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Population of tigers in Polish zoos in 2000–2006

63%
Obecnie w środowisku naturalnym tygrysy zamieszkują tereny od wschodniej Turcji, przez południową Azję, do południowo-wschodniej Syberii, Półwyspu Malajskiego oraz Sumatrę, Jawę i Balię. Generalnie obszar występowania tych drapieżników kurczy się coraz bardziej, a niektóre podgatunki bezpowrotnie wyginęły, np. tygrys jawajski, tygrys balijski, tygrys kaspijski. Ogrody zoologiczne pozostają więc miejscami, gdzie można zobaczyć na żywo te wielkie koty. Utrzymywane są również w polskich zoo, gdzie coraz częściej prowadzi się tam programy hodowli i reprodukcji tego zagrożonego wymarciem gatunku. Celem niniejszej pracy była analiza pogłowia tygrysów i wybranych wskaźników reprodukcyjnych oraz śmiertelności w polskich ogrodach zoologicznych w latach 2000–2006. Na podstawie danych liczbowych z Informatora Ogrodów Zoologicznych oraz kart zwierząt dokonano analizy pogłowia tygrysów: amurskiego, bengalskiego, białego i syberyjskiego w Polsce w latach 2000–2006, uwzględniając wybrane wskaźniki reprodukcji. Populacja tygrysów w badanych latach zmniejszyła się o około 45%. Spadek ten dotyczył w większym stopniu samic. Liczba padłych zwierząt nie była rekompensowana liczbą urodzonego i odchowanego potomstwa. Utrzymanie stanu liczebności tygrysów w polskich ogrodach zoologicznych wymaga podjęcia intensywnych działań zmierzających do zwiększenia reprodukcji tego gatunku oraz zakupu lub „wypożyczenia” samic o sprawdzonej zdolności reprodukcyjnej.
Skulls of 65 American minks from the West Pomeranian Province were examined (farm: n = 33, male: n = 16, female: n = 17; wild: n = 32, male: n = 20, female: n = 12). Craniometric parameters in the number of 24 were determined and measured on each skull. Results were averaged and compared, maintaining the division into sex groups. Males were found to have statistically significant differences between wild and farm animals in 20 parameters; measurements showing no statistically significant differences were: nasal length, postorbital constriction, brain case height and greatest height of the mandibular body. Females were found to have statistically significant differences between wild and farm animals in 6 parameters: condylobasal length, tooth row length, greatest length of the mandible, brain case basis length, postorbital length and palatal length. The percentage conversion of measurements into the greatest length of the skull showed differences in its proportions. Among male skulls, the parameters for which the ratio of differences was more than 2% were palatal length, zygomatic breadth and brain case height. For female skulls, no craniometric parameters showed differences in the skull proportions being greater than 2%. The occurrence of measurable changes in the craniometric parameters between domestic and farm mink populations may indicate that the domestication process is still ongoing and allows distinguishing the population affiliation of an individual specimen. (Folia Morphol 2016; 75, 2: 251–256)
The aim of the study was to determine the effect of hormonal stimulation during the mating season on reproduction performance in American mink females and a selection of both the hormonal formulation and its dosage. The study involved one-year old Pearl females of mink (Neovison vison). The females received one of two hormonal formulations, F1 or F2, with a single injection administered 24 hours before planned mating. The formulations contained: (F1) a pituitary gonadotropin releasing hormone analogue, and (F2) freeze-dried, crystalline serum gonadotropin (PMSG) of a strong FSH- and LH-like effect. Each formulation was administered in three dosage levels. The hormonal stimulation applied 24 hours before the planned mating significantly reduced the number of sterile females, also brought a significant increase in the average litter size, from 1.05 to 1.35 kits, and in the average number of live births, from 1.03 to 1.98. Of the two formulations tested, the analogue of pituitary gonadotropin releasing hormone (F1) at a dose of 36 IU proved to be the most effective; its application allowed attaining the highest reproductive parameters. Using hormonal stimulation of the female mink during the mating can be effectively put into practice on the farm and may in consequence improve the profitability of the production cycle.
The corpus luteum is an endocrine organ that exhibits extremely rapid growth, development, and regression during the course of each oestrus cycle. At the end of the luteal phase there is an orderly sequence of functional and structural changes in the corpus luteum connected with its regression. This article focuses on selected mechanisms controlling these changes. In these mechanisms, apart from central regulation, the essential role of local monocytes/macrophages and endothelial cells is stressed, as well as intercellular interactions. The research of the last years shows that corpus luteum regression is related to apoptosis. The functional changes that have been initialized by prostaglandin F2 are accompanied by the activation of immunological system cells, which while relieving cytokines work like local regulators in remodeling the corpus luteum. Consequently, metabolic changes, the disappearance of luteal tissue and the final expiration of progesterone production occur.
The aim of this study was to analyze the effect of gestational length and multiplicity of mating encounters on selected reproductive parameters within several color varieties of the mink. The material comprised the breeding results of 1285American mink females of three color varieties: Sapphire, Silverblue, and the Scanbrown. The highest fertility and the highest number of live born and weaned per litter were achieved by Silverblue females.Within all the analyzed gestational length intervals in each color variety, the pregnancies with a length of 45 to 55 days were dominant (78.1% for Sapphire, 75.78% for Silverblue and 64.75% for Brown), while the lowest percentage (3.17% for Sapphire, 6.88% for Silverblue and 3.25% for Brown) represented the pregnancies lasting up to 44 days. The study shows that with an increase in the length of gestation litter sizes become smaller, which is consistent with reports of other authors conducting similar research on this group of animals.We observed an increase in the average litter size with an increase in the number of mating encounters within all analyzed mink color varieties.
The aim of this study was to analyze the effect of gestational length and multiplicity of mating encounters on selected reproductive parameters within several color varieties of the mink. The material comprised the breeding results of 1285American mink females of three color varieties: Sapphire, Silverblue, and the Scanbrown. The highest fertility and the highest number of live born and weaned per litter were achieved by Silverblue females.Within all the analyzed gestational length intervals in each color variety, the pregnancies with a length of 45 to 55 days were dominant (78.1% for Sapphire, 75.78% for Silverblue and 64.75% for Brown), while the lowest percentage (3.17% for Sapphire, 6.88% for Silverblue and 3.25% for Brown) represented the pregnancies lasting up to 44 days. The study shows that with an increase in the length of gestation litter sizes become smaller, which is consistent with reports of other authors conducting similar research on this group of animals.We observed an increase in the average litter size with an increase in the number of mating encounters within all analyzed mink color varieties.
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