The mean Cu concentration in blood plasma of bulls of 12 Holstein and 13 Czech Spotted breeds was 22.27 urnol.l" 1 ; P, 1.78 mmol.l" 1 ; Ca, 3.04 mmol.l" 1 ; P:Ca ratio, 0.64. The mean Cu concentration in seminal plasma of bulls was 38.17 u.mol.1' 1 ; P, 12.07 mmol.l" 1 ; and Ca, 3.52 mmol.l" 1 and the P:Ca ratio was 3.31. The relationship between Cu, P and Ca concentration in blood and seminal plasma is expressed by calculated phenotypic coefficients of correlation. Highly significant positive coefficients of correlation (PO.01) were found between the Cu, P and P:Ca ratio in blood and seminal plasma (Cu -r p =0.36, P -r=0.32 and P:Ca ratio r=0.28). In contrast, no positive relationship between the Ca concentration in blood plasma and seminal plasma was found; the calculated coefficient of correlation was negative (r =-0.16). This was probably caused by the higher Ca concentration in blood plasma of bulls.Statistically significant (P<0.05) positive coefficients of correlation were found between the Cu concentration in blood plasma and the total number of sperm in ejaculate (f -0.33), between the Cu concentration in blood plasma and the total number of sperm with progressive motility (r=0.35), and between the Ca concentration and monthly value of sperm motility (r p =0.26).Positive coefficients of correlation were found between the Cu concentration in seminal plasma and the mean monthly volume of ejaculate (r=0.36, PO.01), between the Cu concentration in seminal plasma and sperm motility (r p =0.33, P<0.05), and Cu concentration in seminal plasma and total number of sperm with progressive motility in ejaculate (r p =0.28, P<0.05).The P concentration in seminal plasma of bulls was positively correlated with the sperm concentration in ejaculate collected on test days (r p =0.36, PO.01). The correlation between the P:Ca ratio in seminal plasma and the sperm concentration in ejaculate collected on test days was positive (r p =0.39, PO.01) and so was the correlation between the P:Ca ratio and the mean monthly sperm concentration (r =0.28, PO.05). The calculated coefficient of correlation between the Ca concentration in seminal plasma and the mean monthly sperm motility was negative (r =-0.38, PO.01). It can be concluded that there is a positive relationship between the Cu and P concentrations and P:Ca ratio in seminal plasma of bulls and the quality and quantity parameters of ejaculate of active stud bulls. A higher concentration of Ca in seminal plasma negatively affected mainly sperm motility in this study.

CHLáDEK, G., ČEJNA,V.: The relationship between freezing point of milk and milk components and its changes during lactation in Czech Pied and Holstein cows. Acta univ. agric. et silvic. Mendel. Brun., 2005, LIII, No. 5, pp. 63-70 The freezing point of milk (FPM) is an instant indicator of violated technological quality of raw milk, especially of dilution. FPM can also vary due to numerous effects associated with changes in milk composition and milk characteristics. Beside the effect of season, phase of lactation, breed, milk yield, subclinical mastitis etc. the impacts of nutrition and dietary or metabolic disorders are the most significant and the most frequent (GAJDŮŠEK, 2003). FPM is a relatively stable physical characteristic and due to osmotically active elements it ranges from -0.510 to -0.535 °C (HANUŠ et al., 2003b). Recently ŠUSTOVá (2001) studied the freezing point of milk in pool samples; she observed seasonal changes in FPM of mixed milk and the effect of different diets on FPM values. KOLOŠTA (2003) looked into the effect of grazing season on FPM. HANUŠ et al. (2003a) analysed possible effects of handling of milk components on FPM. The aim of this work was to describe the relationship between FPM and milk components and the impact of breed, number and phase of lactation on FPM. We analysed 328 milk samples in total, out of which 137 samples were of Czech Pied cows and 191 samples of Holstein cows. The effect of number and phase of lactation was evaluated for both breeds together. The greatest coefficients of correlation in total were found between FPM and lactose content (r = 0.600) and solids non fat (r = 0.523). Lower coefficients of correlation were found between FPM and milk fat content (r = 0.235), milk protein content (r = 0.260) and urea concentration (r = 0.256). These coefficients were considerably lower in Holstein cows than in Czech Pied cows. The coefficients of correlation between FPM and number and phase of lactation and somatic cells count were insignificant. The total mean value of FPM was -0.534 °C. Breed statistically significantly (P<0.01) affected FPM (+0.006 °C in C breed) and milk fat content (+0.19 % in H breed). Breed highly significantly (P<0.001) affected daily milk yield (+4.9 kg milk in H), milk protein content (+0.27 % in C) and solids non fat (+0.37 % in C). On the contrary, breed had no significant effect on lactose content, urea concentration and somatic cells count. Variability of FPM was greater in Czech Pied cows (5.9 %) than in Holstein cows (0.9 %). Number of lactation had no significant effect on FPM (maximum difference between lactations was 0.008 °C). Phase of lactation had no significant effect on FPM either. Our study revealed the fact that FPM was most of all affected by lactose content and solids non fat. However, the decrease of lactose content was compensated by a tendency of mammary glad to keep Ročník LIII 7 Číslo 5, 2005 63

KUPCZYńSKI, R., ADAMSKI, M., CHLáDEK, g.: The influence of propylene glycol on body condition and milk yield of cows as well as colostrum and milk composition. Acta univ. agric. et silvic. Mendel. Brun., 2005, LIII, No. 4, pp. 51-60 The research was executed on 24 high yield dairy cows divided into three groups (n = 8). There was the control group (I) that the propylene glycol wasn't given to cows, group II -the cows received 250 ml/ day/per head of the propylene glycol, and the group III ─ the cows received 500 ml/day per head of the propylene glycol. The preparation was administered to cows per os beginning from 2 weeks before parturition to the end of the third week of lactation. During the research the condition of animals was estimated by BCS method, the daily yield was recorded, and analyses of the milk and colostrum composition were performed. The propylene glycol lightened the decrease of cows' condition during entering at the peak of lactation. The higher dose (500 ml) was more profitable, because it had an influence on the content of the colostrum components, low urea level in milk as well as on daily yield, which was higher of about 3.64 kg while the preparation was given, in comparison to the control group. In the 3 rd week of lactation the low level of somatic cells in milk of cows that received the preparation was stated. In conclusion, our study revealed a great positive effect of propylene glycol given to the cows shortly before and after parturition on their body condition and a less significant effect on colostrum quality and milk yield.

The dielectric and electric properties (specific conductivity measured by four electrodes and two electrodes, real part of relative permittivity and high-frequency specific conductivity) of 31 ejaculates from bulls and 25 ejaculates from boars used for insemination were studied on the day of sampling and after 48 h. The correlation of the results with standard indicators of the quality of the ejaculate (sperm concentration, sperm activity and volume of the ejaculate) was investigated. The average concentration of bull sperm was 1.22 + 0.46 mid cm" 3 , of the filtered spermatic fraction of boar sperm 581.00 mil.cm" 3 ; the average sperm activity of bulls and boars was only 68.7 + 6.6% and 78.0 + 4.8%, respectively; the average volume of the ejaculate of bulls and boars was 12.39 + 4.72 and 242.00+111.00 cm 3 , respectively.Correlations between the concentrations of the sperm of bulls and specific and high-frequency conductivity were always negative (r p = -0.09 to -0.75), between the activity and specific fourelectrode conductivity the correlation was positive (r p = 0.48), between the volume of the ejaculate and specific conductivity as well as relative permittivity it was again negative (r p = -0.17 to -0.72).In boars the correlations between sperm activity and all of the studied dielectric and electric properties were always positive.

The aim of this work was to quantify basic feedlot performance and carcass value characteristics of Holstein bulls slaughtered as “young cattle” at 300 kg of live weight. The observation was carried out in a group of 12 Holstein bulls fattened in identical conditions and fed on a diet consisting of ad libitum amount of crushed grain (barley and wheat) and a limited amount of protein concentrate.The mean overall values were as follows: age and live weight at slaughter 275.9 days and 299.3 kg, daily weight gain and net weight gain since birth 0.962 kg and 0.527 kg, dressing percentage 48.3%, weight of cold right carcass half 71.0 kg, weight of bones 17.5 kg, weight of muscle 53.0 kg and separable fat 0.54 kg. The mean weight of hide was 21.6 kg. The great majority of calves were classified as O2, one calf graded R2. The forequarter to hindquarter ratio was 1.4 with mean weights 29.1 kg and 41.9 kg. The mean weight of neck was 3.9 kg, chuck 3.6 kg, shoulder 5.9 kg, fore shank 3.4 kg, loin 4.1 kg, filet 1.5 kg, round 18.2 kg and hind shank 1.3 kg. We found highly significant (P<0.01) coefficients of correlation between carcass weight and live weight at slaughter (r=0.963) or daily weight gain (r=0.723). Net weight gain since birth was highly significantly (P<0.01) correlated to live weight at slaughter (r=0.723) or to daily weight gain (r=0.982) and significantly correlated (P<0.05) to age at slaughter (r= –0.665).Despite the average or worse-than-average feedlot performance parameters our experimental Holstein bulls had an adequate proportion of muscle (comparable with other literature sources), a high ratio of bones and a very low proportion of fat. Thanks to small meat trim, weights of the main dissection parts of fore-and hindquarters were comparable to those usually found in young Holstein bulls.