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1.
OBJECTIVES: To compare the features of farms on which the exposure of young cattle to tick fever organisms is sufficient to ensure that immunity is high and the risk of clinical disease is low (endemic stability) with those of farms on which exposure is insufficient to induce widespread immunity (hence without endemic stability); to examine the relationships between the management of ticks and tick fever, and endemic stability to Babesia bovis, B. bigemina and Anaplasma marginale. DESIGN: Cross-sectional study of 874 cattle between the ages of 6 and 15 months on 64 dairy farms, from three centres in south-eastern Queensland (Mutdapilly, Dayboro and Kenilworth) and one centre in far-north Queensland (Malanda). PROCEDURE: Blood samples collected from between 5 and 20 calves from each farm were submitted for serological assay to determine exposure to B. bovis, B. bigemina and A. marginale. A questionnaire about the farm characteristics and the management of ticks and tick fever was completed with each farmer. RESULTS: On 73% of farms, confirmed clinical cases of tick fever were recalled by the farmer, indicating that tick fever was a threat on most farms. The majority of herds in the study (54 of 64) did not have sufficient numbers of seropositive animals aged between 6 and 15 months to have a low risk of tick fever. Region had an effect on the likelihood of endemic stability for all tick fever organisms. Cattle near Malanda in Far-north Queensland were more likely to be seropositive to B. bovis and B. bigemina. The method, strategy and intensity of tick control were not related to the likelihood of endemic stability when the effect of region was considered. The decision to leave a few ticks on cattle in an effort to induce endemic stability did increase the likelihood of endemic stability to A. marginale. However, in practical terms, it was ineffective, because only 26% of these farms had endemic stability against all three organisms. CONCLUSIONS: Given the low proportion of farms that have endemic stability to the tick fever organisms and the high likelihood of clinical disease, vaccination is recommended to protect dairy cattle from tick fever throughout the tick infested area of Queensland. However, further work is required to determine the economic value of vaccination, taking into account the costs of vaccination, of outbreaks and the protective value of vaccination. 相似文献
2.
Ogden NH Swai E Beauchamp G Karimuribo E Fitzpatrick JL Bryant MJ Kambarage D French NP 《Preventive veterinary medicine》2005,67(2-3):157-170
A cross-sectional study was conducted in Tanga and Iringa regions of Tanzania, and a longitudinal study in Tanga, to investigate tick-control methods and other factors influencing tick attachment to the cattle of smallholder dairy farms. Most farmers reported applying acaricides at intervals of 1-2 weeks, most used acaricides that require on-farm dilution and most farmers incorrectly diluted the acaricides. Rhipicephalus appendiculatus and Boophilus spp. ticks were those most-frequently encountered on the cattle, but few cattle carried ticks of any species (only 13 and 4.6% of tick counts of the cattle yielded adult R. appendiculatus and Boophilus spp., respectively). Animals were more likely to carry one or more adult Boophilus spp. ticks if they also carried one or more R. appendiculatus adults (OR=14.4, CI=9.2, 22.5). The use of pour-on acaricides was associated with lower odds that animals carried a R. appendiculatus tick (OR=0.29, CI=0.18, 0.49) but higher odds that they carried a Boophilus spp. tick (OR=2.48, CI=1.55, 3.97). Animals >4 months old and those with a recent history of grazing had higher odds of carrying either a R. appendiculatus (ORs=3.41 and 2.58, CIs=2.34, 4.98 and 1.80, 3.71), or a Boophilus spp. tick (ORs=5.70 and 2.18, CIs=2.34, 4.98 and 1.49. 3.25), but zero-grazing management did not prevent ticks attaching to cattle even when combined with high-frequency acaricide treatments. The odds that animals carried ticks varied amongst the agro-ecological zones (AEZs) and administrative districts where the farms were situated-but there was still considerable residual variation in tick infestation at the farm level. 相似文献
3.
OBJECTIVE: To establish the cost to the Queensland dairy industry of cattle tick infestation and its control, excluding the costs incurred from control measures directed specifically at tick fever and morbidity and mortality arising from tick fever. STUDY DESIGN: Economic models are described that have been based on empirical data relating to liveweight and milk yield loss, and on a survey of control practices and tick infestation. The first two models were designed to estimate costs of control and losses resulting from tick infestation on a single dairy farm. The third model developed estimates of the cost of tick infestation for each of four regions within the tick-infested area of Queensland. RESULTS: The overall cost to the Queensland dairy industry of the cattle tick (excluding the costs associated specifically with tick fever) and based on 1998 management practices, was $4,096,000 per annum. About 49% of this cost was related to the costs of control and 51% to losses in production. CONCLUSION: Cattle tick infestation represents a significant impost on dairy producers in Queensland, and although the actual cost will change as deregulation results in economic changes in the industry, infestations of ticks will continue to be expensive to control. 相似文献
4.
A case control study was carried out within a cross-sectional survey designed to investigate the management by Queensland dairy farmers of the cattle tick Boophilus microplus. Although 199 farmers were surveyed, data on acaricide resistance were only obtained from 66 farms. Multiple models were used to predict the probability of acaricide resistance associated with 30 putative risk factors. The region of the state in which the farm was located and the frequency of acaricide application were consistently associated with acaricide resistance. The risk of resistance to all synthetic pyrethroids (Parkhurst strain) was highest in Central Queensland and increased when more than five applications of acaricide were made in the previous year, when spray races were used and when buffalo fly treatments with a synthetic pyrethroid were applied frequently. The probability of resistance to amitraz (Ulam strain) was highest in Central Queensland, increased when more than five applications of acaricide were made in the previous year, and decreased on farms when a hand-spray apparatus was used to apply acaricides to cattle. The probability of resistance to flumethrin (Lamington strain) was highest in the Wide Bay-Burnett region. 相似文献
5.
KF TRUEMAN RJ THOMAS AR MACKENZIE LE EAVES PF DUFFY 《Australian veterinary journal》1996,74(5):367-369
Objective: To investigate the presence of Salmonella Dublin in Queensland cattle.
Design: An epidemiological study using diagnostic laboratory information and farm records.
Procedure: Outbreaks of gastroenteritis or pneumonia in calves, and abortions and enteritis in cows were routinely investigated for the presence of salmonellae. Where S Dublin was isolated, attempts were made to gather further epidemiological information.
Results: Prior to 1983 only two outbreaks of S Dublin have been recorded in Queensland dairy cattle. In 1983 S Dublin abortions were diagnosed in dairy heifers introduced from southern Australia to south-east Queensland. Sampling indicated that at least 10% of the 500 introduced heifers were faecal excretors of S Dublin. On 3 of the 7 farms from which S Dublin was recorded, infection spread to other cattle that were in contact. From February 1985 to February 1996, 29 outbreaks of S Dublin in cattle occurred on 29 farms (28 in south east Queensland and 1 in north Queensland). Calves were primarily affected. Continuing outbreaks were confirmed on only 4 of these 29 farms. On 15 farms S Dublin infections were associated with the purchase of infected calves or cows, while another farm adjoined 2 previously infected farms. No source of S Dublin was evident for the other 13 farms, where histories were often inadequate.
Conclusion: There has been a marked increase in S Dublin outbreaks in Queensland dairy cattle since 1983. Introduction of S Dublin carrier and aborting dairy heifers from southern Australia, where S Dublin is not uncommon, was associated with the initial outbreaks. 相似文献
Design: An epidemiological study using diagnostic laboratory information and farm records.
Procedure: Outbreaks of gastroenteritis or pneumonia in calves, and abortions and enteritis in cows were routinely investigated for the presence of salmonellae. Where S Dublin was isolated, attempts were made to gather further epidemiological information.
Results: Prior to 1983 only two outbreaks of S Dublin have been recorded in Queensland dairy cattle. In 1983 S Dublin abortions were diagnosed in dairy heifers introduced from southern Australia to south-east Queensland. Sampling indicated that at least 10% of the 500 introduced heifers were faecal excretors of S Dublin. On 3 of the 7 farms from which S Dublin was recorded, infection spread to other cattle that were in contact. From February 1985 to February 1996, 29 outbreaks of S Dublin in cattle occurred on 29 farms (28 in south east Queensland and 1 in north Queensland). Calves were primarily affected. Continuing outbreaks were confirmed on only 4 of these 29 farms. On 15 farms S Dublin infections were associated with the purchase of infected calves or cows, while another farm adjoined 2 previously infected farms. No source of S Dublin was evident for the other 13 farms, where histories were often inadequate.
Conclusion: There has been a marked increase in S Dublin outbreaks in Queensland dairy cattle since 1983. Introduction of S Dublin carrier and aborting dairy heifers from southern Australia, where S Dublin is not uncommon, was associated with the initial outbreaks. 相似文献
6.
Boophilus microplus, even in the absence of babesiosis, is a major disease of the cattle in New Caledonia where the particular farming system associates continental European breeds and a tropical climate tempered by the Pacific Ocean. In order to have a better understanding of the factors involved in cattle tick infestation, to decrease the possible wastage and use of chemicals and to increase the lifetime of the acaricides, the veterinary authorities investigated the conditions of the chemical treatments. A survey among 148 cattle farms of the whole of New Caledonia was carried out and factors that explain the development of tick resistance and cattle infestation have been determined. From this survey, three typologies for the main characteristics of the farms have been set up, the technical practices of the farmers and the tick control measures applied by the farmers, respectively. Some variables are significantly associated with the tick resistance to deltamethrin but their contribution to the explanation model is always moderate: farms in the south, with a positive resistance gradient from east to west, absence of bush fire and membership to a cattle farmers organization. The more the farmers have intensified their breeding-male castration, weaning, heifer separation, drenching, etc.-and pasture-high stock rate, mowing, extra feeding of the cows, many paddocks, etc.-techniques, the higher was the probability for the ticks in their farm to be resistant to deltamethrin. The technical details of the acaricide treatment had a low contribution to the explanation model. However, the use of a spray generated more resistance than a dip. Furthermore, there is a negative resistance gradient when the farmers increased the treatment interval average. Considering infestation, none of the variables from the three typologies were associated with the two infestation variables (1: semi-engorged tick females and 2: other ticks) at the herd level. However, the seven studied variables-the three typologies, breed, age, body condition score and breeding status-affected significantly the two infestation variables at the cow level, but their predictive ability remained very low (R(2)<3.5%). This result-individual effect more important than herd effect on the infestation-is confirmed by the importance of the variance of the intra-farm factors (99%) when compared with inter-farm factors (1%). Cows of Charolais breed, in poor body condition, old, pregnant or lactating, and those of the farms with irrational and high pressure control of ticks are the most infested. 相似文献
7.
Worm control practices and anthelmintic usage in 177 cattle farms in Iringa district in the southern highlands of Tanzania was determined through a questionnaire survey. A total of 76 traditional, 92 small-scale dairy and 9 large-scale dairy cattle farms were included in the survey. Results indicated that 87.7% traditional, 97.8% small-scale dairy and 100% large-scale farmers relied solely on the use of anthelmintics, 2.7% traditional farmers used traditional medicines while 9.6% traditional farmers had not any form of worm control practice. Worm infection was ranked the second most important constraint of productivity in cattle in the three production systems. Most farms (57.6% traditional, 35.8% small-scale dairy, 66.7% large-scale dairy) used anthelmintics with a combination of levamisole and oxyclozanide. Benzimidazoles were used only in traditional (25.4%) and small-scale dairy (32.1%) farms while nitroxynil (Trodax) was mostly used in large-scale dairy farms (33.3%). Generally, 40% of farmers treated three or four times a year and the frequency in some farms was surprisingly high for resource poor small-scale farmers. The frequency of anthelmintic treatment was mostly the same regardless of the management system. Treatments in most farms depended on availability of money and drugs and not the epidemiology of parasites. A significant proportion (46.3%, P=0.007) of farmers especially in rural areas failed to follow their pre-planned treatment schedules due to lack of money (86%) and unavailability of drugs (6.6%). Many farmers (58.9%) had used the same type of anthelmintic for four or more consecutive years and 85.3% of them would continue with the same anthelmintic. Farmers in all management systems mostly purchased anthelmintics from private veterinary drug shops and about 43% traditional and 33.3% small-scale dairy farmers mostly in rural areas obtained anthelmintics from village extension officers. Despite the fact that all farmers were aware of worm infection and the associated signs in cattle, 42.5% had poor knowledge on the source of worm infection. Small-scale dairy farmers allowed only a 1-day withdraw period for milk regardless of the type of anthelmintic used and there was no milk and slaughter clearance in traditional farms. It was concluded from this study that worm control in Iringa faces serious constrains and that education of farmers and farm hands is not adequate. Moreover, poor quality control and high price of potent anthelmintics, few extension workers, low income and low education among farmers contributed significantly to erratic worm control practices and anthelmintic usage in peri-urban and rural areas. 相似文献
8.
Tick control methods used by resource-limited farmers and the effect of ticks on cattle in rural areas of the Eastern Cape Province,South Africa 总被引：1，自引：1，他引：0
A survey to document tick control methods used by resource-limited farmers in the control of cattle ticks in the Eastern Cape
Province of South Africa was conducted by interviewing 59 cattle farmers using structured questionnaires and general conversation.
Information collected was on external parasites of cattle, their effects and their control methods. Ticks were reported to
be a major problem causing diseases like anaplasmosis (89.8%), babesiosis (55.9%) and ehrlichiosis (16.9%), as well as wounds
that predispose to screwworm infestation, tick worry and teat damage to cows troubling farmers in their farming enterprises.
The main tick control methods were; acaricides provided by government, however 94.9% of the farmers interviewed were of the
opinion that the dip wash is not effective in killing the ticks. As a result, farmers complement the government dipping service
with their own initiatives like spraying with conventional acaricides (22%), household disinfectants such as Jeyes fluid (18.6%),
used engine oil (10.2%), chickens (5.1%), manual removal (5.1%), and pouricides (1.7%). In addition, some farmers also use
plants (6.8%), mainly the leaf of Aloe ferox and the bark of Ptaeroxylon obliquum. The study revealed ticks to be a major problem in the study area. 相似文献
9.
Relative resistance levels of cattle against tick infestations in the communal grazing area of Botshabelo in the south-eastern Free State were determined. The objective was to establish whether differences in resistance can be exploited to contribute to tick control methods used by small-scale farmers in resource-poor environments. Ten cows (Bos taurus crosses) between the ages of 18 months and four years were used and tick counts were conducted once a month over a period of 12 months to compare their total tick burdens. Tick burdens of the various animals were compared mutually as well as with the mean tick burden of the group as a whole. Tick numbers varied throughout the year on all individuals but some animals consistently tended to have either higher or lower numbers than the mean of the group. Tick burdens on cattle classified as having a relatively low resistance to tick infestations increased eleven-fold from January to June 1996 compared to a six-fold increase on cattle categorized as belonging to the high resistance group. Twenty-eight percent of the cattle in the total study group carried 50% of the ticks collected (60,079). It is recommended that farmers in the region visually assess B. decoloratus burdens, the most abundant tick species, and sell or cull the most susceptible animals first in their normal program of utilization of the animals. This should eventually result in the direct improvement of the overall tick resistance of their cattle herds. 相似文献
10.
W. J. Roulston R. H. Wharton‡ J. Nolan J. D. Kerr† J. T. Wilson P. G. Thompson Martina Schotz 《Australian veterinary journal》1981,57(8):362-371
SUMMARY: A survey was made from late 1976 to late 1977 to determine the extent of resistance to acaricides in the cattle tick Boophilus microplus in Queensland. Questionnaires and requests for samples of ticks were forwarded to more than 900 randomly selected stock owners in the tick infested area which had been divided into 4 regions, Far North, Coastal North, Coastal Central and South East. The response measured by the number of tick samples tested was 43%. The prevalence of resistance to organophosphorus (OP) compounds was highest in South East where 96% of the farms had OP-resistant ticks and 95% had the Biarra strain and lowest in Far North where 12% of the farms had OP-resistant ticks and 10% had the Biarra strain which was the predominant one in all regions. The highest percentages of the Ridgelands strain (35%) and the Tully strain (30%) occurred in Coastal North. The South East had the highest percentage of Mt Alford (30%).
Although chlorinated hydrocarbons were banned for use in control of ticks in 1962, 49% of the farms in South East had some ticks resistant to dieldrin but in Far North it was only 2%. DDT-resistant ticks, which because of cross resistance to synthetic pyrethroids will affect the future use of this group, were present on 8% of the farms in both Coastal North and Coastal Central and 3% in South East and Far North.
No resistance to the amidines, chlordimeform, chloromethiuron or amitraz was found. 相似文献
Although chlorinated hydrocarbons were banned for use in control of ticks in 1962, 49% of the farms in South East had some ticks resistant to dieldrin but in Far North it was only 2%. DDT-resistant ticks, which because of cross resistance to synthetic pyrethroids will affect the future use of this group, were present on 8% of the farms in both Coastal North and Coastal Central and 3% in South East and Far North.
No resistance to the amidines, chlordimeform, chloromethiuron or amitraz was found. 相似文献
11.
J. K. ELDER C. R. HASS † T. J. REID J. F. KEARNAN F. R. EMMERSONS § 《Australian veterinary journal》1985,62(7):218-222
Results of a survey of cattle producers in south eastern Queensland in 1982 concerning cattle tick control have been compared with those of a similar survey carried out in 1977-78. During the interval between these surveys the proportion of beef farms with tick resistant (Bos indicus infusion) cattle as the main breed had increased from 47.8% to 60.0%. Chemical control methods had improved but many producers were continuing to treat their cattle more often than necessary. Over the period there was an increase in the proportion of farms with small numbers of animals, and 30% of the farms had less than 50 cattle. 相似文献
12.
13.
Problems with the interpretation of epidemiological data in heartwater: a study on 23 farms 总被引：1，自引：0，他引：1
In an epidemiological study undertaken on 23 farms where heartwater occurs endemically, it was found that on an overall average, antibodies to Cowdria ruminantium were detected in 64.3% of the cattle, 6 adult Amblyomma hebraeum ticks were counted per animal and 7.0% of ticks were infected with the heartwater agent. It was found that the seropositivity of the animals was determined largely by the tick loads to which they were subjected and that the influence of the tick C. ruminantium infection rate was less evident. There was no parallel between the prevalence of heartwater on the farms and the immune status of the animals. In general, higher tick counts were recorded in herds where strategic tick control is practised than on farms with a total tick control programme. The method of tick control did not, however, appear to influence the immune status of the cattle, the tick infection rate, or the prevalence of heartwater. 相似文献
14.
Yawa Mandla Nyangiwe Nkululeko Jaja Ishmael Festus Kadzere Charles T. Marufu Munyaradzi Christopher 《Tropical animal health and production》2020,52(6):3005-3013
The aim of this study was to reveal communal farmer’s knowledge, attitudes and practice on ticks and tick-borne diseases affecting cattle, tick control methods used and their knowledge on acaricide resistance. A total of 160 structured questionnaires are prepared and randomly administered to cattle farmers in Sinqu and Elundini communities in the Eastern Cape Province, South Africa. Associations between the area, gender, age, employment, source of income, level of education and farming experience were statistically tested using Chi-square test. Gall sickness (63%) was the most prevailing tick-borne disease in cattle during the summer season (61%). About 59% of the farmers had no knowledge of the effect of tick-borne diseases on cattle production, and 78% of respondents reported that ticks are the major challenge to cattle farming. Pour-on (61%) was the most commonly used acaricidal treatment system with every fortnight (40%) treatment frequency during the summer season and (31%) during the winter season. Pyrethroids (73%) were the most used acaricide compounds to control ticks, and about 65% of respondents perceived to have no knowledge of the use of ethnoveterinary medicines used to control ticks. Inefficacy of acaricide (44%) and undipped animals (42%) were regarded as the major contributing factors to the increased tick population and acaricide resistance. About 85% of respondents perceived that they do not practice acaricide rotation and 88% of the respondents had no knowledge of the acaricide resistance. Within the context of this study, ticks and tick-associated diseases are perceived by these farmers as the most important disease problem their cattle face. Thus, knowledge regarding the epidemiology of ticks and tick-borne diseases is key to control strategies, and farmer training should be encouraged to achieve better control of ticks and the diseases they transmit.
相似文献15.
Two main methods are currently being used by farmers in the heartwater regions to control this disease in cattle and other stock, namely strategic control of ticks and total control of ticks. Some farmers make successful use of the latter method, particularly in areas which are marginal for the disease. Total tick control requires top managerial skills, which includes continual expert supervision, a relatively rare asset. The majority of farmers, often unintentionally, apply strategic control of ticks to control heartwater, either without or with vaccination against the disease. In this case the objective of tick control is to minimize "tick worry" without interfering too drastically with natural transmission of the disease. This method would make provision for natural immunization of young animals (a more uncertain method than vaccination) and the maintenance of immunity. In practice these methods appear to diminish deaths from heartwater appreciably, but do not protect all animals from the disease. Furthermore, they appear to be more effective in cattle than other stock. Although strategic control has an evolutionary background and considerable merit under African conditions, it is being applied in an empirical way because of paucity of information on the epidemiology of heartwater. More information on the infection rate in and infectivity of ticks (percentage of infected ticks) offer challenging research possibilities. 相似文献
16.
Rodríguez-Vivas RI Rodríguez-Arevalo F Alonso-Díaz MA Fragoso-Sanchez H Santamaria VM Rosario-Cruz R 《Preventive veterinary medicine》2006,75(3-4):280-286
Southern cattle tick, Boophilus microplus, control in the Mexican tropics is based on the application by spray, dip or pour-on of acaricides. In Mexico the first report of ticks resistant to amitraz was reported in 2002. Amitraz resistance affecting the cattle industry of Yucatan State, Mexico, has not been investigated. A cross-sectional study was carried out in order to investigate the possible association between management risk factors and the prevalence of B. microplus ticks resistant to amitraz in Yucatan, Mexico. Ninety-eight cattle farms were randomly selected and a sample of 20–30 engorged B. microplus females was collected from at least 10 cattle from each farm. Collected ticks were taken to the laboratory where the larval progeny were obtained. The modified larval immersion test was used to detect ticks resistant to amitraz. A discriminating dose of 0.0002% amitraz was used. A questionnaire was applied on each collaborating farm. For the statistical analysis a 2 × 2 contingency table was used to identify potential risk factors. The prevalence of farms with B. microplus resistant to amitraz was 19.40%. However, even though tick resistance to amitraz is a present problem there was no evidence that it was associated with the risk factors analyzed in this survey. 相似文献
17.
Objective To estimate the specificity of an absorbed enzyme-linked immuno-sorbent assay kitd for Johne's disease (JD) when used in mature cattle populations resident in northern Australia.
Design Blood samples were collected from beef cattle in northern Queensland, the Northern Territory and northern Western Australia, and from dairy cattle in northern Queensland. The specificity of a serological test for JD was estimated by testing the blood samples with an absorbed ELISA kit. Further samples were collected from cattle with positive ELISA results to determine the presence or absence of infection with Mycobacterium avium subsp paratuberculosis .
Procedure During 1995 and 1996, blood, tissue and gut contents were collected from beef cattle at abattoirs in Queensland and the Northern Territory; and blood and faecal samples were collected from dairy cattle in herds assessed to be most at risk for JD in northern Queensland. The blood samples were tested using an absorbed ELISA kit. Tissues and gut contents from beef cattle that had positive ELISA results were cultured for M avium subsp paratuberculosis , and tissues were examined histo-logically. Faecal samples from dairy cattle with positive ELISA results were cultured for M avium subsp paratuberculosis .
Results Estimates of specificity for this absorbed ELISA in mature northern Australian cattle were 98.0% (97.0 to 98.8%, 95% CI) in beef cattle, and 98.3% (96.7 to 99.3%, 95% CI) in dairy cattle.
Conclusion Estimates of specificity in this study were lower for beef cattle from the Northern Territory and northern Western Australia and for dairy cattle from northern Queensland than those quoted from studies on cattle in southern Western Australia. This should be considered when serological testing using the JD ELISA is carried out on northern Australian cattle. 相似文献
Design Blood samples were collected from beef cattle in northern Queensland, the Northern Territory and northern Western Australia, and from dairy cattle in northern Queensland. The specificity of a serological test for JD was estimated by testing the blood samples with an absorbed ELISA kit. Further samples were collected from cattle with positive ELISA results to determine the presence or absence of infection with Mycobacterium avium subsp paratuberculosis .
Procedure During 1995 and 1996, blood, tissue and gut contents were collected from beef cattle at abattoirs in Queensland and the Northern Territory; and blood and faecal samples were collected from dairy cattle in herds assessed to be most at risk for JD in northern Queensland. The blood samples were tested using an absorbed ELISA kit. Tissues and gut contents from beef cattle that had positive ELISA results were cultured for M avium subsp paratuberculosis , and tissues were examined histo-logically. Faecal samples from dairy cattle with positive ELISA results were cultured for M avium subsp paratuberculosis .
Results Estimates of specificity for this absorbed ELISA in mature northern Australian cattle were 98.0% (97.0 to 98.8%, 95% CI) in beef cattle, and 98.3% (96.7 to 99.3%, 95% CI) in dairy cattle.
Conclusion Estimates of specificity in this study were lower for beef cattle from the Northern Territory and northern Western Australia and for dairy cattle from northern Queensland than those quoted from studies on cattle in southern Western Australia. This should be considered when serological testing using the JD ELISA is carried out on northern Australian cattle. 相似文献
18.
Current cattle tick control practices and producer attitudes towards tick control in the eastern Cape Province of South Africa are discussed. These were ascertained from answers to a questionnaire survey to which 31.2% of farmers responded. In general, producers favoured intensive tick control. Beef and dairy farmers had a definite preference for synthetic pyrethroid acaricides, the majority followed a 25 times p.a. treatment frequency and most changed acaricides because of price. Beef producers favoured pour-on application of acaricides while the majority of dairy producers utilized plunge dipping. Producers who used hand spray techniques experienced the highest percentage of confirmed acaricide resistance. A costs of R11.27 for acaricide treatment per bovine per annum was calculated from data gained in this survey. A cost index of 2,496 was calculated by relating acaricide cost to the prevailing price of beef in the region. Only a small number of producers used heartwater, babesiosis and anaplasmosis vaccines. Relative tick borne disease mortality ratios indicated higher heartwater mortalities at high acaricide treatment frequencies. These results are discussed in relation to the tick control regimes practised. 相似文献
19.
Knopf L Komoin-Oka C Betschart B Jongejan F Gottstein B Zinsstag J 《Preventive veterinary medicine》2002,53(1-2):21-30
In the Central Guinea savannah of C?te d'Ivoire, cattle breeding started only approximately 30 years ago. The impact of parasitism on the overall health status and productivity of the trypanotolerant N'Dama cattle in this area is unknown. In close collaboration with national veterinary institutions and local farmers, we studied spectrum, burden and seasonal dynamics of ticks (including aspects of cowdriosis) on N'Dama village cattle. In a longitudinal study, three randomly selected cattle herds (traditional farming type) of one village were examined repeatedly for ticks. Spectrum, burden, seasonal epidemiology of ticks were assessed. In these traditional herds (which lack (ecto)parasite management), all animals were infested by ticks at monthly counts. Five different tick species were identified; the four genera in order of frequency were: Amblyomma (overall prevalence 96%), Boophilus (47%), Hyalomma (<1%) and Rhipicephalus (<1%). Amblyomma variegatum was the most-abundant tick on cattle in all seasons. Seroprevalence of Cowdria ruminantium was 31% (95% CI: 26, 36%). Most of the animals typically carried low tick burdens. N'Dama cattle seem well adapted to their environment and can resist the tick burdens under this traditional farming system. 相似文献
20.
A A Latif T Hove G K Kanhai S Masaka 《The Onderstepoort journal of veterinary research》2001,68(3):203-208
The Theileria parva carrier-state in cattle on commercial farms on Zimbabwe was investigated using parasitological and serological methods. The proportion of cattle showing Theileria piroplasms on two farms, which had recent histories of disease outbreaks, were 64% (n = 106, total of heifers and weaned calves examined) and 71.5% (n = 60) while the proportion of T. parva antibodies for the same animals were 59% and 98.5%, respectively. On four farms where no cases of the disease occurred for over 10 years, the average proportion of animals showing piroplasms and antibodies were 55.4% (range 32-82, n = 223) and 73% (range 47-91, n = 223), respectively. However, on another three farms which had no history of theileriosis outbreaks these proportions were very low, being 11.4% (0-24, n = 157) for piroplasms and 12.2% (5-23, n = 157) for antibodies. The mean infection rate in unfed Rhipicephalus appendiculatus adults collected from farms with a high prevalence of cattle which were carriers of Theileria piroplasms during the tick activity season was 29% (range 12-60%) with 9.3 (range 2-18.7) mean infected acini per infected tick. The infectivity of different tick batches to susceptible cattle produced a wide spectrum of theileriosis reactions. Laboratory controlled experiments were carried out to study the persistence of T. parva (Boleni) piroplasms in cattle immunized with this strain as well as its infectivity for ticks and its subsequent transmissibility to cattle. Examination of the salivary glands of 15 batches of ticks collected from six immunized cattle on three different occasions over 18 months showed that none were infected with Theileria parasites. However, the infectivity of other ticks in the same batches to susceptible animals was demonstrated 6, 10 and 18 months after cattle had been immunized with Boleni stabilate. 相似文献