43～63日龄黄羽肉公鸡铜需要量

本研究旨在通过研究饲粮铜添加水平对黄羽肉公鸡生长性能、抗氧化性能、肝脏和血清铜含量等的影响,以探讨43~63日龄黄羽肉公鸡铜的需要量。选用43日龄健康、发育良好的快大型岭南黄羽肉公鸡900只,根据体重随机分为6个组,每组6个重复,每个重复25只鸡,组1(对照组)为基础饲粮组(铜水平为2.74 mg/kg),组2~6饲粮在基础饲粮中分别添加4、8、16、32、64 mg/kg铜。结果表明:1)与对照组相比,16和32 mg/kg铜组显著提高试鸡末重、平均日增重和平均日采食量(P<0.05),饲粮中铜添加水平对料重比无显著影响(P>0.05)。2)与对照组相比,16和32 mg/kg铜组血清铜锌-超氧化物歧化酶(Cu Zn-SOD)活性显著升高(P<0.05),32和64 mg/kg铜组肝脏Cu Zn-SOD活性显著升高(P<0.05),饲粮铜添加水平对胸肌中Cu ZnSOD活性无显著影响(P>0.05);饲粮添加32和64 mg/kg铜显著降低了胸肌丙二醛(M DA)含量(P<0.05),各组间血清和肝脏MDA含量均无显著差异(P>0.05);添加16、32、64 mg/kg铜显著降低了血清铜蓝蛋白活性(P<0.05)。3)与对照组相比,8、16 mg/kg铜组肝脏铜含量显著降低(P<0.05),铜添加水平对血清铜含量和肝脏金属硫蛋白含量影响不显著(P>0.05)。综合考虑各项指标,为获得较好生长性能和抗氧化性能,43~63日龄黄羽肉公鸡饲粮铜适宜添加水平分别为16和32 mg/kg,加上基础饲粮铜水平为2.74 mg/kg,则该阶段黄羽肉公鸡铜需要量分别为18.74和34.74 mg/kg;以生长性能和肝脏Cu Zn-SOD活性为依据,通过折线回归分析估测得到43~63日龄黄羽肉公鸡铜需要量分别为19.94和38.34 mg/kg。     

高铜对雏鸭抗氧化酶活性的影响

360只1日龄天府肉鸭随机分为6组,分别喂以对照日粮(Cu 8 mg/kg)和高铜日粮(Ⅰ组Cu 100 mg/kg;Ⅱ组Cu 200 mg/kg;Ⅲ组Cu 400 mg/kg;Ⅳ组Cu 600 mg/kg;Ⅴ组Cu 800 mg/kg),试验期6周.与对照组比较,高铜Ⅳ组和Ⅴ组血清铜锌SOD、CP活性、肝脏铜锌SOD、GSH-Px活性降低(P<0.01);高铜Ⅲ组、Ⅳ、Ⅴ组肝脏黄嘌呤氧化酶、单胺氧化酶含量显著升高(P<0.01);高铜Ⅰ、Ⅱ组血清铜锌SOD、CP活性、肝脏铜锌SOD、GSH-Px活性升高(P<0.01).结果表明,日粮铜水平达400 mg/kg及以上时可引起血清和肝脏抗氧化酶活性降低,使机体抗氧化功能受损.     

有机锰与铬互作对肉鸡脂质代谢及锰与铬在组织沉积的影响

本试验以玉米-豆粕型日粮为基础,添加不同水平的有机锰(以锰计:0,60,120 mg/kg)与有机铬(以铬计:0,400,600μg/kg),研究锰与铬对肉鸡脂质代谢及对肉鸡组织锰、铬沉积的影响。结果表明,7周末,单独添加锰、铬均显著降低血清TC含量(P0.01,P0.05);锰与铬同时添加,互作效应显著(P0.05)。单独添加锰对7周末血清TG含量表现极显著效应(P0.01)。与对照组相比,单独添加60 mg/kg锰或120 mg/kg锰血清TG含量分别降低31.91%或55.32%。单独添加400μg/kg铬和600μg/kg铬,血清G含量分别降低8.50%和26.58%;锰与铬互作对3、7周末血清G含量明显降低(P=0.026 8,orP=0.012 7)。单独添加铬使7周末血清TAA含量显著升高(P=0.006),随铬添加量增加,血清TAA含量分别高出对照组35.93%和40.97%。锰与铬互作,对7周末血清TAA含量表现显著效应(P=0.0388),与对照组相比,60 mg/kg锰600μg/kg铬互作组血清TAA含量增加43.57%;120 mg/kg锰互作组血清TAA含量分别增加29.19%和32.38%。单独添加锰仅对胫骨锰沉积产生显著影响(P0.05)。单独添加铬及锰与铬同时添加对各组织中锰的沉积均未表现出统计学上的显著互作效应(P0.05)。单独添加铬仅增加了肝脏铬沉积(P0.05)。单独添加锰减少了肝脏铬的吸收(P0.01),增加了肾脏铬的排出(P0.05)。锰与铬同时添加,对肝脏铬沉积表现显著互作效应。随饲粮铬添加量增加,60 mg/kg锰水平条件下,肝脏铬含量呈下降趋势;120 mg/kg锰水平条件下,肝脏铬含量显著降低(P0.01)。表现为锰颉颃铬,使铬在肝脏中的沉积明显下降。     

1~21日龄黄羽肉鸡饲粮铜营养需要量的研究

本研究旨在通过研究饲粮铜添加水平对黄羽肉鸡生长性能、免疫器官发育、抗氧化性能、肝脏和血清铜含量等的影响,以探讨1~21日龄黄羽肉鸡铜的营养需要量。选用1日龄健康、发育良好的快大型岭南黄羽肉公雏鸡1440只,根据体重随机分为6个组,每组6个重复,每个重复40只鸡,组1(对照组)饲喂基础饲粮(2.80 mg/kg铜),组2、3、4、5、6饲粮在基础饲粮中分别添加4、8、16、32、64 mg/kg铜。试验期21 d。结果表明：本试验条件下,1)饲粮添加4和64 mg/kg铜显著提高试鸡平均日采食量( P<0.05),饲粮中铜添加水平对末重、平均日增重和料重比无显著影响( P>0.05)。2)与对照组相比,8 mg/kg组法氏囊指数显著升高( P<0.05),而饲粮铜添加水平对胸腺和脾脏指数无显著影响( P>0.05)。3)与对照组相比,8、16、32和64 mg/kg组血清和肝脏铜锌超氧化物歧化酶(CuZnSOD)活性显著升高(P<0.05),各组间血清和肝脏丙二醛含量均无显著差异(P>0.05);添加16、32、64 mg/kg铜显著降低血清铜蓝蛋白活性(P<0.05)。4)与对照组相比,16、32和64 mg/kg组血清铜含量显著降低(P<0.05),铜添加水平对肝脏铜含量和肝脏金属硫蛋白含量影响不显著( P>0.05)。综合考虑各项指标,为获得较好生长性能和免疫器官发育、抗氧化性能,1~21日龄快大型黄羽肉鸡饲粮铜适宜添加水平为8 mg/kg,加上基础饲粮铜含量2.80 mg/kg,则该阶段黄羽肉鸡铜需要量为10.80 mg/kg;以血清CuZnSOD活性为依据,通过非线性回归分析估测得到1~21日龄黄羽肉鸡铜需要量为13.38 mg/kg。     

赖氨酸铜对西门塔尔阉牛血液指标的影响

选用16头平均体重420 kg,年龄2.5岁中国西门塔尔牛阉牛,采用随机区组设计分为4组,以混合精料和风干玉米秸秆为基础日粮,以赖氨酸铜为铜源,在基础日粮中分别添加铜0(对照)8,16和24 mg/kg,研究赖氨酸铜对西门塔尔牛血液指标的影响。结果表明:血清TG、GLU、TC、ALB和TP含量显著增加(P<0.05)。SUN显著下降(P<0.05)。血清GOT、GPT、AKP、ACP、LDH差异均不显著(P>0.05)。血清Cp、SOD和GSH-Px活性显著提高(P<0.05);MDA显著下降(P<0.05)。血清Cu含量随添加铜量逐渐增加,显著高于对照组(P<0.05),但处理组间差异不显著(P>0.05)。结果表明以赖氨酸铜为铜源时日粮铜添加量为8~16 mg/kg。     

高铜对雏鸡血清中含铜酶活性的影响

选用1日龄艾维茵肉鸡420只,随机分为7组,分别喂以对照日粮(Cu11mg/kg)、高铜日粮(Cu100mg/kgⅠ、Cu200mg/kgⅡ、Cu300mg/kgⅢ、Cu400mg/kgⅣ、Cu500mg/kgⅤ、Cu600mg/kgⅥ)6周。结果显示:与对照组相比,Ⅰ组、Ⅱ组雏鸡血清铜蓝蛋白活性显著升高,Ⅴ组、Ⅵ组显著降低(P<0.05或P<0.01),表明100mg/kg和200mg/kg的铜能显著提高雏鸡血清铜蓝蛋白活性,而高于500mg/kg时能使其活性降低。铜锌超氧化物歧化酶活性变化不明显(P>0.05)。     

日粮添加高铜对产蛋鸡生产性能和脂质代谢的影响

试验研究饲粮中添加铜对产蛋鸡生产性能,脂质代谢和组织铜含量的影响。试验共分4个处理,分别在基础饲粮中添加0、100、250、300mg/kg铜,80只360日龄的新罗曼蛋鸡随机分到4个处理中,每个处理5个重复,每个重复4只鸡,试验期28d。结果表明:添加高铜对各阶段产蛋鸡的采食量,产蛋率,蛋重无显著影响(P>0.05);但与对照组相比,添加高铜降低了第14、21、28天鸡蛋中每克蛋黄的胆固醇(TC)含量(P<0.05)和第21天血清中甘油三酯(TG),极低密度脂蛋白胆固醇(VLDL-C)含量(P<0.05)以及第28天肝脏中谷胱苷肽(GSH)的含量(P<0.05)。添加300mg/kg的铜增加了肝脏中铜的沉积(P<0.05),而对蛋黄中铜的含量无影响。本研究表明添加铜能够降低蛋黄中的TC含量,而对蛋鸡的生产性能和蛋黄中铜的含量无显著影响。     

酵母铬对热应激肉鸡抗氧化性能的影响

本试验旨在研究酵母铬不同添加水平对热应激肉鸡体内抗氧化性能的影响.选用14日龄AA肉仔鸡216只,随机分为6个处理,在基础口粮中分别添加铬0(对照组)、1.0、2.0、3.0、4.0和5.0 mg/kg,每组设3个重复,每重复12只鸡,试验期4周,在热应激条件下测定了28和42日龄肉鸡血清和肝脏组织中抑制羟自由基(·OH)能力、抗超氧阴离子自由基(O2-·)活性、MDA含量、GSH-Px、T-SOD、CAT活性和T-AOC.试验结果表明:3.0、4.0 mg/kg铬添加水平能够显著增强热应激肉鸡血清(28日龄)和肝脏(42日龄)中抑制羟自由基能力(P<0.05),提高血清(28和42日龄)和肝脏组织(42日龄)中抗超氧阴离子自由基活性(P<0.05);减少血清(28和42日龄)和肝脏(28日龄)中MDA生成(P<0.05);显著提高血清(28和42日龄)和肝脏组织(28和42日龄)中GSH-Px活性和T-AOC(P<0.05);极显著提高肝脏组织(28和42日龄)中T-SOD活性(P<0.01);并能提高血清(42日龄)CAT活性(P<0.05).结果显示,日粮添加酵母铬可以提高热应激肉鸡血清和肝脏中抑制羟自由基(·OH)能力、抗超氧阴离子自由基(O2-·)活性,减少MDA生成,并能提高血清和肝脏组织中GSH-Px、T-SOD、CAT活性和T-AOC,日粮中适宜的铬添加水平为3.0 mg/kg. (P<0.05);显著提高血清(28和42日龄)和肝脏组织(28和42日龄)中GSH-Px活性和T-AOC(P<0.05);极显著提高肝脏组织(28和42日龄)中T-SOD活性(P<0.01);并能提高血清(42日龄)CAT活性(P<0.05).结果显示,日粮添加酵母铬可以提高热应激肉鸡血清和肝 中抑制羟自由基(·OH)能力、抗超氧阴离子自由基(O2-·)活性,减少MDA生成,并能提高血清和肝脏组织中GSH-Px、T-SOD、CAT活性和T-AOC,日粮中适宜的铬添加水平为3.0 mg/kg. (P<0.05);显著提高血清(28和42日龄)和肝脏组织(28和42日龄)中GSH-Px活性和T-AOC(P<0.05);极显著提高肝脏组织(28和42日龄)中T-SOD活     

日粮添加高剂量铜对山羊生产性能、血脂、屠体的影响

试验在山羊日粮中添加不同水平的铜,旨在研究高铜对山羊生产性能、脂质代谢、屠体成分等的影响。试验采用单因子设计,将18只5月龄,体重为(20.4±2.1)kg的波尔×内蒙古羯羊随机分为3种处理,每个处理设3个重复,每个重复2只;处理1日粮中不添加铜作对照组,处理2和处理3日粮中分别添加100、200mg/kg铜(CuSO4.5H2O),饲养至112日龄时,统计采食量、日增重和料肉比;从每个处理各取3只羊,采集血样后屠宰、采集肝脏和胸部肉样,分别测定血铜、肝铜、血清中总胆固醇(TC)、甘油三酯(TG)、非酯化脂肪酸(NEFA)含量、屠体成分等。结果表明:与对照组相比,添加100mg/kg铜的处理组,日增重、采食量显著增加(P<0.05),料肉比显著降低(P<0.05)。添加100、200mg/kg铜的2个处理组,血铜含量差异不显著(P>0.05),肝铜含量显著增加(P<0.05),血清胆固醇(TC)和甘油三酯(TG)含量差异均不显著(P>0.05),但非酯化脂肪酸(NEFA)含量比对照组显著降低(P<0.05),屠体水分、蛋白、灰分含量均显著升高(P<0.05),粗脂肪含量显著降低(P<0.05),股盆脂肪和体壁脂肪厚度显著降低(P<0.05),全净膛重差异不显著(P>0.05)。     

3种铬源对21日龄热应激肉鸡生长性能、免疫器官、脂肪沉积及血清生化特性的影响

本试验旨在研究饲粮不同铬源和铬水平对21日龄热应激肉鸡生长性能、免疫器官、脂肪沉积及血清生化特性的影响。选用1日龄科宝(Cobb 500)白羽雌鸡252只,随机分为7组,分别饲喂玉米-豆粕型基础饲粮(含铬0.37 mg/kg)及在此基础饲粮上添加0.4、2.0 mg/kg源于丙酸铬(CrPro)、吡啶甲酸铬(CrPic)和三氧化铬(CrCl_3)的铬的试验饲粮。结果表明:饲粮铬添加对热应激肉鸡的平均日增重、胸腺指数、胸肌肌内脂肪、血清AKP活性有显著影响(P0.05),而对平均采食量、饲料增重比、脾脏指数、法氏囊指数、肝脂率、腹脂率、血清甘油三酯(TG)、总胆固醇(TC)、低密度脂蛋白胆固醇(LDLC)、高密度脂蛋白胆固醇(HDLC)含量均无影响(P0.05);铬水平对脾脏指数和TG有显著影响(P0.05);铬源对腹脂率、AKP活性及TC有显著影响(P0.05);铬源与铬水平互作对肝脂率、肌内脂肪、TC及LDLC有显著影响(P0.05)。综合分析,铬源CrPic对降低腹脂率、增加肌内脂肪含量效果最佳;2.0 mg/kg CrCl_3对降低肝脂率效果最佳。     

白术、微米白术和白术多糖对断奶仔猪生长性能和肠道形态及微生态区系的影响

试验选用96头平均体重14.82 kg左右的杜×长×大断奶仔猪,随机分成4组,每组3栏,每栏8头(公母各半)。对照组饲喂基础日粮,试验1、2、3组分别添加1%80目白术、0.2%白术多糖和1%微米白术。试验期30 d。结果表明:在生长性能方面,与对照组相比,1%微米白术添加组可显著提高日增重(P0.05)、降低饲料增重比和腹泻率,而且效果优于1%80目白术组和0.2%白术多糖组,在肠道形态和肠道微生态区系方面,与对照组相比,日粮添加1%80目白术、0.2%白术多糖、1%微米白术均可不同程度的提高十二指肠和空肠的绒毛高度,加深十二指肠和空肠的隐窝深度,并且增加肠道微生态区系的多样性,其中以1%微米白术添加组的效果最佳。     

Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia

Sissay, M.M., Uggla, A. and Waller, P.J., XXXX. Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia. Tropical Animal Health and Production, XXXX. A 2-year abattoir survey was carried out to determine the prevalence, abundance and seasonal incidence of gastro-intestinal (GI) nematodes and trematodes (flukes) of sheep and goats in the semi-arid zone of eastern Ethiopia. During May 2003 to April 2005, viscera including liver, lungs and GI tracts were collected from 655 sheep and 632 goats slaughtered at 4 abattoirs located in the towns of Haramaya, Harar, Dire Dawa and Jijiga in eastern Ethiopia. All animals were raised in the farming areas located within the community boundaries for each town. Collected materials were transported within 24 h to the parasitology laboratory of Haramaya University for immediate processing. Thirteen species belonging to 9 genera of GI nematodes (Haemonchus contortus, Trichostrongylus axei, T. colubriformis, T. vitrinus, Nematodirus filicollis, N. spathiger, Oesophagostomum columbianum, O. venulosum, Strongyloides papillosus, Bunostomum trigonocephalum, Trichuris ovis, Cooperia curticei and Chabertia ovina), and 4 species belonging to 3 genera of trematodes (Fasciola hepatica, F. gigantica, Paramphistomum {Calicohoron} microbothrium and Dicrocoelium dendriticum) were recorded in both sheep and goats. All animals in this investigation were infected with multiple species to varying degrees. The mean burdens of adult nematodes were generally moderate in both sheep and goats and showed patterns of seasonal abundance that corresponded with the bi-modal annual rainfall pattern, with highest burdens around the middle of the rainy season. In both sheep and goats there were significant differences in the mean worm burdens and abundance of the different nematode species between the four geographic locations, with worm burdens in the Haramaya and Harar areas greater than those observed in the Dire Dawa and Jijiga locations. Similar seasonal variations were also observed in the prevalence of flukes. But there were no significant differences in the prevalence of each fluke species between the four locations. Overall, the results showed that Haemonchus, Trichostrongylus, Nematodirus, Oesophagostomum, Fasciola and Paramphistomum species were the most abundant helminth parasites of sheep and goats in eastern Ethiopia.     

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.     

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

Tropical Animal Health and Production -     

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.     

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.     

Y‐chromosomal variation of local goat breeds of Turkey close to the domestication centre

Genetic variations in chromosome Y are enabling researchers to identify paternal lineages, which are informative for introgressions and migrations. In this study, the male‐specific region markers, sex‐determining region‐Y (SRY), amelogenin (AMELY) and zinc finger (ZFY) were analysed in seven Turkish native goat breeds, Angora, Kilis, Hair, Honaml?, Norduz, Gürcü and Abaza. A SNP in the ZFY gene defined a new haplotype Y2C. All domestic haplogroups originate from Capra aegagrus, while the finding of Y1A, Y1B, Y2A and Y2C in 32, 4, 126 and 2 Turkish domestic goats, respectively, appears to indicate a predomestic origin of the major haplotypes. The occurrence of four haplotypes in the Hair goat and, in contrast, a frequency of 96% of Y1A in the Kilis breed illustrate that Y‐chromosomal variants have a more breed‐dependent distribution than mitochondrial or autosomal DNA. This probably reflects male founder effects, but a role in adaptation cannot be excluded.     

Changes in proportion of canine urinary calculi composed of calcium oxalate or struvite in specimens analyzed from 1981 through 2001

The objective of this report was to characterize 20-year changes in proportion of calcium oxalate (CaOx) calculi and struvite calculi in dogs, and associations with breed, age, and sex. In this retrospective study, results of analysis of urinary calculi from dogs were reviewed for specimens received between July 1, 1981, and December 31, 2001. Breed, sex, age, year of submission of the specimen, and mineral type(s) were analyzed statistically. CaOx or Struvite or both were contained in 18,966 of 20,884 (91%) specimens. For both sexes, a 20-year statistically significant increase was observed in the proportion of calculus specimens that contained CaOx. The increase in this proportion was greater in females (1% to 31%) than in males (18% to 82%). From 1998 to 2001, when proportions may have plateaued, the odds of specimens containing CaOx were markedly higher in 18 breeds, markedly lower in 5 breeds, and not significantly different in 13 breeds compared with crossbreds. For both sexes, a 20-year statistically significant decrease was observed in the proportion of calculus specimens that contained struvite. This decrease in proportion was greater for males (79-16%) than for females (97-68%). From 1998 to 2001, when proportions plateaued, the odds of calculi containing struvite were markedly lower in 20 breeds, markedly higher in 1 breed, and not significantly different in 15 breeds when compared with crossbreds. Breed, age, and sex were associated statistically with CaOx or struvite urolithiasis. In conclusion, there appears to have been a long-term increase in the proportion of specimens of canine urinary calculi that contain CaOx as well as a long-term decrease in the proportion of specimens of calculi that contain struvite for both male and female dogs. The rate of change appeared to begin leveling off in the period 1998 to 2001. The recent proportion of dogs with either CaOx- or struvite-associated urolithiasis may depend on breed, age, and sex, and on interactions among these 3 factors.     

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.