14 research outputs found

    Estimation of Genetic Parameters for Concentrations of Milk Urea Nitrogen

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    The objective of this study was to use field data collected by dairy herd improvement programs to estimate genetic parameters for concentrations of milk urea nitrogen (MUN). Edited data were 36,074 test-day records of MUN and yields of milk, fat, and protein obtained from 6102 cows in Holstein herds in Ontario, Canada. Data were divided into three sets, for the first three lactations. Two analyses were performed on data from each lactation. The first procedure used ANOVA to estimate the significance of the effects of several environmental factors on MUN. Herd-test-day effects had the most significant impact on MUN. Effects of stage of lactation were also important, and MUN levels tended to increase from the time of peak yield until the end of lactation. The second analysis used a random regression model to estimate heritabilities and genetic correlations of MUN and the yield traits. Heritability estimates for MUN in lactations one, two, and three were 0.44, 0.59, and 0.48, respectively. Heritabilities for the yield traits were of a similar magnitude. Little relationship was observed between MUN and yield. Raw phenotypic correlations were all <0.10 (absolute value). Genetic correlations with production traits were close to zero in lactations one and three and only slightly positive in lactation two. The results indicate that selection on MUN is possible, but relationships between MUN and other economically important traits such as metabolic disease and fertility are needed

    Wpływ uspokojenia ruchu na klimat akustyczny w otoczeniu ulic

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    The paper presents the methods to improve safety and quality of life of people living in the neighborhood of roads and the situation of road users by means of traffic calming. The focus is kept on positive impact of traffic calming measures on acoustic climate in the surrounding of roads. The paper also contains the characteristics of selected impacts of road traffic on the environment together with a general outline of traffic calming as an instrument to mitigate the negative influence. Various possibilities to frame the acoustic climate and reduce transport-related inconvenience by means of different traffic calming methods are present as well. Then a case study (regional road No 824 in Puławy) is used to assess the effectiveness of specific solutions of comprehensive traffic calming with regard to speed reduction and abatement of noise emissions. Analyses are based on measurements’ results (traffic volumes, driving speeds and noise levels) and on acoustic calculations performed by the authors as part of their own study (internal research &amp; development program of EKKOM). On the basis of measurements’ results and calculations the paper also addresses the problem of lack of correction factors related to traffic calming in the calculation model and the one of errors in noise modeling while preparing the case study.W referacie przedstawiono sposoby poprawy bezpieczeństwa i jakości życia osób mieszkających w sąsiedztwie tras komunikacyjnych i użytkowników ruchu związane z zastosowaniem środków uspokojenia ruchu. Skupiono się na korzystnym wpływie zastosowania środków uspokojenia ruchu na stan klimatu akustycznego na terenach otaczających drogi. W referacie przedstawiono również charakterystykę wybranych oddziaływań ruchu drogowego na środowisko oraz informacje wprowadzające, które dotyczą uspokojenia ruchu jako sposobu na łagodzenie tych uciążliwości. Przeanalizowano również możliwości kształtowania klimatu akustycznego i łagodzenia uciążliwości transportu za pomocą różnych metod uspokojenia ruchu. Następnie, na przykładzie studium przypadku (droga wojewódzka nr 824 w Puławach), określono skuteczność konkretnych rozwiązań kompleksowego uspokojenia ruchu, pod względem redukcji prędkości i zmniejszenia emisji hałasu. W analizach posłużono się wynikami wykonanych pomiarów (natężenia ruchu, prędkości pojazdów i poziomu hałasu) oraz obliczeń akustycznych realizowanych w ramach badań własnych autorów (wewnętrzny program badawczo–rozwojowy firmy EKKOM). Na podstawie wyników pomiarów oraz obliczeń omówiono także problem braku uwzględnienia w modelu obliczeniowym współczynników korygujących z uwagi na charakter ruchu uspokojonego oraz błędów w modelowaniu hałasu dla analizowanego przykładu

    8,11-Dioxa-(3,4-benzo)-(4.3.3)propellane

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    Some new bispirans

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    Genetic Correlations among Selected Traits in Canadian Holsteins

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    In the Canadian dairy industry, there are currently over 80 traits routinely evaluated, and more are considered for potential selection. Particularly, in the last few years, recording has commenced for several new phenotypes required to introduce novel traits with high economic importance into the selection program. However, without a systematic estimation of the genetic correlations that exist among traits, the potential results of indirect selection are unknown. Therefore, 29 traits representative of the trait diversity for first lactation Canadian animals were selected. Their two-by-two genetic correlations were estimated from a dataset of 62 498 first lactation Holstein cows, using a Markov Chain Monte Carlo Gibbs sampling approach. The general tendencies among the groups of traits confirm that production traits are negatively correlated with fertility traits and that functional traits are positively correlated with one another. The association of udder depth with fertility and disease resistance has also been highlighted. This contribution offers a comprehensive overview of current estimates across traits and includes correlations with novel traits that constitute an original addition to the literature. These new estimates can be used for newly developed genomic evaluation models and possibly lead to more accurate estimations of the dairy cows’ overall genetic merit
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