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1.
Banda LJ Kamwanja LA Chagunda MG Ashworth CJ Roberts DJ 《Tropical animal health and production》2012,44(4):715-727
A review of the smallholder dairy production in Malawi was conducted using livestock annual reports and other literature that
was supplemented with primary data from a baseline survey conducted in December 2009. Smallholder dairy farming in Malawi
operates with support from institutions that facilitate access to initial stock and dairy production technologies. Most farmers
(94%) keep the animals in pens where feed is provided throughout the year. Results indicated unsatisfactory feeding, housing
and health management practices, which negatively impact cow fertility. Dairy population trends suggest low replacement rates,
which could be associated to low cow fertility and inadequate management skills. There are challenges related to access to
breeding and health services, which further contribute to low productivity. Low fertility is evidenced by low calving rates
(22–61%) and long calving interval (405–549 days). Existence of programmes on farmer capacity building provides an opportunity
for improved management skills and cow productivity. It is concluded that dairy cow management and fertility have challenges
and opportunities that are influenced by the extent to which farmers have access to important services such as extension,
health, breeding and finance. 相似文献
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As in other sub-Saharan African countries, purebred dairy genetics such as Holsteins were imported to Malawi. The study investigated their economic performance by comparing them with local Zebu-crossbreds based on 131 smallholder dairy farm observations from Southern Malawi. High-yielding purebred cows and crossbred cows showed no significant differences in lactation yield and calving interval. Looking at the farms’ actual costs, by-products such as maize bran clearly dominated the cost structure for both breeds, but crossbreeds showed significantly lower concentrate costs. While there was no statistically significant difference in income for both breed types, a substantial share (23%) of farms under investigation shows negative incomes. Based on survey data, two typical farms were established representing standard costs with homogenous assumptions such as identical milk price. The comparison of typical farms covering the full dairy system clearly indicated that crossbred dairy cows outperformed purebreds. In addition, a simulation of a shorter calving interval for both typical farms revealed a substantial positive impact on income for both breed types with more than 30% increase. We conclude that focusing on crossbreds in combination with improved feeding and fertility management offers a more promising strategy for smallholder dairy farms in Southern Malawi than just acquiring high-yielding purebreds. 相似文献
4.
J. A. Lawrence F. L. Musisi M. W. Mfitilodze K. Tjornehoj A. P. Whiteland P. T. Kafuwa K. E. Chamambala 《Tropical animal health and production》1996,28(4):280-288
Summary Crossbred dairy heifers on a farm in an East Coast fever (ECF) endemic area in Malawi were immunised againstTheileria parva, Anaplasma spp.,Babesia bigemina, Babesia bovis andCowdria ruminantium. They were treated at infrequent intervals with chlorfenvinphos to limit infestation with adult ticks, without providing complete tick control. In one trial, which tested a threshold dipping regimen, 20 heifers were dipped only once in 6 months to control a flush ofBoophilus microplus. Unimmunised controls showed serological evidence of exposure toT. parva andB. bigemina, and one died of ECF, but there were no incidents of tick-borne disease in the immunised group. In a second trial, which tested a strategic dipping regimen, 107 animals were dipped 9 times over a 6 month period. Despite heavy challenge byB. bovis and moderate challenge byB. bigemina andAnaplasma spp, demonstrated serologically, there was only a single clinical case of babesiosis. The observations provide encouragement for the introduction of integrated tick and tick-borne disease control programmes in improved cattle in ECF endemic areas.
Sistemas Integrados De Control De Garrapatas Y Enfermedades Transmitidas Por Garrapatas En Ganado Vacuno Lechero Cruzado En Malawi
Resumen Se inmunizaron terneras lecheras cruzadas frente aTheileria parva, Anaplasma spp.,Babesia bigemina, Babesia bovis yCowdria ruminantium. El experimento se realizó en una granja situada en una zona de Malawi en la que la fiebre de la costa este es endémica. Los animales se trataron de forma infrecuente con clorfenvinfos para limitar la carga de garrapatas adultas, pero no se llevó a cabo ningún programa completo de control de garrapatas. El primer ensayo tuvo como objetivo determinar la frecuencia minima de baños antigarrapata. Un total de 20 terneras recibieron un único baño a lo largo de 6 meses para controlar un aumento en la carga deBoophilus microplus. Los animales control que no habían sido inmunizados mostraron evidencia serológica de exposición aTheileria parva y uno de ellos murió de fiebre de la costa este. Sin embargo, en el grupo de animales inmunizados no se detectó ningún caso de enfermedad transmitida por garrapatas. El segundo experimento tuvo como objetivo comprobar la eficacia de un programa estratégico de baños antigarrapata. Un total de 107 animales fueron bañados 9 veces a lo largo de 6 meses. Si bien se demostró serológicamente una fuerte infestación porBabesia bovis y una infestación moderada porB. bigemina yAnaplasma spp, ningún animal enfermó de babesiosis. Estas observaciones sugieren la conveniencia de introducir programas de control integrados de garrapatas y enfermedades transmitidas por garrapatas en ganado vacuno mejorado en zonas donde la fiebre de la costa este es endémica.
Experience De Lutte Integree Contre Les Tiques Et Leurs Maladies Chez Le Betail Hybride Laitier Au Malawi
Résumé Des génisses hybrides productrices de lait furent immunisées contreTheileria parva, Anaplasma spp.Babesia bigemina, Babesia bovis etCowdria ruminantium dans une ferme située dans une région à East Coast fever (ECF). Elles furent traitées à intervalles irréguliers avec du chlorfenvinphos pour limiter l'infestation des tiques adultes, mais sans pourvoir un contrôle complet sur les tiques. Pendant une expérience, qui testa le seuil limite du lavage avec des acaricides, 20 génisses furent lavées une seule fois en 6 mois pour maîtriser l'infestation parBoophilus microplus. Les contrôles, non immunisés, montrèrent des preuves sérolôgiques d'exposition àTheileria parva etBabesia bigemina, et une genisse mourut d'ECF, mais aucun problème de maladie liée aux tiques ne fut observé dans le groupe immunisé. Lors d'une seconde expérience, testant une approche stratégique du lavage avec acaricide, 107 animaux furent lavés neuf fois en six mois. Malgré une infection importante parB. bovis et modérée parB. bigemina etAnaplasma spp., prouvée par étude sérologique, il n'y eut qu'un cas de babésiose. Les observations encouragent l'introduction de programmes de contrôle des tiques et de leurs maladies associées pour améliorer le bétail dans les zones endémiques à ECF.相似文献
5.
Whitaker DA Goodger WJ Garcia M Perera BM Wittwer F 《Preventive veterinary medicine》1999,38(2-3):119-131
Metabolic profile testing has generally been used as part of a multidisciplinary approach for dairy herds in temperate climates. Our goal was to evaluate the effectiveness of the technique for identifying constraints on productivity in small herds in environments less favorable for milk production. Metabolites tested were chosen for stability in the sample after collection of blood, ease of analysis and practical knowledge of the meaning of the results. Blood levels of five different metabolites in low-producing dairy cows belonging to smallholders in tropical and subtropical environments were measured. The study involved 13 projects with 80 cows in each, carried out in six Latin American, six Asian, and one southern European countries. Data were also collected on feeding, body condition score (BCS) and weight change, parasitism, and reproduction. In Chile, Mexico, Paraguay, Philippines, Uruguay, and Venezuela, globulin levels were high in > 17% of cows sampled on each occasion. Globulin levels were also high in Turkey and Vietnam on one or more occasions. In Paraguay, 49% of cows had high globulin levels at two to three months after calving. These results suggest that inflammatory disease was present to a potentially important degree, although this was not always investigated and not always taken into account. In all countries except Mexico and Venezuela, high beta-hydroxybutyrate (BHB) levels before calving in many cows highlighted the presence of condition loss in late pregnancy, an important potential constraint on productivity and fertility. Fewer cows showed high BHB levels in lactation, whereas change in BCS and weight was more sensitive for measuring negative energy balance. Urea concentrations were low in only small numbers of cows suggesting that dietary protein shortages were not common. Albumin values were low mainly in cows where globulin values were high and, hence, did not generally provide additional information. The exception was in China where pregnant yaks over winter had high BHB and low albumin values, suggesting that they were seriously underfed. This observation stimulated a successful nutritional intervention in the following winter. Inorganic phosphate values were within the reference range in most countries a majority of the time suggesting, contrary to expectation, that this mineral was not commonly a constraint. The use of metabolic profile testing proved valuable in drawing attention to important potential constraints on productivity in dairy cows in tropical and subtropical environments and in confirming those which were not. 相似文献
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Matope G Bhebhe E Muma JB Oloya J Madekurozwa RL Lund A Skjerve E 《Tropical animal health and production》2011,43(5):975-982
A cross-sectional study was conducted to investigate seroprevalence of brucellosis and the associated risk factors in cattle
from smallholder dairy farms in Gokwe, Marirangwe, Mushagashe, Nharira, Rusitu and Wedza areas of Zimbabwe. A total of 1,440
cattle from 203 herds were tested serially for Brucella antibodies using Rose Bengal test and the competitive ELISA. Weighted seroprevalence estimates were calculated and risk factors
in individual cattle investigated using logistic regression analysis. The overall individual animal brucellosis seroprevalence
was low, with mean of 5.6% (95% confidence interval (CI), 4.4%, 6.8%). Gokwe had the highest individual (12.6%; 95% CI, 3.9%,
21.4%) and herd-level (40.0%; 95% CI, 22.1%, 58.0%), while Wedza had the lowest individual (2.3%; 95% CI, 0%, 5.3%) and herd-level
(8.0%; 95% CI, 0.0%, 18.9%) brucellosis seroprevalence, respectively. In individual cattle, the area of origin, age and history
of abortion were independently associated with brucellosis seroprevalence. While the seroprevalence was independent of sex,
it decreased with increasing age. Cattle 2–4 years old had higher odds (odds ratio (OR) = 3.2; 95% CI, 1.1%, 9.1%) of being
seropositive compared to those >7 years. Cows with a history of abortion were more likely to be seropositive (OR = 7.9; 95%
CI, 3.1, 20.1) than controls. In conclusion, the area-to-area variation of brucellosis may be linked to ecological factors
and differences in management practices. The implementation of stamping out policy, bleeding and testing animals before movement
and promoting the use self-contained units are likely to significantly reduce the public health risks associated with Brucella infections in cattle. 相似文献
7.
Swai ES Hulsebosch J Van der Heijden W 《Journal of the South African Veterinary Association》2005,76(4):224-227
A survey to demonstrate the presence or absence of genital campylobacteriosis and trichomonosis in cross-bred breeding bulls kept under smallholding dairy farms in the Tanga region of Tanzania was carried out during the period of January-June 1996. Sheath washings, swabs and preputial scrapings were collected from 58 randomly selected bulls. Campylobacter fetus subsp. venerealis was demonstrated in 3/58 (5.1%) and Tritrichomonas foetus in 0/58 (0%) of all bulls tested. Bull-level variables of level of taurine genes (62.5% taurine genes, F2; 75% taurine genes, F3) and age were not significantly associated with campylobacteriosis (P > 0.05). The result of the study identifies Campylobacterfetus subsp. venerelias as the agent of enzootic infertility in smallholder herds and suggests that may be a significant problem. 相似文献
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K. Suzuki M. Kanameda T. Ogawa T.T.D. Nguyen T.T.S. Dang Q.H. Luu D.U. Pfeiffer 《Livestock Science》2006,101(1-3):242-250
The objective of this field questionnaire survey was to describe the productivity and socio-economic profile of dairy cattle farmers in northern Vietnam considering regional differences in rural smallholder farming communities which have been targeted by a governmental dairy development policy. Using two-stage cluster sampling, a total of 99 dairy farming households (11 per commune) were recruited from 9 of 32 communes in Ba Vi District, Ha Tay Province, northern Vietnam. The results from this study indicate that there were regional differences in relation to basic management practices such as effective utilisation of agricultural by-products for feeding and hygiene practices. These can be explained by variation amongst the regions with respect to environmental factors affecting agricultural activities such as constraints on land use and access to water resources. There were also regional differences in the use of governmental support such as agricultural extension services and financial institutions. These can be attributed to proximity of the communities to each of the extension institutions as well as the phased and community-specific approach to the provision of governmental financial support for dairy development. 相似文献
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A two-year longitudinal study was conducted to assess the reproductive and lactation performances of smallholder crossbred
dairy cattle in Fitche, central Ethiopia. Twenty-four smallholder dairy farms were monitored and data on reproductive, breeding,
lactation and management aspects of crossbred dairy cows (n = 69) were collected and analysed. Moreover, milk samples were collected and analysed for progesterone. The overall Least-squares
means for calving interval (CI), calving to conception interval (CCI) and first observed oestrus after calving were 516, 253
and 141 days, respectively. Suckling significantly prolonged these intervals. The mean first onset of luteal activity (OLA)
after calving was 52 days, while 67.4% (n = 43) had a delayed (>55 days) return to cyclicity after calving. Suckling and parity number significantly (p < 0.05) influenced the OLA. The mean lactation length was 54.4 weeks. The overall daily mean milk yield for the first 43 weeks
of lactation after calving was 11.7 L/day. The estimated daily milk yield increased slowly and reached peak (13.8 L/day) around
the 11th week post partum and declined gradually and steadily. Suckling status, season of calving and parity number significantly influenced the estimated
daily milk yield. In conclusion, the present study indicated that the smallholder crossbred dairy cows in the study area had
prolonged intervals to first oestrus after calving, to conception and to the next calving, and thus their reproductive performance
is unsatisfactory. Delayed first onset of luteal activity (postpartum anoestrus) contributed to these extended intervals.
Further detailed investigation is suggested to examine the effects of other relevant factors on the reproductive and lactation
performances of smallholder crossbred dairy cows for appropriate intervention. 相似文献
10.
Cerebellar abiotrophy in crossbred cattle 总被引:1,自引:0,他引:1
Cerebellar abiotrophy affected 9 of 74 calves sired by a Poll Hereford bull over 2 successive calving seasons. The disease was characterised by episodes of recumbency and ataxia, with hypermetria and wide base stance. Clinical signs commenced between birth and 8 months of age. Two calves which were affected first at 8 months of age recovered clinically 9 months later. Histological lesions were found in the cerebellar cortex of 7 calves and consisted of segmental degeneration and loss of Purkinje cells, and axonal swellings. The clinical signs and pathological findings were consistent with bovine familial convulsions and ataxia, which has not been described previously in Australia. The clinical signs were not attributable to the lesions observed in the cerebellum and an underlying electrophysiological abnormality is proposed. The aetiology of the condition is probably genetic and appears to have a multifactorial basis. 相似文献
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PAW HARPER 《Australian veterinary journal》1993,70(12):456-457
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Summary Information is given on crossbred calves between birth and 6 months of age belonging to 6 genetic groups—3 with 50% inheritance from Holstein, Jersey and Brown Swiss and the other 3 with 75% inheritance from 1 or 2 temperate dairy breeds.The mortality rate in 1,059 calves born was 3·87, 2·84 and 1·22% respectively under 1 month, from 1 to 3 and from 3 to 6 months of age. The mortality rate was lower in halfbreds than in crosses with 75% inheritance from temperate breeds. Season of birth, sex of the calf and birth weight did not show any significant association with mortality rate but the latter showed a definite decline with advancing age.No significant association of cause of mortality with age, genetic group and season of birth of the calves was observed. Percentage mortality was largely due to respiratory diseases in the birth to 1 month age group while diseases affecting the digestive system resulted in more deaths in the 3 to 6 months age group.
Mortalidad De Terneros En Ganado Lechero Cruzado
Resumen Se hace un informe detallado sobre terneros cruzados desde el nacimiento hasta los 6 meses de edad, pertenecientes a 6 grupos genéticos; 3 con 50% herencia de Holstein, Jersey y Pardo Suizo y de otros 3 con 75% herencia de 1 o 2 razas lecheras de áreas templadas.La tasa de mortalidad en 1,059 terneros nacidos fué de 3.87, 2.84 y 1.22% respectivamente, en animales menores de 1 mes, de 1 a 3 y de 3 a 6 meses de edad. La tasa se mortalidad fué más baja en animales media sangre, que en cruces con 75% herencia de razas lecheras de áreas templadas. La época de nacimiento, sexo del ternero y peso al nacer, no tuvo relación con la tasa de mortalidad, la cual disminuzó progresivamente con la edad. A mayor edad menos mortalidad.No se observó relación directa entre causas de mortalidad, edad, grupos genéticos y estación al nacer. El porcentaje de mortalidad fué superior en el grupo estudiado desde el nacimiento hasta el mes de edad, debido a causas respiratorias. Las enfermedades gastrointestinales causaron más mortalidad en el grupo de 3 a 6 meses.
Mortalite Des Veaux Chez Le Betail Laitier Ameliore
Résumé Les auteurs donnent des informations concernant des veaux métis entre leur naissance et l'âge de six mois appartenant à six groupes génétiques différents: trois groupes à 50 p. 100 d'Holstein, de Jersiais et de Suisse Brune et les trois autres groupes à 75 p. 100 de dominance de une à deux races laitières.Pour 1 059 veaux, le taux moyen de mortalité a été de 3,87, 2.84 et 1,22 p. 100 au-dessous de un mois d'âge, de 1 à 3 mois et de 3 à 6 mois.Le taux de mortalité a été plus bas chez les demi-sangs que chez les métis ayant 75 p. 100 de sang d'animaux de races tempérées.La saison de naissance, le sexe du veau et la poids à la naissance n'ont pas montré de relations significatives avec le taux de mortalité, mais il a été constaté par la suite que ce taux déclinait au fur et à mesure que les veaux prenaient de l'âge.Aucune association de nature significative entre les causes de mortalité avec l'âge, le groupe génétique et la saison de naissance n'a été observée.Dans le groupe des animaux de O à 1 mois d'âge ce sont les maladies respiratoires qui ont été le plus largement observées alors que ce sont les affections du système digestif qui ont causé le plus grand nombre de morts dans le groupe des animaux entre 3 et 6 mois d'âge.相似文献
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Abera M Habte T Aragaw K Asmare K Sheferaw D 《Tropical animal health and production》2012,44(6):1175-1179
A cross-sectional study was carried out from October 2008 to May 2009 in smallholder dairy farms in and around Hawassa to estimate the prevalence of mastitis, to isolate and characterize major bacterial pathogens, and to identify possible associated factors. The study involved a total of 201 milking cows randomly drawn from smallholder farms. The prevalence of clinical and subclinical mastitis was determined through clinical examination of the udder and using mastitis indicator paper (Bovivet indicator paper, Kruuse, Denmark). The prevalence of mastitis at cow and quarter level was 30.3 (61/201) and 10.3 (79/766), respectively. Subclinical mastitis was 25.4% and 5.0% was clinical. Stage of lactation significantly affected (P < 0.05) the prevalence of mastitis, with the highest prevalence observed in the late stage of lactation (41.3%) as compared to early (25.0%) and mid (22.1%) stages of lactation. Floor type and bedding had association (P < 0.05) with mastitis prevalence. Cows housed in concrete-floored houses had lower prevalence (19.0%) of mastitis compared to cows kept in soil-floored houses (47.6%). Mastitis prevalence was low in farms which do not use bedding (23.5%) as compared to farms using hay/straw bedding (37.4%). However, age, parity, and history of mastitis had no association (P > 0.05) on the prevalence of mastitis. The pathogens isolated from mastitic cows were Staphylococcus aureus (48.6%), other staphylococci species (15.7%), Streptococcus agalactiae (11.4%), other streptococci (17.1%), Bacillus species (2.9%), and coliforms (Escherichia coli and Klebsiella species) (4.3%). Strict hygienic measure of housing and bedding should be considered, in reducing the prevalence of mastitis. 相似文献
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Jelly S. Chang’a Robinson H. Mdegela Ruth Ryoba Torleiv Løken Olav Reksen 《Tropical animal health and production》2010,42(8):1669-1676
Smallholder farmers’ knowledge and practice of dairy calf management on 129 farms with calves less than 10 months of age in
Southeastern and Southern Highland areas of Tanzania was assessed. The method of study included both a farm visit and completion
of a questionnaire. Most of the farmers were female, with a primary level of education, and majority kept 1–3 milking cows
that yielded 6–10 l milk/cow/day. Most of the calves were fed milk using a residual calf suckling system. Weaning age was
3–8 months. Overall, the body condition of the calves was poor, ranged from 1 to 2.5 with a mode of 2. The majority of the
farmers believed that helminthosis was the most common disease condition affecting the calves; diarrhea was ranked as the
second. Calf death was reported by 20% of the farmers to have occurred in their herd lasting the 2 years prior to the study.
Calf body condition score was related to body weight for calves younger than 9 weeks, and older than 23 weeks of age, whereas
no such relationship existed in the age group 9 to 23 weeks. The sex distribution was skewed with less male calves being older
than 23 weeks. We hypothesize that male calves experience inferior management compared with female calves. This study demonstrates
a low level of knowledge on, and poor practices of calf management among the surveyed farmers that suggest the need for educational
intervention. 相似文献
15.
Muma JB Pandey GS Munyeme M Mumba C Mkandawire E Chimana HM 《Tropical animal health and production》2012,44(4):915-920
A cross-sectional study was performed in Southern and Lusaka provinces of Zambia between March and September 2008 to estimate
Brucella seroprevalence in cattle kept by smallholder dairy farmers (n = 185). Rose Bengal test (RBT) was used as a screening test followed by confirmation with competitive ELISA (c-ELISA). We investigated 1,323 cattle, of which 383 had a history of receiving vaccination against brucellosis and 36 had a history
of abortion. Overall seroprevalence was 6.0% with areas where vaccination was practiced having low seroprevalence. Age was
associated with Brucella seropositivity (P = 0.03) unlike cattle breed (P = 0.21) and sex (P = 0.32). At area level, there was a negative correlation (Corr. coeff = −0.74) between percentage of animals with brucellosis
vaccination history (vaccination coverage) and level of brucellosis; percentage of animals with history of abortion (Corr.
coeff. = −0.82) and brucellosis vaccination coverage. However, a positive correlation existed between brucellosis infection
levels with percentage of animals having a history of abortion (Corr. coeff. = 0.72). History of vaccination against brucellosis
was positively associated with a positive Brucella result on RBT (P = 0.004) whereby animals with history of vaccination against brucellosis were more likely to give a positive RBT test results
(OR = 1.52). However, the results of c-ELISA were independent of history of Brucella vaccination (P = 0.149) but was positively associated with history of abortion (OR = 4.12). Our results indicate a relatively low Brucella seroprevalence in cattle from smallholder dairy farmers and that vaccination was effective in reducing cases of Brucella infections and Brucella-related abortions. Human exposure to Brucella through milk from smallholder farmers could result through milk traded on the informal market since that milk is not processed
and there no quality and safety controls. 相似文献
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T Chamboko A W Mukhebi C J Callaghan T F Peter R L Kruska G F Medley S M Mahan B D Perry 《Preventive veterinary medicine》1999,39(3):191-210
As part of a series of studies associated with the development of improved vaccines for heartwater (a tick-borne disease of ruminant livestock caused by Cowdria ruminantium), field surveys were carried out to assess losses associated with the disease and the costs associated with controlling it in the two main agro-ecological zones of Zimbabwe (lowveld and highveld) where heartwater is believed to be endemic and epidemic, respectively. In each zone, a cross-sectional study was performed in the main farming systems (smallholder (SH) and large-scale commercial (LSC) beef and dairy), followed by longitudinal studies in the same sectors to improve data accuracy for some parameters. Suspected heartwater-specific mortality in cattle was similar in all LSC sectors (p = 0.72) accounting for a median 1% mortality risk. Heartwater-specific mortality in SH areas was not assessed due to poor diagnostic ability of the farmers. Few LSC farms and SH households kept sheep; suspected heartwater-specific mortality in LSC sheep was 0.8% in the lowveld and 2.4% in the highveld. Goats were a major enterprise in SH areas but not on LSC farms. Suspected heartwater mortality in LSC goats was 0.8% at one site in the highveld and 17.5% on a farm in the lowveld. Application of acaricides was the major control method for heartwater and other tick-borne diseases on both SH and LSC farms. On LSC farms, plunge dipping was used most frequently and the number of acaricide applications ranged widely between 3 and 52 per year. The total cost of acaricides per head per annum was higher in highveld dairies than in highveld and lowveld beef enterprises (p = 0.03). In SH areas, cattle plunge dipping was conducted by the government with an average frequency of 8 +/- 2 (sd) immersions per annum in both the lowveld and highveld. The type of tick control on sheep and goats in all production systems was highly variable (ranging from none to hand removal or intensive acaricide treatment). Suspected heartwater cases on LSC farms were treated with tetracyclines; treatment was not reported in SH areas. Reported treatment costs were high (median Z$ 120) and highly variable (range Z$-833). Vaccination against heartwater with the live, blood-based vaccine was reported on only one LSC farm. LSC farms applying acaricide 30 or more times per year reported higher morbidity (p < 0.0001) and mortality (p < 0.0001) than farms applying acaricides less than 30 times a year. This finding supports the use of reduced tick control in the management of heartwater in Zimbabwe. 相似文献
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