小蚕共育与蚕业科技进步

1　小蚕共育的内涵、历史与组织形式 　　1.1　小蚕共育的内涵 　　小蚕共育是根据小蚕的生理特点，将一定数量的小蚕进行集中饲养和管理，以保证小蚕健康成长，为大蚕饲育打好基础的一种养蚕措施，是蚕桑生产高产、稳产、优质、高效的经济饲育形式。 　　1.2　小蚕共育源远流长 　　小蚕共育作为一种饲养形式，具有悠久的历史。日本约在1930年前后提出对小蚕共育实行补助奖励政策，到1960年前后，实行小蚕共育的占养蚕户数的43.9%，到1980年，共有小蚕共育所2514个，占养蚕户数的91.8%，日本由于普及了小蚕共育，从20世纪70年代以来，软化病、脓病等受害蚕茧的比例显著下降，使蚕病发生率控制在2%以下，保证了蚕茧生产的稳产高产。 　　我国在20世纪20～30年代，有关蚕业学校和机关，曾在农村创办了小蚕共育组织，并派出技术人员进行指导。有关消毒药品、加温燃料、桑叶、人工费用、蚕室蚕具租费等，均按参加共育的蚕种张数进行分摊。由于实行小蚕共育小蚕发育强健，饲养成绩好，费用又比独自饲养低，因此，自愿参加者日众。20世纪50年代起，中国小蚕共育得到更大发展，共育规模比过去大，共育组织几乎遍及各蚕区。 　　1.3　小蚕共育的组织形式     

原蚕三眠化对当代和子代成绩的影响

三眠蚕诱导剂应用于蚕种生产已初见报道。笔者等于1989和1990年春应用三眠蚕诱导剂添食原种扩大中试,进一步考察其对当代和子代成绩的影响,试验结果表明,原蚕三眠化后发育经过缩短、用桑量减少,50kg桑制种量有所提高,制成的三眠蚕杂交种在实验室和农村饲养与四眠蚕杂交种相比产质量     

目前蚕药产销中存在的问题与对策措施

蚕药是防治蚕病的物质基础 ,其质量的好坏与消毒防病效果直接相关。为了解我市蚕药的质量情况 ,笔者于１９９９～２０００年春、秋蚕期前作了调查。１蚕药质量情况采用随机取样的办法 ,共调查了蚕室蚕具和蚕体蚕座消毒用氯制剂和醛制剂样品共６４只。调查结果 ,氯制剂合格率６７．６% ,醛制剂合格率６３．３ % ,调查样品的平均合格率为６５．６ % ,见表１。目前蚕药产销中存在的问题与对策措施陈端豪（浙江省湖州市蚕桑科学研究所 ,湖州３１３０００）表 1　蚕药质量调查结果年份期别氯制剂样品(只 )合格(只 )合格率(% )　醛制剂样品(只 )合…     

为什么蚕儿眠了三天还不起？

答：原因是温度太低。影响蚕儿生长发育的气候环境主要有温度、湿度、空气和光线，其中温度对蚕儿生长发育的影响最大。蚕儿在不同的龄期需要不同的温度：一、二龄蚕为27～28℃，三龄蚕为26～27℃，四龄蚕为25～26℃，五龄蚕为24～25℃，温度合适才能保证蚕儿正常的生长进度。而在正常的温度条件下，一、二龄蚕眠中经过20～22小时，     

趋利避害 夺取夏秋茧丰收

夏秋蚕包括夏蚕、秋蚕和晚秋蚕，一般从6月上旬开始，10月上旬结束。是蚕桑生产的主季，占全年的60％～70％，合理安排夏秋蚕既可有效利用桑叶资源，又能提高设施、设备的利用率，最大限度发挥效益。     

浅析近年夏蚕锐减原因与增养夏蚕之对策

<正>我县从1988年至1995年,夏蚕平均发种量为44203张,其中1993年夏蚕最高发种达63081张,按当时全县桑田面积平均每亩饲养夏蚕0.28～0.40张.1996～1997年夏蚕发种量一落千丈,分别为3939张、4849张,只占前8年平均发种量的1/10左右.扣除前二年的挖桑面积,夏蚕亩桑饲养量只有过去的12.55%.由于夏蚕减少,按现行茧价,全县每年减少蚕茧收益1536万元左右.我县夏蚕为何锐减,分析夏蚕饲养与否的利弊关系,若增养夏蚕,提高蚕桑经济效益,应采取哪些对策,现结合我县实际作如下探讨.     

沿口乡蚕台无覆盖二回育饲育技术介绍

<正> 1986～1987年,我们在沿口乡居子忠等12户开展了大蚕期蚕台无覆盖二回育的试验,在取得成效的基础上,从1988年开始,在全乡逐步推广该项技术。全乡饲养小蚕除使用蚕匾、蚕菲外,90%的蚕户大蚕期均使用蚕台饲养,4龄蚕上蚕台,只覆盖蚕用薄膜3天左右,5龄起蚕上蚕台均不覆盖,不仅提高了养蚕工效,节省了蚕具投资,而且蚕作安全,蚕茧稳产。1988～1991年,全乡共养蚕27416张,平均张产茧37.8公斤,比全县同期平均张产茧30.4公斤,提高7.4公斤,比该乡推广此项技术前三年平均张产茧35.1公斤,提高2.7公斤。经多点调查,蚕     

小蚕人工饲料育对减少蚕病发生的作用调查

2002年我区秋蚕期血液型脓病危害严重。蚕病发生的特点:一是发病面广;二是发病时间早,有的农户在2龄就发现血液型脓病,不仅在迟眠蚕中有病蚕,即使在大批蚕中也有蚕病发生;三是发病情况严重,损失较大。据对城区八里店镇调查,有3%农户的210张蚕种因暴发蚕病而颗粒无收;25%农户的1600张蚕种因发病严重,张产仅10～20kg;40%农户的2500张蚕种发病较轻,张产在25kg左右;只有30%左右的农户少量发病,张产在32kg以上。因血液型脓病危害,八里店镇饲养的6431张秋蚕,平均张产仅32.5kg,与去年同期比,平均张产减少3.4kg,损失蚕茧21.9t,估计全镇发病损失率在1…     

“健蚕增丝灵”饲育试验

养蚕是江苏省农村的一项重要副业,而多种蚕病对蚕茧生产的危害十分严重,每年因此而损失的茧量难计其数。尤其是病毒性蚕病,常占发病率的70～80%,当病毒性蚕病发生时,往往导致绝收。为了提高养蚕业的经济效益,我们研制了蚕用新型添食剂“健蚕增丝灵”,业经春、秋蚕的小试和中试,证明具有健蚕促长和抗病增茧的双重效果,现将试验结果报告如下。     

添食和体喷三眠素诱导蓖麻蚕三眠蚕的试验研究

添食和体喷三眠索诱导的蓖麻蚕三眠蚕,全龄经过缩短3～4天。三龄饷食开始添食三眠素诱导的三眠蚕率达95．73%～100％,四龄饷食开始添食三眠素三眠蚕率为零。三龄喷体三眼素诱导的三眠蚕率为8．83%～48．00％,且多数三眠蚕为雄蚕;雄蚕三眠蚕率可达88：10%,雌蚕最高只有6．58%。诱导的三眠蚕子代能恢复四眠。     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Chemotaxis of macrophage in inflammation

Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein