Department of Animal Breeding

The aim of the present study was to test whether it is possible to eliminate a high percentage of morphologically abnormal sperm in male ejaculate by assisted reproduction using the intracytoplasmic sperm injection (ICSI) method. Treatment success was evaluated by comparing fertilization, clinical pregnancy and reproduction rates between males with heavy teratospermia (≤1% morphologically normal spermatozoa) and males with a higher percentage (>1%) of normal sperm. In total, 174 patients who had previously undergone 174 ICSI cycles (1 per each pair) were evaluated retrospectively. In the group of patients with heavily impaired sperm morphology (n=37), the percentage of normal spermatozoa was ≤1%. In the second group, males with >1% normal spermatozoa (n=137) were considered as patients with mildly impaired sperm morphology. The results of partner fertilization in these two groups were compared and a lower number of fertilized oocytes was identified in the patients with heavily impaired sperm morphology (P=0.038). However, neither the gravidity nor the take-home baby rates of the partners differed between the patients with mildly and heavily impaired sperm morphology. Trends opposite to that for fertilization were observed for gravidity and delivery [odds ratio (OR), 0.62; 95% confidence interval (CI), 0.29-1.30; OR, 0.55; 95% CI, 0.26-1.24, respectively]. This indicates that the lower number of fertilized oocytes was not associated with the overall outcome of fertilization and that patients with heavily impaired sperm morphology experience the same benefit from ICSI as patients with mildly impaired sperm morphology.

REČKOVÁ ZUZANA, FILIPČÍK RADEK, MÁCHAL LADISLAV, KŘIVÁNEK IVO, NEVRKLA PAVEL, HORSKÝ ROMAN. 2017. Analysis of Reproductive Traits in the Painted Stork (Mycteria Leucocephala).
Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 65(5): 0000–0000.
The aim of the present study was focused on analysis of reproductive traits in the painted stork (Mycteria leucocephala). The analysis of partial reproductive traits was intended to complete the knowledge necessary for ensuring reproduction of the painted stork in captivity on the required level. The observation was performed in the Zoo Zlín – Lešná from 2011 to 2014. The eggs were measured and weighed after laying and then in several‑day intervals. Other observed traits were hatchability of
the eggs, number of raised young birds and their weight after hatching. During whole observation period, a total of 90 eggs of the painted stork were evaluated from 12 parental pairs. The average share of fertilized eggs was 38.9 %. Average length of eggs was 68.57 mm, average width was 46.43 mm and average weight was 79.79 g. Average weight loss of eggs during their incubation was 9.87 g. Average hatchability of all the laid eggs was 27.8 %. Average hatchability of the fertilized eggs was 71.4 %.
A total of 23 young painted storks were hatched during the observation period. Their average hatching weight was 57.04 g. The overall number of 11 individuals were raised during the four years of observation.
Keywords: mycteria leucocephala, painted stork, ciconiiformes, waterbird reproduction

To cite this article: REČKOVÁ ZUZANA, FILIPČÍK RADEK, MÁCHAL LADISLAV, HORSKÝ ROMAN. 2019. Analysis of Reproduction Indicators of the Yellow-Billed Stork (Mycteria ibis). Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 67(1): 155-161. Abstract The aim of the study was to supplement the original knowledge about the reproduction of one of four species of storks (Mycteria). The storks are classified by IUCN as endangered species with different degrees of extinction and their reproduction in human care is difficult. Therefore, it is necessary to continuously supplement and deepen the knowledge of their reproduction in captivity. The subject of the thesis was the analysis of reproductive indicators of the yellow-billed ibis (Mycteria ibis). By analyzing partial reproduction indicators, we wanted to supplement the knowledge that is needed to ensure the necessary degree of reproduction of the yellow-billed stork in human care. The monitoring was carried out in the ZOO Zlín-Lešná in these years 2011-2014. After laying, the eggs were measured and weighed, which was repeated in several-day intervals. In addition, hatchability, the number of reared young and the weight of the young after hatching were monitored. During the monitoring period, a total of 46 eggs of the yellow-billed stork by 8 parent pairs were evaluated. The average fertilized eggs ratio was 56.5 %. The average eggs length was 66.07 mm, the average eggs width was 47.02 mm and the average eggs weight was 80.46 g. The average eggs weight loss during their incubation was 5.60 g. The average hatchability was 52.2 % from all laid eggs and 92.3 % from fertilized eggs. Altogether, 24 young of the yellow-billed stork hatched during the monitoring period. The average weight of young yellow-billed stork on the day of hatching was 58.14 g. Throughout to the reference period, were reared 15 individuals of the yellow-billed stork.

232 The application of biotechnology in cattle breeding has allowed us to reduce the generation interval and to increase selection pressure in animal populations on the basis of more objective evaluation of the genotype. It facilitates more effective utilization of the reproductive potential of animals, makes a broader range of parental combinations available and thus allows for modification of the animal population in a desired way. The prerequisite for achieving these goals involves efficient cryopreservation methods for long-term storage of embryos, exchange of genetic material and creation of genetic resources. ABSTRACT: The present study was designed to compare the efficiency of bovine embryo production for cryo-preservation between oocytes collected from donors in the growth phase of follicular development (GPFD) and those recovered from donors in the undefined phase (UPFD). Cyclic cows, Czech Siemental or Holstein dairy breeds, 4-6 years of age, slaughtered at the local abbatoir were used. They were divided into two groups based on ovarian morphology: I. GPFD donors with ovaries corresponding to the growth phase of the first follicular wave (estrus cycle days 3-4; n = 52), and II. UPFD donors with ovaries in any other phase of follicular development (undefined estrus cycle days; n = 89). A total of 3 771 oocytes were collected and 1 134 embryos were prepared as two separate populations by standard protocol. In total 352 excellent or good quality embryos at the early, advanced or expanded blastocyst stage from both donor groups were pooled and used for cryotolerance assessment. They were frozen on day 7 (D7) or day 8 (D8) after fertilization by the standard procedure. After thawing, the embryos were cultured for 72 h to the hatching stage. The percentages of both D7 embryos and advanced blastocysts were significantly higher (P ≤ 0.01) for oocytes collected from GPFD donors than for oocytes collected from UPFD donors (33.7 vs 28.6% and 43.0 vs 29.5%, respectively). The percentages of excellent or good quality embryos obtained from both D7 embryos and fertilized oocytes were significantly higher (P ≤ 0.01) for oocytes collected from GPFD donors than for oocytes collected from UPFD donors (63.6 vs 49.4% and 21.4 vs 14.1%, respectively). The post-thaw survival rates were significantly higher (P ≤ 0.01) for D7 than D8 embryos (80.4 vs 66.3%). In relation to the developmental stage, the development and hatching rates were significantly higher (P ≤ 0.01) for D7 than D8 early blastocysts (75.0 vs 41.2% and 50.0 vs 5.9%, respectively) and for D7 than D8 advanced blastocysts, (73.7 vs 57.1 and 52.6 vs 28.6%, respectively). No differences were found between D7 and D8 expanded blastocysts after freezing-thawing. In conclusion, the collection of oocytes from donors in the growth phase positively influenced the in vitro production of bovine embryos for cryopreservation. The development of embryos produced with oocytes from GPFD donor group was accelerated and more excellent and good advanced blastocysts with greater cryotolerance were produced on day 7 after fertilization, as compared to embryos produced with oocytes from the UPFD donor group.

The aim of this work was to characterize oocyte fertilization and embryo cleavage in nine AI bulls to find parameters suitable for prediction of in vitro fertility. According to the d8 blastocysts rate, they were categorized as high, medium and low productive (HP, MP and LP, mean: 25.4, 21.0 and 13.6% respectively) bulls. For these categories, oocyte penetration and fertilization efficiency were assessed at 6 and 18 hours post insemination (hpi), respectively. Some presumptive zygotes were cultured and cleaved and fast-cleaved embryo rates were checked at 44 hpi. The penetration rate was significantly higher for HP bulls than for MP and LP bulls (67.9 versus 50.3 and 33.1%; p < 0.01). The syngamy rate was significantly higher for HP bulls than for MP and LP bulls (21.4 versus 10.2 and 5.7%; p < 0.05). Conversely, no significant differences in fertilization rates were found among HP, MP and LP bulls. The cleavage rate was significantly higher for HP than LP bulls (82.4 versus 74.4%; p < 0.01). The fast cleavage rate was significantly higher for both HP and MP bulls, as compared with LP bulls (82.1 and 84.7 versus 73.5%; p < 0.01). A strong correlation was found between blastocyst production and penetration (r = 0.803), syngamy (r = 0.826), cleavage (r = 0.635) and fast cleavage (r = 0.709). In conclusion, all the evaluated parameters showed a predictive value, the most significant being early penetration and syngamy.

A good functional status of cryopreserved boar spermatozoa is very important for successful fertilization of porcine oocytes and in vitro embryo production. The purpose of the study was to evaluate the changes in functional status of boar spermatozoa separated from frozen-thawed semen and capacitated in vitro by caffeine. The effect of acrosome reaction development in spermatozoa on the efficiency of oocyte fertilization has been studied in boars A, B and C. Motile spermatozoa were separated by Percoll gradient, untreated (control) or treated with both 1mM and 2mM caffeine, and capacitated or co-cultured with matured oocytes. The motility, viability, chromatin and acrosome integrity, and fertilizing ability of spermatozoa were assessed. The separation significantly increased (P < 0.05) the percentage of viable spermatozoa in all tested boars and percentages of motile and acrosome intact spermatozoa in boars B and C. The capacitation significantly decreased (P < 0.05) the percentages of viable and motile spermatozoa, but after capacitation, the motility and viability were significantly higher (P < 0.05) for the caffeine-treated spermatozoa than for the untreated controls. A fall in the proportion of acrosome-intact spermatozoa was different for each caffeine concentration and each boar, but in all boars, acrosome reaction progress was faster and, similarly, monospermy and the total efficiency of fertilization were significantly higher (P < 0.01) for the spermatozoa treated with 1mM caffeine than for those treated with 2mM caffeine. It can be concluded that there is a potential relationship between the acrosome reaction progress in frozen-thawed boar spermatozoa and the efficiency of fertilization of porcine oocytes. A faster AR induced in spermatozoa by appropriate caffeine treatment resulted in a higher monospermy rate and total efficiency of fertilization. Thus, it is important to test sires before their semen is used for in vitro embryo production. The faster AR induced by 1mM caffeine was more effective in terms of monospermy and total efficiency of fertilization.

The aim of the study was to investigate the efficiency and kinetics of fertilization in oocytes with different meiotic competence, as defined by the phase of the follicular wave and follicle size. Oocytes were recovered from cows with synchronized estrus cycles, slaughtered in either the growth (day 3) or the dominant (day 7) phase, separately from large, medium and small follicles. The oocytes were matured and fertilized by a standard protocol. Twenty-four hours after fertilization, the oocytes were denuded from cumulus cells, fixed and stained with bisbensimid Hoechst-PBS. Fertilization was more efficient and the first cleavage was accelerated in growth phase-derived oocytes, as shown by significantly higher (p ≤ 0.01) proportions of both normally fertilized and cleaved oocytes (68.8 and 25.1%), in comparison with dominant phase-derived oocytes (44.2 and 10.3%). In the growth-phase derived oocytes, proportions of normally fertilized and cleaved oocytes were significantly higher (p ≤ 0.01) in oocytes from large (100.0 and 36.4%) and medium (83.3 and 36.5%) follicles than in those from small (54.8 and 14.6%) follicles. The dominant phase-derived oocytes showed higher proportions of normally fertilized and cleaved oocytes in the populations recovered from small (51.5 and 10.0%) and medium (43.1 and 12.0%) follicles than in those from large (25.0 and 0%) follicles; however, the differences were not significant. It can be concluded that: (i) efficiency and kinetics of fertilization differ in relation to oocyte's meiotic competence; (ii) improved development of embryos from oocytes with greater meiotic competence is associated with a more effective fertilization process.

The efficiency oí in aitro embryo production is highly variable amongst individual sires in cattle. To eliminate that this variability is not caused by sperm chromatin damage caused by separation or capacitacion, chromatin integrity was evaluated. Seventeen of AI bulls with good NRRs but variable embryo production efficiency were used. For each bull, motile spermatozoa were separated on a Percoll gradient, resuspended in IVF-TALP medium and capacitated with or incubated without heparin for 6 h. Samples before and after separation and after 3-h and 6-h capacitacion or incubation were evaluated by the Sperm Chromatin Structure Assay (SCSA) and the proportion of sperm with intact chromatin structure was calculated. Based on changes in the non-DFl-sperm proportion, the sires were categorized as DNA-unstable (DNA-us), DNA-stable (DNA-s) and DNA-most stable (DNA-ms) bulls (n:3, n:5
and n:9, respectively). In DNA-us bulls, separation produced a significant increase of the mean non-DFl-sperm proportion (p < 0.01), as compared with the value before separation. Capacitacion produced a significant decrease in the mean non-DFl-sperm proportion in H+ sperm (p < 0.01). In DNA-s bulls, separation significantly increased the mean non-DFl-sperm proportion (p < 0,01) but during capacitacion, the mean non-DFl-sperm proportion remained almost unchanged. In DNA-ms bulls, neither separation nor capacitacion had any effect on the mean non-DFl-sperm proportion. It can be concluded that, although separation and capacitacion may produce some changes in sperm chromatin integrity, these are not associated with different in aitro fertility of the bulls involved.
Ke},words: Bulls, Chromatin integrity, ln uitro capacitacion, Spermatozoa

NEVRKLA PAVEL, VÁCLAVKOVÁ EVA, HORKÝ PAVEL, KAMANOVÁ VENDULA, ZUZANA REČKOVÁ, MÁCHAL LADISLAV. 2018. Growth and Meat Quality of Prestice Black-Pied and (Landrace × Large White) × Duroc Pigs. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 66(3): 701-705. The objective of the performed experiment was to evaluate growth performance and selected carcass traits and meat quality parameters in pigs of a native Czech breed Prestice Black-Pied pig (PB) and a commercial hybrid (H) used for meat production. The observation included 40 pigs, 20 pigs of the native breed PB and 20 pigs of the hybrid combination. The PB piglets showed higher (P ≤ 0.05) birth weight than the H piglets. The lifetime weight gain was higher (P ≤ 0.01) in the H pigs than in the PB pigs. The results also showed higher (P ≤ 0.01) backfat thickness in the PB breed than in the H pigs. Lean meat content was higher (P ≤ 0.01) in the hybrid pigs than in the PB breed. Higher (P ≤ 0.01) values of intramuscular fat content were found in the PB pigs than in the H pigs. Drip loss value was higher (P ≤ 0.01) in the H pigs by 1.3 % than in the PB pigs. The PB pigs showed more favourable (P ≤ 0.05) values of pH 45,24 in comparison with the hybrid pigs.

The aim of the study was to compare in vitro fertility in boars with high field fertility to select those suitable for embryo production and determine conditions for oocyte fertilization in terms of spermatozoa treatment and time of gamete coincubation. Fresh semen of four AI-boars, A, B, C and D were used for the experiments. Oocytes were matured by standard protocol. They were fertilized by spermatozoa isolated by Percoll gradient and preincubated in modified Tris-buffered medium (mTBM) without or with 1.5 mM caffeine for 30 min. Both the untreated and caffeine treated spermatozoa were coincubated with oocytes for 3h, 3h 45min or 4h 30min. Oocytes were cultured in PZM-3 medium for twelve hours and than fixed, stained with 33258-Hoechst and examined by epifluorescence. The penetration rates were higher for the untreated spermato-zoa of boars A and B compared with those of boars C and D (74.1 ± 11.2 and 77.3 ± 2.8% vs. 12.1 ± 2.8 and 19.7 ± 0.9%). The penetration rate increased from 19.7 ± 0.9 to 74.4 ± 11.4% in spermatozoa of boar D after the caffeine treatment but not in boar C. The normal fertilization rates for untreated spermatozoa of boars A and B were higher than those of boars C and D (25.9 ± 4.2% and 20.6 ± 5.2 vs. 3.0 ± 0.3 and 6.1 ± 0.2%). They increased to 28.8 ± 4.6% in boar B but decreased to 15.4 ± 1.5% in boar A after the spermatozoa treatment; no response was found in boars C and D. In order to improve the course of fertilization process, gamete coincubation time was modified for IVF-suitable boars. The 4h and 30min-coincubation of oo-cytes with either untreated or caffeine treated spermatozoa was more effective in boars A and B respectively compared with 3h-coincubation interval. It can be concluded that a) It is important to test in vitro fertility of AI-boars before their employment for embryo production b) There is variability in response of boar spermatozoa to caffeine treatment during fertilization c) Independently on the spermatozoa response, the efficiency of fertilization is influenced by time of gamete coincubation.

In this field study, embryos were derived from genetically highly valuable cows excluded from breeding due to reproductive disorders. Cows, 5 to 10 years old, of Czech Siemmental, Holstein Dairy and Beef Cattle breeds were used as oocyte donors. Oocytes were obtained either in the growth phase of the first follicular wave from cows with synchronized oestrus or in any other phases of follicular development from cows without oestrus synchronization. The embryos were prepared by a standard protocol described previously. The mean number of usable oocytes, transferable and freezable embryos per donor, and the mean percentage of usable, transferable and freezable embryos were assessed. The results were analyzed by Student's-t and Chi-squared tests. The embryos were frozen according to a slow freezing protocol. After thawing, they were transferred to recipients on Day 7 after oestrus. Irrespective of the breed, the mean numbers of usable oocytes and transferable and freezable embryos collected per donor were significantly higher (P < 0.01) for the synchronized than for the nonsynchronized donors (20.4 vs 11.7, 4.3 vs 1.0 and 3.2 vs 0.8, respectively). Similarly, the mean percentages of usable oocytes, transfer-able and freezable embryos were significantly higher (P < 0.01) for the synchronized than for the nonsynchronized donors (28.5% vs 20.5%, 20.9% vs 9.0% and 15.8% vs 6.5%, respectively). On comparison of the synchronized and nonsynchronized donors of each breed, the difference in the mean percentage of usable oocytes was significant (P < 0.01) in cows of all three breeds, the difference in the mean percentage of transferable embryos was significant in Czech Siemmental and Holstein Dairy cows (P < 0.01) and the difference in the mean percentage of freezable embryos was significant only in Holstein Dairy cows (P < 0.01). After the transfer of 41 frozen-thawed embryos and 43 fresh embryos, 20 heifers and 24 heifers became pregnant, respectively. In conclusion: (a) higher number of oocytes from infertile, genetically valuable cows was recovered in the growth phase compared with the other phases of follicular development; (b) greater development of these oocytes resulted in more embryos for transfer and cryopreservation; (c) the transfer of frozen-thawed and fresh embryos resulted in pregnancy rates of 48.8% and 55.8% , respectively.

REČKOVá, Z., MACHATKOVá, M., RyBář, R., MáCHAL, L.: Monitoring of chromatin integrity changes in the population of motile bovine sperm capacitated in vitro. Acta univ. agric. et silvic. Men-del. Brun., 2007, LV, No. 2, pp. 65-70 The objective of our study was to standardize a method for chromatin integrity assessment in a separated population of bovine sperm and monitor the changes occurring during sperm capacitation stimulated with heparin. frozen sperm of 11 young bulls of the Czech pied breed with a defined fertility in both in vitro system (from 12.9% to 25.8% embryos) and in insemination (from 60.2% to 66.4% pregnancy) was used in our experiments. Bovine spermatozoa were isolated by Percoll gradient centrifugation from frozen-thawed semen using Tyrode's medium (SP-Talp) and resuspended in a fertilization medium (IVf-Talp). The spermatozoa were incubated at laboratory temperature at a concentration 25 × 10 6 per cm 3 for 6 h either in IVf-Talp medium with heparin (H +) or without heparin (H-). Samples were obtained immediately after sperm thawing (PS), following motile spermatozoa separation (P0), and their three (P3) and six hour (P6) incubation. The samples were examined by flow cytometry. Two measurements were carried out in each of the samples so that a total of 10 thousand spermatozoa were analysed. Proportion of spermatozoa with undetectable DNA fragmentation index (non-DfI sperm) i.e. spermatozoa with undamaged chromatin structure were determined using SCSA-soft software. Chromatin integrity changes of spermatozoa before and after separation and capacitation differed markedly in individual bulls. Separation of motile spermatozoa increased significantly the mean proportion of non-DfI sperm in tested bulls (from 94.2 to 96.4%, P ≤ 0.01). While in most of the bulls the mean proportion of non-DfI sperm remained nearly constant during incubation (H-) (mean, P0-96.4%, P3-95.6%, P6-95.5%), it gradually decreased during capacitation (H +) (mean, P0-96.4%, P3-95.2%, P6-94.2%). The differences were statistically significant (P0 vs. P3H + , P0 vs. P6H + , P ≤ 0.05). Significant difference (P ≤ 0.05) in the mean proportion on non-DfI sperm was also found between capacitated (P6h +) and incubated (P6H-) spermatozoa. The results of our study suggest the following outcomes. Separation of motile spermatozoa by Percoll gradient increased the proportion of spermatozoa with undamaged chromatin structure. Sperm incubation induced gentle damage of chromatin integrity which was potentiated by heparin in capacitated spermatozoa. The proportion of spermatozoa with undamaged chromatin structure remained relatively high in the course of capacitation, therefore we can assume it to be high enough for a potential oocyte fertilization. bulls, spermatozoa, chromatin integrity, flow cytometry

The objective of the study was to characterize the effect of the oestrous cycle stage on the yield, morphology and meiotic competence of porcine oocytes. A total of 46 cycling gilts, at 8.5-9 months of age, were used as oocyte donors. Their oestrous cycle was synchronized by Regumate and the onset of oestrus was checked (Day 0). The gilts were slaughtered at the early (Days 1-5), middle (6-10) and late (11-14) luteal or early (Days 15-16), middle (17-19) and late (20-21) follicular phase. Oocytes were isolated separately from medium (5-9 mm) and small (≤ 4 mm) follicles. Cumulus-oocyte complexes with dark, evenly granulated cytoplasm and at least two compact layers of cumulus cells were selected as useful for maturation. They were matured by a standard protocol, denuded from cumulus cells, fixed in glutaraldehyde, stained with 33258-Hoechst and examined by epifluorescence. The oocytes collected from small and medium follicles differed in their yield, morphology and meiotic competence regardless of the phase. The mean number (± S.E.M.) of oocytes isolated per donor was higher (187.7 ± 48.4 vs. 16.9 ± 6.1) but the mean percentage (± S.E.M.) of useful oocytes was lower (22.4 ± 7.5% vs. 80.2 ± 6.8%; P < 0.01) for small than for medium follicles. The mean number (± S.E.M.) of useful oocytes per donor was significantly (P < 0.01) higher (42.1 ± 16.8 vs. 11.9 ± 4.3) but the mean percentage of matured oocytes was significantly (P < 0.01) lower (48.4 ± 17.8% vs. 79.9 ± 7.9%) for small than for medium follicles. The oocyte population collected from small follicles varied during the oestrous cycle. The mean number (± S.E.M.) of oocytes isolated per donor from small follicles increased during the luteal and decreased during the follicular phase, except for the late follicular phase when it increased again. The mean percentage (± S.E.M.) of useful oocytes did not differ too much during this period, except for the late follicular phase when it decreased significantly (P < 0.01). The mean number (± S.E.M.) of useful oocytes per donor increased during the luteal and decreased during the follicular phase, but the differences were not significant except for the late follicular phase (P < 0.01). Similarly, the mean percentage (± S.E.M.) of matured oocytes increased during the luteal and decreased during the follicular phase, and the differences were significant. Compared with the oocyte population from small follicles, the oocyte population from medium follicles was less variable in the period from the middle luteal to middle follicular phase, when these follicles were present on the ovaries. It can be concluded that the porcine oocyte population changes in terms of quantity, morphological quality and meiotic competence according to the stage of follicular development. The late luteal and early follicular phases appeared to be most productive for oocyte recovery, because more morphologically normal oocytes with greater meiotic competence were collected, as compared with the other stages of the oestrous cycle.

This study was designed to investigate the characteristics of acrosomal changes during capacitation of bovine spermatozoa in relationship to in vitro fertility of individual bulls. Motile spermatozoa were separated from frozen-thawed semen by a swim-up procedure and capacitated in IVF-TALP medium with or without heparin. The spermatozoa were evaluated in terms of acrosomal changes at 0, 3, 4, 5, 6 and 8 h of capacitation. Proportions of acrosome-reacted spermatozoa at 5 h and 0 h of capacitation were used for calculation of the heparin response index. Variations in the heparin response index were found among individual bulls. Based on the mean response index value of all bulls, they fell into three categories: bulls with greater, intermediate and no response to heparin (GRH, IRH and NRH, respectively). Differences in the heparin response index between the bull categories were significant (P < 0.05). Higher D7 and D8 embryo development rates were found in the IRH vs. NRH bulls (P < 0.05). In conclusion, this study shows that the spermatozoa of bulls with a greater or intermediate response to heparin appear to be most suitable for in vitro embryo production compared with spermatozoa of bulls with no response to heparin.

Significance of a short-time survival test for the prediction of quality parameters of sperm obtained by gradient centrifugation was evaluated from an aspect of their functional resistance. Frozen semen samples from 27 bulls before and after separation were assessed by a 120-min survival test. The evaluation of morphological examination of ejaculates was carried out using the SASMO computer program. Statistically significant interrelationship between sperm quality parameters in the initial insemination doses, the amounts of obtained sperm after separation and their functional and vital resistance in the survival test was documented.

The goal of this study was to analyze the genetic and environmental factors of selected meat yield indicators in Fleckvieh cattle in the Czech Republic, through the application of station (S) and field (F) testing methods. Data collected from fattened bulls were analyzed for F (n = 9378) and for S (n = 6346). In the F method and the S method, the values of the main meat yield indicators were as follows: carcass weight 402.91 kg (F), 339.37 kg (S); carcass daily gain 626.05 g/day (F), 609.74 g/day (S); SEUROP carcass classification 2.73 (F), 2.19 (S). Environmental factors were found to have a significant impact on the selected meat yield indicators; their heritability ranged from 0.14 (SEUROP classification) to 0.33 (dressing percentage). The genetic trend was significantly positive only in relation to those meat yield traits, which had a positive link to the size or weight of the animal. The genetic correlation between observations obtained in the S and F methods of testing was ver...

This review summarises the most significant findings related to the issue of the quantitative and qualitative indicators of stallion ejaculates, its processing when producing chilled insemination doses and the possibility of influencing the individual steps of the entire process. Artificial insemination, with cooled-storage semen, is increasingly used in horse breeding because it offers many advantages over natural breeding. The parameters of sperm quality and, above all, the standardization of conditions in the production of cool-stored insemination doses are still not clearly specified. There is considerable scope for further development and research in this area.

The limited range of Milky Stork in its natural habitat, as well as in under captivity, makes it difficult to learn more about it. This paper aimed to examine the breeding biology of Milky Stork raised in captivity in the Zlín-Lešná Zoo in the Czech Republic. By analyzing partial reproduction characteristic, we wanted to supplement the knowledge that is needed to ensure the necessary degree of reproduction of the Milky Stork in human care. The monitoring was carried out in the Zlín-Lešná Zoo and the following reproductive indicators were analysed: annual laying rate, size and weight of eggs laid, monitoring of egg weight loss during incubation, hatchability, and hatching weight. During the four years, a total of 23 eggs of the Milky Stork by one parent pair were evaluated. The average proportion of fertilised eggs over the whole period reached 56.5%. The average eggs length was 65.7 mm, the average eggs width was 47.0 mm and the average eggs weight was 79.7 g. Average weight loss of eggs during their incubation was 8.4 g. Average hatchability of all the laid eggs was 56.5%. A total of 13 young Milky Storks were hatched during the observation period. Their average hatching weight was 55.7 g. A total of five individuals were raised during the four years of observation. Knowledge in the field of reproduction is one of the basic prerequisites to give this species a chance to survive in the future, whether in the natural environment or human care.

The objective of our study was to standardize a method for chromatin integrity assessment in a separated population of bovine sperm and monitor the changes occurring during sperm capacitation stimulated with heparin. frozen sperm of 11 young bulls of the Czech pied breed with a defined fertility in both in vitro system (from 12.9% to 25.8% embryos) and in insemination (from 60.2% to 66.4% pregnancy) was used in our experiments. Bovine spermatozoa were isolated by Percoll gradient centrifugation from frozen-thawed semen using Tyrode's medium (SP-Talp) and resuspended in a fertilization medium (IVf-Talp). The spermatozoa were incubated at laboratory temperature at a concentration 25 × 10 6 per cm 3 for 6 h either in IVf-Talp medium with heparin (H +) or without heparin (H-). Samples were obtained immediately after sperm thawing (PS), following motile spermatozoa separation (P0), and their three (P3) and six hour (P6) incubation. The samples were examined by flow cytometry. Two measurements were carried out in each of the samples so that a total of 10 thousand spermatozoa were analysed. Proportion of spermatozoa with undetectable DNA fragmentation index (non-DfI sperm) i.e. spermatozoa with undamaged chromatin structure were determined using SCSA-soft software. Chromatin integrity changes of spermatozoa before and after separation and capacitation differed markedly in individual bulls. Separation of motile spermatozoa increased significantly the mean proportion of non-DfI sperm in tested bulls (from 94.2 to 96.4%, P ≤ 0.01). While in most of the bulls the mean proportion of non-DfI sperm remained nearly constant during incubation (H-) (mean, P0-96.4%, P3-95.6%, P6-95.5%), it gradually decreased during capacitation (H +) (mean, P0-96.4%, P3-95.2%, P6-94.2%). The differences were statistically significant (P0 vs. P3H + , P0 vs. P6H + , P ≤ 0.05). Significant difference (P ≤ 0.05) in the mean proportion on non-DfI sperm was also found between capacitated (P6h +) and incubated (P6H-) spermatozoa. The results of our study suggest the following outcomes. Separation of motile spermatozoa by Percoll gradient increased the proportion of spermatozoa with undamaged chromatin structure. Sperm incubation induced gentle damage of chromatin integrity which was potentiated by heparin in capacitated spermatozoa. The proportion of spermatozoa with undamaged chromatin structure remained relatively high in the course of capacitation, therefore we can assume it to be high enough for a potential oocyte fertilization. bulls, spermatozoa, chromatin integrity, flow cytometry

SummaryThe aim of this work was to characterize oocyte fertilization and embryo cleavage in nine AI bulls to find parameters suitable for prediction ofin vitrofertility. According to the d8 blastocysts rate, they were categorized as high, medium and low productive (HP, MP and LP, mean: 25.4, 21.0 and 13.6% respectively) bulls. For these categories, oocyte penetration and fertilization efficiency were assessed at 6 and 18 hours post insemination (hpi), respectively. Some presumptive zygotes were cultured and cleaved and fast-cleaved embryo rates were checked at 44 hpi. The penetration rate was significantly higher for HP bulls than for MP and LP bulls (67.9 versus 50.3 and 33.1%;p&lt; 0.01). The syngamy rate was significantly higher for HP bulls than for MP and LP bulls (21.4 versus 10.2 and 5.7%;p&lt; 0.05). Conversely, no significant differences in fertilization rates were found among HP, MP and LP bulls. The cleavage rate was significantly higher for HP than LP bulls (82.4 versus ...