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

Znaleziono wyników: 10

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

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

Bydlo dzikie i domowe w polskich ogrodach zoologicznych

100%
Pawlina E., Satola A.
Bydło
|
2008
|
nr 12
36-39
2
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Wpływ wybranych czynników na zawartość mocznika w mleku krów rasy polskiej holsztyńsko-fryzyjskiej

100%
Satola A., Ptak E.
Roczniki Naukowe Polskiego Towarzystwa Zootechnicznego
|
2016
|
tom 12
|
nr 3
Celem pracy było zbadanie zależności między zawartością mocznika w mleku a takimi czynnikami, jak: numer laktacji, faza laktacji, miesiąc i sezon pobrania próby, wiek krów przy wycieleniu, poziom wydajności mleka i zawartość białka. Do obliczeń wykorzystano dane z 7731 próbnych udojów 1078 krów rasy polskiej holsztyńsko-fryzyjskiej odmiany czarno-białej. Próbne udoje z pierwszej, drugiej i trzeciej laktacji wykonano w okresie od grudnia 2010 roku do grudnia 2011 roku. Obliczenia wykonano przy użyciu procedury MIXED z pakietu SAS/STAT. Zastosowano model liniowy mieszany, w którym parametry estymowane były za pomocą metody największej wiarogodności z ograniczeniami (REML). Średnie najmniejszych kwadratów dla efektów stałych w modelu porównano testem Tukeya-Kramera. Stwierdzono, że laktacja pierwsza różniła się istotnie od laktacji drugiej i trzeciej pod względem zawartości mocznika w mleku, natomiast między laktacją drugą i trzecią nie występowały istotne różnice. U pierwiastek zawartość mocznika w mleku rosła przez cały okres laktacji, natomiast u krów starszych tylko do siódmego, ósmego miesiąca laktacji. Nie stwierdzono statystycznie istotnych różnic między zawartością mocznika w tych samych fazach sąsiednich laktacji, tzn. pierwszej i drugiej oraz drugiej i trzeciej. Natomiast między laktacją pierwszą i trzecią statystycznie istotne różnice w zawartości mocznika wystąpiły tylko w 9. i 10. miesiącu laktacji. Zmiany zawartości mocznika związane z sezonem pobrania próby miały różny charakter w zależności od numeru laktacji. W laktacji pierwszej najniższa zawartość mocznika w mleku wystąpiła w sezonie wiosennym, a najwyższa w sezonie jesiennym. Tendencja ta nie powtórzyła się w kolejnych laktacjach, tj. drugiej i trzeciej. Odnotowano, że wraz ze wzrostem zawartości białka w mleku rosła również zawartość mocznika w mleku. Podobnie, wraz ze wzrostem wydajności mleka rosła zawartość mocznika w mleku.
3

Genetic parameters of milk fat-to-protein ratio in first three lactations of Polish Holstein-Friesian cows

100%
Satola A., Ptak E.
Journal of Animal and Feed Sciences
|
2019
|
tom 28
|
nr 2
The aim of the study was to estimate the genetic parameters of milk fat-to-protein ratio in the first three lactations of Polish Holstein-Friesian cows. Data included 104 875 test-day records of 6299 cows calving from years 2000–2012. Genetic parameters were estimated with a multitrait random regression model using the Bayesian method via Gibbs sampling. The linear model for fat-to-protein ratio and milk traits (milk yield, lactose percentage, milk urea concentration) included fixed herd-test-day effect, fixed regressions within age at calving by season of calving subclasses, and random regressions for additive genetic and permanent environmental effects. All regressions were modelled using fourth-order Legendre polynomials. The average daily heritability of fat-to-protein ratio ranged from 0.24 to 0.31. Fat-to-protein ratio was negatively genetically correlated with milk yield for almost every day in milk in each lactation, with means of −0.52, −0.24 and −0.05 in the first, second and third lactations, respectively. Average genetic correlations of fat-to-protein ratio with lactose percentage and milk urea concentration were rather low or close to zero (−0.08 to 0.10) except for the genetic correlation with milk urea content in the second lactation (0.32). The results suggest that fat-to-protein ratio is a heritable trait and might be used in the selection of Polish Holstein-Friesians assuming that the relationship between fat-to-protein ratio and economically important traits will be investigated.
4

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

81%
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.
5

The relationship between fertility and intermediate optimum type traits in Polish Holstein-Friesian cows

81%
Jagusiak W., Ptak E., Zarnecki A., Satola A.
Journal of Animal and Feed Sciences
|
2014
|
tom 23
|
nr 1
The purpose of this study was to find early indicators of cow fertility. Genetic correlations of two types of conformation evaluations, routine and modified, with reproduction traits were estimated. Data consisted of type evaluations and fertility measures of primiparous Holstein-Friesian cows born from 2005 to 2006. The number of records ranged between 4731 and 8041 depending on the trait. Type traits with intermediate optima were evaluated using routine and modified scales. In the modified system, the more desirable form of a trait received the higher score. A multi-trait animal model and Gibbs sampling were applied. Among modified type traits the highest genetic correlations were found between non-return rates for cows and rear legs side view (–0.36), between days open and rump angle (0.36), and between interval from calving to first insemination and rump angle (0.35). Genetic correlations of routine type traits with fertility measures were low for udder traits and rump angle (–0.08 to 0.10) and moderate for leg traits (–0.34 to 0.44) and body depth (–0.41 to 0.36). Modified scores for rear legs side view and rump angle, and routine scores for body depth and foot angle may be used as early indicators of cow fertility in Polish Holstein-Friesians
6

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

81%
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.
7

Modeling lactation curves of Polish Holstein-Friesian cows. Part II: Prediction of 305-d lactation milk, fat and protein yields

81%
Otwinowska-Mindur A., Ptak E., Jagusiak W., Satola A.
Journal of Animal and Feed Sciences
|
2014
|
tom 23
|
nr 1
The objective of the study was to compare five lactation curve models, Ali and Schaeffer, Guo, Wilmink, and third- and fourth-order normalized Legendre polynomials, for their ability to reliably predict 305-d lactation yields from test-day records. The analysis covered 27 589 422 test-day yields from 3 350 638 first three lactations of 1 621 796 Polish Holstein-Friesian cows. All of the functions were fitted to the test-day yields of milk, fat and protein using a multiple-trait prediction (MTP) method. Based on the fitted curves, 305-d yields were calculated and the results were compared with the official lactation yields of cows assumed as true yields. Lactation curve models differed significantly (P < 0.01) when 305-d yields of milk traits were estimated and compared. Legendre polynomials showed the smallest bias and the highest accuracy among five compared models for all milk traits, whereas the Guo model for milk and the Wilmink model for fat and protein had the highest bias and the lowest accuracy. All of the functions produced similar estimates of milk, fat and protein yields at peak day; the estimated day of peak depended on the model.
8
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Sezonowość w aktywności rozpłodowej samców szynszyli na fermie reprodukcyjnej w warunkach klimatycznych Polski południowej

81%
Szeleszczuk O., Kowalczyk A., Satola A.
Roczniki Naukowe Polskiego Towarzystwa Zootechnicznego
|
2017
|
tom 13
|
nr 4
9

Modeling lactation curves of Polish Holstein-Friesian cows. Part I: The accuracy of five lactation curve models

81%
Otwinowska-Mindur A., Ptak E., Jagusiak W., Satola A.
Journal of Animal and Feed Sciences
|
2013
|
tom 22
|
nr 1
The objective of this study was to compare five mathematical functions used for modeling lactation curves and to choose the most suitable one for Polish Holstein-Friesian cows. The data used were 1,944,818; 1,548,700; and 1,081,107 test-day milk yields from 220,487 first, 181,165 second, and 128,774 third lactations. Five models were fitted to the test-day data: the Ali and Schaeffer (ALI), Guo (GUO), and Wilmink (WIL) functions, and thirdorder (LEG3), and fourth-order (LEG4) Legendre polynomials. The milk lactation curves were fitted using a multiple-trait prediction method. Several criteria based on the analysis of residuals were used to compare the models. Of the five models, five-parameter functions (ALI and LEG4) gave the best goodness of fit for standard lactations (305-d), whereas three-parameter functions (GUO and WIL) were the worst. For extended lactations (400-d), the ALI function ensured the most correct prediction.
10

Prediction of 305-day lactation milk, fat and protein yields using Legendre polynomials and test-day yields from different parts of lactation

80%
Ptak E., Satola A., Czaja H.
Animal Science Papers and Reports
|
2004
|
tom 22
|
nr 2
Applicability was evaluated of second-, third- and fourth-order Legendre polynomials (LPs) as lactation curve models for prediction the 305-day lactation yields. First lactation milk, fat and protein yields were calculated using the standard lactation curve method (LCM) and data collected during lactations truncated at 60, 100, 200 and 305 days-in-milk. All results were compared with the official lactation yields of cows. Data consisted of 5,289,576 test-day yields from 668,964 lactations of Black-and-White heifers. Standard lactation curves were modelled by LPs of the second (L2), third (L3) and fourth (L4) orders within 64 classes of genetic group by age at calving by season of calving.LPs of the highest order (L4) were the best-fitted lactation curve models, followed by L2 and L3 polynomials, showing that LPs of even orders are more suitable for fitting lactation curves. It is concluded that 305-day yields of heifers can be predicted with sufficient accuracy when the lactation curve parametres are derived using tests from the first 200 days-in-milk.
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.