基于响应面设计的饲草型小黑麦新品系C31栽培条件优化筛选

为筛选饲草型小黑麦新品系C31最适合的栽培条件,利用三因素(种植密度,氮肥施用量,降水量)五水平的中心复合试验响应面设计法,研究了种植密度、氮肥施用量和降水量对饲草型小黑麦草产量和营养品质的影响,构建饲草型小黑麦新品系C31草产量和营养品质的三元二次回归预测模型。结果表明:1)种植密度、氮肥施用量和降水量对饲草型小黑麦的草产量与营养品质均有显著影响(P0.05),降水量×氮肥施用量交互作用对小黑麦干草产量有显著影响(P0.05),降水量×种植密度交互作用对小黑麦干草的营养品质有显著影响(P0.05)。2)三元二次回归分析结果显示,种植密度、氮肥施用量和降水量与小黑麦草产量和营养品质间的回归模型极显著(P0.01),表明干草产量和营养品质回归模型能够代表饲草型小黑麦的实际干草产量和营养品质。3)小黑麦新品系C31适合在生长季降水量为318～325mm的合作地区生长。4)生长季降水量为322.07mm时,小黑麦新品系C31的干草产量最高,营养品质最佳。在此降水量下,氮肥施用量为289.17kg N·hm~(-2),种植密度为579.40万基本苗·hm~(-2),模型预测小黑麦干草产量为16732.50kg·hm~(-2),干草营养品质的最大值为0.71。本研究将为评价小黑麦种质草产量和营养品质表现及适宜种植区域提供简便有效的分析手段。     

小黑麦新品系的草产量及营养价值研究

论文通过研究小黑麦新品系（Triticale Wittmack）（P1,P2,P3,P4,P5）在2013年和2014年的株高、草产量和营养价值以筛选高产稳产和营养价值较高的品系,为小黑麦新品种登记奠定基础。结果表明：不同小黑麦新品系的株高和鲜（干）草产量均存在显著差异,P3的平均鲜（干）草产量最高,其次为P2;各小黑麦品系2014年的平均株高和鲜（干）草产量均显著高于2013年;小黑麦新品系P3在2013年的株高、鲜草产量和干草产量均最高。参试小黑麦新品系的粗蛋白含量（Crude Protein,CP）和中（酸）性洗涤纤维（Neutral/Acid Detergent Fiber,NDF/ADF）也存在显著差异,P2的CP含量最高,P3的酸性洗涤纤维含量最低,P1的中性洗涤纤维含量最低;不同年份间的CP,ADF和NDF含量均无显著差异。综合评价结果表明,5个小黑麦新品系中,P3的综合性状最好,其次为P2,以上2品系可进一步进行区域试验和生产试验,以申报登记小黑麦新品种。     

基于响应面设计的饲草型小黑麦新品系C31栽培条件优化筛选

为筛选饲草型小黑麦新品系C31最适合的栽培条件,利用三因素(种植密度,氮肥施用量,降水量)五水平的中心复合试验响应面设计法,研究了种植密度、氮肥施用量和降水量对饲草型小黑麦草产量和营养品质的影响,构建饲草型小黑麦新品系C31草产量和营养品质的三元二次回归预测模型。结果表明:1)种植密度、氮肥施用量和降水量对饲草型小黑麦的草产量与营养品质均有显著影响(P<0.05),降水量×氮肥施用量交互作用对小黑麦干草产量有显著影响(P<0.05),降水量×种植密度交互作用对小黑麦干草的营养品质有显著影响(P<0.05)。2)三元二次回归分析结果显示,种植密度、氮肥施用量和降水量与小黑麦草产量和营养品质间的回归模型极显著(P<0.01),表明干草产量和营养品质回归模型能够代表饲草型小黑麦的实际干草产量和营养品质。3)小黑麦新品系C31适合在生长季降水量为318~325 mm的合作地区生长。4)生长季降水量为322.07 mm时,小黑麦新品系C31的干草产量最高,营养品质最佳。在此降水量下,氮肥施用量为289.17 kg N·hm^-2,种植密度为579.40 万基本苗·hm^-2,模型预测小黑麦干草产量为16732.50 kg·hm^-2,干草营养品质的最大值为0.71。本研究将为评价小黑麦种质草产量和营养品质表现及适宜种植区域提供简便有效的分析手段。     

小黑麦新品系在甘肃省陇中冬小麦区的种子产量及产量构成因素的研究

以小黑麦新品系P1为试验材料,研究了该品系在甘肃省陇中冬小麦区的种子产量及产量稳定性,并分析了种子产量构成因素(穗粒数,穗粒质量,小穗数,穗长)与种子产量的相关性。研究结果表明:小黑麦新品系P1抗倒伏,生育期比2个对照缩短7~14d;除株高和小穗数外,小黑麦新品系P1的种子产量(4 464.49kg/hm2)、穗粒数(42.93个)、穗长(9.39cm)和穗粒质量(1.66g)均显著高于其他2个对照品种;3个试点中,临夏点小黑麦种质的平均种子产量最高(4 513.47kg/hm2),兰州点小黑麦的穗长最长(9.49cm)。综合分析显示,小黑麦新品系P1在3个试验点种子产量较稳定,在临夏点种子产量最高(5 280.70kg/hm2),为最适宜种植区。     

青藏高原川西北牧区一年两季饲草种植模式对土壤理化性质及酶活性的影响

【目的】川西北高寒牧区气候寒冷,牧草生长季短,选用抗寒性强的小黑麦品种进行秋播,翌年复种不同作物,可以有效提高土地利用效率和牧草产量。【方法】以8个小黑麦种质（甘农2号小黑麦、甘农3号小黑麦、甘农4号小黑麦、甘农7号小黑麦、藏饲1号小黑麦、小黑麦品系C16、C23、C25）作为秋播材料,次年复种不同作物：B1(50%藏饲1号小黑麦混播50%饲用豌豆),B2(50%藏饲1号小黑麦混播50%箭筈豌豆),B3(50%青甜1号燕麦混播50%饲用豌豆),B4(50%青甜1号燕麦混播50%箭筈豌豆),以研究秋播小黑麦复种不同作物对土壤理化性质（pH值、有机质、全氮、全钾、全磷、速效氮、速效磷及速效钾含量）及土壤酶（过氧化氢酶、碱性磷酸酶、脲酶及蔗糖酶）活性的影响。【结果】秋播小黑麦复种不同作物后,土壤养分含量及酶活性均有所提高。【结论】秋播甘农4号小黑,翌年麦复种50%藏饲1号小黑麦混播50%饲用豌豆模式对土壤理化及酶活性影响最大,能够改善土壤理化环境及酶活性,有助于提高牧草产量。     

基于隶属函数法和GGE双标图的饲草型小黑麦种质适应性评价

为筛选甘肃省不同地区适宜种植的小黑麦品种(系)和甘肃省最适宜种植小黑麦的试验点,以4个小黑麦种质(新品系P₂,新品系P₄,石大1号,中饲1048)为材料,于2014-2015年研究了上述种质在甘肃省不同试验点(临洮,玛曲,夏河,合作,肃南县马蹄乡和肃南县康乐乡)开花期的干草产量、营养价值(粗蛋白含量,中性洗涤纤维含量,酸性洗涤纤维含量)以及干物质消化率,其中临洮点有灌溉条件,其他试点无灌溉条件,为雨养区。利用方差分析、隶属函数法和GGE(基因型和基因与环境互作效应)双标图法,对测定数据进行了分析,得到以下结果: 1)参试的4个小黑麦种质中,品系P₂的干草产量最高(12.94 t·hm^-2),营养评价值最高(0.67),在临洮点和玛曲点具有广阔推广利用前景;品系P₄的干草产量较高(10.90 t·hm^-2),营养评价值较高(0.5);石大1号和中饲1048由于营养评价值低或干草产量低,在甘肃省6个试验点表现均不理想,不适合种植。2)6个试点中,临洮点小黑麦的干草产量(14.13 t·hm^-2)较高(位居第2),营养评价值(0.51)最高;玛曲点小黑麦的干草产量(14.07 t·hm^-2)较高(位居第3),营养评价值(0.50)较高(位居第2),其他4个试点小黑麦的干草产量和营养品质均较差;综合6个试验点小黑麦的干草产量和营养评价值,临洮和玛曲为种植小黑麦最理想的区域。研究将为评价小黑麦种质草产量和营养品质表现及适宜种植区域提供了简便有效的分析手段,可以为小黑麦种质鉴定与推广提供理论依据。     

甘南高寒牧区3种饲草不同种植模式下的生产性能及经济效益

为明确甘南高寒牧区3种饲草不同种植模式的生产性能及经济效益,设置了秋播小黑麦(×Triticale Wittmack)套作式复种箭筈豌豆(Vicia sativa)、50%春播小黑麦混播50%箭筈豌豆、小黑麦秋季单播、箭筈豌豆春季单播和燕麦(Avena sativa)春季单播5个处理,分析不同处理的干草产量、营养价值(粗蛋白含量、酸性洗涤纤维含量、中性洗涤纤维含量)、经济效益及土壤养分含量。结果表明,秋播小黑麦套作式复种箭筈豌豆和50%春播小黑麦混播50%箭筈豌豆的干草产量分别为14.06和12.31 t·hm–2,纯收益分别为6286和11011元·hm–2,显著高于3种单播模式(P<0.05),且显著提高了土壤的全氮含量,可作为甘南高寒牧区高效种植模式进行种植推广。     

黑龙港地区晚春播青贮玉米品种的生产性能及适应性评价

在河北省黑龙港地区选择深州市护驾迟、威县赵村和沧县前营3个试验点,对14个青贮玉米品种的生育期、农艺性状、抗逆性、生物产量和饲用品质等指标进行综合评定,旨在筛选出晚春播条件下适宜和饲用小黑麦搭配种植的青贮玉米品种,为该地区"粮改饲"及草牧业发展提供技术支撑。结果表明:北农青贮2932、北农青贮208和辽单青贮625与饲用小黑麦搭配种植较好。3个品种生物产量均超过1 300kg/hm~2,一致表现为抗病、抗倒,生长期适中、叶量丰富、饲用品质优,适宜在黑龙港地区晚春播条件下和饲用小黑麦复种,形成饲用小黑麦-青贮玉米复种模式。     

甘南高寒牧区秋播小黑麦与复种作物耦合对土壤养分的影响

通过研究甘南高寒牧区秋播小黑麦套作式复种不同作物(50％小黑麦×50％箭菩豌豆混播,40％黑麦×60％箭菩豌豆混播,50％燕麦×50％箭筈豌豆混播,小黑麦单播,黑麦单播,燕麦单播,箭筈豌豆单播)土壤养分含量的变化,以明确秋播小黑麦与复种作物耦合对土壤养分含量的影响.结果 表明:7个复种处理,秋播小黑麦复种50％小黑麦×50％箭菩豌豆混播处理土壤pH7.46(较春播前降低了1.84％)、有机质含量65.37 g/kg(较春播前增加了76.63％)、全氮含量2.14 g/kg(较春播前增加了9.18％)、全磷含量1.19 g/kg(较春播前增加了30.77％)、全钾含量8.71 g/kg(较春播前降低了1.36％)、速效磷含量17.08mg/kg(较春播前增加了33.83％)、速效钾含量126.51 mg/kg(较春播前降低了12.07％);秋播小黑麦复种50％燕麦×50％箭筈豌豆混播处理时土壤pH7.39(较春播前降低了2.72％)、有机质含量75.67 g/kg(较春播前增加了104.46％)、全氮含量2.20 g/kg(较春播前增加了12.24％)、全磷含量1.23 g/kg(较春播前增加了35.16％)、全钾含量8.70 g/kg(较春播前降低了1.47％)、速效磷含量18.21 mg/kg(较春播前增加了42.71％)、速效钾含量127.73mg/kg(较春播前降低了11.22％).两种种植方式的土壤肥力综合评价值分别为0.645、0.739,属于高等级肥力水平,说明这两种复种混播模式耦合效应较好,有利于改良土壤养分条件,可作为甘南高寒牧区饲草复种模式进一步研究.     

甘肃省高寒牧区小黑麦新品系的生产性能

通过研究小黑麦(×Triticosecale Wittmack)新品系(P_2、P_4)在甘肃省高寒牧区(肃南、合作、玛曲)的草产量及营养价值,以筛选适宜种植区域,以石大1号和中饲1048为对照品种。结果表明,不同试点间、小黑麦材料间和材料×试点交互作用间的草产量和营养价值均有显著差异(P0.05)。4个小黑麦材料在3个试点的干草产量表现为P_2(14.42t·hm~(-2))P_4(11.72 t·hm~(-2))中饲1048小黑麦(10.03 t·hm~(-2))石大1号小黑麦(9.70 t·hm~(-2)),粗蛋白总含量为P_2(13.31%)P_4(12.17%)中饲1048小黑麦(8.37%)石大1号小黑麦(7.40%),中性洗剂纤维总含量为P_2(61.65%)中饲1048小黑麦(63.82%)P_4(64.89%)石大1号小黑麦(68.14%),酸性洗剂纤维总含量为P_2(41.97%)中饲1048小黑麦(42.15%)P_4(43.35%)石大1号小黑麦(45.06%)。综合分析,小黑麦新品系P_2高产优质,最适宜在甘肃省高寒牧区种植。     

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.     

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.     

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.