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Jonsson NN, Miller RJ, Robertson JL. Critical evaluation of the modified-adult immersion test with discriminating dose bioassay for Boophilus microplus using American and Australian isolates. Vet Parasitol 2007; 146:307-15. [PMID: 17433549 DOI: 10.1016/j.vetpar.2007.02.031] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2006] [Revised: 02/23/2007] [Accepted: 02/26/2007] [Indexed: 10/23/2022]
Abstract
Similar adult immersion tests (AITs) for acaricide susceptibility of Boophilus microplus were done in Texas, USA (Muñoz strain) and in Queensland, Australia (N-strain and Ultimo isolates). Engorged adult female ticks were immersed in one of a series of dilutions of commercial acaricide in water and then incubated at room temperature for 7 days. Data on oviposition were collected 7 days after exposure to acaricide and subjected to probit analysis. For most data, we observed poor fit to the probit model. Substantial differences in both LC50 and LC99 for the susceptible strains occurred between the respective laboratories and confidence intervals for all acaricides and all strains were unacceptably wide. For amitraz, the discriminating concentration (double the LC99.9 or LC99) recommended by FAO was 0.25%, but our estimates ranged from 0.46% to 9000%. For cypermethrin, the recommended DD was 0.0050%, with our estimates ranging from 0.00022% to 0.74%. For coumaphos the recommended DD was 0.50% but our estimates ranged from 0.66% to 130%. Finally, for moxidectin, the recommended DD was 0.10%, while our estimates ranged from <0.0001% to 5.9%. The method does not provide a means to discriminate between amitraz-susceptible and -resistant, nor between cypermethrin-susceptible and -resistant B. microplus.
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Affiliation(s)
- N N Jonsson
- School of Veterinary Science, University of Queensland, Qld 4072, Australia.
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52
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Eisler MC, Magona JW, Jonsson NN, Revie CW. A low cost decision support tool for the diagnosis of endemic bovine infectious diseases in the mixed crop-livestock production system of sub-Saharan Africa. Epidemiol Infect 2006; 135:67-75. [PMID: 16740196 PMCID: PMC2870548 DOI: 10.1017/s0950268806006571] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/10/2006] [Indexed: 11/06/2022] Open
Abstract
Diagnosis and treatment of endemic infectious disease is crucial for productivity of cattle in rural sub-Saharan Africa, but shortages of trained veterinary professionals necessitate support for less well-trained cadres of animal health worker. A Delphi survey of veterinary experts provided quantitative information on key clinical signs associated with eight endemic bovine diseases, then heuristics and dendrogram analysis identified a reduced sign set to be incorporated in a diagnostic decision support tool implemented as a simple colour-banded card. One hundred and seventy disease-sign questionnaire returns were obtained from 32 veterinary research scientists and 14 veterinary practitioners. Preliminary validation of the decision support tool for 16 prototypical cases resulted in 'correct' diagnosis over 90% of the time. The card potentially serves as a training aid and aide-mémoire, and could improve the diagnostic competence of animal healthcare providers.
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Affiliation(s)
- M C Eisler
- Department of Veterinary Clinical Studies, University of Glasgow Veterinary School, Glasgow, UK.
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53
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Jonsson NN. The productivity effects of cattle tick (Boophilus microplus) infestation on cattle, with particular reference to Bos indicus cattle and their crosses. Vet Parasitol 2006; 137:1-10. [PMID: 16472920 DOI: 10.1016/j.vetpar.2006.01.010] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2005] [Revised: 01/04/2006] [Accepted: 01/10/2006] [Indexed: 10/25/2022]
Abstract
In response to uncertainty among cattle producers in Australia regarding the need to treat Bos indicus and B. indicus crossbreeds, the scientific literature relating to the productivity effects of Boophilus microplus on cattle of all breeds was reviewed. Estimates of the mean effect of each engorging tick (damage coefficient, d) were made from a simple analysis of the reported data. On average, each engorging female tick is responsible for the loss of 1.37 +/- 0.25 g bodyweight in B. taurus cattle. The comparable value for B. taurusxB. indicus cattle is 1.18 +/- 0.21 g/engorging tick. These values were not statistically significantly different, indicating that if a threshold approach to tick control were taken, then the threshold number of standard ticks would be the same regardless of cattle genotype. No studies provided useable estimates of the effect of tick infestation on pure B. indicus cattle. An economic threshold for treatment, below which acaricide application is not beneficial, can be predicted, using known values for the cost of acaricide application and the price of beef. However, the application of a threshold approach to control has not been embraced by government advisers and runs contrary to the accepted principals of strategic control programs.
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Affiliation(s)
- N N Jonsson
- School of Veterinary Science, University of Queensland, Qld 4072, Australia.
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Holdsworth PA, Kemp D, Green P, Peter RJ, De Bruin C, Jonsson NN, Letonja T, Rehbein S, Vercruysse J. World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) guidelines for evaluating the efficacy of acaricides against ticks (Ixodidae) on ruminants. Vet Parasitol 2006; 136:29-43. [PMID: 16377090 DOI: 10.1016/j.vetpar.2005.11.011] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
These guidelines have been prepared to assist in the planning, conduct and interpretation of studies for the assessment of the efficacy of acaricides (excluding vaccines and other bio-control agents) against single and multi-host ticks (Ixodidae) on ruminants. Information is provided on the selection of animals, dose determination, dose confirmation and field studies, record keeping and result interpretation. The use of pen facilities is advocated for dose determination and confirmation studies for defining therapeutic and persistent efficacy. A minimum of two studies per tick species for which claims are sought is recommended for each dose determination and dose confirmation investigation. If dose confirmation studies demonstrate greater than 95% efficacy the sponsor may proceed to field studies, where a minimum of two studies per geographical location is preferred to confirm the therapeutic and persistent efficacy under field conditions. If dose confirmation studies demonstrate less than 95% efficacy then longer-term field studies can be conducted over two tick seasons with a minimum of two studies per geographical location. These studies can incorporate other control methods such as tick vaccines, to demonstrate stable long-term tick management. Specific advice is also given on conducting studies with paralysis ticks. These guidelines are also intended to assist investigators on how to conduct specific experiments, to provide specific information for registration authorities involved in the decision-making process, to assist in the approval and registration of new acaricides, and to facilitate the worldwide adoption of standard procedures.
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Affiliation(s)
- P A Holdsworth
- Avcare Limited, Locked Bag 916, Canberra 2601, ACT, Australia.
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55
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Abstract
OBJECTIVE To measure haematological values of clinical significance for rusa deer and provide reference data for farmed animals. DESIGN Blood samples were collected regularly from eight male rusa deer from 14 days to 27 months old. PROCEDURE Blood samples, collected by venipuncture, were analysed within 6 hours of collection for red cell count, haemoglobin, packed cell volume, plasma glucose, white cell count and differentials. RESULTS Haemoglobin concentrations appeared to increase with age and ranged from 6.0 to 20.9 g/dL. Packed cell volume and plasma glucose concentration did not appear to vary with age. White cell counts ranged from 6.3 to 7.0 x 10(9)/L and differential counts indicated neutrophils > lymphocytes > monocytes > eosinophils > basophils. In general, the values for packed cell volume, red cell count, mean cell volumes and mean cell haemoglobin concentrations were within ranges previously reported for captive or sedated rusa deer. CONCLUSIONS Physical restraint and resultant stress was sufficient to generate some of the effects previously reported for physically immobilised or agitated deer. The values reported here do not differ greatly from those previously reported for rusa deer and can be used as reference values for clinically healthy young farmed male rusa deer.
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Affiliation(s)
- N W Tomkins
- School of Veterinary Science, University of Queensland, Brisbane, Queensland 4072.
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56
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Alfredo AAN, Jonsson NN, Finch TM, Neves L, Molloy JB, Jorgensen WK. Serological Survey of Babesia bovis and Anaplasma marginale in cattle in Tete Province, Mozambique. Trop Anim Health Prod 2005; 37:121-31. [PMID: 15742867 DOI: 10.1023/b:trop.0000048513.80797.97] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A serological survey of bovine babesiosis and anaplasmosis in communal cattle was conducted in the northwestern province of Tete, Mozambique. Blood was collected from cattle ranging from 4 to 15 months old from randomly selected farms from six districts. Thirty-nine per cent of all 478 calves tested in Tete Province were seropositive to the ELISA for Babesia bovis antibodies and 63% of all calves were seropositive in the card agglutination test for Anaplasma marginale. Seroprevalence of B. bovis ranged from 22.8% in Tete City District to 48.1% in Angonia District. For A. marginale, it ranged from 34.4% in Angonia District to 87.3% in Moatize District. The dominant factor affecting seroprevalence for both haemoparasites was district and there was a trend for higher intensity of tick control to be associated with a higher seroprevalence of B. bovis and a lower seroprevalence of A. marginale. The obvious differences were the low prevalence of B. bovis in Tete City Council District and the low prevalence of A. marginale in Angonia District. The levels of exposure to B. bovis seen in our study are well below any that could be considered to be consistent with endemic stability, yet they are sufficiently high to ensure that clinical disease would be a risk. The seroprevalence of A. marginale, however, suggests that endemic stability with respect to this disease could exist in districts other than Angonia. There was no strong and consistent relationship between the intensity of control and the likelihood of seropositivity to either of the diseases.
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Affiliation(s)
- A A N Alfredo
- School of Veterinary Science, University of Queensland, Queensland 4072, Australia
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57
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Magona JW, Walubengo J, Anderson I, Olaho-Mukani W, Jonsson NN, Eisler MC. Portable haemoglobinometers and their potential for penside detection of anaemia in bovine disease diagnosis: a comparative evaluation. Vet J 2004; 168:343-8. [PMID: 15501154 DOI: 10.1016/j.tvjl.2003.10.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/24/2003] [Indexed: 10/26/2022]
Affiliation(s)
- J W Magona
- Department of Veterinary Clinical Studies, University of Glasgow Veterinary School, Bearsden Road, Glasgow G61 1QH, UK.
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58
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Foil LD, Coleman P, Eisler M, Fragoso-Sanchez H, Garcia-Vazquez Z, Guerrero FD, Jonsson NN, Langstaff IG, Li AY, Machila N, Miller RJ, Morton J, Pruett JH, Torr S. Factors that influence the prevalence of acaricide resistance and tick-borne diseases. Vet Parasitol 2004; 125:163-81. [PMID: 15476966 DOI: 10.1016/j.vetpar.2004.05.012] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
This manuscript provides a summary of the results presented at a symposium organized to accumulate information on factors that influence the prevalence of acaricide resistance and tick-borne diseases. This symposium was part of the 19th International Conference of the World Association for the Advancement of Veterinary Parasitology (WAAVP), held in New Orleans, LA, USA, during August 10-14, 2003. Populations of southern cattle ticks, Boophilus microplus, from Mexico have developed resistance to many classes of acaricide including chlorinated hydrocarbons (DDT), pyrethroids, organophosphates, and formamidines (amitraz). Target site mutations are the most common resistance mechanism observed, but there are examples of metabolic mechanisms. In many pyrethroid resistant strains, a single target site mutation on the Na(+) channel confers very high resistance (resistance ratios: >1000x) to both DDT and all pyrethroid acaricides. Acetylcholine esterase affinity for OPs is changed in resistant tick populations. A second mechanism of OP resistance is linked to cytochrome P450 monooxygenase activity. A PCR-based assay to detect a specific sodium channel gene mutation that is associated with resistance to permethrin has been developed. This assay can be performed on individual ticks at any life stage with results available in a few hours. A number of Mexican strains of B. microplus with varying profiles of pesticide resistance have been genotyped using this test. Additionally, a specific metabolic esterase with permethrin-hydrolyzing activity, CzEst9, has been purified and its gene coding region cloned. This esterase has been associated with high resistance to permethrin in one Mexican tick population. Work is continuing to clone specific acetylcholinesterase (AChE) and carboxylesterase genes that appear to be involved in resistance to organophosphates. Our ultimate goal is the design of a battery of DNA- or ELISA-based assays capable of rapidly genotyping individual ticks to obtain a comprehensive profile of their susceptibility to various pesticides. More outbreaks of clinical bovine babesisois and anaplasmosis have been associated with the presence of synthetic pyrethroid (SP) resistance when compared to OP and amidine resistance. This may be the result of differences in the temporal and geographic patterns of resistance development to the different acaricides. If acaricide resistance develops slowly, herd immunity may not be affected. The use of pesticides for the control of pests of cattle other than ticks can affect the incidence of tick resistance and tick-borne diseases. Simple analytical models of tick- and tsetse-borne diseases suggest that reducing the abundance of ticks, by treating cattle with pyrethroids for example, can have a variety of effects on tick-borne diseases. In the worst-case scenario, the models suggest that treating cattle might not only have no impact on trypanosomosis but could increase the incidence of tick-borne disease. In the best-case, treatment could reduce the incidence of both trypanosomosis and tick-borne diseases Surveys of beef and dairy properties in Queensland for which tick resistance to amitraz was known were intended to provide a clear understanding of the economic and management consequences resistance had on their properties. Farmers continued to use amitraz as the major acaricide for tick control after the diagnosis of resistance, although it was supplemented with moxidectin (dairy farms) or fluazuron, macrocyclic lactones or cypermethrin/chlorfenvinphos.
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Affiliation(s)
- L D Foil
- Entomology Department, 402 Life Sciences Building, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA
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59
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Affiliation(s)
- N N Jonsson
- University of Queensland, Brisbane, Queensland 4072, Australia
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60
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Magona JW, Mayende JSP, Olaho-Mukani W, Coleman PG, Jonsson NN, Welburn SC, Eisler MC. A comparative study on the clinical, parasitological and molecular diagnosis of bovine trypanosomosis in Uganda. Onderstepoort J Vet Res 2003; 70:213-8. [PMID: 14621317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023] Open
Abstract
The clinical, parasitological and molecular diagnosis of bovine trypanosomosis were compared using samples from 250 zebu cattle exposed to natural trypanosome challenge in Uganda. Clinical examination, molecular and parasitological diagnoses detected 184 (73.6%), 96 (38.4%) and 36 (14.4%) as diseased, respectively. The sensitivity and specificity of clinical examination were 87.5% and 35%, and 78 % and 27 % based on molecular and parasitological diagnoses, as gold standards, respectively. Of the 33, 3, 13 and 12 parasitological-positive cattle that had Trypanosoma brucei, Trypanosoma congolense, Trypanosoma vivax or mixed infections, 78 %, 33 %, 84 % and 100 % respectively manifested clinical signs. Of the 24, 89, 12, 3, 6 and 27 cattle detected by molecular diagnosis to have mixed infections, T. brucei, T. vivax, T. congolense forest-, Savannah- and Tsavo-type, 100%, 83%, 91%, 100%, 67% and 81 % had clinical signs, respectively. In conclusion, treatment of cattle based on clinical examination may clear up to 87.5 % or 78 % of the cases that would be positive by either molecular or parasitological diagnosis, respectively. Under field conditions, in the absence of simple and portable diagnostic tools or access to laboratory facilities, veterinarians could rely on clinical diagnosis to screen and treat cases of bovine trypanosomosis presented by farmers before confirmatory diagnosis in diagnostic centres for few unclear cases is sought.
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Affiliation(s)
- J W Magona
- University of Glasgow Veterinary School, Bearsden, Glasgow, UK
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61
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Abstract
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.
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Affiliation(s)
- J N Sserugga
- School of Veterinary Science, The University of Queensland, PO Box 125, Kenmore, Queensland 4069
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62
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Affiliation(s)
- S C Armstrong
- Department of Veterinary Clinical Studies, University of Glasgow Veterinary School, Bearsden
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63
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Abstract
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.
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Affiliation(s)
- N N Jonsson
- Farm Animal Medicine and Production, University of Glasgow Veterinary School, United Kingdom
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64
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65
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Abstract
In two experiments, the milk production of 59 Holstein-Friesian cows in mid lactation was measured over 1 week before artificial infestation with 2,500 or 5,000 Boophilus microplus larvae. Host resistance, the proportion of female ticks applied but not engorging was estimated from weekly counts of engorging female ticks of 4.5-8. 0mm long. Mean host resistance was 79 and 67% in two experiments. Host resistance was not significantly related to milk yield before infestation, to early pregnancy, or to parity. Culling the 10% of cattle with the least resistance to ticks would result in removal of 19-21% of ticks in a herd. The results suggest that selection to improve the existing low levels of resistance to B. microplus might be undertaken without compromising milk production. However, low levels of resistance among the cattle studied and difficulties in assessment of resistance are likely to limit the usefulness of selection within the Holstein-Friesian breed.
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Affiliation(s)
- N N Jonsson
- Department of Primary Industries, Queensland, Australian Tropical Dairy Institute, Mutdapilly Research Station, Brisbane, Australia.
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66
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Jonsson NN, Matschoss AL, Pepper P, Green PE, Albrecht MS, Hungerford J, Ansell J. Evaluation of tickGARD(PLUS), a novel vaccine against Boophilus microplus, in lactating Holstein-Friesian cows. Vet Parasitol 2000; 88:275-85. [PMID: 10714465 DOI: 10.1016/s0304-4017(99)00213-7] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The effects of vaccination with the Bm 86 vaccine TickGARD(PLUS) against infestation with cattle tick (Boophilus microplus) and of holding cattle on a feedpad until 09:00 hours after the morning milking was tested on 40 mid lactation Holstein cattle using a factorial design. Vaccination resulted in a 56% reduction in tick numbers in the field over one generation, and a 72% reduction in laboratory measures of the reproductive efficiency of ticks. The liveweight gain of vaccinated cattle over 27 weeks was 18.6 kg higher than that of controls, and vaccinated cattle tended to have lower somatic cell count in milk (SCC). There were no other significant differences in measures of production. Cattle kept on the feedpad after the morning milking carried 26% more ticks than those returned immediately to their paddocks.
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Affiliation(s)
- N N Jonsson
- Department of Primary Industries, Queensland Australian Tropical Dairy Institute, Mutdapilly Research Station, Peak Crossing.
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67
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Abstract
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.
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Affiliation(s)
- N N Jonsson
- Department of Veterinary Clinical Studies, University of Glasgow Veterinary School, UK.
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68
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Jonsson NN, Fulkerson WJ, Pepper PM, Mcgowan MR. Effect of genetic merit and concentrate feeding on reproduction of grazing dairy cows in a subtropical environment. J Dairy Sci 1999; 82:2756-65. [PMID: 10629823 DOI: 10.3168/jds.s0022-0302(99)75532-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
This study was conducted to determine the effects of genetic merit for milk production and concentrate feeding on the intervals to the onset of postpartum cyclic ovarian activity, first insemination, and establishment of pregnancy. Other factors considered included biochemical measures of energy balance, liveweight, and measures of production. A farmlet study was conducted with two lines of cattle that differed in Australian Breeding Value by 735 L milk and 47 kg of fat plus protein that were fed 300 or 2000 kg of concentrate per cow per year in a subtropical grazing system based on ryegrass, clover, and kikuyu pasture. Milk yield was higher in cows fed 2000 kg of concentrate per cow per year (23.6 L/d) than those fed 300 kg/cow per year (18.2 L/d), and cows of medium genetic merit (19.6 L/d) produced less milk than those of high genetic merit (22.2 L/d). Plasma glucose concentration was lower in the cows of high genetic merit (3.11 mmol/L), than in the cows of medium genetic merit (3.39 mmol/L). The cumulative probabilities of ovulation, insemination, and establishment of pregnancy by any day postpartum were determined by a Weibull distribution. Medium genetic merit cows in winter were more likely to ovulate by any day postpartum than in summer and more likely than high genetic merit cows in either summer or winter. The cumulative probability of insemination was lower in primipara than multipara and in summer than in winter. Primiparous cattle had a lower cumulative probability of pregnancy by any day postpartum.
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Affiliation(s)
- N N Jonsson
- New South Wales Agriculture, Wollongbar Agricultural Institute, NSW
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69
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Mayer DG, Davison TM, McGowan MR, Young BA, Matschoss AL, Hall AB, Goodwin PJ, Jonsson NN, Gaughan JB. Extent and economic effect of heat loads on dairy cattle production in Australia. Aust Vet J 1999; 77:804-8. [PMID: 10685183 DOI: 10.1111/j.1751-0813.1999.tb12950.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To investigate the extent of heat load problems, caused by the combination of excessive temperature and humidity, in Holstein-Friesian cows in Australia. Also, to outline how milk production losses and consequent costs from this can be estimated and minimised. PROCEDURES Long-term meteorological data for Australia were analysed to determine the distribution of hot conditions over space and time. Fifteen dairy production regions were identified for higher-resolution data analysis. Both the raw meteorological data and their integration into a temperature-humidity thermal index were compiled onto a computer program. This mapping software displays the distribution of climatic patterns, both Australia-wide and within the selected dairying regions. Graphical displays of the variation in historical records for 200 locations in the 15 dairying regions are also available. As a separate study, production data from research stations, on-farm trials and milk factory records were statistically analysed and correlated with the climatic indices, to estimate production losses due to hot conditions. RESULTS Both milk yields and milk constituents declined with increases in the temperature-humidity index. The onset and rate of this decline are dependent on a number of factors, including location, level of production, adaptation, and management regime. These results have been integrated into a farm-level economic analysis for managers of dairy properties. CONCLUSION By considering the historical patterns of hot conditions over time and space, along with expected production losses, managers of dairy farms can now conduct an economic evaluation of investment strategies to alleviate heat loads. These strategies include the provision of sprinklers, shade structures, or combinations of these.
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Affiliation(s)
- D G Mayer
- Queensland Beef Industry Institute, Department of Primary Industries
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70
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Jonsson NN, Mayer DG. Estimation of the effects of buffalo fly (Haematobia irritans exigua) on the milk production of dairy cattle based on a meta-analysis of literature data. Med Vet Entomol 1999; 13:372-376. [PMID: 10608225 DOI: 10.1046/j.1365-2915.1999.00179.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Published reports on the effect of buffalo fly Haematobia irritans exigua De Meijere (Diptera: Muscidae) and the closely related horn fly (H. irritans) were examined and analysed using non-linear weighted regression techniques in an attempt to establish the relationship between daily production loss (D), average number of parasites (n) and the average damage per parasite per day (d), and to provide estimates of expected losses in milk yield (MYD) and live-weight gain (LWG) in dairy cattle. A Mitscherlich three-parameter model was used to explain the relationship between the total loss of production attributable to buffalo flies and the average number of flies associated with cattle. This model was significant (P<0.01), with R2 = 20.2% and predicted a threshold number of flies (n = 30) below which no adverse effects would be noted. At a moderate level of infestation (n = 200) dMYD was 2.6 ml/fly/day and dLWG was 0.14 g/fly/day, resulting in estimated daily losses in milk yield (D(MYD)) and live-weight gain (D(LWG)) of 520 ml and 28 g, respectively.
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Affiliation(s)
- N N Jonsson
- Australian Tropical Dairy Institute, Queensland.
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Abstract
OBJECTIVE To determine practices for the control of cattle ticks on dairy farms in Queensland, the attitudes of farmers to tick infestations and to identify opportunities for and barriers against the introduction of non-chemical methods of tick control. DESIGN A survey of 199 dairy farmers from tick-infested parts of Queensland was undertaken by 20 dairy advisers and stock inspectors from October 1996 to June 1997. The sample was a proportional, random selection of dairy farms from four regions. A personal interview was conducted with each farmer and answers to 134 questions were obtained. RESULTS AND CONCLUSIONS Most farmers were not concerned by cattle ticks on their own farms, although they believed that ticks are important to the dairy industry. They were most concerned about the development of chemical resistance by cattle ticks. Inadequate facilities and lack of motivation appeared to be the factors most limiting to improving the methods of control. Most farmers claimed to have only small numbers of ticks at worst. Although a control program recommended by the Queensland Dairyfarmers' Organisation was well regarded by farmers, few had adopted it. Many farmers saw no need to implement a strategic control program.
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Affiliation(s)
- N N Jonsson
- Department of Primary Industries, Australian Tropical Dairy Institute, Queensland
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Jonsson NN, Mayer DG, Matschoss AL, Green PE, Ansell J. Production effects of cattle tick (Boophilus microplus) infestation of high yielding dairy cows. Vet Parasitol 1998; 78:65-77. [PMID: 9703620 DOI: 10.1016/s0304-4017(98)00118-6] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Forty mid-lactation Holstein-Friesian cows, 100% lot fed, were assigned to four groups for 15 weeks. Two groups of 10 cows were infested each week with a gradually increasing number of Boophilus microplus larvae, while the other two groups were maintained free of ticks. Milk yield and composition (including somatic cell count, SCC), liveweight, dry matter intake, packed cell volume (PCV) and total plasma protein (TPP) were measured throughout the 15 week period. By week 15, control cows produced 2.86 l more milk and 0.14 kg more butterfat each day and had gained 10.6 kg more liveweight than infested cows. Each engorging female tick was estimated to be responsible for the loss of 8.9 ml of daily mild production and 1.0 g of bodyweight over the trial period. Milk composition, PCV and TPP were not significantly affected by cattle tick infestation. The dry matter intake of control cows was 0.83 kg greater than infested cows in week 12.
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Affiliation(s)
- N N Jonsson
- Department of Primary Industries, Australian Tropical Dairy Institute, Mutdapilly Research Station, Australia
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Jonsson NN, Daniel RC, Mayer D, Verrall R. Effects of oral dosing with calcium propionate on total calcium and glucose concentrations in the plasma of the cow. Zentralbl Veterinarmed A 1998; 45:127-36. [PMID: 9673568 DOI: 10.1111/j.1439-0442.1998.tb00808.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This study aimed to determine the effect of oral drenching with molasses, calcium propionate and MgO on plasma glucose and calcium concentrations of dairy cows. Four trials were undertaken, each using three lactating and three non-lactating Jersey cows. In Trial 1, the effect of drenching with 200 ml molasses was measured. Trial 2 measured the effect of a single treatment with 349 g calcium propionate in 200 ml molasses. In Trial 3, the effect of 60 g MgO in molasses alone and in combination with calcium propionate was measured. Trial 4 tested the effect of repeating treatments with 349 g calcium propionate in 200 ml molasses 24 h apart. Dosing with 349 g calcium propionate in molasses increased plasma total calcium (Catot) concentration by 10% in lactating and non-lactating cows for periods less than 7 h, and this was not augmented by simultaneous administration of MgO or treatment 24 h earlier with 349 g calcium propionate in molasses. Treatment with 200 ml molasses alone resulted in increased plasma Catot of 7%. Plasma glucose concentrations were elevated by 11% for less than 3 h after treatment with calcium propionate. For the prevention of subclinical hypocalcaemia and ketosis in early lactation, drenching with calcium propionate solutions is unlikely to be of value due to the short duration of its effects, but the inclusion of calcium propionate in the postpartum ration deserves further investigation.
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Affiliation(s)
- N N Jonsson
- Australian Tropical Dairy Institute, School of Veterinary Science, University of Queensland, Australia
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Affiliation(s)
- N N Jonsson
- Department of Primary Industries, Australian Tropical Dairy Institute, Mutdapilly Research Station, Peak Crossing, Queensland
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Abstract
On the basis of clinical signs and histological findings eight 9-month-old male rusa deer (Cervus timorensis) were diagnosed with sheep associated-malignant catarrhal fever. Following a variable course involving rectal temperatures around 40.5 degrees C, depression, inappetence, diarrhoea, corneal opacity and hypopyon all animals died or were euthanased over a 5-week period. Severe multifocal vasculitis, mainly periglomerular and in the arcuate vessels were consistent histological findings which in the past have been adequate to confirm clinical diagnosis of sheep associated-malignant catarrhal fever. A nested polymerase chain reaction test has been used to detect a sheep associated-malignant catarrhal fever PRC product, 238 base-pairs in size, in DNA extracted from lymphocyte preparations. The result supported the diagnosis of sheep associated-malignant catarrhal fever in these deer.
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Affiliation(s)
- N W Tomkins
- Division of Farm Animal Medicine and Production, University of Queensland
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Jonsson NN, McGowan MR, McGuigan K, Davison TM, Hussain AM, Kafi M, Matschoss A. Relationships among calving season, heat load, energy balance and postpartum ovulation of dairy cows in a subtropical environment. Anim Reprod Sci 1997; 47:315-26. [PMID: 9360770 DOI: 10.1016/s0378-4320(97)00014-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The study was designed to examine the relationships among calving season, energy balance, temperature humidity index (THI), and postpartum ovulation in high producing cows in a subtropical environment. Holstein cows calving in a feedlot dairy in southeast Queensland during winter (n = 23) and summer (n = 21) were monitored during the first 9 weeks of lactation. Cows were weighed and blood samples collected twice weekly: plasma progesterone, plasma metabolites related to energy and mineral balance, and haematological measurements were performed. Milk production was measured, body condition score was estimated, and trans-rectal ultrasound examinations of the ovaries were each undertaken once a week. The interval between calving and first ovulation was significantly longer in cows calving in summer (22.8 vs. 17.6 days, P < 0.05). Interval from calving to the first postpartum ovulation (FOVL) was inversely related to the mean plasma glucose concentration for the first 9 weeks after calving (GLU): FOVL = 80.0-17.9GLU, (R2 = 0.25, P < 0.001). Plasma progesterone concentration during the life of the second corpus luteum after calving was negatively correlated with THI during the first 2 weeks after calving (r = 0.55, P < 0.001). Plasma glucose concentration (GLU) was negatively correlated with milk yield (MYD) and rectal temperature (RT), and positively correlated with plasma calcium concentration (Ca) according to the following regression equation. GLU = 33.1 - 0.02MYD + 0.91Ca - 0.48RT, (R2 = 0.58, P = 0.0001).
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Affiliation(s)
- N N Jonsson
- Department of Farm Animal Medicine and Production, University of Queensland, St Lucia, Australia
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Abstract
The objectives of the study were to use sheep as a model to determine whether a reduction in plasma calcium concentration similar to that observed during periods of postpartum subclinical hypocalcaemia in lactating dairy cattle might affect the blood flow to the ovaries. Different levels of hypocalcaemia were induced in each of six, non-pregnant sheep by the slow intravenous infusion of Na2-EDTA. Measurements of blood flow to the ovaries were made before and after the induction of hypocalcaemia, using 113Sn and 46Sc radiolabelled microspheres. As plasma ionized calcium was reduced, there was a significant decline in ovarian blood flow. Ovarian blood flow (percentage of resting) = 0.54 Ca++ (percentage of resting) + 58.4. This model was significant at P < 0.01, with R2 = 0.92. Accordingly, a reduction in plasma ionized calcium of 50% would yield a reduction in ovarian blood flow of 16%.
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Affiliation(s)
- N N Jonsson
- Department of Farm Animal Medicine and Production, University of Queensland, St Lucia, Australia
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Affiliation(s)
- N N Jonsson
- Department of Farm Animal Medicine and Production, University of Queensland
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Jonsson NN. Reduction and repair of colonic intussusception in a wapiti/red hybrid hind (Cervus elaphus). Aust Vet J 1995; 72:471-2. [PMID: 8825316 DOI: 10.1111/j.1751-0813.1995.tb03494.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- N N Jonsson
- Department of Farm Animal Medicine and Production, University of Queensland, Pinjarra Hills
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