共查询到20条相似文献,搜索用时 15 毫秒
1.
Martin Tjernberg 《Ecography》1981,4(1):12-19
During a five-year period, 1975–1979, a total of 2881 prey individuals of 65 prey species were collected at 162 golden eagle nests from northern Sweden and from the island of Gotland. In northern Sweden birds are taken in higher numbers than mammals but calculated as weight the two categories are of equal importance, The main prey during the breeding season are capercaillie, black grouse, willow grouse, ptarmigan, mountain hare and reindeer fawns which together form 91% of the total food biomass. The capercaillie and the black grouse are taken more in the southern part of the coniferous region than in the northern. In contrast, in northern areas, reindeer fawns are more preyed upon than in the South, Ptarmigan and willow grouse are the most commonly captured prey species in mountain areas. The total number of reindeer fawns taken (dead and/or alive) by the Swedish golden eagle population during one summer is estimated at 600 individuals. On Gotland the golden eagles take mammals more often than in its northern distribution area. Rabbit and hedgehog arc the most important species. 相似文献
2.
Nutrient dynamics of reindeer forage species along snowmelt gradients at different ecological scales
Growing season nutrient dynamics of four reindeer forage species (Betula nana, Eriophorum angustifolium, Rumex acetosa and Vaccinium myrtillus) were studied in a mountainous sub-arctic landscape in N Sweden. Changes in nitrogen (N), phosphorus (P) and fibre (ADF) concentrations in leaves and shoots were analysed (from a reindeer foraging perspective) along four ecological gradients significant to regional and local snowmelt regimes: season, oceanicity, altitude, and snow-patch retreat. N and P concentrations showed marked seasonal variations with peaks occurring from the middle of June to the end of July depending on species and snowmelt progression. The seasonal pattern for ADF concentrations, as well as differences between snowmelt regimes, were less consistent and showed large differences between species. N concentrations increased along snowmelt gradients at small (within snow-patches) and medium (along altitude gradients) spatial scales. Furthermore, variations in N concentrations were temporally and spatially scale-dependent, which underlines the importance of scale for understanding plant nutrient dynamics in sub-arctic and alpine systems, as well for plant–animal interactions. The greatest temporal and spatial differences in nutrient quality were observed early in the season, i.e., at the time of highest nutrient requirements for reindeer. Climate-induced changes of the start and the progress of the growing season may result in significant consequences to the development of calves and subsequently to the population demography of reindeer, mediated through spatial and temporal changes in the distribution of high quality food. These results provide basic knowledge for reindeer management in the light of the ongoing global warming. 相似文献
3.
Hänninen ML Sarelli L Sukura A On SL Harrington CS Matero P Hirvelä-Koski V 《Journal of applied microbiology》2002,92(4):717-723
AIMS: To study the prevalence of Campylobacter spp. in the faecal material of reindeer, and to identify the isolates by means of a polyphasic approach. In addition, to study the genetic diversity of Camp. hyointestinalis subsp. hyointestinalis reindeer isolates by pulsed-field gel electrophoresis (PFGE). METHODS AND RESULTS: The material, collected during the slaughter period in autumn 1998, comprised 399 faecal contents from the reindeer (Rangifer tarandus), a semi-domesticated, meat-producing ruminant of northern Finland. These samples came from 16 herds in the areas of eight reindeer slaughterhouses. Samples were cultured by methods suitable for isolation of fastidious Campylobacter species. Of all samples, 6% (24/399) were Campylobacter-positive. Phenotypic characteristics, SDS-PAGE protein patterns, dot blot DNA-DNA hybridization, 23S rDNA restriction fragment polymorphism analysis and PFGE identified the isolates as Camp. hyointestinalis subsp. hyointestinalis. CONCLUSIONS: Campylobacter hyointestinalis subsp. hyointestinalis was the only Campylobacter species isolated from reindeer in this study. The isolates showed high genomic diversity in PFGE with the restriction enzymes SmaI and KpnI. SIGNIFICANCE AND IMPACT OF THE STUDY: PFGE analysis is a useful subtyping method for epidemiological studies. Contaminated reindeer meat can be a source for human infections. 相似文献
4.
Miraglia N Costantini M Polidori M Meineri G Peiretti PG 《Animal : an international journal of animal bioscience》2008,2(3):410-418
In the Molise region (Italy), some autochthonous populations are still bred and, between them, some wild horses named 'Pentro horses.' The breeding area is a natural pasture. It is 2200 ha extended including a broad plane surrounded by wooden hills. The aim of this research was to determine the nutritional characteristics of this area over a 2-year period to improve the management of the herd and to define the stocking rate in relation to the forage production in terms of production and quality. The forage samples were collected over two successive years during the grazing period (May to October) from five experimental areas and analysed for dry matter (DM), organic matter (OM), crude protein (CP), crude fibre (CF), neutral-detergent fibre (NDF), acid-detergent fibre (ADF), acid-detergent lignin (ADL) and gross energy (GE). Horse feed units (HFU) and horse-digestible crude protein (HDCP) were also predicted. Data were analysed with a one-way ANOVA test using month and area as factors. The DM, HFU and HDCP total production was determined to be compared with the total nutrient requirements of the herds from May to October. The results show that seasonal and yearly climatic variations significantly affect chemical composition and nutritive value of the pasture. The parameters most influenced were DM, CP, ADF and to a less extent NDF, while OM, ADL and GE show smaller differences during the observed period. The results show a low production per ha; nevertheless, because of the low stocking rate (0.3 to 0.6 head per ha), nutrient production meets the nutrient requirements of the horses regarding DM and energy. The differences among the areas have to be ascribed to the different botanical compositions and to the different draining capacity of the soil, and also in this case the greatest variations are for DM, CP and ADF. 相似文献
5.
The relationship between tree canopy cover and forb species in savanna was investigated by examining the effect of tree canopy cover on the yield, crude protein, fibre and lignin content of forb species.The yield of some forb species show a tendency of being higher under tree canopy than in the open though no statistical significance can be shown. A higher forb yield is obtained under high tree canopies than under lower ones.No significant differences in mean crude protein, fibre and lignin content were observed between forb species growing under tree canopy and those in the open. 相似文献
6.
Decomposition processes of beech leaf litter were studied over a 3-year period in a cool temperate deciduous forest in Japan. Organic chemical and nutrient dynamics, fungal biomass and succession were followed on upper (Moder) and lower (Mull) of a forest slope. Litter decomposition rates were similar between the sites. Nutrient dynamics of the decomposing litter was categorized into two types: weight changes in nitrogen and phosphorus showed two phases, the immobilization (0–21 months) and the mobilization phase (21–35 months), while those in potassium, calcium and magnesium showed only the mobilization phase. The rate of loss of organic chemical constituents was lignin < holocellulose < soluble carbohydrate < polyphenol in order. The changes in lignocellulose index (LCI), the ratio of holocellulose in lignin and holocellulose, were significantly correlated to the changes in nitrogen and phosphorus concentrations during the decomposition. During the immobilization phase, increase in total fungal biomass contributed to the immobilization of nitrogen and phosphorus. The percentage of clamp-bearing fungal biomass (biomass of the Basidiomycota) to total fungal biomass increased as the decomposition proceeded and was significantly correlated to LCI. Two species in the xylariaceous Ascomycota were dominantly isolated by the surface sterilization method from decomposing litter collected in the 11th month. The organic chemical, nitrogen and phosphorus dynamics during the decomposition were suggested to be related to the ingrowth, substrate utilization and succession of the Xylariaceae and the Basidiomycota. Twenty-one species in the other Ascomycota and the Zygomycota isolated by the washing method were classified into three groups based on their occurrence patterns: primary saprophytes, litter inhabitants and secondary sugar fungi. These species showed different responses to LCI and soluble carbohydrate concentration of the litter between the groups. 相似文献
7.
Studies on the nutritive ecology of red colobus monkeys (Colobus badius preussi) in Korup National Park, Cameroon, investigated food plants and the parts eaten as well as nutritive values of the various food items. Food plants were identified through direct observations and collected for laboratory determination of nutrient content. Food plants were analysed for crude protein (CP), crude fibre (CF), ether extract (EE), nitrogen‐free‐extractive (NFE) and total ash (A). A total of seventeen species belonging to nine different families were identified as food plants for red colobus. Food and feeding habits showed that the species were highly folivorous, tending to prefer the young leaves of food plants. Lecomtedoxa klaineana (27.0%) and Xylopia aethiopica (22.2%) of families Sapotaceae and Annonaceae, respectively, constituted about 50% of total food items consumed. Results of nutrient composition indicated individual nutrients varied significantly (P < 0.01) with food species. 相似文献
8.
Secondary metabolites in Cladina stellaris in relation to reindeer grazing and thallus nutrient content 总被引:2,自引:0,他引:2
We analysed concentrations of phenols and key macro-nutrients in a dominant mat-forming lichen, Cladina stellaris, in dry heath forests subjected to heavy reindeer grazing in Finnish Lapland. Lichen samples were collected in the beginning of two growth seasons from six to eight sites with old reindeer exclosures that served as control plots within sites. The concentration of perlatolic acid in lichen apices (top 10 mm) was higher in grazed plots than in control ones, whereas usnic acid did not seem to respond unequivocally to grazing. Moreover, there was a strong negative relationship between nitrogen and phenolic content of Cladina stellaris in intact plots but this relationship was absent in grazed ones. Changes in nitrogen and phosphorus contents caused by reindeer grazing were not correlated with changes in the level of phenolics in lichen thalli. The present result demonstrated that the carbon-nutrient balance (CNB) hypothesis may well explain some of the variation in lichen phenolic content but is not sufficient for explaining changes caused by reindeer grazing. We hypothesized that physical changes in the lichen microenvironment induced by reindeer have more profound impact on lichen phenolic content than alterations in thallus nutrient content. 相似文献
9.
Northern hardwood forests experience annual maximal loss of nutrients during spring. The vernal dam hypothesis predicts that spring ephemeral herbs in northern hardwood forests serve as sinks for nutrients during this season and reduce the loss of nutrients from the terrestrial ecosystem. Soil microbes of northern hardwood forests also sequester nutrients during spring. We compared the vernal nutrient acquisition ability of a soil microbial community and an understory plant community with species of mixed leaf phenology. We monitored nitrogen and phosphorus pool sizes in understory vegetation and soil microbes during spring from 1999 through 2001 in a northern hardwood forest in the Catskill Mountains, New York. Vegetation nutrient content increased during two spring seasons by an average of 3.07 g N m–2 and 0.19 g P m–2 and decreased during one spring by 0.81 g N m–2 and 0.10 g P m–2. Evergreen, wintergreen, and deciduous plant species were able to sequester nutrients during spring. Soil microbial nutrient content decreased during one spring by 1.29 g N m–2 and remained constant during the other two springs. Streamwater nitrogen losses were not correlated with biotic nutrient uptake suggesting a temporal disconnect between the two processes. We conclude that understory vegetation is a larger potential sink for vernal nutrients than are soil microbes in this northern hardwood forest and understory and species representing multiple phenologies are capable of vernal nutrient uptake. 相似文献
10.
Festus Wanderi Ihwagi Robert Mutugi Chira Geoffrey Kironchi Fritz Vollrath Iain Douglas‐Hamilton 《African Journal of Ecology》2012,50(2):152-159
The magnitude of debarking by elephants was investigated in Samburu and Buffalo Springs National Reserves. About 1617 plants were monitored for debarking intensities for 6 months spanning through dry and wet seasons. Debarking indices ranged from no debarking at all during the wet months to complete stem girding at the height of the dry season. A negative correlation was found between rainfall and debarking indices. It was hypothesized that nutrient content of the bark influenced the magnitude to which trees were debarked. Bark samples were collected from least, moderate and intensely debarked plants throughout the 6 months. These were analysed for calcium (Ca), sodium (Na), phosphorus (P), magnesium (Mg), potassium (K), nitrogen (N), iron (Fe), copper (Cu), manganese (Mn) and zinc (Zn). Significant positive correlations were found between debarking intensity and each of the nutrients N [crude protein (CP)], P, K and Zn. Bark was found to be richest in CP and Calcium. Neutral detergent fibre content was on average 67%. Monthly variations in nutrient composition were minimal. Acacia elatior, the most preferred species had significantly higher quantities of each of the four elements N, P, K and Zn than Acacia tortilis, the second most preferred woody species. 相似文献
11.
Endozoochory varies with ecological scale and context 总被引:1,自引:0,他引:1
Kari Anne Bråthen Victoria T. González Marianne Iversen Siw Killengreen Virve T. Ravolainen Rolf A. Ims Nigel G. Yoccoz 《Ecography》2007,30(2):308-320
Several studies on endozoochory have established large herbivores as important for seed dispersal, yet no studies have evaluated how endozoochory is dependent on ecological scale and context. Here we address effects of reindeer density on endozoochory in a hierarchical, multi-scale study, encompassing several ecological contexts.
We found reindeer density effects on endozoochory to vary with spatial scale. Higher reindeer densities at the level of landscape areas, as indexed through faeces abundance, were related to both less species and lower abundance of emerging plants from faeces. In contrast, there was no effect of higher reindeer densities at the level of herding districts (i.e. large scale assemblages of landscapes). Lack of consistency between scales reflects ecological hierarchy, indicating that reindeer density effects on endozoochory best matches at the scale of landscapes.
Pasture seed plant composition was only partly an important ecological factor. That is, ericoid species, the dominating plants in the pastures, were also the most abundant seed plants found to emerge from the faeces. However, most herbaceous seed plant species in the pastures were not emerging from the faeces and the few that emerged were positively related to the site fertility and altitude of the pasture.
Studies addressing endozoochory of ruminants are typically concerned with seed plants, whereas in this study we also found indications of that diaspores of ferns are viable after passing the digestive tract of large herbivores. Vascular spore plants were even more abundant in the faeces than were vascular seed plants.
Results from this study demonstrate that reindeer may counteract a potentially negative impact on seed limitation from their grazing by returning viable seeds in their faeces. However, in Finnmark, northern Norway, this effect is only marginal, relates only to a very few species and individuals and shows ecological scale and context dependence. 相似文献
We found reindeer density effects on endozoochory to vary with spatial scale. Higher reindeer densities at the level of landscape areas, as indexed through faeces abundance, were related to both less species and lower abundance of emerging plants from faeces. In contrast, there was no effect of higher reindeer densities at the level of herding districts (i.e. large scale assemblages of landscapes). Lack of consistency between scales reflects ecological hierarchy, indicating that reindeer density effects on endozoochory best matches at the scale of landscapes.
Pasture seed plant composition was only partly an important ecological factor. That is, ericoid species, the dominating plants in the pastures, were also the most abundant seed plants found to emerge from the faeces. However, most herbaceous seed plant species in the pastures were not emerging from the faeces and the few that emerged were positively related to the site fertility and altitude of the pasture.
Studies addressing endozoochory of ruminants are typically concerned with seed plants, whereas in this study we also found indications of that diaspores of ferns are viable after passing the digestive tract of large herbivores. Vascular spore plants were even more abundant in the faeces than were vascular seed plants.
Results from this study demonstrate that reindeer may counteract a potentially negative impact on seed limitation from their grazing by returning viable seeds in their faeces. However, in Finnmark, northern Norway, this effect is only marginal, relates only to a very few species and individuals and shows ecological scale and context dependence. 相似文献
12.
Traditional reindeer herding of northern Fennoscandia has been based on seasonal movements independent of national borders. At the beginning of the 19th century, these yearly movements of reindeer were excessive, but during that century the borders between the Fennoscandian countries were closed. By analysing a 190‐base pair fragment of the mitochondrial DNA control region in 79 museum samples, we show that the reindeer of northern Fennoscandia were one homogenous population shortly after the national borders were closed. However, anthropogenic activity has effectively ended genetic exchange within northern Fennoscandia and has made the reindeer population within this region heterogeneous. Genetic input of eastern origin is also suggested within the extant Russian reindeer of the Kola Peninsula. 相似文献
13.
Abstract. We studied the effects of Svalbard reindeer on the abundance of lichens in Spitsbergen. A survey was carried out in 14 areas with contrasting reindeer densities. Separate cover estimates for crustose, fructose and foliose lichens were taken in each area, and related to the density of reindeer pellet groups, a measure of reindeer density. Dominant macro lichen families were identified in 10 areas, and a full record of macrolichen species was taken in four additional areas. Variation in reindeer density is partially due to past overhunting, and subsequent incomplete recovery, releasing some areas from reindeer grazing for 100–200 yr. The cover of fruticose lichens was negatively related to reindeer pellet group density, indicating suppression by Svalbard reindeer. This makes their impact comparable to other members of the Rangifer genus around the northern hemisphere. The generally recorded low abundance of lichens in the diet of Svalbard reindeer compared to other Rangifer species, therefore, was interpreted as the depletion of fruticose lichens in Spitsbergen, and a subsequent switch to alternative foods. Of all fruticose lichens, Stereocaulon spp. appeared least sensitive to grazing. Crustose and foliose lichen cover was independent of reindeer pellet group density. The cover of crustose lichens was significantly related to latitude, with greater cover in more northern areas. Foliose lichens were more abundant in places where moss cover was high. We conclude that the impact of Svalbard reindeer on lichens is dependent on growth form, with fruticose lichens suffering from grazing, whereas foliose lichens might indirectly benefit from higher densities of reindeer or, like crustose lichens, be controlled by other factors. 相似文献
14.
Several of the most important reindeer forage plants in Svalbard were analysed for content of minerals (Na, K, P, Ca, Mg, S, Cl, Fe, Cu, Mn, Zn, Mo and Co) and for content of ash, crude protein, crude fiber, ether extracts and nitrogen free extracts. Some forage plants were also examined in in vitro digestibility trials. The results were compared with results from similar analyses of alpine mountain plants from southern Norway. Also freshly voided fecal samples were analysed for the same components as the forage plants.
The Svalbard vegetation had a higher content of Na, Ca, Mg, Cl, Fe and Co, than similar plants from Southern Norway. The content of other elements examined seemed to be more equal in Norway and on Svalbard. Within the Svalbard area plants growing in limestone areas had the highest content of calcium and magnesium. Also plants growing on manured soil below bird cliffs appeared to have high nutritional value. It is furthermore concluded that the closeness to the sea as well as the occurrence of several plants with high mineral content, gave the Svalbard reindeer the possibility to further improve their mineral balance compared with continental reindeer. Also the dietary shift from lichens as a major dietary component in Norway, to mosses on Svalbard, may increase mineral intake, but may also have an inferior effect on digestibility.
Although balance experiments and carcass analyses of minerals in Svalbard reindeer are missing, it is concluded that Svalbard reindeer apparently had adequate intake of most mineral elements. In spite of low standing biomass of reindeer forage plants, the quality of the vegetation seemed to compare favourably with continental reindeer pasture. 相似文献
The Svalbard vegetation had a higher content of Na, Ca, Mg, Cl, Fe and Co, than similar plants from Southern Norway. The content of other elements examined seemed to be more equal in Norway and on Svalbard. Within the Svalbard area plants growing in limestone areas had the highest content of calcium and magnesium. Also plants growing on manured soil below bird cliffs appeared to have high nutritional value. It is furthermore concluded that the closeness to the sea as well as the occurrence of several plants with high mineral content, gave the Svalbard reindeer the possibility to further improve their mineral balance compared with continental reindeer. Also the dietary shift from lichens as a major dietary component in Norway, to mosses on Svalbard, may increase mineral intake, but may also have an inferior effect on digestibility.
Although balance experiments and carcass analyses of minerals in Svalbard reindeer are missing, it is concluded that Svalbard reindeer apparently had adequate intake of most mineral elements. In spite of low standing biomass of reindeer forage plants, the quality of the vegetation seemed to compare favourably with continental reindeer pasture. 相似文献
15.
Sedentary populations, like the Svalbard reindeer, tend to select the most nutritious and easily available plants during the different seasons. It has been shown that plants selected during grazing season are reflected in the pollen content of modern faeces from Svalbard reindeer. In this study the pollen and spore content of fossil reindeer faeces and peat from Raddedalen, western Edgeøya, Svalbard, are presented. The pollen content of the fossil faeces is first compared to published pollen data from modern Svalbard reindeer faeces so as to determine which season they were deposited, and second the pollen in the fossil faeces are compared to the pollen content of the peat in which they were found. The lower part of the peat section is dated to 3435±105?cal?yr BP. The faeces are dominated by pollen from early flowering species such as Saxifraga oppositifolia‐type, S. nivalis‐type, Brassicaceae, and Pedicularis spp. thereby indicating that grazing and faeces deposition took place in spring and early summer. The peat and faeces have some similarities in their pollen and spore content, but different methods of deposition and concentration of pollen in faeces and peat result in different fossil assemblages. The results suggests that the climate of Raddedalen was warmer and moister than today, allowing peat to form in the past. 相似文献
16.
The wolverine (Gulo gulo) hunts and scavenges for food. We examined how the presence of a semi-domesticated reindeer (Rangifer tarandus tarandus) influences the diet of breeding female wolverines in Finland. We compared the dietary composition of wolverines breeding in the reindeer management area (northern Finland) with that of wolverines breeding outside this area (eastern Finland) by analyzing 421 scats collected from six active dens in northern Finland and four dens in eastern Finland during 2004–2006. The occurrence of food sources in the diet was assessed for both areas using logistic mixed-effects models. Diet breadth per study area was also calculated. As expected, semi-domesticated reindeer was the most important food source (66 %) in northern Finland. Mountain hares (Lepus timidus) were the second most important food item (16 %). Wolverines also utilized grouse (7 %), small rodents (6 %), and moose (Alces alces; 4 %) in their diet. In eastern Finland, the most utilized prey species was moose (55 %), while the diet also comprised mountain hares (13 %), domestic pigs (Sus scrofa; 13 %), grouse (11 %), and small rodents (2 %). The diet of wolverines in eastern Finland included more moose and less semi-domesticated reindeers and small rodents than in northern Finland. The niche breadth did not differ between the study areas. In eastern Finland, the diet of wolverines shifted to 55 % moose and 0 % semi-domesticated reindeer; compared to 4 % moose and 66 % semi-domesticated reindeer in northern Finland. Our study highlights the important role of ungulates in the diet of breeding female wolverines. In areas with a low density of medium-sized ungulates, scavenging for wolf- and human-killed moose and carcasses on feeding sites plays an essential role in food acquisition by wolverines. 相似文献
17.
A D Venosa M T Suidan D King B A Wrenn 《Journal of industrial microbiology & biotechnology》1997,18(2-3):131-139
Much of the variability inherent in crude oil bioremediation field studies can be eliminated by normalizing analyte concentrations
to the concentration of a nonbiodegradable biomarker such as hopane. This was demonstrated with data from a field study in
which crude oil was intentionally released onto experimental plots on the Delaware shoreline. Five independent replicates
of three treatments were examined: no nutrient addition, addition of inorganic mineral nutrients alone, and nutrient addition
plus indigenous oil-degrading microorganisms from the site. Samples collected biweekly were analyzed for the Most Probable
Numbers (MPNs) of alkane and aromatic degraders and oil component analysis by GC/MS. The data were normalized to either
the mass of sand that was extracted or to the concentration of hopane that was measured. Hopane normalization enabled detection
of significant treatment differences in hydrocarbon biodegradation that were not detected when the data were normalized to
sand mass. First-order loss rates for the hopane-normalized data were lower than those for the sand-normalized data because
hopane normalization accounts only for loss due to biodegradation whereas sand normalization includes all loss mechanisms.
Plots amended with nutrients alone and nutrients plus the inoculum showed enhanced removal of hydrocarbons compared to unamended
control plots. However, no differences were detected between the nutrient-amended plots and the nutrient/inoculum-amended
plots.
Received 06 November 1995/ Accepted in revised form 26 June 1996 相似文献
18.
《Comparative biochemistry and physiology. A, Comparative physiology》1994,107(1):63-73
Nitrogen and mineral (Fe, Mg, Na, K, and Ca) compositions of foodstuffs consumed by and dung produced by male, pregnant and lactating female adult Icelandic reindeer and calves were determined during May of 1992. Iron levels in foodstuffs are consistently above the reported toxicity level for similar-sized sheep (0.5 ppt) and may lead to iron toxicity when consumed by reindeer during periods of high lean body mass catabolism. Male and female reindeer meet nutrient requirements for all measured elements and nitrogen with the possible exception of calcium for males during antler growth. 相似文献
19.
Data on nearest neighbours and aggressive behaviour were collected within rutting groups of semi-domesticated reindeer (Rangifer t. tarandus L.) in a 1300-ha pasture in Finnish Lapland, and wild forest reindeer (Rangifer t. fennicus Lönnb.) in a 15-ha enclosure in Central Finland. Adult cows of forest reindeer charged yearling males, yearling females and calves in that order of decreasing frequency. Semi-domesticated reindeer cows rushed yearling females more often than they did one another. One suggested influence of antagonism by cows were the observed intragroup associations of yearling females. Cows were tolerant toward their own yearling females, but not toward their own yearling males. Although no maternal aggression toward calves was found, male calves moved away more often from their mothers than did female calves during the post-rut period. 相似文献
20.
《Archives of animal nutrition》2013,67(6):442-454
In 2006 in Germany new recommendations for the supply of energy and nutrients to pigs were published, including a modification of the energy evaluation on the basis of metabolisable energy for pigs (MES). It was the objective of this meta-analysis to calculate equations that can be used for predicting MES in compound feeds for pigs on the basis of their nutrient concentrations. Data from digestibility studies with a total of 290 compound feeds were provided by different research institutions. Feeds for both piglets and growing-finishing pigs were contained in the data set. The MES concentration ranged from 10.4–16.6 MJ/kg DM, with the majority of data ranging between 15 and 16 MJ/kg DM. The data were processed with a cross validation method and a multiple regression approach by using MES as the independent variable. A corrected Akaike-Information-Criterion (AIC_ cor) was used for model evaluation. Various models were developed and validated independently. Calculations were made both for piglet and growing-finishing pig feeds, separately and together, for all feeds. It was shown that the MES concentration in compound feeds can be predicted with good accuracy if the concentrations of crude protein, crude fat, crude fibre, and starch are known. Prediction equations were presented. The lack of data for highly fibrous feeds as well as the analysis of different fibre fractions was identified as a challenge for further improvement of the prediction equations. 相似文献