were statistically non-significant at the most. But, a slight trend of a higher activity of the tube-samples predominated The both methods of the long-time-preserved semen packaging appear to be quite equal, at least in terms of post-thawing sperm motility.

The objective of this study was to assess the health status and the most common health problems occurring in beef cattle in the Czech Republic.Thirty five beef herds of different breeds were monitored from 1 January to 31 December 2006. The health status of 4872 animals (2601 cows and 2271 of their calves) was analyzed. Herds of up to 50 cows and those over 50 cows were evaluated both separately and together. Farm management data were collected by means of a questionnaire completed by the farmers. Both geographic and herd characteristics were evaluated, as well as the course of calving, mortality and morbidity in calves, and disease occurrence in cows. Calving was unassisted in about 80% of the cows, and the conception rate was approximately 90%. More difficult courses of calving were reported from the small herds than from the large ones (p < 0.001). Total calf losses were 10% on the average. Most calf deaths occurred during the first week of life (p < 0.01), the most common cause of death being diarrhoea (p < 0.001). The situation was similar in large and small herds. Diarrhoea was also most often diagnosed in those calves that survived the early life stage. At the age of 120 days, the calves that had suffered from diarrhoea showed a lower body weight by 12.6 kg than the calves of the same age from the same herd that did not have diarrhoea. The occurrence of diarrhoea in small and large herds was 12.1% and 6.7% per herd, respectively (p < 0.05). Also, other health disorders were more often reported from small herds, in calves as well as in adult cows (p < 0.001).

The objective of the study was to verify the hypothesis that GEN (genistein - phytoestrogen and an inhibitor of tyrosine protein kinase - TPK) effects on pig oocyte maturation and cumular cell expansion under in vitro conditions are connected with its estrogenic activity. Oocytes were cultivated for 24 hours up to the stage of the first meiotic metaphase (MI). Three different doses of GEN (13, 40, 80 µg/ml of medium) and also three doses of GIN, genistin, an analogue of GEN without effects on TPK, (80, 160 and 240 µg/ml of medium) were tested. To verify the reversibility of GEN effects, the oocytes were first cultivated for 24 hours with 80 µg of GEN per 1 ml of medium and then for another 24 hours without any GEN. GEN blocked pig oocyte maturation at the stage of the germinal vesicle (GV), depending on the dose. After rinsing out the GEN the oocyte maturation recovered, but with abnormalities (32%). GIN in a concentration of 80 µg/ml of medium induced a significant blockage at the GV stage (18%). With an increase in the GIN concentration, the number of oocytes blocked at the GV stage significantly decreased, but the abnormal maturation increased (up to 31%). GEN inhibited the cumular cell expansion in proportion to its dose. GIN had a less pronounced effect. As GEN and GIN effects demonstrate similar patterns, it is probable that estrogenic activity is involved.

The objective of this study was to assess the effect of vitamin E and selenium (Se) supplementation on the plasma levels of F2-isoprostanes as a marker of oxidative stress in horses in their training period. Twelve healthy 3-year-old English thoroughbred horses were divided into two groups: control (n = 6) and experimental (n = 6). Feeding rations were adapted to a moderate workload. The horses of the experimental group received supplements of DL-α-tocopheryl acetate E (2 250 mg/day/horse) and of sodium selenite (0.5 mg/day/horse). The plasma concentrations of both antioxidants and F2-isoprostanes were monitored on days 0, 44 and 70. After 70 days of supplementation, the concentrations of selenium in the experimental group were significantly higher (P < 0.05) compared to the beginning of the experiment (mean ± SE: 135.81 ± 10.19 μg l -1 vs. 98.70 ± 10.88 μg l -1), as well as to the control group (day 0: 101.78 ± 11.06 μg l -1, day 70: 108.18 ± 7.77 μg l -1). In the horses of the experimental group, plasma α-tocopherol levels significantly increased from the 44th day of supplementation compared to the beginning of the study as well to the control group (5.23 ± 0.52 mg l -1 vs. 2.45 ± 0.25 mg l -1 or 3.46 ± 0.34 mg l -1, respectively). The plasma concentration of F2-isoprostanes tended to be lower in the experimental group at the end than at the beginning of monitoring (156.8 ± 12.89 pg l -1 vs. 170.3 ± 60.8 pg l -1), although the control group showed the opposite trend (181.2 ± 15.67 pg l -1 vs. 137.0 ± 47.05 pg l -1). Nevertheless, none of these differences were significant because of the large variability of the individual values. It can be stated that supplementation of the diet used with selenium and vitamin E caused a non-significant decrease of F2-isoprostane concentration in the blood plasma only, and a significant increase of plasma concentrations of these antioxidants. The variation of isoprostane levels probably reflected rather the individual responses of the horses' organisms to the training workload.