Template-Type: ReDIF-Article 1.0 Author-Name: L. Zavadilová Author-Workplace-Name: Institute of Animal Science, Prague-Uhříněves, Czech Republic Author-Name: J. Wolf Author-Workplace-Name: Institute of Animal Science, Prague-Uhříněves, Czech Republic Author-Name: M. Štípková Author-Workplace-Name: Institute of Animal Science, Prague-Uhříněves, Czech Republic Author-Name: E. Němcová Author-Workplace-Name: Institute of Animal Science, Prague-Uhříněves, Czech Republic Author-Name: J. Jamrozik Author-Workplace-Name: Centre for Genetic Improvement of Livestock, Department of Animal and Poultry Science, University of Guelph, Guelph, Canada Title: Genetic parameters for somatic cell score in the first three lactations of Czech Holstein and Fleckvieh breeds using a random regression model Abstract: A multiple-lactation random regression model was applied to test-day somatic cell score (SCS) records from the first three lactations of Czech Holstein and Fleckvieh cows. For Holstein, the data included 26 314 cows, with 244 953, 76 188 and 26 153 test-day records in the first, second and third lactation, respectively. For Fleckvieh, the data included 24 061 cows, with 223 421, 93 358 and 31 305 test-day records in the first, second and third lactation, respectively. The linear model for SCS included the following factors (for the given parity): fixed herd-test date effect, fixed regressions on days in milk within the age-season class, random regressions for the animal genetic and random regressions for the permanent environmental effect of the cow. Third-degree Legendre polynomials were used for all regressions. Gibbs sampling was used to generate samples from the marginal posterior distributions of the model parameters. The resulting daily heritability ranged from 0.08 to 0.11 in the middle part of lactation and it increased only slightly with parity. Extremely high values (0.25, 0.21) observed especially at the beginning and end of the third lactation for Holstein might be caused by the "end-of-range" problem. The average daily heritabilities computed for the part of lactation between 45 and 255 days in milk (DIM) were in the range from 0.10 to 0.14. Daily permanent environmental variances were higher than the genetic variances and daily residual variances decreased with DIM. The residual variances in early lactation increased with lactation number. For both breeds, the highest genetic correlations computed for the part of lactation between DIM 45 and DIM 255 were obtained between the second and third lactation (0.95). The lowest daily genetic correlations of SCS in the same DIM between different lactations occurred at the beginning of lactation, especially between the first and third lactation. The permanent environmental correlations for selected DIM were lower than the respective genetic correlations. Keywords: test-day somatic cell score, random regression model, genetic parameters, Holstein cattle, Czech Fleckvieh Journal: Czech Journal of Animal Science Pages: 251-260 Volume: 56 Issue: 6 Year: 2011 DOI: 10.17221/1286-CJAS File-URL: http://cjas.agriculturejournals.cz/doi/10.17221/1286-CJAS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjs-201106-0001.txt Handle: RePEc:caa:jnlcjs:v:56:y:2011:i:6:id:1286-CJAS Template-Type: ReDIF-Article 1.0 Author-Name: P. Kišac Author-Workplace-Name: Animal Production Research Centre in Nitra, Slovak Republic Author-Name: J. Brouček Author-Workplace-Name: Animal Production Research Centre in Nitra, Slovak Republic Author-Name: M. Uhrinčať Author-Workplace-Name: Animal Production Research Centre in Nitra, Slovak Republic Author-Name: A. Hanus Author-Workplace-Name: Animal Production Research Centre in Nitra, Slovak Republic Title: Effect of weaning calves from mother at different ages on their growth and milk yield of mothers Abstract: The aim of this study was to determine the impact of the length of calf sucking milk from its own mother on calf growth at the age of 3 months and milk yield of mothers. We tested a hypothesis that the nursing of calves by their own mothers increases the body weight of calves and decreases the milk production. 50 Holstein primiparous cows and their calves were divided into three groups according to the sucking length of calves: 7 days (A), 14 days (B) and 21 days (C). All calves suckled mother's colostrum and milk while mothers were milked twice per day. After weaning from mother calves were kept in individual hutches until 56 days of life, and then in group housing pens. In the period from birth to weaning the calves of group A reached the lowest and the calves of group C the highest daily gains (0.35 kg, 0.46 kg, 0.54 kg; P < 0.01). The lowest gain was recorded in animals of group A (0.55 kg) and the highest gain was reached by calves of group C (0.74 kg) for the period from birth to three months of age. For the first 305 days of lactation cows of group A produced insignificantly more milk than group C (7356.5 kg, 6779.2 kg, 6663.9 kg). A significant difference in milk production was recorded only during the first seven months of lactation (5494.5 kg, 5041.9 kg, and 4872.3 kg; P < 0.05). The long stay of calves with their mothers influences the growth of calves positively, but the milk production of mothers may decrease. Therefore, the stay of calves with the dam within 21 days after birth is not recommended for high-yielding dairy cows. Keywords: calf, cow, restricted suckling, weaning, growth, milk production Journal: Czech Journal of Animal Science Pages: 261-268 Volume: 56 Issue: 6 Year: 2011 DOI: 10.17221/1287-CJAS File-URL: http://cjas.agriculturejournals.cz/doi/10.17221/1287-CJAS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjs-201106-0002.txt Handle: RePEc:caa:jnlcjs:v:56:y:2011:i:6:id:1287-CJAS Template-Type: ReDIF-Article 1.0 Author-Name: L. Křížová Author-Workplace-Name: Department of Animal Nutrition and Quality of Livestock Products, Agriresearch Rapotín Ltd., Pohořelice, Czech Republic Author-Name: J. Watzková Author-Workplace-Name: Department of Animal Nutrition and Quality of Livestock Products, Agriresearch Rapotín Ltd., Pohořelice, Czech Republic Author-Name: J. Třináctý Author-Workplace-Name: Department of Animal Nutrition and Quality of Livestock Products, Agriresearch Rapotín Ltd., Pohořelice, Czech Republic Author-Name: M. Richter Author-Workplace-Name: Department of Animal Nutrition and Quality of Livestock Products, Agriresearch Rapotín Ltd., Pohořelice, Czech Republic Author-Name: M. Buchta Author-Workplace-Name: Moravol, spol. s r.o., Kramolín, Czech Republic Title: Rumen degradability and whole tract digestibility of flavonolignans from milk thistle (Silybum marianum) fruit expeller in dairy cows Abstract: The objective of this study was to determine rumen degradability and total digestibility of flavonolignans from a milk thistle fruit expeller in dairy cows considering milk production and changes in plasma flavonolignans. The experiment was carried out on three lactating Holstein cows and was divided into three periods as follows: preliminary period (Pr, 3 days) was used for the diet stabilization followed by the adaptation period (A, 6 days) in which the treatment was applied and by the balance period (B, 4 days). Cows were fed individually twice a day (6:40 and 16:40 h) ad libitum the diet based on maize silage, lucerne hay and supplemental mixture. In the periods A and B the diet was supplemented with 150 g/day of milk thistle fruit expeller applied in two equal portions at each feeding. Average daily intake of dry matter and basic nutrients was similar in all periods (P > 0.05). Milk yield and composition were not affected by the treatment (P > 0.05). The milk thistle fruit expeller used in this experiment contained 4.10 ± 0.10 mass percentage of the silymarin complex. Digestibility of silybin A and silybin B was 40.0 and 45.5%, respectively. Digestibility of other components of the silymarin complex was 100%. The highest value of the effective degradation was found for taxifolin (59.11%), while the effective degradation of the other flavonolignans ranged from 23.28 to 35.19%. Animals receiving the milk thistle fruit expeller had a higher content of plasma conjugated silybin (P < 0.001) than those without its supplementation. Keywords: silymarin complex, in sacco technique, digestibility, plasma Journal: Czech Journal of Animal Science Pages: 269-278 Volume: 56 Issue: 6 Year: 2011 DOI: 10.17221/1285-CJAS File-URL: http://cjas.agriculturejournals.cz/doi/10.17221/1285-CJAS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjs-201106-0003.txt Handle: RePEc:caa:jnlcjs:v:56:y:2011:i:6:id:1285-CJAS Template-Type: ReDIF-Article 1.0 Author-Name: A. Gümen Author-Workplace-Name: Department of Obstetrics and Gynaecology, Faculty of Veterinary Medicine, University of Uludag, Bursa, Turkey Author-Name: A. Keskin Author-Workplace-Name: Department of Obstetrics and Gynaecology, Faculty of Veterinary Medicine, University of Uludag, Bursa, Turkey Author-Name: G. Yilmazbas-Mecitoglu Author-Workplace-Name: Department of Obstetrics and Gynaecology, Faculty of Veterinary Medicine, University of Uludag, Bursa, Turkey Author-Name: E. Karakaya Author-Workplace-Name: Department of Obstetrics and Gynaecology, Faculty of Veterinary Medicine, University of Uludag, Bursa, Turkey Author-Name: S. Cevik Author-Workplace-Name: TARFAS Co., Bursa, Turkey Author-Name: F. Balci Author-Workplace-Name: Department of Zootechny, Faculty of Veterinary Medicine, University of Uludag, Bursa, Turkey Title: Effects of GnRH, PGF2α and oxytocin treatments on conception rate at the time of artificial insemination in lactating dairy cows Abstract: In several studies, hormones such as gonadotropin-releasing hormone (GnRH), prostaglandins and oxytocin were used to increase pregnancy rate by inducing ovulation and improving the sperm transport in the female reproductive tract in lactating dairy cattle. The objective of this study was to compare the effects of GnRH, prostaglandin F2α (PGF2α) and oxytocin treatments at the time of artificial insemination (AI) after spontaneous oestrus on the conception rate (CR) of lactating dairy cows. Oestrus was detected by visual observations by experienced personnel. All cows (n = 430, 308 Holstein-Frisian and 122 Swedish-Red dairy cows) were inseminated based on the am/pm rule by veterinarians of the farm. After AI, cows were alternately assigned to one of the four treatment groups: (1) GnRH (n = 113); (2) PGF2α (n = 106);(3) oxytocin (n = 106) and (4) non-treated control (n = 105). Pregnancy diagnosis was performed 28-34 and 58-64 days post-insemination by transrectal ultrasonography. Conception rates on days 28-34 and 58-64 were not different among GnRH (46.0%; 52/113 and 44.3%; 50/113), PGF2α (37.7%; 40/106 and 35.9%; 38/106) and control (49.5%; 52/105 and 47.6%; 50/105) groups. However, conception rates were lower (P = 0.02) in oxytocin (31.1%; 33/106 and 30.2%; 32/106) than in GnRH and control groups on days 28-34 and 58-64. Other covariant factors, such as milk production, days in milk (DIM), breed, parity, service number did not affect the conception rate. Thus, there were no beneficial effects of treatments with GnRH and PGF2α at the time of AI, and oxytocin had an adverse effect on CR in lactating dairy cows in this study. Keywords: cow, spontaneous oestrus, GnRH, PGF2α , oxytocin, pregnancy Journal: Czech Journal of Animal Science Pages: 279-283 Volume: 56 Issue: 6 Year: 2011 DOI: 10.17221/1283-CJAS File-URL: http://cjas.agriculturejournals.cz/doi/10.17221/1283-CJAS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjs-201106-0004.txt Handle: RePEc:caa:jnlcjs:v:56:y:2011:i:6:id:1283-CJAS Template-Type: ReDIF-Article 1.0 Author-Name: M. Heidari Amale Author-Workplace-Name: Department of Animal Science, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran Author-Name: A. Zare Shahne Author-Workplace-Name: Department of Animal Science, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran Author-Name: A. Abavisani Author-Workplace-Name: Physiology Section, Department of Basic Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran Author-Workplace-Name: Embryonic and Stem Cell Biology and Biotechnology Research Group, Institute of Biotechnology, Ferdowsi University of Mashhad, Mashhad, Iran Author-Name: S. Nasrollahi Author-Workplace-Name: Department of Animal Science, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran Title: Effects of inhibiting nitric oxide synthase on cumulus expansion and nuclear maturation of sheep oocytes Abstract: Nitric oxide (NO) is a biological signaling molecule that plays a crucial role in oocyte maturation of mammalians. It is generated by the nitric oxide synthase (NOS) enzyme from l-arginine. Although the effect of NO has been shown in oocyte maturation of some species, there is no report about its effect on the in vitro maturation of sheep oocyte. So, this study aimed to investigate the importance of NO/NOS system in the in vitro maturation of ovine oocytes. Different concentrations of L-NAME (a NOS inhibitor) (0.1, 1 and 10mM) were added to maturation medium to evaluate the effect of inhibiting NOS on cumulus expansion and meiotic resumption of sheep oocytes. After 26 h culture, low and medium concentrations of L-NAME (0.1 and 1mM) had no significant effect on cumulus expansion, however, its higher concentration (10mM) decreased percentage of oocytes with total cumulus expansion as compared to control (P < 0.05). The extrusion of the first polar body was also suppressed in a dose-dependent manner, so that the addition of 10mM L-NAME to maturation medium significantly stopped oocytes in GV stage (P < 0.05). Moreover, to confirm the results and to evaluate if this effect is reversible, 0.1mM sodium nitroprusside (SNP, a NO donor) was added only to the maturation medium which had the highest concentration of L-NAME (10mM). The concomitant addition of NOS inhibitor with NO donor reversed the inhibitory effect of L-NAME on cumulus expansion and meiotic maturation. These results indicated that NO/NOS system is involved in the maturation of sheep oocytes. Keywords: sheep, oocyte maturation, nitric oxide, L-NAME Journal: Czech Journal of Animal Science Pages: 284-291 Volume: 56 Issue: 6 Year: 2011 DOI: 10.17221/1284-CJAS File-URL: http://cjas.agriculturejournals.cz/doi/10.17221/1284-CJAS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjs-201106-0005.txt Handle: RePEc:caa:jnlcjs:v:56:y:2011:i:6:id:1284-CJAS