日粮添加二氢杨梅素对肉仔鸡肠黏膜形态结构、碱性磷酸酶及生产性能的影响

本试验旨在研究二氢杨梅素(DMY)对内仔鸡肠黏膜形态结构及碱性磷酸酶(AKP)活性的影响.420只0日龄AA肉仔鸡雄雏,随机分为5个处理组,日粮中分别添加0%、0.025%、0.05%、0.1%和0.2%的DMY.试验期42d.结果表明,日粮添加0.025%的I)MY可显著提高肉仔鸡日采食量和日增重(P<0.05),并可使料重比降低了6.6%(P>0.05);添加0.025%～0.05%Gj DMY可显著提高肉仔鸡肠上皮细胞碱性磷酸酶活性(P<0.05),提高小肠绒毛高度和黏膜厚度,降低小肠隐窝深度(P<0.05).     

二氢杨梅素对肉仔鸡生长性能、免疫器官指数及血液生化指标的影响

1日龄AA肉公雏300只,随机分为5个组,每组6个重复,每个重复10只鸡。试验Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ组在基础日粮中分别添加0%、0.025%、0.05%、0.1%和0.25%的二氢杨梅素(DMY),研究DMY对肉仔鸡生长性能、免疫器官指数及血液常规理化指标等影响。结果表明:1)日粮中添加不同剂量的DMY对肉仔鸡日增重有提高的趋势,0.05%的DMY显著提高肉仔鸡饲料转化率(P<0.01);试验期间,各组试验鸡生长发育正常,各组织器官未见异常。2)0.05%DMY显著提高21d肉仔鸡法氏囊指数(P<0.05);3)0.25%DMY组显著降低21d肉仔鸡血清总蛋白、白蛋白含量,对球蛋白无显著影响;4)0.025%、0.05%DMY显著降低21d肉鸡血清谷丙转氨酶(GPT)活性(P<0.05,P<0.01),0.025%～0.1%剂量的DMY能显著降低42d肉鸡血清GOT活性(P<0.05);5)各剂量的DMY对21、42d肉鸡血清谷草转氨酶(GOT)无显著影响。     

半胱胺对肉仔鸡生产性能和胴体品质的影响

选择324只AA肉仔鸡随机分成6组,基础日粮中分别添加0、40、60、80、100、120mg/kg的半胱胺饲喂7周,结果表明:①日粮中添加60mg/kg半胱胺显著提高了3周末肉仔鸡的增重8.41%(P<0.05)和胸肌率13.6%(P<0.05)。②日粮中添加100mg/kg半胱胺显著提高了4～7周龄肉仔鸡的增重5.62%(P<0.05),降低料肉比12.97%(P<0.05),提高其屠宰率和胸肌率分别为4.1%(P<0.05)和12.4%(P<0.01),显著降低了肉仔鸡的腹脂率31.6%(P<0.05)。③日粮中添加60mg/kg半胱胺是改善1～3周龄肉仔鸡生产性能和胴体品质的最适剂量,100mg/kg半胱胺是改善生长全期肉仔鸡生产性能和胴体品质的最适添加剂量。     

溶血卵磷脂提高肉仔鸡对禽脂的表观消化率

试验研究日粮中禽脂水平(30和24 g/kg)以及是否添加外源乳化剂溶血卵磷脂(LPC)对肉仔鸡生长性能、脂肪酸表观消化率以及日粮表观代谢能(AME)的影响.本试验选用168只1日龄AA肉仔鸡(公雏),按照2×2因子设计,分4个处理,每个处理7个重复,每个重复6只鸡.试验中测定生长性能、营养物质表观消化率以及日粮AME.结果表明,禽脂添加水平对肉仔鸡生长性能、脂肪酸表观消化率以及日粮AME没有显著影响(P>0.05).日粮中添加LPC提高肉仔鸡体增重(P<0.05)、降低料重比(P<0.05)、提高14～17日龄日粮AME(P<0.05).添加LPC有提高14～17日龄肉仔鸡粗脂肪表观消化率的趋势(P=0.086).日粮中添加外源乳化剂LPC提高了C18:0脂肪酸的表观消化率(P<0.05),对其他脂肪酸、粗蛋白质以及粗脂肪表观消化率没有显著影响(P>0.05).这些结果表明,在含禽脂的日粮中添加500 mg/kg LPC能改善肉仔鸡生长性能;LPC改善肉仔鸡生长性能的作用是通过提高脂肪表观消化率实现的.     

复合短链脂肪酸对肉仔鸡生产性能的影响及相关作用机制的探讨

试验旨在研究复合SCFAs对肉仔鸡生产性能的影响及其相关的作用机制。120只AA肉仔鸡随机分成2组(复合SCFAs添加组和对照组),每组6个重复,每个重复10只鸡。结果表明,与对照组相比,添加复合SCFAs组的肉仔鸡的体增重、耗料量、胰腺相对重量分别提高了4.4%、5.6%、16%(P<0.05),小肠淀粉酶和胰蛋白酶的活性分别提高了48.5%和37.3%(P<0.05),降低了十二指肠中大肠杆菌的数量(P<0.05)以及血清中葡萄糖和胰岛素的含量(P<0.05)。日粮中使用复合SCFAs可以提高肉仔鸡小肠消化酶活性,减少消化道中大肠杆菌的数量,改善肉仔鸡的生产性能。     

黄曲霉毒素解毒酶对岭南黄肉仔鸡日粮中黄曲霉毒素B1解毒效果的研究

本文通过测定岭南黄肉仔鸡生长性能和血清指标及对肝脏组织切片的观察,旨在探讨黄曲霉毒素解毒酶对黄曲霉毒素B1(AFB1)的解毒作用.选用1日龄健康岭南黄肉仔鸡420羽,随机分为7个处理,每个处理4个重复,每个重复15羽,雄鸡10羽,雌鸡5羽.7个处理分别为基础日粮组、基础日粮+100 μg/kg AFBi组、基础日粮+100μg/kg AFB1+0.1%解毒酶组、基础日粮+100 μg/kg AFB1+0.2%解毒酶组、基础日粮+100μg/kg AFB1+0.3%解毒酶组、基础日粮+100μg/kg AFB1+0.4%解毒酶组、基础日粮+100μg/kg AFB1+0.5%解毒酶组,试验期42 d.结果表明:1)基础日粮中加入100μg/kg AFBi,肉仔鸡的平均日采食量、平均日增重和平均末重有所下降(P>0.05);血清中总蛋白(P<0.05),白蛋白(P>0.05)和球蛋白(P<0.05)含量下降,谷草转氨酶、谷丙转氨酶活性升高(P<0.05);肝脏组织病理切片观察到肝细胞广泛性坏死,胆管异常增生;2)在100μg/kg AFB1日粮中加入黄曲霉毒素解毒酶,能一定程度的改善肉仔鸡的平均日采食量、平均日增重和平均末重(P>0.05),0.2%、0.4%和0.5%的水平能显著降低毒素在肝脏和血液中的残留(P<0.05),减弱毒素对肝脏的损伤,一定程度地改善血清学指标.由此可知,黄曲霉毒素解毒酶能有效保护肉仔鸡肝脏,减轻或基本消除AFB1对肉仔鸡组织器官的不良影响,一定程度的提高肉仔鸡的平均日采食量和日增重.     

单宁酸对肉仔鸡生产性能和消化道酶活性的影响研究

为研究单宁酸对肉仔鸡生产性能和消化道酶活性的影响,选取2 400只1日龄健康AA肉仔鸡随机分为4个处理,每个处理6个重复,每个重复100只鸡.分别饲喂4种日粮,分别为基础日粮、基础日粮+0.05％单宁酸、基础日粮+0.10％单宁酸、基础日粮+0.15％单宁酸.结果显示,单宁酸对肉仔鸡前期生长有显著抑制作用(P＜0.05),对后期生长速度、饲料报酬均有显著改善作用(P＜0.05)；可以显著提高生长后期肉仔鸡淀粉酶、胰蛋白酶、脂肪酶活性(P＜0.05).研究表明加入适量的单宁酸(1.5 kg/t)可以明显改善肉鸡后期生产性能和提高消化酶活性.     

不同剂型植酸酶对肉仔鸡生长性能和钙、磷利用率的影响

选用160只1日龄肉仔鸡随机分为4组,每组设4个重复,以正常磷日粮为对照,研究在低磷日粮中分别添加相同剂量(100 g/t)不同剂型植酸酶(粉状、液体状、包被颗粒状)对肉仔鸡生长性能及钙、磷利用率的影响。结果表明:(1)低磷日粮中添加不同剂型植酸酶均可提高肉仔鸡的平均日增重和饲料利用率,包被颗粒状植酸酶添加效果最好;(2)各组胫骨的各项指标差异均不显著(P>0.05);(3)各组血清磷、血清钙、血清碱性磷酸酶差异不显著(P>0.05);(4)与对照组比较,各试验组的总磷表观消化率显著提高(P<0.05),钙、粗蛋白质、干物质表观消化率也均有提高;(5)与对照组比较,各试验组肉仔鸡磷排出量(g/kg采食日粮)分别降低了28.28%、28.97%和32.41%(P<0.05)。由结果可知:在42 d的试验中,包被颗粒状植酸酶对肉仔鸡生长性能及钙磷利用率的作用效果最好,其次是液体状植酸酶,粉状植酸酶的作用效果要次于前两者。     

日粮中不同维生素A和维生素E添加水平对肉仔鸡维生素生物学利用率的影响

本文旨在研究肉仔鸡日粮中添加不同水平维生素A、维生素E对其生物学利用率的影响.选用1日龄爱拔益加(AA)肉仔鸡960只,随机分为4个处理,每个处理3个重复,每个重复80只鸡.试验日粮参照AA肉仔鸡推荐标准配制,4个处理的日粮维生素A、维生素E添加水平分别为:6 375和37.5 IU/kg、8 500和50 IU/kg、10 625和62.5 IU/kg、12 750和75 IU/kg.试验期49 d.研究表明:增加日粮维生素A、维生素E水平可以改善肉仔鸡增重和料重比.肉仔鸡血清和肝脏中维生素A、维生素E水平均随日粮添加水平的增加而提高.维生素A、维生素E水平从AA肉仔鸡推荐量(8 500和50 IU/kg)降至6 375和37.5 IU/kg时,肉仔鸡血清中维生素A、维生素E水平降低了8.42%(P>0.05)和12.14%(P<0.05),肝脏中维生素A、维生素E降低了9.04%和5.12%(P>0.05);维生素A、维生素E水平分别增加至12 750和75 IU/kg时,血清维生素A、维生素E水平提高了6.44%(P>0.05)和42.21%(P<0.01),肝脏维生素A、维生素E提高了192.58%和65.03%(P<0.01).由此可知,提高日粮维生素A、维生素E水平可提高肉仔鸡血清和肝脏中维生素A、维生素E的水平.     

牛磺酸对肉仔鸡屠宰性能和肌肉品质的影响

本研究旨在探讨牛磺酸对肉仔鸡屠宰性能和肌肉品质的影响。选用240只1日龄艾维茵肉仔鸡,随机分为5组,每组3个重复。对照组饲喂玉米-豆粕型基础日粮,试验组在基础日粮中添加0.05%、0.10%、0.15%和0.20%的牛磺酸,试验期42 d。结果表明:(1)日粮中添加0.10%牛磺酸能够显著降低42日龄肉仔鸡胸肌失水率和粗脂肪含量(P<0.05),显著提高胸肌pH和粗蛋白质含量(P<0.05);(2)添加0.15%的牛磺酸显著提高42日龄肉仔鸡胸肌率和瘦肉率(P<0.05),显著降低皮脂厚(P<0.05),显著提高胸肌pH和粗蛋白质含量(P<0.05),显著降低胸肌粗脂肪含量(P<0.05);(3)0.20%的牛磺酸显著提高胸肌pH、肉色和粗蛋白质含量(P<0.05)。     

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.