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We tested the hypothesis that seasonal differences in passage rate and digestibility of native forage in wapiti Cervus elaphus canadensis Erxleben, 1777 were due to seasonal appetence and digestive adaptation as well as plant phenology and compo­sition. To this end, we compared digestive characteristics of seasonal pasture with those of a standard alfalfa-barley pellet fed to wapiti hinds throughout the year. No evidence of seasonal effects independent of forage quality was found. Although dry matter intakes differed 2-3 fold, the digestibility of the standard pelleted diet was not signficantly different in winter (0.68 ± 0.02), spring (0,74 ± 0.01) and summer (0.71 ± 0.01). However, digestibilities of natural forages increased greatly from winter (0.51 ± 0.01), to spring (0.77 ± 0.02), with a gentle decline into autumn (0.65 ± 0.02). Because retention times of pelleted diets were not significantly different among seasons (winter 28 + 1 h, spring 24 ± 2 h, summer 22 ± 1 h), digestive kinetics also seemed to be mainly a function of seasonal composition of native forage rather than specific seasonal adaptation. The mean retention time of winter herbage (41 ± 2 h) was significantly longer than that of spring (28 + 3 h) and summer (25 ± 2 h) forages. Pasture forages were retained longer (51 ± lh) than pellets in winter but not in spring (28 ± 1 h) and summer (27 ± 1 h). Fecal moisture was a good indicator of digesta retention time despite forage type and may provide a simple index of digestive function for field studies.
Cryopreservation of red deer sperm is essential for establishing the biodiversity of this species. The aim of the study was to test four extenders and two freezing methods on the cryosurvival of red deer spermatozoa. Semen collected with an artificial vagina from 4 stags was diluted with compared extenders: A (citrate- -fructose-egg yolk-glicerol), B (Tris-fructose-citric acid-egg yolk-glicerol), C (Triladyl® with egg yolk) and D (Bioxcell®). Sperm, loaded into 0.25 ml straws, was frozen in nitrogen vapor (method L) and in the Minicool 40 PC (method M) cryogenic unit. After thawing the motility of spermatozoa was evaluated subjectively. Viability was assessed using nigrosin-eosin (N-E test), SYBR-14 with propidium iodide (L/D test) and hypoosmotic swelling test (test HOS) to detect membrane integrity. The best post-thaw motility was obtained with the use of extender D (43.0 ± 14.2%). Similarly, more viable spermatozoa (p < 0.05) at N-E and L/D tests (42.4 ± 11.3% and 39.9 ± 14.0% respectively) were preserved in extender D. The lowest results in those tests were received in extender A. The percentage of HOST-responsive spermatozoa was higher (p < 0.05) in method M than in L (19.8 ± 9.8 % vs 14.3 ± 7.6 %), independently of the utilized extenders. In conclusion, the use of extender D in combination with freezing method M significantly improved freezability of red deer spermatozoa.
The objective of this research was to determinate importance of grass and meadow species in red deer diet and influence, that is caused in open habitats by these animals. Study was based on foreign and local literature review. Meadow and grass species are, on average, 1/3 of plants in red deer diet, and in some places could be preferred form of forage. Availability of meadow habitats in red deer territory can reduce negative impact of this specie on forest and agricultural plantations. Influence of red deer on open habitats depends on many factors, among others – productivity of habit.
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