南海黄麻鸡不同产蛋阶段蛋品质研究

为进一步分析南海黄麻鸡父母代种鸡的种用特性,对南海黄麻鸡不同产蛋阶段(开产后6、11、20、25周)的蛋品质进行了研究,检验指标包括蛋重、蛋形指数、蛋壳品质(蛋比重、蛋壳厚度、蛋壳强度)、哈氏单位、蛋黄颜色、蛋黄蛋白比等。结果表明:蛋品质的各项指标与产蛋阶段密切相关,南海黄麻鸡的蛋重在产蛋初期(开产后6周)较轻,显著低于产蛋中后期(开产后11、20、25周)(P0.05),蛋重随着产蛋日龄的增大而增大;蛋的比重、蛋壳强度、蛋壳厚度三个指标都在开产后11周达到最大值;哈氏单位、蛋黄颜色在产蛋初期显著高于产蛋中后期,并都随着产蛋阶段的延长而下降。由此可见,南海黄麻鸡在不同产蛋阶段的蛋品质具有一定的规律性,产蛋高峰阶段的蛋品质达到最好水平,产蛋中后期的蛋品质有逐渐下降的趋势。     

绍兴鸭、康贝尔鸭产蛋性能的比较研究

本文对绍兴鸭和康贝尔鸭开产至 69周龄的群体产蛋性能进行了比较研究。绍兴鸭和康贝尔鸭分别于 1 1 7和 1 1 9日龄开产 ,开产后产蛋率增加较快 ,都仅用 6周 ,其产蛋率就超过 80 %,维持较高产蛋水平分别达 4 2和 4 0周 ,产蛋后期迅速下降。开产时平均蛋重分别为 4 0和 4 5g左右 ,然后逐渐增加 ,3 5周龄后蛋重相对稳定 ,康贝尔鸭蛋重始终高于绍兴鸭。平均日产蛋量绍兴鸭和康贝尔鸭具有类似的变化规律 :随着产蛋率和平均蛋重的增加而增加 ,开产时低于 5g左右 ,6周后超过 4 5g,3 0周龄时超过 55g。开产至 69周 ,康贝尔鸭平均日产蛋量 ( 51 .1 6± 0 .68vs4 9.2 8± 0 .61g)和蛋重 ( 64 .64± 0 .3 5vs60 .69± 0 .3 6g)显著高于绍兴鸭     

三个地方鸡种产蛋性状配合力测定

以文昌鸡、如皋黄鸡、仙居鸡为素材,采用完全双列杂交测定配合力,统计各周龄体重、开产蛋重、产蛋高峰期蛋重、开产至40周龄料蛋比、开产至40周龄平均产蛋率,计算一般配合力和特殊配合力效应值.结果表明:父本对开产至40周龄平均产蛋率及入舍母鸡产蛋数贡献较大,母本对蛋重影响较大;文昌鸡♂×仙居鸡♀组合开产至40周龄料蛋比最低、40周龄产蛋数最高,为最佳配套组合,可在生产中配套使用.     

酵母培养物对产蛋鸡生产性能和蛋品质的影响

本试验旨在研究酵母培养物(YC)对产蛋鸡生产性能和鸡蛋品质的影响.选用1656只150日龄的海兰褐产蛋鸡随机分为4个处理,每个处理6个重复,每个重复69只鸡,在玉米-豆粕-杂粕型饲粮基础上分别添加0、0.1%、0.2%和0.3% YC,研究其对产蛋鸡产蛋率、平均蛋重、平均日采食量、死淘率和料蛋比及鸡蛋哈夫单位、蛋壳强度、蛋壳重量、蛋壳厚度和蛋黄颜色的影响,试验期20周.试验结果表明:与对照组相比,饲粮中添加0.1%、0.2%和0.3%的YC可降低第1～20周产蛋鸡料蛋比2.15%、3.36%和2.10%(P<0.10,P<0.10,P<0.10);提高第1～20周产蛋鸡产蛋率1.25、0.94和1.36个百分点(P>0.10,P>0.10,P<0.10);延长产蛋鸡90%以上的产蛋率2.2、2.3和2.8周(P>0.10,P>0.10,P<0.10);降低产蛋鸡死淘率2.17、0.73和1.45个百分点(P>0.10,P>0.10,P>0.10).饲粮中添加YC有助于维持气温急剧升高时稳定、较高的产蛋率.饲粮添加YC显著改善了第20周的产蛋鸡蛋黄颜色(P<0.10),对其他蛋品质指标和产蛋鸡的体重增加没有显著影响(P>0.10).产蛋鸡饲粮中添加YC能够改善料蛋比、提高产蛋率和平均蛋重、延长产蛋高峰期、降低死淘率;虽然3个处理之间对生产性能指标的影响差异不明显,但0.2% YC组,在改善平均蛋重、料蛋比、平均日采食量方面表现优异.     

高温季节三种中药组方对文昌鸡产蛋性能及蛋品质的影响

为研究三种中草药组方对高温季节对文昌鸡产蛋性能及蛋品质的影响,选用28周龄1200只产蛋文昌鸡,随机分为4个处理(对照组及3个中药添加组),每个处理3个重复。每个重复100只鸡。对照组饲喂基础日粮,试验组日粮中分别添加1%的三种不同的中药组方。结果表明:日粮中添加1%的中草药组方C可以明显改善文昌鸡的产蛋性能,产蛋率提高9.37%,料蛋比比对照组降低11.23%。畸蛋率、破壳率明显降低(P0.05)。明显增加平均蛋重、蛋白高度、蛋壳重、蛋壳厚度和蛋黄重(P0.05),改善文昌鸡蛋品质。     

抗热应激添加剂对文昌鸡产蛋性能影响的比较研究

为探究热应激条件下,五味子、碳酸氢钠、维生素C、维生素E、大蒜素和西瓜皮6种不同抗热应激添加剂对文昌鸡生产性能的影响规律。选取健康文昌鸡840只,平均分成7组,每组120只。对照组饲喂标准日粮,不添加任何添加剂;试验组1在标准日粮中添加1%五味子;试验组2添加0.5%碳酸氢钠;试验组3添加0.1%维生素C;试验组4添加0.025%维生素E;试验组5添加1%大蒜素;试验组6添加10%西瓜皮。试验期30 d,鸡舍内白天平均温度33℃,比较不同添加剂对文昌鸡生产性能及蛋品质的影响规律。结果表明:试验组2、5、6与对照组比较产蛋率差异不显著(P0.05),试验组2的产蛋率与蛋重略低于对照组。试验组1、3、4与对照组比较,产蛋率和蛋重明显高于对照组,差异显著(P0.05)。试验组2的破蛋率与对照组比较差异不显著(P0.05),其他试验组均明显低于对照组,差异显著(P0.05)。各试验组的蛋形指数、哈氏单位、蛋黄重、蛋黄颜色与对照组比较差异不显著(P0.05)。试验组1、3、4、6的蛋壳厚度与蛋壳重均明显高于对照组,差异显著(P0.05)。试验组2、5的蛋壳厚度与蛋壳重与对照组比较差异不显著(P0.05)。因此,热应激条件下添加1%五味子、0.1%维生素C、0.025%维生素E抗热应激添加剂试验组的产蛋性能均明显高于对照组,差异显著(P0.05),可以用于文昌鸡蛋鸡抗热应激,添加成分无毒、无害、残留低、来源广泛,符合无公害产品生产要求。     

如皋黄鸡产蛋性能与遗传参数分析

研究以如皋黄鸡第4世代的15个家系351只母鸡为实验素材,测定开产日龄、开产体重、开产蛋重和40周龄产蛋数,统计各周龄群体产蛋率,估算开产性状和40周龄产蛋数的遗传参数。结果表明:如皋黄鸡开产日龄为(153.9±13.13)d,开产体重为(1 366.5±135.51)g,开产蛋重为(32.8±3.17)g,40周龄产蛋数为(101.0±8.94)个;高峰产蛋率为82.1%,70%以上产蛋率维持16周;开产日龄、开产体重、开产蛋重和40周龄产蛋数均为中等遗传力0.177~0.320;开产日龄、开产体重和开产蛋重间两两呈遗传正相关0.736~0.971,40周龄产蛋数与开产日龄、开产体重、开产蛋重间均呈遗传负相关-0.832~-0.639;性状间的表型相关性质和遗传相关一致,且均达到极显著的程度。     

北京油鸡不同产蛋期鸡蛋品质分析及变化规律研究

选用北京油鸡为试验材料,在相同的饲养条件下进行饲养。分别在产蛋前期(50%产蛋率)、产蛋中期(43周龄)和产蛋后期(63周龄)进行蛋品质测定。结果表明:蛋壳强度、蛋壳厚度、蛋形指数和蛋壳比率等感官物理指标以及胆固醇等营养化学指标在不同产蛋阶段不存在显著差异,而其余指标存在显著(P0.05)或极显著(P0.01)的差异。蛋品质随着产蛋日龄的增加呈现一定的变化规律。总体而言,北京油鸡鸡蛋大小适中、蛋壳粉色、蛋黄比率高、蛋黄颜色较深,并且在卵磷脂、不饱和脂肪酸、氧化型谷胱甘肽、粗蛋白及粗脂肪等营养化学指标方面具有较高的营养价值。     

蛋鸭产蛋高峰期色氨酸适宜需要量

本试验旨在通过研究饲粮中不同色氨酸水平对蛋鸭产蛋性能、蛋品质、机体抗氧化指标和屠宰指标的影响,拟合出蛋鸭产蛋期色氨酸适宜需要量。选取120日龄山麻鸭900只,随机分为6个组,每个组6个重复,每个重复25只。各组蛋鸭分别饲喂色氨酸水平为0.12%、0.16%、0.20%、0.24%、0.28%、0.32%的试验饲粮,试验期20周。结果表明:1)饲粮色氨酸水平对蛋鸭产蛋率、平均蛋重、日产蛋重、料蛋比等无显著影响(P0.05),但0.20%组在数值上表现出最高的产蛋率和日产蛋重。饲粮色氨酸水平对蛋壳强度、哈氏单位、蛋黄重、蛋黄比例、蛋壳重量、蛋壳比例、蛋壳厚度等蛋品质指标无显著影响(P0.05),但显著影响蛋黄色泽(P0.05),表现为0.20%组蛋黄色泽显著低于其他各组(P0.05)。2)饲粮色氨酸水平对蛋鸭血清白蛋白、总蛋白、尿酸含量无显著影响(P0.05)。3)饲粮色氨酸水平对蛋鸭血清和肝脏抗氧化指标(除肝脏总超氧化物歧化酶)均无显著影响(P0.05)。4)饲粮色氨酸水平对输卵管重量、输卵管长度、卵巢重量无显著影响(P0.05)。根据折线模型拟合得出:饲粮色氨酸水平为0.20%时可满足产蛋高峰期蛋鸭营养需要。     

维生素E对蛋鸡产蛋后期产蛋性能和蛋品质的影响

文章旨在研究日粮中不同梯度维生素E添加水平对蛋鸡产蛋后期产蛋性能和蛋品质的影响。试验选择60周龄罗曼白壳商品蛋鸡300羽,试验随机分为5组,添加水平分别为0(对照组),30、60、120、240 mg/kg,每组6个重复,每个重复10羽鸡,预试期1周,正试期8周。结果表明:与对照组相比,蛋鸡产蛋后期日粮中添加120 mg/kg的维生素E可显著提高蛋鸡产蛋后期产蛋性能(P<0.05);与对照组相比,蛋鸡产蛋后期日粮中添加120 mg/kg的维生素E可显著提高蛋壳硬度、蛋壳相对重、蛋黄相对重以及蛋黄颜色(P<0.05),蛋黄总胆固醇含量极显著降低(P<0.01)。综上所述,在蛋鸡产蛋后期日粮中添加120 mg/kg的维生素E可显著改善其产蛋性能和蛋品质。     

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.     

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.     

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.     

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.     

Feline intracranial neoplasia: retrospective review of 160 cases (1985-2001)

The purpose of this study was to determine the frequency of different tumor types within a large cohort of cats with intracranial neoplasia and to attempt to correlate signalment, tumor size and location, and survival time for each tumor. Medical records of 160 cats with confirmed intracranial neoplasia evaluated between 1985 and 2001 were reviewed. Parameters evaluated included age, sex, breed, FeLV/FIV status, clinical signs, duration of signs, number of tumors, tumor location(s), imaging results, treatment, survival times, and histopathologic diagnosis. Most of the cats were older (11.3 +/- 3.8 years). Primary tumors accounted for 70.6% of cases. Metastasis and direct extension of secondary tumors accounted for only 5.6 and 3.8% of cases, respectively. Twelve cats (7.5%) had 2 or more discrete tumors of the same type, whereas 16 cats (10.0%) had 2 different types of intracranial tumors. The most common tumor types were meningioma (n = 93, 58.1%), lymphoma (n = 23, 14.4%), pituitary tumors (n = 14, 8.8%), and gliomas (n = 12, 7.5%). The most common neurological signs were altered consciousness (n = 42, 26.2%), circling (n = 36, 22.5%), and seizures (n = 36, 22.5%). Cats without specific neurological signs were common (n = 34, 21.2%). The tumor was considered an incidental finding in 30 (18.8%) cats. In addition to expected relationships (eg, meninges and meningioma, pituitary and pituitary tumors), we found that lesion location was predictive of tumor type with diffuse cerebral or brainstem involvement predictive of lymphoma and third ventricle involvement predictive of meningioma.     

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.     

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.