Czech Journal of Animal Science, 2011 (vol. 56), issue 6
Genetic parameters for somatic cell score in the first three lactations of Czech Holstein and Fleckvieh breeds using a random regression model
L. Zavadilová, J. Wolf, M. Štípková, E. Němcová, J. Jamrozik
Czech J. Anim. Sci., 2011, 56(6):251-260 | DOI: 10.17221/1286-CJAS 
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...
Effect of weaning calves from mother at different ages on their growth and milk yield of mothers
P. Kišac, J. Brouček, M. Uhrinčať, A. Hanus
Czech J. Anim. Sci., 2011, 56(6):261-268 | DOI: 10.17221/1287-CJAS
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...
Rumen degradability and whole tract digestibility of flavonolignans from milk thistle (Silybum marianum) fruit expeller in dairy cows
L. Křížová, J. Watzková, J. Třináctý, M. Richter, M. Buchta
Czech J. Anim. Sci., 2011, 56(6):269-278 | DOI: 10.17221/1285-CJAS
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...
Effects of GnRH, PGF2α and oxytocin treatments on conception rate at the time of artificial insemination in lactating dairy cows
A. Gümen, A. Keskin, G. Yilmazbas-Mecitoglu, E. Karakaya, S. Cevik, F. Balci
Czech J. Anim. Sci., 2011, 56(6):279-283 | DOI: 10.17221/1283-CJAS
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...
Effects of inhibiting nitric oxide synthase on cumulus expansion and nuclear maturation of sheep oocytes
M. Heidari Amale, A. Zare Shahne, A. Abavisani, S. Nasrollahi
Czech J. Anim. Sci., 2011, 56(6):284-291 | DOI: 10.17221/1284-CJAS
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...