高寒草甸草地在全封育下的植物量变化

用钢丝网封育高寒草甸类的高山嵩草－异针茅草地０．３６ｈｍ￣２，封育时间１９９０—１９９３年。对封育草地内地上及地下植物量测定结果：封育第一年优良牧草鲜草量增加明显，由原来的１７４．０ｇ／ｍ￣２增加到３２５．０ｇ／ｍ￣２（Ｐ＜０．０１），第２、３年产量变化不明显（Ｐ＞０．０５）；封育的第１、２年，优良牧草成份呈上升趋势，杂毒草成份呈下降趋势，封育的第３年优良牧草成份开始下降，杂毒草开始上升；地下植物总量（４０ｃｍ内），在封育的第１年下降明显，由原来的６４６９．５６ｇ／ｍ￣２下降到４７２１．６８ｇ／ｍ￣２（Ｐ＜０．０１），封育的第２、３年根量开始明显回升，至第３年上升为７３１０．０ｇ／ｍ￣２（Ｐ＜０．０１）。测定结果表明，高寒草甸草地封育时间以２年为佳。建议利用现有围栏，针对冬春草地采取冬季刮用枯草，早春禁牧（４—７月）的措施，封育退化草地两年，即可达到封育效果。     

果洛地区“黑土滩”中秃斑地测定

“黑土滩”中的秃斑地和原草地相比，毒草量增加６４．８％，优良牧草明显减少；地下根量（０—１０ｃｍ）减少２３７６．６ｇ／ｍ￣２；土壤趋于碱性、旱化，肥力下降，蓄水能力下降。以上差异均达到显著水平（Ｐ＜０．０５）。     

辽宁绒山羊绒直径变异的研究

本文系统分析了环境因素对辽宁绒山羊绒直径的影响、绒直径的遗传特点及其群体绒直径的分布情况。羊绒自根部至尖部逐渐变粗，尖部与根部绒直径相差３．３１μｍ；体躯绒直径最小部位与最大部位差异为２．０９μｍ；３周岁时绒直径最大，公羊平均绒直径比母羊高１．０μｍ；同一公羊雄性后代的绒直径比雌性后代平均高０．５１μｍ；公羊年龄对后代具有显著的影响（Ｐ＜０．０５）；绒直径的遗传力为０．４２１，与产绒量、体重的遗传相关分别为０．６５８和０．１１２。部分公羊的后代具有产绒量高、体重大而绒直径小的理想组合。在整个群体中２６．４０％的母羊和５３．５１％的公羊生产１４．５μｍ以下的羊绒，９．６％的３周岁母羊和５．９％的３周岁公羊生产１４．５μｍ以下的羊绒     

种草改良江苏滨海盐土效果的研究

为寻求江苏滨海盐土改良的最佳途径，１９９０￣１９９３年在竹港垦区进行了种草改土研究。结果表明，土壤有关性状种草比不种草有显著改善。种草第四年表层土（０￣５ｃｍ）盐分下降０．２％（绝对值，下同），土壤容量下降０．１３￣０．２５ｇ／ｃｍ＾３，孔隙率增加５￣８％，耕作层增厚５￣７ｃｍ，〉０．２５ｍｍ团聚体增加１０￣２０％，有机质增加０．３％，全氮增加０．０３％，微生物总数增加３￣１４倍，生物活性显著提高     

霜霉病对苜蓿幼苗生长和结瘤的影响

接种试验表明，霜霉病对苜蓿幼苗生长发育影响显著，感病植株幼苗高度减低４２．６％￣５２．０％，生长速度明显减慢，健苗的平均增长率为４５．７％，而病苗仅为２２．７％；地下部主根入土深度（根长）减少２７％，根的直径（根颈部）减少４４．３％，根鲜重减少７５％，根瘤的数量减少５４．１％，而且病苗的根瘤均为白色无效根瘤，健苗的根瘤约半数为粉红色的有效根病。根的长度与根瘤数量呈明显正相关，健苗的相关系数ｒ＝０．     

提高母猪受胎率及产仔数的研究

母猪输精前令其嗅闻公猪尿液２￣３ｍｉｎ，然后再将输精管插入阴道内，来回抽动刺激阴道壁及子宫颈２￣３ｍｉｎ后再注入精液，试验结果，情期受胎率比对照组提高１６．７％，差异显著（Ｐ〈０．０５）；平均每窝产仔数比对照组多产２．１１头，差异显著（Ｐ〈０．０５）。     

葛叶粉饲喂农养肉猪试验

在山区农家饲养肉猪日粮中添加５、１０、１５、２０％的葛叶粉。结果表明：添加５％葛叶粉的不同处理的试验１、２、３组日增重分别为４８３、５１２、４９６克，与农养常规对照组４９８克之间差异均不显著（Ｐ＞０．０５）。试验２组同１０％葛叶粉的试验４组４５７克间差异明显（Ｐ＜０．０５），与１５％、２０％葛叶粉的对应试验５组４０２克、试验６组３３９克间差异均极显著（Ｐ＜０．０１）。试验４组同对照组比虽日增重低８．２％，但差异不显著（Ｐ＞０．０５）。试验５、６组与对照组、试验１、３组间差异均极显著（Ｐ＜０．０１），且该两组彼此存在明显差别（Ｐ＜０．０５）。在饲料报酬、日采食量上，对照组与试验１、２、３组间均无显著差别（Ｐ＞０．０５）。试验４组在饲料报酬上与对照组、试验２、３组间分别有明显差异（Ｐ＜０．０１），试验５组与对照组、试验１、２、３、４、６组间皆存有显著差别（Ｐ＜０．０５），试验６组同对照组、试验１、２、３组间都是差异极明显（Ｐ＜０．０１）。饲料适口性以试验２组最好，其次为对照组、试验３组，试验５、６组最差。     

稀土饲料添加剂饲养绵羊的剂量选择试验

选用半舍饲的周岁龄青海细毛羊５６只，分为三组，试验１、２组各２０只，对照组１６只。在同等饲养管理条件下，试验１、２组每只羊每日分别添加０．２ｇ和０．１ｇＲＣＦ－３稀土添加剂，进行６０ｄ饲养试验。结果：试验１、２组绵羊平均日增重分别比对照组提高３０．６％（Ｐ＜０．０１）和１２．６％（Ｐ＞０．０５）；平均羊毛长度分别比对照组提高２２．１％（Ｐ＜０．０１）和５．５％（Ｐ＞０．０５）；经济效益分别比对照组提高２５．２％（Ｐ＜０．０１）和８．７％（Ｐ＞０．０５％）。试验１组平均日增重，羊毛长度和经济效益分别比２组提高１５．９％（Ｐ＜０．０５）、１５．７％（Ｐ＜０．０５）和１５．２％（Ｐ＜０．０５）以试验１组的效果为佳。     

转基因猪研究中供体母猪激素水平与胚胎发育阶段的关系

选择３６头青年母猪进行超数排卵，发现孕酮含量与黄体数（排卵点数）呈显著相关（ｒ＿１＝０．４４４１，ｐ＜０．０１）；但与冲出胚胎数没有相关（ｒ＿２＝０．２２９６，Ｐ＞０．０５）；与２细胞以上胚胎数（不包括２细胞）均表现出强正相关（ｒ＿３＝０．６６９２，Ｐ＜０．０１）。因此，孕酮含量在一定程度上可作为胚胎发育阶段的指标。     

饲喂不同蛋白水平日粮的牦牛瘤胃氮代谢与十二指肠各氮组分流量

采用瘘管手术方法对３头生长牦牛在饲喂代谢能ＭＥ均为９．６ＭＪ／ｋｇＤＭ，粗蛋白（ＣＰ）为８％和１２％的日粮时的复胃氮代谢与瘤胃、肠道消化代谢进行研究。试验结果表明，日粮ＣＰ水平升高后，生长牦牛瘤胃氨氮浓度由３．３升至５．９ｍｇ／１００ｍｌ（Ｐ＜０．０１），瘤胃内氮的消失率由１．９％升到２１．１％（Ｐ＜０．０１）。瘤胃微生物蛋白质合成效率基本不变（平均６９．１ｇＣｐ／ｋｇＤＯＭ）；一昼夜进入十二指肠的食糜量及食糜干物质量基本不变；食糜总氮、氨氮及非氨氮量均显著增加（Ｐ＜０．０１），其中非氨氮增加２０％：非氨氮中微生物氮的比例由４５％降至３９％（Ｐ＜０，０５）；日粮ＤＭ，ＯＭ，ＣＰ和ＡＤＦ整体消化率分别提高１２．９％、１３．４％、３４％和２２．３％（Ｐ＜０．０１）。日粮ＣＰ由８％升至１２％后，生长牦牛瘤胃ＴＶＦＡ中乙酸比例由５４％降至４３．５％（Ｐ＜０．０１）．丙酸比例由２４．８％升至２８．４％（Ｐ＜０．０５），丁酸比例也由２１．１％增至２８．５％（Ｐ＜０．０１）。同时Ｃ２／Ｃ３比由２．１９降至１．５４（Ｐ＜０．０１）。     

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.     

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.     

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.     

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