Forage and bed sites characteristics of Indian muntjac (<Emphasis Type="Italic">Muntiacus muntjak</Emphasis>) in Hainan Island,China

Microhabitat factors associated with forage and bed sites of Indian muntjac (Muntiacus muntjak) were examined and compared in Hainan Island from 2001 to 2002. Habitat characteristics at forage and bed sites were measured by tracking five radio-collared adult muntjacs (three females, two males) and locating from fresh sign or muntjac flushed during transect surveys. Among six available habitat types, Indian muntjac preferred shrub grassland and thorny shrubland, and used dry savanna in proportion to its availability. Muntjac avoided woods, cultivated grassplot and deciduous monsoon forests. Comparing forage sites with bed sites, food availability was greater at forage sites. For bed sites, taller trees with larger canopies, taller shrubs, denser shrub canopy covers and concealment covers were essential factors. No seasonal difference (wet season vs. dry season) was found in food abundance at either forage sites or at bed sites. During the wet season, canopy closure for both types of sites was higher and at bed sites concealment cover was higher than during the dry season. Principal component analysis indicated that tree height, d.b.h. and maximum canopy diameters were important factors in habitat selection. The different microhabitat characteristics at forage and bed sites can be a clue to understanding the survival strategy of Indian muntjac, a small-bodied ungulate, in savanna woodlands.     

Inheritance of transgenes in transgenic tall fescue (<Emphasis Type="Italic">Festuca arundinacea</Emphasis> schreb.)

Summary Tall fescue (Festuca arundinacea Schreb.) is the most important forage species worldwide of the Festuca genus. Single genotype-derived embryogenic suspension cultures were established from tall fescue cultivar Kentucky-31, and were used as target cells for biolistic transformation. A chimeric hygromycin phosphotransferase gene (hph) was used as the selectable marker, and a chimeric β-glucuronidase (gusA) gene was co-transformed with hph. Transgenic plants were recovered after microprojectile bombardment of suspension cells and subsequent selection in the presence of a high concentration of hygromycin. Fertile transgenic plants were obtained after vernalization under field conditions. T1 and T2 progenies were obtained after reciprocal crosses between transgenic and untransformed control plants. PCR and Southern hybridization analyses revealed a 1∶1 segregation ratio for both transgenes in the T1 and T2 generations. Southern hybridization patterns were identical for T0, T1, and T2 plants. The results demonstrated for the first time the stable meiotic transmission of transgenes following Mendelian rules in transgenic tall fescue.     

An assessment of the ability of the stay-green phenotype in lolium species to provide an improved protein supply for ruminants

The stay-green phenotype results from a naturally occurring mutation in which senescent leaves retain their chlorophyll and the associated apoprotein, LHCPII. Protection of this protein pool could deliver grass with enhanced protein content and could decrease the extent of protein degradation by plant proteases in the rumen. This would enhance the efficiency of protein utilization in livestock to the benefit of the environment. Field plots of stay-green and wild-type Lolium perenne were defoliated at intervals to simulate grazing. There were variations in foliar protein content and proteolysis throughout the year, but no significant differences between genotypes when material was analysed fresh or after it was cut and dried to simulate hay-making, which possibly induced senescence. In a subsequent experiment with stay-green and wild-type L temulentum, increased protein retention and decreased protein degradability were observed in stay-green leaves that were allowed to senescence naturally and extensively on the plant. That there is no difference between the two L. perenne genotypes suggests that as a field crop in grazed pastures the stay-green genotype would not confer a nutritional advantage in terms of protein degradability. It is possible that grazing promotes a high proportion of non-senescent to senescent leaf material within the sward and thus any advantage conferred by the stay-green phenotype would be effectively masked by an abundance of mature foliage. It is suggested that the stay-green trait would be of benefit in areas where agricultural practice permits extensive natural senescence to occur.     

饲料营养对林麝麝香产量和品质的影响

上海地区引种林麝取得成功后,首次进行了饲料营养对麝香产量和品质影响的研究,试验麝饲养在上海市郊崇明岛东平林场,进行分期对比试验,分别用青绿饲料,青绿饲料加代蛋白饲料,青绿饲料加高蛋白饲料,配合饲料饲喂受试麝,考察饲料营养对麝香产量和质量的影响。结果表明,饲料营养显著影响麝香产量和品质,单独饲青绿饲料不能满足泌香的营养需要,平均产香量３．２１ｇ,麝香色深而湿,品质差,提高营养水平后,麝香产量显著提高     

Population structure and food habits of white crappie Pomoxis annularis Rafinesque in a turbid Oklahoma reservoir

We assessed population structure and food habits of white crappie Pomoxis annuluris Rafinesque in Lake Carl Blackwell, a turbid reservoir in north-central Oklahoma, U.S.A. White crappie [ n = 8549; total length ( t.l. ) mean = 147 mm, s.d. = 28 mm, range = 73–445 mm] were collected with gillnets, frame nets, and hoop nets. Proportional stock density was 2, as 97% of the fish were under 200 mm t.l . Relative stock density was 96, 2, 1, and 1 for 'stock-quality', 'quality-preferred', 'preferred-memorable', and 'memorable-trophy' lengths. Total annual mortality rate was 54% for fish older than 2 years. Growth was poor and lower than the Oklahoma-Arkansas regional averages ( P <0.01). Relative weights were 79, 86, 106, 109, and 123 for fish in the stock-quality, quality-preferred, preferred-memorable, memorable-trophy, and trophy size categories. Ephemeroptera nymphs were an important dietary component for fish 150 mm t.l. or smaller. Gizzard shad Dorosoma cepedianum (Lesueur) was a major forage item, especially for fish greater than 150 mm t.l. ( P <0.01). Empirical information on prey availability indicates that the white crappie population is forage limited and that gizzard shad are not available in appropriate sizes or sufficient numbers to sustain the predator population. Poor fish condition, slow growth, and high mortality are probably the result of inadequate forage.     

FORAGE LOSSES CAUSED BY GRASSHOPPER CHORTHIPPUS DUBIUS (ZUB.1 ON GRASSLAND IN INNER MONGOLIA OF CHINA

Abstract To quantitatively assess the losses of forage, we conducted experiments to determine the average amount of forage destroyed (forage consumed plus forage cut-off and dropped to the ground) per day by the grasshopper, Chorthippus dubius (Zub.), at its different life stages in laboratory and then extrapolated estimates of losses caused by the field grasshopper population from these results and the population densities of this grasshopper. The main results are as follows:

• 1 Ch. dubius is a late-occurring species of grasshoppers in Inner Mongolian grassland. It occurred from June to October. The duration for each instar and the longevity of the adult under natural conditions ranged from 9. 09–9. 81 fdays) and 17. 65–19. 441days) respectively.
• 2 Both consumption and forage defoliation rates by Ch. dubius increase with its developemnt. The consumption rates had significantly linear relationships with the grasshopper's body weights.
• 3 Average losses caused by one grasshopper in its whole lifespan were 487. 55–784. 4 mg (dry weight) and the average amount of forage consumed and wasted per day was 7. 64–11. 45 mg.
• 4 Total losses caused by Ch. dubius population in 1990 ranged from 0. 762–1. 647 g/m² in the three types of vegetation, and the largest value was found in restorative type. The seasonal courses of cumulative forage losses would fit logistic equations in the three vegetation types.
• 5 Population densities (18. 5, 194., 11. 8/m², 4th instar nymph predominantly) were suggested as the levels at which control should be initiated on the three types of pastures respectively.

     

太空搭载决明属牧草种子对其农艺性状的影响

太空搭载决明属牧草6个品种种子,通过盆栽试验观测其SP1和SP2代搭载效应,试验结果表明,航天搭载能提高部分决明品种种子出苗率、能改良部分决明品种的农艺性状,对决明品种的生殖生长期影响较大。     

Grass silage particle size when fed with or without maize silage alters performance,reticular pH and metabolism of Holstein-Friesian dairy cows

The particle size of the forage has been proposed as a key factor to ensure a healthy rumen function and maintain dairy cow performance, but little work has been conducted on ryegrass silage (GS). To determine the effect of chop length of GS and GS:maize silage (MS) ratio on the performance, reticular pH, metabolism and eating behaviour of dairy cows, 16 multiparous Holstein-Friesian cows were used in a 4×4 Latin square design with four periods each of 28-days duration. Ryegrass was harvested and ensiled at two mean chop lengths (short and long) and included at two ratios of GS:MS (100:0 or 40:60 dry matter (DM) basis). The forages were fed in mixed rations to produce four isonitrogenous and isoenergetic diets: long chop GS, short chop GS, long chop GS and MS and short chop GS and MS. The DM intake (DMI) was 3.2 kg/day higher (P<0.001) when cows were fed the MS than the GS-based diets. The short chop length GS also resulted in a 0.9 kg/day DM higher (P<0.05) DMI compared with the long chop length. When fed the GS:MS-based diets, cows produced 2.4 kg/day more (P<0.001) milk than when fed diets containing GS only. There was an interaction (P<0.05) between chop length and forage ratio for milk yield, with a short chop length GS increasing yield in cows fed GS but not MS-based diets. An interaction for DM and organic matter digestibility was also observed (P<0.05), where a short chop length GS increased digestibility in cows when fed the GS-based diets but had little effect when fed the MS-based diet. When fed the MS-based diets, cows spent longer at reticular pH levels below pH 6.2 and pH 6.5 (P<0.01), but chop length had little effect. Cows when fed the MS-based diets had a higher (P<0.05) milk fat concentration of C18 : 2n-6 and total polyunsaturated fatty acids compared with when fed the GS only diets. In conclusion, GS chop length had little effect on reticular pH, but a longer chop length reduced DMI and milk yield but had little effect on milk fat yield. Including MS reduced reticular pH, but increased DMI and milk performance irrespective of the GS chop length.     

Feeding and territorial behaviour in juveniles of three co-existing triggerfishes

Of three coexisting triggerfishes, in the intertidal and immediate subtidal zones of a coral reef within the Kenting National Park, southern Taiwan, Balistoides viridescens was observed only in the subtidal zone and foraged preferentially by nipping directly at small invertebrates among algal covered substrata. They fed also, although at a lower frequency, by using a water-jet technique to uncover prey on sandy substrata. Territory size ranged from 61·05 to 161·57 m² but was not related to rates of feeding or defence. Feeding frequency was, however, positively related to the area of algae present in the territory, and inversely related to the frequency of defence. In contrast to B. viridescens, Rhinecanthus verrucosus and R. aculeatus foraged mainly in the intertidal zone when the tide was high. They fed preferentially off rocky substrata and used only nipping (not water-jetting) to secure prey.     

Les α-galactosides du saccharose au cours de la germination des graines de betteraves sucrières et fourragères

During the first three hours of beet seed germination, sucrose α-galactosides briefly appear while sucrose and UDPGal contents decrease. The ¹⁴C-sucrose penetration into 12-hour-old embryos is followed by a partial eclipse of this compound and its replacement by sucrose α-galactosides. These two processes are more important in sugar than in forage beet. The significance of these results in sugar metabolism is discussed.