青海东部农区高产优质燕麦品种筛选

为筛选出适宜青海东部农区种植的优质燕麦(Avena sativa)品种,以8个当地主栽燕麦品种为供试材料,对其农艺性状、产量和品质进行比较分析,并利用隶属函数法进行综合评价。结果表明,开花期8个燕麦品种的饲草产量及品质从高到低依次为青海444>青海甜燕麦>青燕1号>青引1号>加燕2号>白燕7号>青引2号>林纳,其中青海444饲草产量最高,达39091.29 kg·hm^-2,青海甜燕麦排名第2,且两者纤维含量低,适口性较好;青燕1号饲草产量、粗蛋白含量较高。因此收获饲草建议种植青海444、青海甜燕麦和青燕1号。成熟期8个燕麦品种的种子产量及饲草品质综合评价从高到低依次为白燕7号>青海甜燕麦>青燕1号>林纳>青海444>青引2号>加燕2号>青引1号,白燕7号粗蛋白含量(3.74%)最高,但白燕7号的种子产量(5528.01 kg·hm^-2)低于林纳(5888.69 kg·hm^-2),青燕1号种子产量较低,因此以种子高产为目的建议种植白燕7号、青海甜燕麦和林纳。     

西藏河谷区9个引进燕麦品种的生产性能和营养品质比较研究

为了筛选出适合在西藏河谷区种植的燕麦品种,本研究通过田间试验测定了9个燕麦品种的产量和营养品质。参试的燕麦品种为阿坝燕麦、青引1号、青引2号、青海444、青燕1号、林纳、边锋、加燕2号和青海甜燕麦,于2016年5月8日播种,小区面积为3 m×4 m,设3次重复。对9个燕麦品种抽穗期、孕穗期和成熟期的鲜重、干重、干鲜比、株高和叶茎比以及成熟期的营养品质[粗蛋白(CP)、粗脂肪(EE)、粗灰分(Ash)、酸性洗涤纤维(ADF)、中性洗涤纤维(NDF)、木质素(ADL)]进行测定。成熟期的地上部干重结果表明,青燕1号、林纳、边锋和加燕2号的产量均大于26000 kg·hm~(-2),青引1号、青引2号、青海444和青海甜燕麦产量为22000～26000 kg·hm~(-2),阿坝燕麦产量低于22000 kg·hm~(-2)。9个燕麦品种的CP、EE、Ash、ADF、NDF、ADL含量的变化范围分别为4.5%～7.2%、21.7%～57.3%、4.5%～5.7%、24.9%～35.4%、58.2%～80.5%和30.6%～42.0%,营养品质结果表明,青燕1号、青引2号和加燕2号的CP含量显著低于其他品种(P0.05);边锋的NDF含量显著低于其他品种(P0.05),青海甜燕麦含量最高;青海444的EE含量显著高于其他品种(P0.05)。应用灰色关联度理论方法对9个燕麦品种的产量与营养品质指标进行综合分析得出,青海444、青燕1号和阿坝燕麦较其他燕麦品种更适宜在该地区种植推广。     

西藏河谷区9个引进燕麦品种的生产性能和营养品质比较研究

为了筛选出适合在西藏河谷区种植的燕麦品种,本研究通过田间试验测定了9个燕麦品种的产量和营养品质。参试的燕麦品种为阿坝燕麦、青引1号、青引2号、青海444、青燕1号、林纳、边锋、加燕2号和青海甜燕麦,于2016年5月8日播种,小区面积为3 m×4 m,设3次重复。对9个燕麦品种抽穗期、孕穗期和成熟期的鲜重、干重、干鲜比、株高和叶茎比以及成熟期的营养品质[粗蛋白(CP)、粗脂肪(EE)、粗灰分(Ash)、酸性洗涤纤维(ADF)、中性洗涤纤维(NDF)、木质素(ADL)]进行测定。成熟期的地上部干重结果表明,青燕1号、林纳、边锋和加燕2号的产量均大于26000 kg·hm^-2,青引1号、青引2号、青海444和青海甜燕麦产量为22000～26000 kg·hm^-2,阿坝燕麦产量低于22000 kg·hm^-2。9个燕麦品种的CP、EE、Ash、ADF、NDF、ADL含量的变化范围分别为4.5%～7.2%、21.7%～57.3%、4.5%～5.7%、24.9%～35.4%、58.2%～80.5%和30.6%～42.0%,营养品质结果表明,青燕1号、青引2号和加燕2号的CP含量显著低于其他品种(P<0.05);边锋的NDF含量显著低于其他品种(P<0.05),青海甜燕麦含量最高;青海444的EE含量显著高于其他品种(P<0.05)。应用灰色关联度理论方法对9个燕麦品种的产量与营养品质指标进行综合分析得出,青海444、青燕1号和阿坝燕麦较其他燕麦品种更适宜在该地区种植推广。     

日喀则市不同燕麦品种种植试验研究

为筛选出适宜日喀则市推广种植的燕麦品种,试验取10个燕麦品种(以其中青引2号作为对照)进行种植,从物候期、鲜草产量和干草产量等方面进行了对比分析。结果表明:所选燕麦品种均能在种植区域正常生长;其中青引1号、青海444、白燕7号、领袖燕麦、甜燕麦、加燕2号、青引3号的干、鲜草产量均显著高于对照品种(P0.05),青海444、领袖燕麦和青引1号的鲜草产量超过了50 000 kg/hm~2,青引1号、青海444和白燕7号的干草产量超过了20 000 kg/hm~2;除领袖燕麦和青燕1号外,其余品种植株均显著高于对照品种(P0.05),干鲜比白燕2号、青燕1号和甜燕麦高于对照品种(P0.05)。综合各项指标说明青海444、青引1号、领袖燕麦、白燕7号可以作为日喀则地区饲草生产的主推品种。     

川西北7个燕麦品种产量及营养成分比较分析

在川西北红原县通过对7个燕麦(Avena sativa)品种的产量、茎叶比、株高、相对叶绿素含量(SPAD)及营养成分进行比较研究,结果表明:综合草产量和营养成分比较,青引1号、青海444和青海甜燕麦优于伽利略、林纳、加燕2号和阿坝燕麦。建议川西北牧民选择青引1号、青海444和青海甜燕麦作为燕麦栽培品种。     

燕麦幼苗对低温胁迫的响应

在0、12、36、60 h不同时间梯度下,对7个燕麦(Avena sativa)品种(青引1号、青引2号、青引3号莜麦、青海甜燕麦、青海444、青燕1号和林纳)进行连续低温(5℃)胁迫,比较其抗寒能力。结果表明,与低温胁迫前(0 h)相比,低温处理后(12、36和60 h)7个燕麦品种幼苗叶片丙二醛、脯氨酸含量和超氧化物歧化酶、过氧化物酶活性均显著增加(P0.05);各燕麦品种幼苗叶片丙二醛、脯氨酸含量和过氧化物酶、超氧化物歧化酶活性在低温胁迫初期(0-12 h)显著增加(P0.05)并达到最大值;随着低温胁迫时间延长,其含量开始下降。7个燕麦品种抗寒能力依次表现为青引3号莜麦青海甜燕麦青引2号林纳青燕1号青海444青引1号。     

呼伦贝尔地区10个引进燕麦品种生产性能及饲草品质比较

为筛选出适宜在呼伦贝尔地区种植的优质燕麦品种,测定10个引进燕麦品种（青燕1号、青海444、加燕2号、青引1号、林纳、青海甜燕麦、青引2号、莫妮卡、青莜3号、骏马）的田间农艺性状、饲草产量、营养成分及籽粒产量,使用相对饲喂价值（RFV）和粗饲料分级指数（GI）对饲草品质进行评价,使用灰色关联度分析法综合评价各品种的生产性能。结果表明,供试燕麦品种在呼伦贝尔地区早熟,生育周期73~88 d。青海444株高最高,达到113.22 cm（P<0.05）;且其开花期的鲜草产量和干草产量均最高,分别为36623.3和9990.5 kg·hm^-2（P<0.05）。各品种燕麦的鲜、干草产量与生育周期、株高、旗叶长、旗叶宽、茎粗、穗长呈极显著正相关（P<0.01）,与叶茎比和干鲜比呈极显著负相关（P<0.01）。籽粒产量最高的是青引1号,达到5348.85 kg·hm^-2,与加燕2号无显著差异（P>0.05）,但显著高于其他品种（P<0.05）。籽粒产量与生育周期、株高、茎粗、穗长、轮层数和千粒重呈极显著正相关（P<0.01）,与小穗数呈极显著负相关（P<0.01）。粗脂肪含量最高的是乳熟期青燕1号（P<0.05）,粗蛋白含量最高的是抽穗期青引1号（P<0.05）,粗灰分含量最高的是抽穗期青燕1号（P<0.05）,干物质最高的是抽穗期青引2号（P<0.05）。GI与RFV饲草等级划分总体趋势相同。综合分析得出,青引1号、加燕2号和青海444的生产性能、营养品质及饲喂价值表现较好,综合排名靠前,具有作为优质燕麦品种在呼伦贝尔地区推广种植的潜力。     

川西北高寒地区6个燕麦品种生长特性的比较分析

为筛选适宜在川西北地区种植的优良燕麦(Avena sativa)品种,对国内外6个燕麦品种(青海444、青引1号、林纳、定燕2号、讴歌、莫妮卡)的生育期、株高、茎粗、产草量、鲜干比、茎叶穗构成及营养成分(粗蛋白、粗脂肪、粗灰分、酸性洗涤纤维、中性洗涤纤维)进行了品比试验。结果表明,除定燕2号外,其余5个燕麦品种均能完成生育期,其中青海444和青引1号生育期最短,分别为130和133d。供试燕麦的株高在81.53~90.54cm,品种间没有显著差异(P0.05)。莫妮卡的茎粗最大,为4.35mm;青引1号最小,为3.32mm。林纳干草产量最高,达到10 448.52kg·hm-2;而青引1号最低,仅8 554.81kg·hm-2。青海444和青引1号鲜干比显著低于其他品种(P0.05)。林纳的叶和穗重量占总干物质量的比例最高。林纳粗蛋白含量最高,为7.82%;定燕2号最低,为5.83%。青引1号粗脂肪含量最高,为2.93%;讴歌最低,为2.48%。粗灰分、酸性洗涤纤维和中性洗涤纤维含量最高的品种是青海444,分别为4.60%、35.57%和63.27%;含量最低的定燕2号则分别为3.76%、32.00%和54.47%。综合评价分析结果表明,品种林纳和莫妮卡最适宜在该区域推广种植。     

新疆塔城和石河子地区燕麦品种生产性能比较研究

为了比较丹麦440、青海444、青燕1号、青引1号在新疆塔城、石河子地区的生长状况,并筛选出适宜当地种植的燕麦品种,试验采用完全随机区组设计,测定不同地区不同品种燕麦株高、干草产量、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)、可溶性碳水化合物(WSC)、粗蛋白(CP)、粗脂肪(EE)、粗灰分(Ash)及相对饲喂价值(RFV)等指标,并通过隶属函数对不同品种燕麦在不同地区的生产性能进行综合评价。结果表明:塔城地区丹麦440干草产量最高,为12.25 t/hm~2,与塔城地区其他燕麦品种差异显著(P0.05);石河子地区青燕1号干草产量最高,为7.91 t/hm~2,除丹麦440外,与石河子地区其他燕麦品种差异显著(P0.05)。青引1号株高在塔城和石河子地区均为最高。塔城地区青海444 RFV显著高于本地区其他品种(P0.05),石河子地区青引1号RFV显著高于本地区其他品种(P0.05)。塔城地区青燕1号CP含量最高,为9.88%,与青海444差异显著(P0.05);石河子地区丹麦440 CP含量最高,为11.68%,显著高于本地区其他品种(P0.05)。塔城地区青海444 NDF、ADF含量显著低于本地区其他品种(P0.05),分别为45.02%、22.30%;石河子地区青引1号NDF含量显著低于其他品种(P0.05),为46.27%;丹麦440 ADF含量最低,为20.99%,除青引1号外,与本地区其他2个品种差异显著(P0.05)。塔城地区青燕1号WSC含量、Ash含量最高,分别为11.03%、7.08%,除丹麦440外,与其他2个品种均差异显著(P0.05);石河子地区丹麦440 WSC含量、EE含量显著高于其他品种,分别为11.04%、4.64%(P0.05)。塔城地区青燕1号EE含量显著高于其他品种(P0.05),为6.07%。石河子地区青燕1号Ash含量最高,为7.87%,与丹麦440差异显著(P0.05)。说明塔城地区适合种植青海444,石河子地区适合种植丹麦440。     

西藏当雄10个引进燕麦品种的生产性能和营养品质比较

为了筛选出适合在西藏当雄种植的燕麦（Avena sativa）品种,本研究通过田间试验测定了10个燕麦品种的产量和营养品质。结果表明：青燕1号和青海甜燕麦的干草产量大于8 000 kg·hm^-2,青莜1号、青莜3号、林纳、阿坝燕麦、青引1号和加燕2号的干草产量在6 000~8 000 kg·hm^-2之间,青引3号和白燕7号的干草产量低于6 000 kg·hm^-2。10个燕麦品种的粗蛋白、粗脂肪、粗灰分、酸性洗涤纤维、中性洗涤纤维、木质素含量的变化范围分别为5.35%~8.54%,21.67%~58.33%,3.83%~5.23%,27.27%~37.50%,49.73%~67.51%和23.81%~34.27%。结合灰色关联度理论方法对10个燕麦品种的产量与营养品质指标进行综合分析得出,青燕1号、青海甜燕麦和林纳较其他燕麦品种更适宜在该地区种植。     

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.