铬对待测饲料物理性状的影响

前言 饲料蛋白质在瘤胃的降解率随着饲料在瘤胃中停留的时间长短而变异,同一饲料在瘤胃停留时间较长,则降解率也较高,反之则较低。所以确定饲料蛋白质降解率时应将饲料通过瘤胃的部分外流速度(K)结合考虑,才能得到合乎实际的降解率。目前测定饲料部分外流速度大多使用铬标记待测饲料,即饲料用重铬     

外流速率实测与参考对羊常用饲料瘤胃有效降解率的影响

本研究旨在测定半细毛羊6种常用饲料瘤胃外流速率,并分析外流速率实测值与普遍采用的参考值对所测饲料瘤胃有效降解率的影响。选用16只3周岁、健康状况良好、体重63～65 kg的云南半细毛羊公羊作为试验动物,其中4只装有永久性瘤胃瘘管。4只瘘管羊只用来测定铬标记饲料干物质回收率,12只非瘘管羊用来测定瘤胃外流速率。待测瘤胃外流速率的6种饲料分别为豆粕、菜籽粕、玉米、鸭茅、大豆秸秆和小麦秸秆。结果表明:1)采食豆粕、菜籽粕、玉米3种铬标记精饲料后粪中铬含量达到高峰的时间为24～28 h,采食鸭茅、大豆秸秆、小麦秸秆3种铬标记粗饲料后则为24～36 h。2)不同饲料之间瘤胃外流速率有差异,豆粕、菜籽粕、玉米、鸭茅、大豆秸秆、小麦秸秆的瘤胃外流速率分别为7.30%/h、7.49%/h、6.84%/h、5.02%/h、5.59%/h、3.97%/h。3)基于外流速率实测值与参考值计算所得6种饲料干物质、有机物和粗蛋白质有效降解率差异较大,且采用实测值计算所得数值全部低于采用参考值计算所得数值。由此可见,基于外流速率实测值计算所得瘤胃有效降解率与基于外流速率参考值计算所得瘤胃有效降解率差异较大,在利用瘤胃尼龙袋法测定饲料瘤胃有效降解率的实际研究工作中,建议对饲料瘤胃外流速率进行实测。     

粗饲料品质差或饲喂不当给奶牛生产带来的危害

奶牛具有非常发达的瘤胃和反刍功能，粗饲料是维持奶牛正常生理所必需的饲料。日粮粗饲料中的纤维素和半纤维素对保持正常瘤胃功能非常重要。粗饲料可影响和控制瘤胃的温度、PH值、酸碱的缓冲能力、渗透压、瘤胃内容物的外流速度、挥发性脂肪酸（主为乙酸、丙酸和丁酸）的产生量以及乙酸、丙酸、丁酸之间的比例等。     

饲料通过梅花鹿瘤胃外流速度的研究

梅花鹿是我国珍贵的野生经济动物,属反刍动物。其采食的饲料种类与牛、羊有所不同,野生时以食嫩树枝叶为主,家养条件下则以嫩树枝叶和青贮饲料为主。本试验选用三头带有瘤胃瘘管体重约为130kg的三锯梅花鹿,测定了四种有代表性精、粗饲料(豆饼、玉米面、柞树叶、青贮玉米)的瘤胃外流速度。试验期每期15天,预试期10天,正试期5天。日粮能量水平为16317.6KJ/kg;蛋白质水平为17.08％;Ca、P含量分别为0.87％和0.47％。采用铬标记     

全混合日粮粗饲料水平对奶牛的挑食行为、瘤胃内容物及血清指标的影响

本试验旨在研究全混合日粮粗饲料水平对奶牛挑食行为、瘤胃内环境及血清指标的影响。选用12头泌乳中期[泌乳天数(119±26)d]经产荷斯坦奶牛[体重(629±46)kg],随机分为4组,每组中1头安装瘤胃瘘管,按4×4拉丁方设计,饲喂粗饲料水平分别为40%、50%、60%和70%(干物质基础)的4种全混合日粮。共进行4期动物试验,每期试验21 d。结果表明:饲粮粗饲料水平对奶牛挑食行为有显著(P0.05)或极显著(P0.01)影响。饲粮粗饲料水平为40%时,奶牛喜食粒度≥4 mm饲粮,厌食粒度4 mm饲粮,但饲粮粗饲料水平40%时,奶牛喜食粒度4 mm饲粮,厌食粒度≥4 mm饲粮。饲粮粗饲料水平对瘤胃内容物各层粒度分布无显著影响(P0.05)。随饲粮粗饲料水平的增加,瘤胃液外流速度和瘤胃固相外流速度呈显著线性增加(P0.05),瘤胃内容物重量和瘤胃液体积无显著变化(P0.05);血清胰岛素样生长因子-1(IGF-1)含量呈显著线性增加(P0.01),瘦素(LEP)和非酯化脂肪酸(NEFA)含量有线性增加趋势(0.05≤P0.10),血清生长激素(GH)和胰岛素(INS)含量有线性降低的趋势(0.05≤P0.10)。综上所述,饲粮粗饲料水平是影响奶牛挑食行为、瘤胃内容物及血清指标的重要因素。     

全混合日粮粗饲料水平对奶牛的挑食行为、瘤胃内容物及血清指标的影响北大核心CSCD

本试验旨在研究全混合日粮粗饲料水平对奶牛挑食行为、瘤胃内环境及血清指标的影响。选用12头泌乳中期[泌乳天数(119±26)d]经产荷斯坦奶牛[体重(629±46)kg],随机分为4组,每组中1头安装瘤胃瘘管,按4×4拉丁方设计,饲喂粗饲料水平分别为40%、50%、60%和70%(干物质基础)的4种全混合日粮。共进行4期动物试验,每期试验21 d。结果表明:饲粮粗饲料水平对奶牛挑食行为有显著(P<0.05)或极显著(P<0.01)影响。饲粮粗饲料水平为40%时,奶牛喜食粒度≥4 mm饲粮,厌食粒度<4 mm饲粮,但饲粮粗饲料水平>40%时,奶牛喜食粒度<4 mm饲粮,厌食粒度≥4 mm饲粮。饲粮粗饲料水平对瘤胃内容物各层粒度分布无显著影响(P>0.05)。随饲粮粗饲料水平的增加,瘤胃液外流速度和瘤胃固相外流速度呈显著线性增加(P<0.05),瘤胃内容物重量和瘤胃液体积无显著变化(P>0.05);血清胰岛素样生长因子-1(IGF-1)含量呈显著线性增加(P<0.01),瘦素(LEP)和非酯化脂肪酸(NEFA)含量有线性增加趋势(0.05≤P<0.10),血清生长激素(GH)和胰岛素(INS)含量有线性降低的趋势(0.05≤P<0.10)。综上所述,饲粮粗饲料水平是影响奶牛挑食行为、瘤胃内容物及血清指标的重要因素。     

粗饲料种类对梅花鹿瘤胃消化代谢的影响

选用4头装置永久性瘤胃瘘管的成年梅花鹿，采用4种粗饲料，按4×4拉丁方试验设计，进行了饲养试验。采集瘤胃液并对pH值、氨态氮（NH3－N）、三氯乙酸沉淀蛋白（TCA－P）、粗蛋白质（CP）和总挥发性脂肪酸（TVFA）浓度进行了测定，并研究了它们的动态变化规律以及VFA组分百分率。试验结果表明，瘤胃内pH值。TCA－P浓度均随粗饲料种类的不同而存在显著的差异（P＜0．01）；瘤胃内NH3－N、CP及TVFA浓度均不因该四种粗饲料种类不同而受影响（P＞0．05）；各试验组的瘤胃发酵类型基本相同。     

育肥羊饲喂全混合日粮条件下瘤胃固相食糜外流速度及其有效降解率的评定

试验旨在测定育肥羊饲喂全混合日粮（TMR）条件下瘤胃食糜外流速度（Kp）及干物质（DM）、有机物（OM）及粗蛋白质（CP）的有效降解率。选取3只安装有永久性瘤胃瘘管、体重（30.0±3.7） kg的哈萨克公羔羊作为试验动物,代谢笼内单笼饲养。按3×3拉丁方试验设计,分别饲喂3种能量水平一致而CP水平不同（11%、12%和13%）的TMR。采用醋酸镱（Yb-ac）作为固相食糜标记物,测定镱（Yb）元素的浓度,绘制浓度衰减曲线,利用非线性回归法拟合其Kp,并计算全混合日粮的瘤胃有效降解率。结果显示,3种TMR的瘤胃固相食糜的Kp值分别为6.71、6.66和7.59 %/h,TMR1的DM、OM和CP的有效降解率分别为39.82%、38.58%和43.87%;TMR2的为35.70%、34.40%和36.86%;TMR3的为42.46%、41.29%和51.28%。3种TMR的DM在瘤胃中的有效停留时间分别为26.49、28.98和21.73 h。此结果为进一步评定TMR的DM及过瘤胃氨基酸的小肠消化率研究提供了重要参数。     

反刍动物饲料营养价值评定方法及在水牛中的应用

水牛饲料包括各种粗饲料和精饲料,因其瘤胃特有的微生物生态环境及反刍行为,水牛日粮中粗饲料占60%~80%,而粗饲料中的纤维素含量达55%~95%,为反刍动物提供60%~70%的能量。不同粗饲料因其品质不同及同种粗饲料不同部位和收获时间、环境因素致使粗饲料在不同反刍动物的利用率也不同,因此对水牛常用饲料进行营养价值评定并利用化学分析和仪器分析手段所得的饲料的化学成分来预测饲料的有效能值具有重要的现实意义和理论指导作用。     

不同有机物进食量和外流速度对瘤胃发酵及微生物蛋白合成效率的影响

采用2×2随机因子试验设计研究持续动态瘤胃模拟装置(RSI-Ⅱ)不同有机物进食量(OMI)(27．67g、36．74g、46．00g)和瘤胃外流速度(0．02/h、0．035/h、0．05/h)对稻草-玉米-豆粕型日粮瘤胃发酵及微生物蛋白合成效率的影响。结果表明,RSI内pH值不受有机物进食量和外流速度的影响;在低外流速度下各OMI组瘤胃内0～72h干物质、有机物、粗蛋白、NDF、ADF降解率均高于高外流速度(P＜0．05)。随着OMI的增加,同一外流速度下日粮可发酵有机物产生VFA量(TVFA/FOM,mmol/g)逐渐下降(P＜0．05);相同OMI组饲料降解氮转化为微生物氮的效率在外流速度为0．02h时显著高于高外流速度(P＜0．05)。     

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