Finding best exotic breed proportion in crossbred lactating sheep kept under farmers’ conditions in Ethiopia determined by use of nested Legendre polynomials with limited data     

W. G. Haile  S. Banerjee  A. Ayele  T. Mestawet  G. Klemetsdal  T. Ådnøy 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2018,68(4):174-180

ABSTRACT

The present study was conducted to estimate milk production performance and fit lactation curves for groups of ewes of Local and of Awassi crosses, with a variable blood level, reared under farmer’s environment. The Weigh-Suckle-Weigh method plus hand milking was used to estimate milk yield for ewes. A total of 466 observations from 115 ewes were used. Estimated least-squares adjusted means for the milk production over 120 days were 0.56?kg day^?1 (Local), 0.67 (<30% Awassi), 0.86 (30–50% Awassi), and 0.96 (>50% Awassi). Groups with 30–50% Awassi and >50% Awassi ewes produced significantly (p?<?0.05) more milk than Local ewes. Significant differences were observed between <30% Awassi and >50% Awassi crossbred groups. The best crosses (>50% Awassi) produced over 70% more milk than the local ewes which demonstrates the potential that exists in increasing milk production through the initiated crossbreeding programme with sheep in Ethiopia.  相似文献   

Quantifying the nitrogen retention capacity of natural wetlands in the large-scale drainage basin of the Baltic Sea   总被引：3，自引：0，他引：3  

Jansson  Åsa  Folke  Carl  Langaas  Sindre 《Landscape Ecology》1998,13(4):249-262

We estimate the nitrogen retention capacity of natural wetlands in the 1.7 million km² Baltic Sea drainage basin, using a wetland GIS data base. There are approximately 138,000 km² of wetlands (bogs and fens) in the Baltic Sea drainage basin, corresponding to 8% of the area. The input of nitrogen to natural wetlands from atmospheric deposition was estimated to 55,000–161,000 ton y¹. A map of the deposition of both wet and dry nitrogen is presented. The input from the human population was estimated to 255,000 ton y¹ in terms of excretory release in processed sewage water. There may also be leakage from forests and agricultural land into the wetlands. Due to lack of data on hydrology and topography, such potential nitrogen sources are not accounted for here. The capacity of the wetlands to retain the atmospheric deposition of nitrogen was estimated to 34,000–99,000 ton y¹. The potential retention by wetlands was estimated to 57,000–145,000 ton y¹ when the nitrogen input from the human population was added. If drained wetlands were to be restored and their area added to the present wetland area, the nitrogen retention capacity was estimated to increase to 196,000–261,000 ton y¹. Our results indicate that existing natural wetlands in the Baltic Sea drainage basin annually can retain an amount of nitrogen which corresponds to about 5–13% of annual total (natural and anthropogenic) nitrogen emissions entering the Baltic Sea. The ecosystem retention service performed by wetlands accounts for a substantial nitrogen removal, thereby reducing the eutrophication of the Baltic Sea.  相似文献   

Variation in seed oil composition of species from the genera Barbarea and Lepidium     

P. Nilsson  Sven‐Åke Johansson  Arnulf Merker 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(3):159-164

The seed oil composition and content in a number of accessions from species of the genera Barbarea and Lepidium were analysed. The oil from most accessions of B. verna contained more than 50% erucic acid, while the oil from B. vulgaris contained ～ 30% erucic acid, and 22% each of oleic and linoleic acid. The oil from B. intermedia resembled that of B. verna. The oil content was ～ 30% in all three species. The oil composition of L. campestre and L. heterophyllum is ～ 35% linolenic acid and 23% erucic acid. Other Lepidium species had up to 47% linolenic acid in the oil. The oil content of L. campestre and L. heterophylhim was just below 20%, but other species had more than 30% oil in their seeds. The variation in oil composition found within and between species is considered sufficient for the breeding of valuable oil qualities in both genera.  相似文献   

Performance and yield of 14 eucalypt species on Imperata cylindrica (L.) Beauv. grassland 3 years after planting     

Antti Otsamo  Tjuk Sasmito Hadi  Göran Ådjers  Jussi Kuusipalo  Risto Vuokko 《New Forests》1995,10(3):257-265

A species trial with 14 eucalypt species with randomized complete blocks design was planted on Imperata cylindrica dominated grassland in South Kalimantan, Indonesia in January 1987. The site was prepared mechanically. No fertilizers were used. At the age of three years E. camaldulensis had clearly the highest survival rate (95%) and mean annual increment (5.9 m³ha^–1a^–1) compared with the other species tried. It was followed by E. urophylla, E. deglupta, E. pellita, E. tereticornis, E. alba, E. torelliana, E. intermedia, E. grandis and E. pilularis. Four other species, E. phaeotricha, E. resinifera, E. cloeziana and E. microcorys died either in the nursery or immediately after planting. All the eucalypts tried had narrow crowns and open canopies. It is suggested that eucalypts are not recommendable for grassland reforestation under minimum plantation tending. Effects of intensive weeding, spacing, fertilizing and performance in second rotation or mixed stands should be tested to elaborate the suitability of eucalypts on grasslands.  相似文献   

Reducing error in feline platelet enumeration by addition of Iloprost to blood specimens: comparison to prostaglandin E1 and EDTA          下载免费PDF全文

Harold W. Tvedten  Kerstin Bäcklund  Inger E. Lilliehöök 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2015,44(2):179-187

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The potential drivers in forming avian biodiversity hotspots in the East Himalaya Mountains of Southwest China   总被引：1，自引：0，他引：1       下载免费PDF全文

Fumin LEI  Yanhua QU  Gang SONG  Per ALSTRÖM  Jon FJELDSÅ 《Integrative zoology》2015,10(2):171-181

Little has been published to describe or interpret Asian biodiversity hotspots, including those in the East Himalayan Mountains of Southwest China (HMSC), thus making necessary a review of the current knowledge. The Pliocene and Pleistocene geological and glacial histories of the Asian continent differ from those of Europe and North America, suggesting different mechanisms of speciation and extinction, and, thus, different responses to climate changes during the Quaternary glaciations. This short review summarizes potential drivers in shaping and maintaining high species richness and endemism of birds in the HMSC. The geographical location at the junction of different biogeographical realms, the wide range of habitats and climates along the extensive elevational range, the complex topography and the distinct geological history of this region have probably contributed to the evolution of an exceptionally species‐rich and endemic‐rich, specialized montane avian fauna. The Mountain systems in the HMSC may have provided refugia where species survived during the glacial periods and barriers for preventing species dispersal after the glacial periods. More studies are required to further test this refugia hypothesis by comparing more cold‐tolerent and warm‐tolerent species.  相似文献   

The effect of water-borne magnesium on the dietary magnesium requirement of the rainbow trout (Oncorhynchus mykiss)     

Karl D. Shearer  Torbjørn Åsgård 《Fish physiology and biochemistry》1992,9(5-6):387-392

Rainbow trout (Oncorhynchus mykiss) (mean initial weight 0.84 g) were fed diets containing graded levels of magnesium (Mg) (78 to 725µg/g) while being exposed to one of several levels in the rearing water (1.4 to 1000 mg/l). Uptake of Mg from the water, in Mg-deficient fish, was linearly related to the water Mg concentrated. It appears that the fish's Mg requirement can be met from either or both the diet or water. Under the experimental conditions, a water-borne concentration of 46 mg/l was calculated to be sufficient to meet the Mg requirement of the fish fed a Mg-free diet.  相似文献   

Theoretical analysis of decomposition of heterogeneous substrates     

Ernesto Bosatta  Göran I. Ågren 《Soil biology & biochemistry》1985,17(5):601-610

A theory is proposed for the decomposition of a heterogeneous substrate, in which the heterogeneity is described by a continuously varying quality variable, q. Two microbial properties, efficiency in substrate utilization, e(q), and rate of substrate utilization, u(q), depend on the quality variable and decrease with decreasing substrate quality. General results of the theory can be displayed either in terms of time or quality. It turns out that the quality representation is both more general and more lucid. Only very weak specifications of the functions u(q) and u(q) are necessary to determine whether the decomposition process will end after a finite time and whether all substrate eventually will become mineralized. The final nitrogen-to-carbon ratio is shown to be independent of these two functions but depends on the initial nitrogen concentration and quality of the substrate. Using specific functions for u(q) and u(q) it is possible to derive a number of models used to describe decomposition and the variation in the critical nitrogen-to-carbon ratio with specific decomposition rate of the substrate. The theoretical predictions are compared to a number of decomposition experiments.  相似文献   

Episodic Events in Water Chemistry and Metals in Streams in Northern Sweden during Spring Flood     

Frida Edberg  Hans Borg  Jan-Erik Åslund 《Water, air, and soil pollution》2001,130(1-4):1697-1702

Thirteen streams in the province of Jämtland in northern Sweden were monitored during spring in 1995 (December 94 – July 95) to study changes in water chemistry and metal concentrations during snow melt. The brooks are not treated with lime, with one exception, and can be approximately divided into three groups according to watershed characteristics; A) > 65% above tree line, B) > 65 % wetland, C) > 55% forested. During peak flow, pH dropped 0.5–2.5 units and alkalinity generally to zero. The brooks above tree line were lowest in base cations and reached the lowest pH-values (4.4–4.6) during peak flow, while sulphate levels were about the same as in the forested watersheds. During peak flow, organic anions showed the highest increase in the wetland and forested catchments. Compared to base flow, Al, Zn, Pb and to some extent Mn was enriched during peak flow. The results also illustrate the difficulties in generalising the reasons for alkalinity losses during spring flood in this kind of streams. In some of the brooks, the use of either base cations or silica, when calculating dilution effects, gave deviating results concerning the relative contribution of strong acids in the snow pack.  相似文献   

Frequent long-distance plant colonization in the changing Arctic     

Alsos IG  Eidesen PB  Ehrich D  Skrede I  Westergaard K  Jacobsen GH  Landvik JY  Taberlet P  Brochmann C 《Science (New York, N.Y.)》2007,316(5831):1606-1609

The ability of species to track their ecological niche after climate change is a major source of uncertainty in predicting their future distribution. By analyzing DNA fingerprinting (amplified fragment-length polymorphism) of nine plant species, we show that long-distance colonization of a remote arctic archipelago, Svalbard, has occurred repeatedly and from several source regions. Propagules are likely carried by wind and drifting sea ice. The genetic effect of restricted colonization was strongly correlated with the temperature requirements of the species, indicating that establishment limits distribution more than dispersal. Thus, it may be appropriate to assume unlimited dispersal when predicting long-term range shifts in the Arctic.  相似文献