二氢吡啶对蛋品质的影响及其机理研究

取３００ 日龄罗曼蛋鸡１ ５３６ 只，随机分为４ 组（ 每组设４ 个重复，每个重复９６ 只） ，在自由采食、饮水和光照１６ｈ 的条件下，分别饲喂添加０ｍｇ／ｋｇ 、１００ｍｇ／ｋｇ 、１５０ｍｇ／ｋｇ 、２００ｍｇ／ｋｇ二氢吡啶的玉米—豆粕型饲粮１３ 周。结果发现：①饲粮中含１００ｍｇ／ｋｇ 、１５０ｍｇ／ｋｇ 或２００ｍｇ／ｋｇ的二氢吡啶， 能使蛋壳厚度分别增加１１ ．３３ ％ （Ｐ＜ ０ ．０１） 、１６ ．８５％ （Ｐ＜ ０ ．００１） 和２０．１７ ％ （Ｐ＜ ０ ．００１） ；②饲粮中含１５０ｍｇ／ｋｇ 或２００ｍｇ／ｋｇ 的二氢吡啶，能使蛋比重和蛋壳相对重分别增加０ ．４４％ （Ｐ＜ ０ ．０５） 、０ ．５３ ％ （Ｐ＜ ０．０５） 和５ ．６６％ （Ｐ＜ ０ ．０５） 、６ ．９７ ％ （Ｐ＜ ０．０５） ，血清钙含量分别提高了１６．９０ ％ （Ｐ＜ ０ ．０５） 和１８ ．３３％ （Ｐ＜ ０．０５） ，而血清甲状旁腺素水平则分别下降了１８．０４ ％ （Ｐ＜ ０ ．０５） 和２０．００％ （Ｐ＜ ０ ．０５） 。     

不同锰源及锰水平对雏鸭肝脏脂肪沉积的影响

选用１日龄北京雏鸭３００只，研究不同锰源及其锰添加水平对雏鸭肝脏脂肪沉积和肝锰含量的影响。试验１随机分为７组，每组３０只试鸭，在基础饲粮中（含Ｍｎ１９ｍｇ／ｋｇ），钙源及锰添加水平依次为４５、８５、１３５ｍｇ／ｋｇ（试剂级ＭｎＳＯ＿４·Ｈ＿２Ｏ或ＭｎＣＯ＿３）。试验２随机分４组，每组３０只试鸭，在基础饲粮上（含Ｍｎ１９ｍｇ／ｋｇ），补锰水平依次为０、１１０、１０００、３５００ｍｇ／ｋｇ（试剂级ＭｎＳＯ＿４·Ｈ＿２Ｏ），试验３周。结果为：锰源不影响雏鸭肝脏脂肪沉积，肝锰含量和千克活体肝重（Ｐ＞０．０５），锰缺乏（含Ｍｎ１９ｍｇ／ｋｇ）或锰过量（补Ｍｎ３５００ｍｇ／ｋｇ）均影响雏鸭肝脏脂肪沉积和肝锰含量变化（Ｐ＜０．０５或Ｐ＜０．０１）。综合试验结果为：如以肝锰变化作为机体锰营养状况评定指标，则饲粮锰适宜添加量为８５～１３５ｍｇ／ｋｇ。     

不同化学形式铜盐对仔猪生长性能和微量元素代谢的影响

选用１５０头杜长大三元杂交仔猪,分别饲喂含不同化学形式铜的饲粮,研究它们对仔猪生长性能、微量元素代谢等的影响,并评定不同化学形式铜盐的生物效价。试验结果表明：①饲粮中添加不同化学形式铜盐均影响了仔猪的生长,其中以５０ｍｇ／ｋｇ酪蛋白铜组生长最快,较对照组提高了１４．０％（Ｐ＜０．０５）,其次为２４０ｍｇ／ｋｇ硫酸铜,提高了１２．７％（Ｐ＜０．０５）;②添加２４０ｍｇ／ｋｇ硫酸铜和蛋白铜均可显著提高饲粮粗脂肪的消化率（Ｐ＜０．０５）;③饲粮中添加２４０ｍｇ／ｋｇ硫酸铜组和５０ｍｇ／ｋｇ酪蛋白铜组也显著提高了试验猪脑铜含量（Ｐ＜０．０５）,其中前者还使肝铜、胆汁铜、铁浓度明显上升（Ｐ＜０．０５）;④酪蛋白铜的生物效价显著高于常规使用的硫酸铜。     

烟酰胺对肉仔鸡性能影响的研究

用１日龄Ａｒｂｏｒ Ａｃｒｅｓ雏鸡３８４只进行试验，研究饲粮添加烟酰胺对肉仔鸡生长，血清生化指标，组织辅酶Ｉ（ＮＡＤ＾＋）含量及脂肪沉积的影响。试鸡按体重，性别随机分别为４组，每组８个重复，各组分别喂以不添加烟酰胺的玉米－豆粕型基础饲粮和分别添加１５，３０，４５ｍｇ／ｋｇ烟酰胺的相同基础饲粮。     

甜菜碱对杜长大肥育猪生长性能、胴体组成和肉质的影响

１５０口“杜长大”肥育猪（始重６３±０．４２ｋｇ）,按饲养试验要求分成５组（每组设３个重复）,分别饲喂甜菜碱含量（ｍｇ／ｋｇ）为０、１０００、１２５０、１５００、１７５０的饲粮,体重达９３ｋｇ左右时结束饲养试验;然后从每组选择体重相近的试验猪１２口,公、母各半,共６０口,进行屠宰测定。结果表明,①饲粮中添加甜菜碱均提高了日增重,其中以１７５０ｍｇ／ｋｇ组效果最为显著,提高了１３．３２％（Ｐ＜０．０１）;②添加甜菜碱出现了采食量增加和料重比降低的趋势（Ｐ＞０．０５）：③添加不同剂量的甜菜碱均显著提高了胴体瘦肉率,降低了胴体脂肪率,其中１０００ｍｇ／ｋｇ组最明显。瘦肉率提高了５．７１％（Ｐ＜０．０１）,脂肪率降低了１８．２７％（Ｐ＜０．０１）;④添加甜菜碱使眼肌面积显著增大,其中１７５０ｍｇ／ｋｇ组和１０００ｍｇ／ｋｇ组较明显,分别增大了１２．９％（Ｐ＜０．０１）和９．２％（Ｐ＜０．０１）;⑤首次发现,不同骨骼肌对甜菜碱的反应存在明显差异。其中１７５０ｍｇ／ｋｇ组背最长肌、股二头肌及半膜肌的重量分别增大了１０．８４％（Ｐ＜０．０２）、１１．０２％（Ｐ＜０．０５）和２２．８７％（Ｐ＜０．０３）;⑥添加甜菜碱明显增     

日粮中添加高剂量铜对肉用仔鸡生长和肝、粪铜浓度的影响

用１６４只１周龄ＡＡ肉用仔鸡进行的两次试验结果显示，在含铜８—１４ｍｇ／ｋｇ的玉米—豆饼日粮中，添加１２５ｍｇ／ｋｇ铜（ＣｕＳＯ４５Ｈ２Ｏ），提高４—７周龄平均增重７．１－１０．８％（Ｐ＜０．０５或０．０１），提高１—３周龄平均增重２．１－２．５％（Ｐ＞０．０５，试验Ⅱ）或６．２％（Ｐ＜０．０１，试验Ⅰ），降低１—３周龄饲料／增重６．３－１５．３％，添加１２５ｍｇ／ｋｇ铜，对胸肌含水量无影响（Ｐ＞０．０５），明显提高了肝铜含量（Ｐ＜０．０５），但幅度不太大，由对照组的１３．８ｍｇ／ｋｇ提高到２３．８ｍｇ／ｋｇ（风干基础），而正常鸡肝含铜量低，因此对食品卫生无不利影响。大量铜由粪中排出体外，试验组粪铜浓度比对照组提高９倍。     

肉鸡后期日粮中添加不同水平铜的饲养效应

将２８０ 只２１ 日龄商品代ＡＡ 肉鸡随机分成５ 组， 组内设两个重复， 基础日粮含铜为５ ．７ｍｇ／ｋｇ（ 测定结果） ，分别添加４ ．３ｍｇ／ｋｇ 、４４．３ｍｇ／ｋｇ 、８４ ．３ｍｇ／ｋｇ 、１２４．３ｍｇ／ｋｇ 、１６４ ．３ｍｇ／ｋｇ无机铜进行３ 周饲养试验，记录各组采食量（ＡＤＦＩ） ，测定日增重（ＡＤＧ） 和料重比（Ｆ／ Ｇ） 。结果表明：日粮铜水平影响ＡＤＧ、ＡＤＦＩ和Ｆ／Ｇ（Ｐ＜ ０．０５） ，随着铜浓度的上升，ＡＤＧ、ＡＤＦＩ呈下降趋势，Ｆ／ Ｇ 呈上升趋势， 高水平铜对肉鸡无增重效果。根据试验结果， 建议肉鸡后期日粮中铜给量为１０ｍｇ／ｋｇ 。     

硫辛酸对黄羽肉鸡生长性能、抗氧化能力和免疫功能的影响

本试验旨在研究饲粮中添加硫辛酸对黄羽肉鸡生长性能、抗氧化能力和免疫功能的影响。将 ６０只 ２１日龄体重相近的黄羽肉鸡随机分为 ２组,即对照组和硫辛酸组,每组 ５个重复,每个重复 ６只鸡。对照组饲喂基础饲粮,硫辛酸组饲喂在基础饲粮中添加 ３００ｍｇ／ｋｇ硫辛酸的试验饲粮,试验期 ３０ｄ。结果表明,硫辛酸对黄羽肉鸡的生长性能无显著影响（Ｐ＞０．０５）;在试验第 １５天时,硫辛酸可以显著提高黄羽肉鸡血清总超氧化物歧化酶活性（Ｐ＜０．０５）、降低一氧化氮含量（Ｐ＜０．０５）,促进脾脏的发育（Ｐ＜０．０５）,提高血清免疫球蛋白 Ｇ含量（Ｐ＜０．０１）;在试验第 ３０天时,硫辛酸可以显著降低黄羽肉鸡血清丙二醛含量（Ｐ＜０．０５）、提高抑制羟自由基的能力（Ｐ＜０．０１）,提高由伴刀豆球蛋白 Ａ和脂多糖刺激的外周血淋巴细胞转化率以及血清免疫球蛋白 Ｇ含量（Ｐ＜０．０５）。由本试验可知,饲粮中添加 ３００ｍｇ／ｋｇ硫辛酸可以在一定程度上提高肉鸡抗氧化能力,增强其免疫功能。     

饲粮不同维生素 Ｅ水平对鹅生产性能、胴体品质、血清生化指标和生殖激素含量的影响

本试验以 ０～１２周龄肝用型鹅为研究对象,通过探讨饲粮不同维生素 Ｅ水平对青农灰鹅生产性能、胴体品质、血清生化指标和生殖激素含量的影响,确定育雏、育成期鹅维生素 Ｅ的需要量。试验选择 １日龄青农灰鹅 １８０只,随机分为 ６个处理,每个处理 ３个重复,每个重复 １０只。试验鹅饲喂在玉米 －豆粕型饲粮的基础上分别添加 ０（对照组）、５、１０、２０、４０、８０ＩＵ／ｋｇ维生素 Ｅ的饲粮,试验期为 １２周。结果表明：１）与对照组相比,饲粮添加 ４０、８０ＩＵ／ｋｇ维生素 Ｅ可显著提高 ０～４周龄鹅平均日增重和平均日采食量（Ｐ＜０．０５）,饲粮添加 ４０ＩＵ／ｋｇ维生素 Ｅ可显著提高 ５～１２周龄鹅平均日增重和平均日采食量（Ｐ＜０．０５）。２）饲粮添加 ４０、８０ＩＵ／ｋｇ维生素 Ｅ可显著降低 １２周龄鹅胸肌剪切力和失水率（Ｐ＜０．０５）,饲粮添加 ８０ＩＵ／ｋｇ维生素 Ｅ可显著提高 １２周龄鹅半净膛率和胸肌率（Ｐ＜０．０５）。３）提高饲粮维生素 Ｅ水平可显著提高 ４周龄鹅血清尿素氮含量（Ｐ＜０．０５）,显著降低１２周龄鹅血清尿素氮含量（Ｐ＜０．０１）,饲粮添加４０ＩＵ／ｋｇ维生素 Ｅ可显著提高 ４周龄和 １２周龄鹅血清碱性磷酸酶活性（Ｐ＜０．０５）。４）与对照组相比,４０、８０ＩＵ／ｋｇ维生素 Ｅ组１２周龄母鹅血清中雌二醇含量显著升高（Ｐ＜０．０５）,促卵泡素含量显著降低（Ｐ＜０．０５）。２０、４０、８０ＩＵ／ｋｇ维生素 Ｅ组 １２周龄公鹅血清中雌二醇、睾酮含量均显著升高（Ｐ＜０．０５）,促卵泡素含量显著降低（Ｐ＜０．０５）。本研究结论如下：１）维生素 Ｅ对鹅的生产性能、胴体品质、血清中尿酸、尿素氮、生殖激素含量和碱性磷酸酶活性具有一定调控作用;２）根据建立的回归方程确定肝用型鹅饲粮维生素 Ｅ最适添加量为：０～４周龄４２．９８ＩＵ／ｋｇ,５～１２周龄 ３８．９２～４３．４１ＩＵ／ｋｇ;３）根据鹅血清中生殖激素含量的变化确定饲粮维生素 Ｅ最低添加量为２０ＩＵ／ｋｇ。     

饲粮铜和维生素 Ａ及其互作效应对肉仔鸡生长性能及抗氧化功能的影响

本研究旨在探讨铜和维生素 Ａ及其互作效应对肉仔鸡生长性能及抗氧化功能的影响。试验选用 １日龄艾维茵肉仔鸡 ４４８只，随机分为 ８组，每组 ４个重复，每个重复 １４只鸡。采用４×２（铜 ×维生素 Ａ）完全随机设计，饲粮铜的添加量分别为 ０、８、１５０、２２５ｍｇ／ｋｇ，维生素 Ａ的添加量分别为 １５００、５０００ＩＵ／ｋｇ，分为 ２个生长阶段，前期为 １～４周龄，后期为 ５～７周龄。结果表明：１）高铜（１５０、２２５ｍｇ／ｋｇ）抑制了全期肉仔鸡生长性能，提高了全期血清铜蓝蛋白（Ｃｐ）和后期血清总超氧化物歧化酶（Ｔ ＳＯＤ）活性（Ｐ＜０．０５）。２）５０００ＩＵ／ｋｇ维生素 Ａ组获得较好的生长性能，提高了全期血清 Ｔ ＳＯＤ活性，降低了前期血清 Ｃｐ活性（Ｐ＜０．０５）。３）铜和维生素 Ａ互作效应对前期体增重、血清 Ｃｐ和 Ｔ ＳＯＤ活性及全期料重比有显著影响（Ｐ＜０．０５），且二者间存在互补作用。铜（８ｍｇ／ｋｇ）×维生素 Ａ（５０００ＩＵ／ｋｇ）组与铜（０ｍｇ／ｋｇ）×维生素 Ａ（５０００ＩＵ／ｋｇ）组对前期肉仔鸡获得良好生长性能和提高血清 Ｔ ＳＯＤ活性均有促进作用，但对血清 Ｃｐ活性有显著降低作用（Ｐ＜０．０５）。由此可见，在基础饲粮铜水平为 １６～２３ｍｇ／ｋｇ时，铜的适 宜 添 加 量 为 前 期 ８ｍｇ／ｋｇ，后 期 ０～８ｍｇ／ｋｇ；全 期 维 生 素 Ａ 的 适 宜 添 加 量 为５０００ＩＵ／ｋｇ。     

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