Preferencje help
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

Wyszukiwano:
w słowach kluczowych:  Bison bonasus bonasus
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
Twenty years of the Lowland European bison Bison bonasus bonasus conservation in captivity. The aim of the work was to track back changes taking place in the Lowland European bison population kept in captivity in years 1995-2015. The material for the study was data from European Bison Pedigree Book, collected from the years 1924-2015. The parameters such as inbreeding coefficient, kinship coefficient, contribution of founder genes and completeness of pedigree information were analyzed as well as the demographic structure of the population. Over the past 20 years, a steady increase in the population size has been observed. The share of different countries in Lowland wisent breeding also changed. The study showed that the accuracy of pedigree information decreased significantly between 1995 and 2015. In 1995 169 from 342 animals living in captivity had full pedigree information. In 2005 it was 76 from 320 animals. Within the population being alive in 2015, only 62 form 577 (10%) of all animals from Lowland line have full pedigree information, that leads to the founders of the population. An increase in the average values of inbreeding coefficient in the population and mean kinship was also observed.
The European bison belongs to endangered species. Its restitution requires a complete knowledge of the structure and function of its genital organs. The aim of this study was a histological and morphometric examination of the uterus of immature and adult females. Material for the study came from 55 females living in the Białowieża Forest. According to the Polish law, the post mortem use of tissues does not require an approval from an ethics committee. The animals were divided into 2 groups: group I included 36 prepubertal females aged from 2 months to 1.5 years, while group II consisted of 19 sexually mature females aged 2 to 20 years. The samples were stained with haematoxylin and eosin (H&E). Histological and morphometric examinations included measurements of the height of the epithelium, thickness of the endometrium, thickness of the myometrium, thickness of the inner and outer muscular layers, and thickness of the perimetrium. The results were analyzed using the Statistica 12.0™ software. Statistically significant differences were found between the two groups in all morphometric parameters examined. The results revealed a high degree of similarity of the histological structure of the uterus between European bison and domestic cattle.
We studied the variation of linear measurements and skull capacity in Lowland European bisonBison bonasus bonasus (Linnaeus, 1758) during postnatal development, and the dependencies of the parameters in relation to sex, age, and body mass of the animals. Material consisted of 599 bison skulls (310 males and 289 females), within the age range of 1 month to 21 years (males) and to 27 years (females). In the group of calves to 1 year old, no sex connected differences in skull measurements were observed, whereas the skull capacity in older calves was significantly larger (0.01>p>0.001) in males than in females. From the third year of life, most skull measurements display characteristics of sexual dimorphism. Skull development in both sexes is most intensive during the first three years of life, and slows from the age of 5. In older individuals of both sexes (≥ 6 years), orbital breadth continues growing and, in females, breadth of splanchnocranium continues increasing. Growth in a bison’s skull capacity is most intensive up to the third year of life and slows from the age of 5. During postnatal development, a bison skull grows proportionally except the neurocranium, which grows slightly slower in comparison with basal length and its development finishes earlier than that of splanchnocranium. In ontogenesis, a bison skull grows much slower compared to body mass. In relation to body mass, skull capacity and the height of neurocranium grow most slowly while orbital breadth grows most intensively. The results obtained were compared with data on skull sizes of bison born in 1930–1950 and bred in captivity and with skulls of the American bisonBison bison. Inbreeding is probably responsible for some types of phenotypic abnormalities in the skull which appear in modern European bison.
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.