Seroprevalences of vector-transmitted infections of small-holder dairy cattle in coastal Kenya     

Maloo SH  Thorpe W  Kioo G  Ngumi P  Rowlands GJ  Perry BD 《Preventive veterinary medicine》2001,52(1):1-16

A cross-sectional study was carried out from July to September 1989 in Kaloleni Division, Coast Province, Kenya to estimate the prevalence of vector-transmitted diseases in small-holder dairy cattle and to identify the risk factors associated with different management systems. One hundred and thirty of the 157 herds with dairy cattle in Kaloleni Division were surveyed. These were from three agro-ecological zones (coconut-cassava, cashew nut-cassava and livestock-millet), comprised two management systems (stall-feeding and herded grazing) and were herds with either dairy cattle only or with Zebu and dairy cattle. A formal questionnaire sought answers to questions on cattle health and management practices. A total of 734 dairy and 205 Zebu cattle in 78 dairy and 52 mixed (dairy and Zebu) herds were sampled and screened for haemoparasites (Trypanosoma, Anaplasma, Babesia, and Theileria infections). Sera were tested for antibodies to Theileria parva, using the schizonts-antigen indirect fluorescent-antibody (IFA) test and to antibodies for Babesia bigemina and antigens to Anaplasma marginale by enzyme-linked immunosorbent assay (ELISA). Packed-cell volume (PCV) also was measured. Tick-control measures were practised by all except three of the farmers. Despite this, overall seroprevalence to T. parva was >70%--suggesting either that control practices were not strictly implemented or they were ineffective. The seroprevalence of T. parva in adult cattle kept in stall-feeding systems in the coconut-cassava zone was significantly lower (57+/-8% (S.E.)) than in herded-grazing systems (79+/-3%) and there was no association between antibody prevalence and age of cattle in this zone. Antibody prevalences in cattle in the cashew nut-cassava and the drier livestock-millet zone increased with age. Cattle in herded-grazing systems had an overall lower seroprevalence of T. parva infection in the livestock-millet zone (45+/-6%) than in the other two zones.Analysis was confined to the coconut-cassava zone for B. bigemina and to the coconut-cassava and cashew nut-cassava zones for A. marginale. Mean prevalences of B. bigemina were 40.9+/-9 and 73+/-6% for dairy cattle under stall-feeding and herded-grazing systems, respectively, and increased with age. Antigen prevalences of A. marginale were over 80% in all age groups of cattle in the coconut-cassava and cashew nut-cassava zones. Overall trypanosome prevalence in cattle was <1%. Trypanocidal treatment was uncommon. The variations in antibody prevalence associated with risk factors such as feeding system, agro-ecological zone and age of animal suggest that management system influenced exposure to tick-borne infection (particularly, T. parva infections) in small-holder dairy cattle in coastal Kenya.  相似文献   

Identification of a target population for immunisation against East Coast fever in coastal Kenya     

Maloo SH  Ngumi P  Mbogo S  Williamson S  Thorpe W  Rowlands GJ  Perry BD 《Preventive veterinary medicine》2001,52(1):31-41

Two experiments were carried out to identify the target population of cattle for immunisation against East Coast fever (ECF) using the infection-and-treatment method. Firstly, a sentinel-calf study was used to determine the age window for ECF immunisation by determining ages at clinical detection of infection with Theileria parva. Six groups of five naive cross-bred (Bos taurus/Bos indicus) male calves, introduced at intervals of 2 months at a mean age of 26 days, were exposed to natural tick challenge on a high ECF-risk, small-holder farm in the coastal lowland, coconut-cassava agro-ecological zone of coastal Kenya. Secondly, a challenge study evaluated the relationship between the presence of T. parva antibodies and immunity. Ten indigenous adult Zebu cattle and nine Zebu young stock purchased from farmers in the same zone, and eight cross-bred calves (survivors of the sentinel-calf study) were challenged with 10 times the immunising dose of T. parva Marikebuni stock. Twenty-four of these 27 cattle had high antibody titres before challenge. Two cross-bred calves, obtained from an ECF-free area and seronegative to T. parva schizont antigen, also were challenged and used as susceptible controls. Twenty-five (83%) of the 30 sentinel calves contracted ECF over an age range of 36-116 days (mean 72 days). The remaining five calves died of other causes within 2 months of arrival on the farm. Fourteen of the 25 calves survived the infection and developed antibodies to T. parva. Despite tick control, seven of these 14 calves had a second episode of ECF and two died. In total, 13 of the 25 calves that contracted ECF died. Only one of 19 indigenous Zebu animals developed clinical ECF when challenged with T. parva Marikebuni (mild clinical signs with spontaneous recovery). Of the eight cross-bred survivors from the first experiment, only one succumbed to ECF when challenged and it died. Both susceptible cross-bred calves developed severe clinical signs of ECF and one died. The experimental studies show that in the high ECF-risk areas of the coconut-cassava zone of coastal Kenya, immunisation against ECF in cross-bred (B. taurus/B. indicus) cattle should be targeted at an early age (preferably within 1-2 months of birth).  相似文献   

A fatal syndrome in a dog following administration of phenylbutazone     

J Tandy  E Thorpe 《The Veterinary record》1967,81(16):398-399

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Agar well technique for antibiotics in animal feeds.     

V A Thorpe 《Journal of the Association of Official Analytical Chemists》1975,58(1):95-98

The agar well technique compares favorably with the cylinder plate assay in accuracy, sensitivity, and precision. It is more flexible and more rugged, and growth of seed organism is not inhibited. The wells are precision cut with Grafar gel punch assembly with sets (6) of 10, 7, 5, 4, and 3 mm cutters. The wells are easily and rapidly filled with short, disposable Pasteur pipets fitted with rubber bulbs. The smaller wells are filled with capillary pipets. The diameter of the well (independent of volume) appears to be a function of concentration. For every decrease in the diameter size of the well, concentration can be increased, at least to the next higher level of the standard response line. Extracts of chlortetracycline containing as much as 3.2 mu-g/ml can be analyzed if the 3 mm wells are used and with no sacrifice in accuracy or precision. This works especially well for antibiotic premixes. The technique has been used successfully for penicillin, streptomycin, chlortetracycline, oxytetracycline, oleandomycin, and tylosin.  相似文献   

In vitro regeneration of Pacific silver fir (Abies amabilis) plantlets and histological analysis of shoot formation     

Kulchetscki L  Harry IS  Yeung EC  Thorpe TA 《Tree physiology》1995,15(11):727-738

A protocol is described for the in vitro propagation of Abies amabilis (Dougl.) Forbes. Over 60% of the cotyledonary explants from 5-day-old cotyledons formed shoots when cultured for 7 days on Schenk and Hildebrandt's (SH) medium containing 10 micro M N(6)-benzyladenine (BA) followed by another 7 days on SH medium containing 10 micro M each of BA and zeatin. Shoot multiplication was unsuccessful. Seventeen percent rooting was obtained after pulsing for 4 h in 1 mM indole-3-butyric acid and planting pulsed shoots in 1/1 (v/v) perlite/vermiculite. Cell clusters (promeristemoids) of five to seven cells were observed on the cotyledonary explants after 7 days of culture in the presence of cytokinin. These cells developed further into meristematic domes and apical meristems. In the absence of cytokinin, stomata and resin canals reached maturity, whereas cells within the cortex became vacuolated and developed into palisade and spongy mesophyll.  相似文献   

In vitro plantlet formation from embryonic explants of eastern white cedar (Thuja occidentalis L.)     

Harry IS  Thompson MR  Lu CY  Thorpe TA 《Tree physiology》1987,3(3):273-283

A protocol is described for the in vitro production of plantlets from embryonic explants of eastern white cedar (Thuja occidentalis L.). Bud induction was optimal when embryonic explants were cultured for 20-25 days on half-strength Quoirin and Le Poivre mineral salts containing equimolar concentrations (10(-6) M) of N(6)-benzyladenine and 2-isopentyl adenine. Bud development was achieved in phytohormone-free medium in the presence of activated charcoal. Maximal shoot elongation occurred on half-strength Quoirin and Le Poivre salts, whereas shoot multiplication was optimal on half-strength Bornman's MCM salts in the presence of cytokinin. Hardened shoots, dipped in commercial rooting powder containing indole-3-butyric acid, rooted optimally in mist under non-sterile greenhouse conditions. Both rooting and subsequent plantlet growth was best when Redi-Earth((R)) was used as a substrate. Over 250 plantlets per embryo can be produced annually by this technique.  相似文献   

Ascorbic acid changes the pattern of purine metabolism during germination of white spruce somatic embryos     

Stasolla C  Loukanina N  Ashihara H  Yeung EC  Thorpe TA 《Tree physiology》2001,21(6):359-367

It has previously been shown that exogenous applications of ascorbic acid (AA) increase the conversion frequency of somatic embryos of white spruce (Picea glauca (Moench) Voss). To determine whether ascorbic acid alters purine metabolism during the early phases of embryo germination, the relative rates of purine salvage and degradation were investigated by following the metabolic fates of exogenously applied [8-14C]adenine, [8-14C]adenosine, and [8-14C]inosine, and the activities of several key enzymes. We demonstrated that both the salvage and the degradation pathways operate during germination. Specifically, adenine and adenosine were mainly salvaged to nucleotides and nucleic acids, whereas an appreciable amount of inosine was degraded to CO2 and ureides. Comparisons of purine metabolism between control and AA-treated embryos showed that exogenous applications of ascorbic acid enhanced the ability of the embryos to take up adenine and adenosine throughout the germination period. Furthermore, the higher enzymatic activities of adenosine kinase and adenine phosphoribosyltransferase were responsible for the larger proportion of adenine and adenosine being salvaged in AA-treated embryos compared with control embryos. Thus, there was a positive correlation between the ability to anabolize purine precursors and successful embryo conversion.  相似文献   

Transepithelial ion exchange in smolting atlantic salmon (Salmo Salar L.)     

D. R. N. Primmett  F. B. Eddy  M. S. Miles  C. Talbot  J. E. Thorpe 《Fish physiology and biochemistry》1988,5(4):181-186

Whole-body (but predominantly gill) Na⁺ exchange, gill Na⁺/K⁺/ATPase activity and seawater tolerance were examined in juvenile Atlantic salmon during the smolting period. Transepithelial net Na⁺ gain decreased steadily from late February showing a net loss in April and early May, returning to approximate equilibrium in mid-May. This seasonal net loss of Na⁺ to the environment occurred slightly after maximal gill epithelial Na⁺/K⁺/ATPase activity and preceded maximal seawater tolerance. The results are discussed in relation to changes in gill permeability and salt intake via the diet.  相似文献   

Gonadotropin‐induced Puberty Does Not Impair Reproductive Performance of Gilts over Three Parities     

OHO Eckhardt  SMMK Martins  ME Pinese  FC Horta  AC Rosseto  MA Torres  AFC De Andrade  BBD Muro  CT Marino  PHM Rodrigues  AS Moretti 《Reproduction in domestic animals》2014,49(6):964-969

The aim of this study was to evaluate the reproductive performance of three parities of gilts treated or not treated with gonadotropin to induce puberty. Sixty gilts received 600 IU of equine chorionic gonadotropin (eCG) followed by 2.5 mg of porcine luteinizing hormone (LH) 72 h later. Fifty‐nine other gilts were exposed only to a mature boar for 15 min twice daily. Artificial insemination (AI) was performed at 0, 12 and 24 h after the detection of oestrus, and gestation was confirmed by ultrasound after 35 days. Sows were inseminated at the first post‐weaning oestrus. The total numbers of piglets born, piglets born alive, stillborn, mummified foetuses, as well as pregnancy and farrowing rates were evaluated for each of the three parities. Culling rates, farrowing intervals and weaning‐to‐oestrous intervals (WEI) were also analysed. Mean age at puberty and oestrous manifestation were not significantly different between treatments (p = 0.0639; 179.20 ± 17.52 compared with 173.96 ± 16.94, 91.66% compared with 94.92%) across the experimental period. However, females that underwent puberty induction showed modest increases both in the number of total pigs born and in the number of piglets born alive. In conclusion, puberty induction through exogenous gonadotropin administration in field conditions did not induce a more concentrated first oestrous manifestation, but trended to a modest increase in the number of pigs born alive in the first parity and a reduced culling rate during the first gestation.  相似文献   

Modelling the Vertical Transport of Pollutants by Fronts     

Jae-Cheol Nam  Deb J. Fish  Alan J. Thorpe  Soon-Ung Park 《Water, air, and soil pollution》2001,130(1-4):361-366

A quantitative study of the amount of air transported between the boundary layer and the free atmosphere is important for understanding air quality and upper tropospheric ozone, which is a greenhouse gas. Frontal systems are known to be an effective mechanism for the vertical transport of pollutants. Numerical experiments have been performed with a simple two-dimensional front model to simulate vertical transport of trace gases within developing cold fronts. Three different trace gases experiments have been done numerically according to the different initial fields of trace gases such as aerosol, ozone and H₂O₂. Trace gas field tilts to the east while the front tilts to the west. Aerosol simulation shows that pollutants can be transported out of the boundary to altitudes of about 10 km. The stratospheric ozone is brought downwards in a tropopause fold behind of the frontal surface. The meridional gradient in trace gas (H₂O₂) can cause a complicate structure in the trace field by the meridional advection.  相似文献