两株H9N2亚型禽流感病毒的遗传演化及其致病性分析

为了解H9N2亚型禽流感病毒(AIV)的分子特征及其对家禽和哺乳动物小鼠的致病性,本研究对2020年分离到的两株H9N2亚型AIV:A/chicken/Jiangsu/S1625/2020(H9N2)(简称CK/JS/S1625/2020)株和A/duck/Sichuan/S1537/2020(H9N2)(简称DK/SC/S1537/2020)株,进行了基因组测序、序列分析及其对SPF鸡、鸭和BALB/c小鼠的致病力评价。同源性分析结果显示,两株病毒HA和NA基因的同源性分别为93.3%和95.8%,其编码氨基酸序列的同源性分别为95.4%和95.9%,同源性较低。且两株病毒HA蛋白裂解位点分别为~(333)PSRSSR↓GLF~(341)、~(333)PSRSNR↓GLF~(341),均不存在多个连续的碱性氨基酸,符合低致病性禽流感病毒(LPAIV)HA序列特征。两株病毒的HA蛋白均为典型的人源受体结合特征,即~(155)T、~(183)N和~(226)L。遗传演化分析结果显示,两株病毒的HA、NA基因均属于欧亚分支,但二者的亲缘关系较远。鸡感染性试验结果显示,CK/JS/S1625/2020株感染组鸡可通过喉头和泄殖腔向外界环境排毒。虽然在全部鸡的喉头中检测到了DK/SC/S1537/2020株,但仅在部分鸡的泄殖腔检测到了该病毒,且喉头的排毒量明显高于泄殖腔。鸡血清抗体检测结果显示,两株病毒感染鸡血清的HI抗体全部阳转,效价在1.128～1.2 048。表明,鸡源H9N2病毒比鸭源H9N2病毒在鸡体内的适应性和复制能力更强;鸭感染性试验结果显示,两株病毒均只能通过鸭的喉头向外界环境排毒,但病毒滴度均较低,且均不能在鸭体内有效复制;小鼠感染性试验结果显示,两株病毒仅能在小鼠的鼻甲中有效复制,而在小鼠的脑、脾脏和肾脏中均未检测到病毒。以上结果表明两株H9N2亚型AIV对家禽和小鼠均呈低致病力。本研究为进一步了解H9N2 AIV提供了一定的参考数据,有必要对自然界中传播的H9N2流感病毒持续监测和进化分析。     

H6亚型禽流感病毒的分离鉴定与生物学特性分析

为了解低致病性禽流感病毒(LPAIVs)在广西地区家禽中的流行情况,对广西地区活禽市场的家禽进行LPAIVs流行病学监测,分离鉴定出7株H6亚型禽流感病毒(AIV)。通过在广西地区活禽市场采集家禽咽喉和泄殖腔棉拭子样品,将其接种SPF鸡胚,收集尿囊液进行HA和HI试验,结果显示这7株只与H6亚型AIV的阳性血清发生反应,产生血凝抑制现象,初步鉴定为H6亚型AIV。通过HA和NA基因的克隆与测序鉴定,进一步确定为H6亚型AIV,与NA基因存在5种组合,包括H6N1、H6N2、H6N5、H6N6和H6N8。鸡致病性试验表明分离株可感染但不致死SPF鸡,并通过咽喉和泄殖腔排毒,结合HA裂解位点附近的氨基酸序列,表明所分离到的7株H6亚型AIV符合LPAIV的特征。     

一株鸭源H5N2禽流感病毒全基因组序列分析及对鸡的致病性研究

2012年在我国重庆市活禽交易市场进行流行病学调查时,从鸭体内分离到1株H5N2亚型禽流感病毒(AIV),DK/CQ036/12(H5N2).为了解该株H5N2亚型AIV的生物学特性,本研究对其进行了全基因组分析及对SPF鸡和BALB/c小鼠的致病性试验.序列分析显示:HA裂解位点序列为341R-----346TRGLF350,为低致病性AIV特征.内部基因来源较复杂,与KD/CQ/036/12分离株的M基因NP基因同源性最高的病毒株均来自H4、H7等亚型分离株,呈明显的异源性.分离株的感染性试验显示,该分离株在鸡体内可以通过呼吸道和消化道向外排毒,但并不能在鸡体内有效的复制.对小鼠的感染性试验结果显示,仅在鼻甲和肺能检测到病毒存在,其他脏器病毒滴定结果为阴性,表明病毒对鸡和小鼠均呈低致病性.     

一株多重配H13N8亚型禽流感病毒分子进化以及对鸡致病性研究

2018年对宁夏回族自治区沙湖自然保护区进行禽流感病毒(AIV)流行病学调查中,本研究室分离到一株H13N8亚型AIV。为了解这株H13N8亚型AIV生物学特性,本研究对其全基因组进行了测序及遗传演化分析。结果显示,该病毒HA和NA基因分别来自H13N6和H3N8亚型AIV,内部基因来源于H13N8、H6N2、H13N6、H13N2亚型AIV,是一株多亚型重组AIV,其HA蛋白碱性裂解位点氨基酸序列为ISNR↓GLF,为低致病AIV分子标志。关键氨基酸位点分析显示,其M1蛋白具有N30D和T215A的突变,NS1蛋白具有P42S、L98F和I101M的突变,表明其具有增强对哺乳动物致病性的潜在能力。SPF鸡的感染性试验显示,鸡感染该病毒后不能通过喉头或泄殖腔排毒,在感染鸡各脏器均不能有效复制,其感染鸡的潜在风险较小。本研究对禽流感的综合防控具有一定的指导意义。     

二株鸭源H11N9亚型禽流感病毒的遗传进化及致病性分析

为了解从湖南省洞庭湖区鸭群中分离的2株H11N9亚型禽流感病毒变异特点、进化规律及生物学特性,本研究对2株H11N9亚型禽流感病毒的HA、NA序列进行同源性和遗传进化分析,并用2株毒株对SPF鸡进行致病性试验。结果显示,本试验分离到2株H11N9亚型禽流感毒株的HA裂解位点均没有多个连续的碱性氨基酸插入,属于低致病性毒株;HA基因的受体结合位点均非常保守,具有典型的禽源性特征;NA基因序列与在周边国家野鸟中分离的H11N9亚型毒株的氨基酸同源性较高;鼻腔接种SPF鸡后,均能使鸡感染并通过喉头或泄殖腔排毒,但感染的鸡均不表现明显的临床症状,并且不能使同居鸡感染排毒。     

两株野鸟源H9N2亚型禽流感病毒的进化分析和对小鼠的感染性研究

为了解2015年分离自我国四川省野鸟粪便中的两株H9N2亚型禽流感病毒(AIV)Wild Bird/SC/S1264/2015(H9N2)(WB/SC/264/15)和Wild Bird/SC/S1411/2015(H9N2)(WB/SC/411/15)的生物学特性,本研究对其进行了全基因组序列测定和BALB/c小鼠的感染性试验。序列分析结果显示:两个分离株的HA裂解位点基序均为333PSRSSR↓GL340,符合低致病性AIV(LPAIV)的氨基酸序列特征,HA蛋白受体结合位点处的第226以及228位氨基酸残基分别为谷氨酰胺(Q)和甘氨酸(G),具有结合禽源AIV受体的分子特征。内部基因片段来源复杂,呈现明显的基因多样性。BALB/c小鼠的感染性试验结果显示,这两个分离株只在小鼠的上呼吸道鼻甲中有效复制,小鼠体重变化轻微,未见明显临床症状。     

2株鸭源 H11N9亚型禽流感病毒的基因遗传进化及致病性分析

为了解从湖南省洞庭湖区鸭群中分离的2株 H11N9亚型禽流感病毒变异特点、进化规律及生物学特性,本研究对2株H11N9亚型禽流感病毒的HA、NA序列进行同源性和遗传进化分析,并用2株毒株对SPF鸡进行致病性试验。结果显示,本试验分离到2株 H11N9亚型禽流感毒株的 HA裂解位点均没有多个连续的碱性氨基酸插入,属于低致病性毒株;HA基因的受体结合位点均非常保守,具有典型的禽源性特征;NA基因序列与在周边国家野鸟中分离的H11N9亚型毒株的氨基酸同源性较高;鼻腔接种SPF鸡后,均能使鸡感染并通过喉头或泄殖腔排毒,但感染的鸡均不表现明显的临床症状,并且不能使同居鸡感染排毒。     

一株鸭源H8N4亚型禽流感病毒分离株的全基因组序列分析及致病性的研究

本研究对2012年从湖南活禽市场中分离到的一株鸭源H8N4亚型禽流感病毒(AIV)A/duck/HuN/S3160/2012(H8N4)进行全基因组序列和进化分析,并对其进行SPF鸡、SPF鸭和BALB/c小鼠的致病性试验.序列分析显示:HA裂解位点序列为339pSIEPK ↓ GLF347,为典型的低致病性AIV特征.内部基因来源较复杂,HuN/160/12的PB1、NS基因分别与A/spot-billed duck/Xianghai/427/2011 (H5N2)和A/wild bird/Korea/A81/2009(H5N2)的同源性最高,其余内部基因同源性最高的病毒株来自H2、H3、H4、H7、H10等亚型分离株,呈现明显的异源性.感染性试验结果显示,病毒在SPF鸭体内可以通过呼吸道和消化道向外排毒,并且能够在气管、肾脏、盲肠扁桃体及法氏囊检测到病毒,而不能在鸡体内有效复制及排毒.对小鼠的感染性试验结果显示,仅在鼻甲和肺检测到病毒存在,其他脏器病毒滴定结果为阴性,体重呈一过性下降,表明该病毒为低致病性AIV.     

H9N2亚型禽流感病毒的遗传进化分析及F株灭活疫苗的免疫效果评价

为了解H9N2亚型禽流感病毒(AIV)变异情况及评价作为H9亚型F株禽流感灭活疫苗的免疫效果,本研究对2009年～2010年期间从免疫鸡群中分离的9个H9N2亚型AIV株进行血凝素(HA)基因序列测定和分析。这9个病毒株HA基因编码区长度均为1 683 nt,HA基因核苷酸序列同源性为90.7%～98.9%,其推导氨基酸序列同源性为92.2%～98.8%;分离株与F株的HA基因之间的核苷酸序列同源性为91.6%～99.6%,氨基酸序列同源性为92.9%～99.3%;9个分离株与F株均属于Beijing/1/94-like进化分支,但分别属于3个不同的基因亚型。免疫试验结果显示:3周龄SPF鸡接种F株灭活疫苗21 d后,产生的HI抗体效价在log2 9以上;而且免疫鸡对分离株及F株攻毒后的喉头和泄殖腔排毒产生明显的抑制作用。本研究数据表明,F株灭活疫苗可以提供对这些分离株的有效免疫保护。     

一株H6N6亚型野鸟禽流感病毒全基因组序列分析以及对小鼠的感染性研究

为进一步了解2015年分离于我国新疆野鸟粪便中的一株H6N6亚型禽流感病毒(AIV)A/WB/XJ/S1541/2015(H6N6)的生物学特性,本研究对其进行了全基因组测序、遗传演化分析以及BALB/c小鼠的感染性试验。序列分析结果显示:该分离株HA蛋白裂解位点的氨基酸序列为~(339)PQIETR↓GL~(346),仅有1个碱性氨基酸,具有低致病性AIV的分子特征。此外,分离株表面基因HA、NA均与一株H6N6亚型猪流感病毒A/swine/Guangdong/K6/2010高度同源,而内部基因均与H6N6亚型AIV A/pigeon/Guangxi/161/2014(H6N6)高度同源,提示该分离株基因来源的多样性。小鼠的感染性试验结果显示:该病毒可在小鼠的肺脏和鼻甲中有效复制,病毒滴度分别为5.33 log_(10) EID_(50)/mL、4.50 log10EID50/m L,提示其具有感染哺乳动物的潜在风险。本研究结果为H6亚型AIV的持续性监测和相关生物学特性的研究奠定基础。     

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.     

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.     

A brief history of the prevention of infectious diseases by immunisations

Infectious diseases have always been a terrible scourge for humans. The appearance of these plagues, as they were called without distinction, was generally connected to various conditions: asters, climatic changes or religious reasons. The concept of contagious, and then infectious, diseases came slowly. Variolation, i.e. transmission of ‘virulent’ matter to induce a natural disease and the immunity against it, was brought from Constantinople to England by Lady Montague, in 1721. This ‘variolation’ technique was also often performed in veterinary medicine against diseases like sheep-pox or pleuropneumonia. As ‘vaccination’ is the term generally accepted for ‘immunisation’, variolation can be the word designating such a technique. The second period of the history of immunisation began, in 1880, with the studies of Pasteur and his collaborators. A great number of bacterial vaccines were developed: dead, live but attenuated or only parts of pathogens. The viruses were produced in animals, then in eggs and at last, in tissue cultures. Second generation vaccines appeared with genetic engineering: recombinant vaccines, vector vaccines, nucleic acids vaccines, and markers vaccines, among others. These novel technologies can permit the development of new ones and improve the quality of the vaccines already existing.     

Micronutrient Content of Certain Tropical Conventional and Unconventional Feed Resources of Southern India

The ash, silica and certain important micronutrients were estimated in conventional and unconventional feed and fodder resources available in Southern India. Commonly used dry roughages, such as paddy straw, ragi straw, maize kadbi/stalk, jowar kadbi/stalk, bajra stalk and wheat straw, were high in ash (9.9% +/- 0.77%) and silica (6.4% +/- 0.65%) and low in most of the other micronutrients, except iron, with paddy straw containing most silica (>9%). Cultivated non-leguminous (maize, jowar) and improved green crops (hybrid napier, guinea, green panic, NB-21, CO-1) were also high in ash (10.5% +/- 0.60% and 12.5% +/- 0.51%) but were moderate sources of P, Mg and Cu and good sources of Zn (98 +/- 13.8 ppm and 55 +/- 6.7 ppm). Leguminous green fodders (stylosanthus, lucerne, cow pea, soyabean) were excellent sources of Ca (1.9% +/- 0.16%), Mg (0.40% +/- 0.05%), Cu (30 +/- 5.2 ppm), Zn (121 +/- 14.7 ppm) and Fe (1234 +/- 166 ppm) and moderate sources of P. Mixed local grasses and weeds were high in silica (6.9% +/- 1.00%) but were good sources of Cu, Zn and Fe. Cereal grains (maize, wheat, rice, ragi) were low in ash (2.9% +/- 0.33%) and were relatively poor sources of Ca (0.22% +/- 0.03%), Mg (0.19% +/- 0.03%) and Cu (13 +/- 3.1 ppm). Pulses were low to medium sources of most minerals and good sources of Fe (1230 +/- 293 ppm). Oil seed cake/extractions (groundnut cake, cotton seed cake, soyabean meal, sunflower cake, safflower cake) and cereal by-products (rice polish, rice bran, wheat bran) were excellent sources of P (1.1% +/- 0.47% and 2.3% +/- 0.19%) and good sources of Zn (65 +/- 3.9 ppm and 66 +/- 10.7 ppm) and Fe (938 +/- 130 ppm and 662 +/- 126 ppm). Among the unconventional feeds screened, orange peel, sunflower heads, meat meal, rubber seed cake, spirulina algae and sea weeds contained plentiful Ca, Zn and Fe: tree leaves/top feeds (mulberry, erythrina, glyricidia, banana, subabul, groundnut haulms) were excellent sources of Ca (1.5% +/- 0.13%), Zn (120 +/- 22.9 ppm) and Fe (1033 +/- 133 ppm) but relatively poor sources of P. Soyabean husk, cocoa seed husk, rubber seed cake and meat meal were moderate to good sources of P (1.0% and 0.33%). The high Zn and Fe values of most feeds/fodders were probably due to soil contamination. This account of the micronutrient content of feed/fodder resources should help in strategic supplementation intended to alleviate local deficiencies.     

Bovine Mastitis in Selected Areas of Southern Ethiopia

A study on bovine mastitis, designed to determine the causal agents, prevalence of infection and impact of risk factors in three cattle breeds, was conducted in selected areas of southern Ethiopia. A total of 307 lactating and non-lactating cows, of which 162 were indigenous Zebu, 85 Jersey and 60 Holstein-Friesian, were examined by clinical examination and the California mastitis (CMT) test. Of these, 40.4% were positive by CMT and bacteriology for clinical or subclinical mastitis, with prevalence rates of 37.1% and 62.9%, respectively. Out of 1133 quarters examined, 212 (18.7%) were found to be infected, 83 (39.2%) clinically and 129 (60.8%) subclinically. The prevalence of mastitis was significantly higher in Holstein-Friesian than in indigenous Zebu, in non-lactating cows than in lactating cows, in the early lactation stage than in the mid-lactation stage, in cows with lesions and/or tick infestation on skin of udder and/or teats than in cows without this factor, and in the wet season than in the dry season. Mastitis increased with parity number (R = 0.9). Of 248 CMT and clinically positive udder quarter samples analysed microbiologically, 212 were culturally positive for known mastitis pathogens and 36 were negative. Of the 199 positive samples, Staphylococcus accounted for 39.2%, Streptococcus for 23.6%, coliforms for 14.1%, Micrococcus and Bacillus species for 8.0% each and Actinomyces or Arcanobacterium (Corynebacterium) for 7.0%. It was concluded that there was a high prevalence of clinical and subclinical mastitis, mainly caused by Staphylococcus aureus, Streptococcus agalactiae and Escherichia coli, in this study area.     

不同日粮氮水平对山羊氮代谢和微生物蛋白质合成的影响

本试验旨在探讨不同日粮氮水平对内蒙古白绒山羊氮代谢和微生物蛋白质合成(MCP)的影响,以达到提高氮利用率,减少环境污染和饲料资源的浪费。试验选用9只体况良好、体重为(43.83±2.95)kg,装有瘤胃瘘管的内蒙古白绒山羊,按体重随机分为3组,每组3只。日粮分为低氮7.5%、中氮10.5%、高氮13.5%3个氮水平。试验使用常规试验方法分析测定粪尿血液等生化指标,通过全收尿法和尿嘌呤衍生物法估测MCP。结果表明:随着氮水平增加,氨氮(NH3-N)浓度、氮摄入量、尿氮排出、尿中尿素氮(UUN)和MCP显著增加(P0.05),干物质采食量(DMI)显著降低(P0.01);沉积氮占总摄入氮的比例在中氮组最高,MCP在高氮组最高。综上所述,适当降低日粮氮水平可减少粪尿氮排放,提高反刍动物氮利用率。     

Microsporidial keratopathy in two dogs

A microsporidial keratopathy is described in two dogs. Both dogs presented with a unilateral stromal keratopathy characterized by multifocal coalescing opacities, and the diagnosis was made on histopathologic examination of keratectomy specimens. Transmission electron microscopy (TEM) on formalin‐fixed, paraffin‐embedded corneal tissue was performed in one dog, and the morphologic features were consistent with Nosema species infection. Both dogs were initially diagnosed and treated by superficial keratectomy. One dog received additional antifungal medication and underwent a penetrating keratoplasty following local recurrence two years later. No other systemic lesions attributable to the microsporidial infection were identified clinically. The clinical and diagnostic pathology findings, treatment, and follow‐up are discussed.     

优质肉鸡S3系体重与体尺性状指标的主成分分析

为研究地方优质肉鸡S3系体重和体尺性状之间的内在相关性,12周龄时选取同一饲养条件下的150只鸡(公母各半)进行体重和体尺性状等7个指标的测定。结果表明:S3系公鸡的体重、体斜长、龙骨长、胸角均显著高于母鸡(P0.05);公母鸡体重、体斜长、胸宽、胫围这4项指标变异系数较大,有较大选育空间;体重与体斜长、龙骨长、胸宽、胸角、胫围呈极显著正相关(P0.01),相关系数分别为0.57、0.52、0.51、0.49和0.47,与胸深、胫长呈显著相关(P0.05),相关系数分别为0.44和0.39;其他各体尺指标间也存在不同程度的正负相关性(P0.05或P0.01);体重和7个体尺性能指标综合成5个复合指标,累计贡献率达92.6355%,其中第l、2、3、4、5主成分分别解释总变异的36.5353%、22.8642%、13.3115%、10.4535%和8.4710%;各主成分的特征根分布较广,经统计计算入选的5个主成分所包含信息的侧重点各有相同,分别都在一定程度上反映了S3鸡的体型特征和生长发育规律,为今后选育出更加符合市场需求的屠宰加工优质型肉鸡指明了的方向。     

Efficacy of tropicamide,homatropine, cyclopentolate,atropine and hyoscine as mydriatics in Angora goats

Abstract

AIM: To document the efficacy of five commercially available mydriatics for their potential for diagnostic and therapeutic use in Angora goats.

METHODS: Over 8 weeks, the mydriatic effects of 1% tropicamide, 2% homatropine, 1% cyclopentolate, 1% atropine and 0.25% hyoscine were evaluated. Given as block treatments, drugs were applied randomly to one eye of 10 Angora goats, and the contralateral eye served as a control. Vertical and horizontal pupil diameters were measured to document onset ofeffect, time to reach a difference of 5 mm in the vertical/horizontal pupil diameter between eyes, time to maximum pupillary dilation, and duration of mydriatic action.

RESULTS: Onset of mydriasis for all drugs occurred within 15 minutes. Time to reach a difference of 5 mm in the vertical pupil diameter between eyes was shortest for 1% tropicamide and 0.25% hyoscine (0.5 h), then 2% homatropine and 1% atropine (0.75 h), and longest for 1% cyclopentolate (1.5 h). The maximum vertical pupillary dilation occurred earliest with 1% tropicamide and 1% atropine (2 h), followed by 0.25% hyoscine (3 h), 2% homatropine (4 h), and latest with 1% cyclopentolate (8 h). The duration of vertical dilation of the pupil was shortest with 1% tropicamide (6 h), then 2% homatropine (12 h), 1% cyclopentolate (12 h), 1% atropine (24 h), and longest for 0.25% hyoscine (96 h).

The time to reach maximum horizontal dilation of the pupil in treated eyes was shortest with 1% cyclopentolate (1 h), followed by 1% tropicamide (1.5 h), 0.25% hyoscine (3 h), 2% homatropine (3.5 h), and 1% atropine (4 h). The duration of horizontal pupil dilation was shortest with 1% tropicamide (4.5 h), and longest with 0.25% hyoscine (48 h).

CONCLUSION: All five mydriatics induced clinical dilation. Tropicamide (1%) had the shortest duration of effect, but gave incomplete dilation. Good dilation was achieved with 1% cyclopentolate and 2% homatropine, but took too long to reach maximum dilation for routine mydriasis. The largest vertical dilation of the pupil was achieved with 1% atropine and 0.25% hyoscine, but pupils remained dilated for more than 24 h.

CLINICAL RELEVANCE: For routine mydriasis in goats, it is recommended that 1% tropicamide be used, though there may be incomplete dilation. For a longer duration of mydriasis, such as in the treatment of anterior uveitis, 1% atropine or 0.25% hyoscine would be the drugs of choice.