Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 9

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  urea concentration
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
1

Urea in lake ecosystem: the origin, concentration and distribution in relation to trophic state of The Great Mazurian Lakes (Poland)

100%
Siuda W., Kiersztyn B.
Polish Journal of Ecology
|
2015
|
tom 63
|
nr 1
The distribution, concentrations and origin of urea were studied in surface and profundal waters of meso-eutrophic and highly eutrophic parts of The Great Mazurian Lake System (GMLS) during spring — autumn period. Urea concentrations varied from 0.25 µM in surface layer to 3.36 µM in profundal zone of studied lakes and were in the range of concentrations noted in other non-polluted freshwater habitats. In the photic zone of lakes of GMLS Urea N made up to 10 % the total DON pool and often exceeded 2-3 times of NH₄-N concentrations. Pattern of changes in urea concentrations observed during three-years study excludes external urea input and suggests supplementation of lake waters with this compounds by phytoplankton decomposition processes. Generally, urea concentrations were negatively correlated with the trophic state index calculated from “algal” as well as from “bacterial” determinants. However, more detailed analysis showed that the relationships between production and assimilation of urea by various plankton components as well as the ecological role of this compound in meso- and eutrophic lakes could be different.
2

Genetic relationship of conformation traits with lactose percentage and urea concentration in milk of Polish Holstein‑Friesian cows

84%
Satola A., Ptak E., Jagusiak W., Otwinowska-Mindur A.
Animal Science Papers and Reports
|
2017
|
tom 35
|
nr 3
The objective of this study was to estimate genetic correlations of lactose percentage and urea concentration in milk with conformation traits related to udder and legs of Polish Holstein-Friesian cows. Data consisted of 5,813 test-day records and type scores of 791 primiparous cows. The analysis involved two descriptive traits (udder, feet and legs, scored from 50 to 100) and 11 linearly scored traits (describing udder: fore udder height, rear udder height, central ligament, udder depth, udder width, fore teat placement, teat length, rear teat placement; describing legs: rear legs - side view, foot angle, rear legs - rear view; on a scale of 1 to 9). Genetic correlations were calculated based on (co)variances estimated using the Bayesian method via Gibbs sampling and the multitrait animal model. Genetic correlations between lactose content and conformation traits ranged from -0.18 to 0.23, while those between milk urea concentration and conformation traits ranged between -0.02 and 0.43, respectively. Absolute values of average genetic correlations with daily lactose percentage exceeded 0.15 only for udder (descriptive trait) and several linearly scored traits, i.e. central ligament, udder depth, rear teat placement, and rear legs - rear view. Milk urea content was weakly or moderately genetically correlated with six type traits: udder, and five linearly scored traits: fore udder height, central ligament, udder width, teat length, and rear legs - side view. Absolute values of genetic correlations between these traits exceeded 0.15. Our results showed that type traits connected with udder were more highly genetically correlated with both lactose and milk urea contents than type traits describing legs. It meant that an increase in both lactose percentage and urea concentration in milk might be expected as an indirect response to selection for better udder, whereas selection for improvement of legs would not affect lactose percentage and milk urea content.
3

Relations between blood plasma lipids, glucose and urea concentrations in cows in post partum period and their reproductive performance

84%
Machal L., Chladek G., Hibner A., Zizlavsky J.
Zeszyty Naukowe Akademii Rolniczej we Wrocławiu. Zootechnika
|
1999
|
tom 45
Blood samples were taken from 134 Holstein cows between day 20 to 100 postpartum to determine the concentration of urea, cholesterol, glucose and total lipids and to define their relation to the reproductive performance traits: interval (I), service period (SP) and insemination index (II). Investigations were carried out in monthly intervals from October 1996 to October 1997. Average values of plasma urea, total lipids, cholesterol and glucose for the entire period studied were 5.78 mmol.1⁻¹, 3.61 g.l⁻¹, 3.34 mmol. l⁻¹ and 3.61 mmol. l⁻¹, respectively. High concentration of blood urea was related negatively with the value of the insemination index (rp = -0.51). When the average concentrations of total lipids were low in plasma in the specified time (month) negative correlations were found between total lipids and the length of service period (rp = from -0.23 to -0.54) and value of the insemination index (rp = -0.42). The concentration of plasma total lipids increased in time from post partum. Traits of reproductive performance were affected by the internal environment. Especially negative influences were observed when the concentration of plasma urea as well as total lipids and cholesterol increased or decreased abnormally.
4

Genetic parameters for lactose percentage and urea concentration in milk of Polish Holstein‑Friesian cows

84%
Satola A., Ptak E., Otwinowska-Mindur A., Jagusiak W.
Animal Science Papers and Reports
|
2017
|
tom 35
|
nr 2
In the future an approach incorporating cows’ measured phenotypes and marker genotypes of cows and bulls within a single model can be applied. The most important advantage of such a model is the simultaneous use of pedigree and marker-based genomic relationship data. Such a solution allows the use of both genotyped and non-genotyped animals in the prediction procedure. This pilot study is aimed towards implementation of a one-step approach in a random regression test day model context for the Polish Holstein Friesian population, considering various ways of adjusting the relationship matrix. Data consisted of 890 animals (10 genotyped bulls, 100 cows with phenotypic data and 780 ancestors without genotypes or phenotypes). Random regression test day models with a polygenic effect on milk yield modeled by second order Legendre polynomials for the estimation of variance-covariance parameters and were used for prediction of genomically enhanced breeding values (GEBV). In this model, a matrix combining pedigree and marker-based information was used instead of a traditional numerator relationship matrix. In this matrix the proportions of information coming from pedigree and markers were defined by weighting parameters w and 1-w for pedigree and marker-based information matrices, respectively. Various weights of the two sources of information were considered. The accuracy of GEBV both for genotyped bulls and for cows with phenotypes was highest for weighting parameter w=0 and lowest for w=l. Incorporating genomic information into a conventional genetic evaluation improves reliabilities of breeding value prediction, however, pedigree information is important to maintain the stability of evaluation for non-genotyped animals. Implementation of the single-step approach in a random regression test day model framework is very attractive for genomic prediction in dairy cattle, since it allows to incorporate genomic information directly into a conventional genetic evaluation. However, for accurate predictions it is essential to achieve the right balance between the numerator relationship and markers-based relationship information.
5

Effects of some non-genetic factors on concentration of urea in milk in Polish Holstein-Friesian cows

84%
Rzewuska K., Strabel T.
Journal of Animal and Feed Sciences
|
2013
|
tom 22
|
nr 3
The objective of this study was to estimate lactation curves of milk urea concentration for primiparous Polish Holstein-Friesian cows, milked in different months and air temperatures, using random regression test-day models. In the study, 6 086 431 test-day records collected in the years 2001 to 2009 from 900 962 cows were analysed. Regression curves in classes of environmental effects were modeled with Legendre polynomials. The pattern of lactation curves for milk urea (MU) resembled the lactation curve for milk. In summer and early fall, the MU concentration was higher than in the winter months. At the same time, the increase in the MU concentration was even more strongly associated with the increase of temperature, also in the winter months. In herds with higher milk production, the MU concentration was also higher, however, interaction between average herd milk production and month-temperature was found. A greater influence of month and air temperature was observed in herds with low milk production.
6

The influence of urea concentration on some physical properties of combined fertiliser and protection liquids

84%
Rogalski L., Marozas J.
Natural Sciences
|
2000
|
tom 04
7

The diagnostic value of physiological blood traits tested in the lactating cows

67%
Animal Science. Scientific Papers of Agricultural University of Poznan
|
2003
|
tom 05
8

Urea and ureolytic activity in lakes of different trophic status

67%
Siuda W., Chrost R. J.
Polish Journal of Microbiology
|
2006
|
tom 55
|
nr 3
Urea and uraease (U-ase) activity were determined in water samples taken from the surface layers of 17 lakes of different trophic status. Urea concentrations were inversely correlated with the trophic status of the studied lakes and varied from below the detection limit to 25 μmol 1⁻¹. Maximal potential ureolytic activity (Vmax) ranged from 0.2 to 7.0 μmol 1⁻¹ h⁻¹. The highest urea concentrations and the lowest U-ase activities were recorded in the spring, whereas the lowest urea concentrations and the highest rates of urea hydrolysis were observed late in summer, during heavy phytoplankton blooms. Since in the majority of the Great Mazurian Lakes microplankton growth was limited by nitrogen supply, urea was an important N source for both auto- and heterotrophic planktonic microorganisms throughout the growth period. U-ase activity was mainly related to the seston. Only up to 25% of total activity could be attributed to free enzymes dissolved in lake water. In epilimnetic water samples the bulk of the ureolytic activity originated from seston-attached bacteria. However, a positive, statistically significant correlation between ureolytic activity and chlorophyll a (Chla) concentrations suggests that phytoplankton may also be responsible for at least a some of the observed ureolytic activity in the highly eutrophic Great Mazurian Lakes.
9

Wpływ żywienia krów paszami konserwowanymi lub zielonką z traw na przemiany w żwaczu i poziom niektórych metabolitów w osoczu krwi

34%
Minakowski D., Rapczynska I., Markiewicz E., Bednarska A., Wysocka Z.
Acta Academiae Agriculturae ac Technicae Olstenensis. Zootechnica
|
1988
|
tom 31
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.