Observations on a heard of beef cattle maintained in a tsetse area

Summary Three groups of Boran cattle were maintained under different trypanocidal drug regimes for 29 months in an area of “medium” tsetse challenge. The development of immunity to trypanosomiasis in the cattle was assessed on the basis of changes in trypanocidal drug requirement, development of parasitaemia, ability to maintain normal blood values, growth and response to challenge after the withdrawal of the drugs. Observations were also made on serum antibody content by immunofluorescence and on serum immunoglobulin levels. Cattle treated with Berenil on the development of clinical disease developed a partial immunity to trypanosomiasis after two years. Cattle treated as a group with Berenil on the development of patent parasitaemia in any one animal of the group did not develop immunity. Cattle treated as a group with Samorin using the same criterion for treatment developed a degree of immunity to the disease. It was concluded that group treatment with Samorin was the most suitable of the three regimes examined for the maintenance of beef cattle in a tsetse infested area.

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Resumen Se mantuvieron tres grupos de ganado Boran durante 29 meses bajo differentes regímenes terapéuticos en un área donde la concentración de moscas tsetse era mediana. Se llevó a cabo la evaluación del desarrollo de la inmunidad contra la tripanosomiasis teniendo como base los diferentes cambios en el requerimiento de drogas, desarrollo de parasitemia, abilidad para mantener los valores sanguíneos normales, crecimiento y respuestas a la descarga de parásitos después del retiro de la terápia. Se hicieron también observaciones del nivel de anticuerpos séricos por inmunofluorescencia y se determinó el nivel de inmunoglobulinas. Los animales tratados con Berenil cuando mostraban signos clínicos de la enfermedad, desarrollaron una inmunidad parcial a la tripanosomiasis después de dos a?os. Los animales tratados en grupo con Berenil cuando se detectó parasitemia en cualquier animal del grupo no desarrollaron inmunidad. El ganado tratado con Samorin en base de grupo siguiendo el mismo criterio para el tratamiento, desarrolló cierto grado de resistencia a la enfermedad. Se concluye que el tratamiento de grupo utilizando Samorin fue el mejor de los tres regímenes estudiados para el mantenimiento de ganado de carne en un área infestada de moscas tstse.

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Résumé Trois groupes de bovins Boran ont été maintenus vingt neuf mois, sous différents traitements trypanocides, dans une zone “moyennement” infestée de tsé-tsé. Le développement de l'immunité à la trypanosomiase a été évalué à partir des changements dans les besoins en trypanocides, du développement de la parasitémie, de l'aptitude à maintenir les valuers normales du sang, de la croissance et de la réaction à l'infection après la suppression des médicaments. Des observations ont aussi été faites sur la présence d'anticorps sériques par immunofluorescence et sur les teneurs en immunoglobines sériques. Le bétail traité au Berenil à l'apparition de signes cliniques a été partiellement immunisé au bout de deux ans. Dans le groupe du bétail traité au Berenil à l'apparition d'une parasitémie évidente, aucun animal n'a présenté d'immunité. Le groupe de bovins traité au Samorin, selon les nêmes critères a été bien immunisé.

     

Maintaining zebu Maure cattle in a tsetse infested area of Mali. II. Epidemiological considerations

Summary Scheduled monitoring of tsetse and other biting flies at Tienfala Forest, Republic of Mali from December 1979 until June 1981 yielded more than 14,500 specimens. Comparisons of the monthly totals of tsetse and other biting flies with the monthly incidence of bovine trypanosomiasis in sentinel cattle suggested that biological transmission by a single riverine species of tsetse,Glossina palpalis gambiensis, accounted for most if not all disease transmission at the study site. The data obtained also suggested that human decisions had contributed to the magnitude if not the degree of the disease problem at the study site and that viable solutions to the disease problem exist.

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Resumen En un estudio programado de moscas tsetse y otras moscas picadoras en el bosque de Tienfala, República de Malí, de diciembre 1979 hasta junio 1981, se colectaron 14.500 especímenes. La comparación de los totales de tsetse y otras moscas picadoras con la incidencia mensual de tripanosomiasis en ganado centinela, sugiere que la transmisión biológica de la enfermedad, casi en su totalidad, esta ligada a laGlossina palpalis gambiensis. Los datos obtenidos tambien sugieren que las decisiones humanas han contribuido a la magnitud del problema en el sitio de estudio, y que existen soluciones al problema planteado.

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Résumé Le suivi planifié des tsé-tsé et d’autres mouches piqueusus dans la forêt de Tienfala, République du Mali, de décembre 1979 à juin 1981 a permis la récolte de plus de 14 500 échantillons. La comparaison des captures mensuelles de tsé-tsé et d’autres mouches piqueuses avec l’incidence mensuelle de la trypanosomose sur des bovins sentinelles permet de suggérer que la transmission biologique par une seule espèce de glossine riveraine,Glossina palpalis gambiensis, explique en grande partie, si ce n’est en totalité la transmission de la maladie dans le site d’étude. Les données enregistrées suggérent également que les décisions humaines ont contribué à l’ampleur, si ce n’est au degré, des problèmes pathologiques dans le site d’étude, mais aussi que des solutions existent pour le résoudre.

     

Sulfur-induced polioencephalomalacia in a herd of rotationally grazed beef cattle

Central nervous system disease occurred in a herd of rotationally grazed beef cattle consuming water containing 3400 ppm sulfate. Clinical signs, pathologic findings, and high water sulfate levels confirmed the diagnosis of sulfur-induced polioencephalomalacia. The incidence of disease reduced when the herd was switched to a low sulfate water source.     

Assessment of impacts of tsetse and trypanosomosis control measures on cattle herd composition and performance in southern region, Ethiopia

This study was conducted to assess the impact of tsetse and trypanosomosis control measures on cattle herd size and composition, herd dynamics, and milk yield in Wolaita and Gamogofa Zones, southern Ethiopia. The study showed that the average number of cattle herd size in tsetse challenged areas was significantly higher than those in tsetse-controlled areas. The number of non-pregnant dry cows, bulls and oxen were significantly higher in tsetse challenged areas than the other two study areas. The rate of cattle addition to and disposal from the herd were significantly higher in tsetse challenged areas. Cows in Southern Tsetse Eradication Project (STEP) and community tsetse controlled areas were able to give 26-27?%, 25-29?% and 17-21?% more daily milk yield at the beginning, middle and end of lactation, respectively, than those in tsetse-challenged areas. In addition, cows in STEP and community tsetse controlled areas had lactation length longer by 1.20 to 1.35?months; age at first calving was shorter by 5.30 to 5.10?months; and calving interval was shorter by 4.20 to 3.20?months than cows in tsetse-challenged area, respectively. Hence, tsetse and trypanosomosis control both by the community and project would play key role in the improvement of cattle productivity.     

Assessment using ELISA of the herd immunity levels induced in cattle by foot-and-mouth disease oil vaccines

The development of a liquid-phase blocking sandwich ELISA (LPBE) to measure antibodies (Ab) produced in cattle with the O, A and C foot-and-mouth disease virus (FMDV) types of commercial vaccines used in Argentina is described. The test was specific: 99% of naïve cattle sera (n = 130) gave titres below log₁₀ = 1.2, and none had a titre above log₁₀ = 1.5. Comparative studies with serum neutralization test (SNT) using sera from cattle which received one or more vaccine doses is reported. The overall rank correlation coefficient (Spearman's , r_s) between SNT and LPBE were highly significant (r_s > 0.67, P < 0.0001) for all vaccine strains. LBPE Ab titres on sera collected 90 days post vaccination were compared with results of cattle protection tests by applying a logistic regression. The minimum Ab titres at which 85% and 75% of the cattle were protected for each FMDV type were determined in order to interpret field Ab data in terms of protection. Application of this method allows large scale serological examinations to monitor antibody levels in vaccinated animals as an indirect indicator of the FMD control program status in the field. Its use in the evaluation of commercial batches of FMD vaccine is discussed.     

Investigation of an outbreak of mucosal disease in a beef cattle herd in southwestern Saskatchewan.

This study describes the epidemiological investigation of an outbreak of mucosal disease that occurred on a ranch in southwestern Saskatchewan. Over a six-month period during the fall and winter of 1991-1992, in a herd of 515 beef cattle and 96 bison, 20 yearling cattle from a group of 105 housed in one feedlot pen died from mucosal disease. A further eight yearlings were slaughtered for salvage because they were at risk of dying from mucosal disease. Mucosal disease mortalities were the first observed evidence of fetal infections with bovine viral diarrhea virus in this herd. Animals that died from mucosal disease exhibited signs of ill thrift prior to death. Deaths from mucosal disease were confined to the progeny of one herd of beef cows. Following an outbreak of fetal infection with bovine viral diarrhea virus during 1989-1990, at least 28 (22%) of the 128 calves born from this herd of cows in the spring of 1990 were persistently infected with bovine viral diarrhea virus. However, only one calf born from this herd in 1991, and five calves born from all herds in 1992 were persistently infected. Of the five persistently infected calves born in 1992, three were born to persistently infected replacement heifers born in 1990. These heifers calved without assistance in 1992, but only one of their calves survived past three days of age, and it was persistently infected. In January 1992, 82% of the total herd had reciprocal antibody titers to bovine viral diarrhea virus of > or = 1024 which suggested a high level of herd immunity to bovine viral diarrhea virus.(ABSTRACT TRUNCATED AT 250 WORDS)     

Maintaining zebu maure cattle in a tsetse infested area of Mali

Summary A study was initiated to evaluate two trypanocidal drugs, the prophylactic isometamidium chloride (Trypamidium) and the curative diminazene aceturate (Berenil) as to their potential for long-term maintenance of zebu cattle in a tsetse infested area of Mali. Trypamidium was administered quarterly and Berenil was administered only as animals were found to be positive for trypanosomes. During the 21-month study trypanosomiasis was the most frequently encountered disease in the cattle in the Berenil treatment group with an average of 5·5 reinfections. The predominant trypanosome species encountered wasTrypanosoma vivax and the most important vector wasGlossina palpalis gambiensis. The results indicate that, even though the direct costs for drugs under the two maintenance regimens were almost identical, the use of Trypamidium resulted in a significantly greater annual weight gain, prevented death loss due to trypanosomiasis and resulted in a herd with a greater market value.

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Mantenimiento De Ganado Cebu Maure En Una Zona Infestada Por Moscas Tsetse

Resumen Se evaluaron dos drogas contra la tripanosomiasis en Mali. Una profiláctica, Trypamidium, y la otra curativa, Berenil. El Trypamidium (cloruro de isometamidium) se aplicó cada tres meses y el Berenil solo cuando los animales se encontraron positivos. Durante los 21 meses del estudio, tripanosomiasis fue la enfermedad más comunmente encontrada en el grupo tratado con Berenil, con un promedio de reinfección de 5·5. Los tripanosomas predominantes fueron elTrypanosoma vivax y el vector más importante laGlossina palpalis gambiensis. Los resultados del estudio indican que aunque el costo de las drogas para los dos grupos fue casi idéntico, el uso del Trypamidium resultó en un aumento significativo de peso de los animales tratados, previniendo muertes por tripanosomiasis.

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Maintien De Bovins Zebu Maure Dans Une Region Du Mali Infestee De Glossines

Résumé Une étude fut entreprise pour évaluer deux médicaments trypanocides, le chlorure d'isometamidium (Trypamidium) à titre préventif et l'acéturate de diminazène (Bérénil) à titre curatif, en ce qui concerne leur valeur potentielle pour le maintien à long terme de bovins zébu dans une zone infestée de glossines au Mali. Le Trypamidium était infecté tous les trois mois et le Bérénil seulement lorsque les animaux s'avéraient porteurs de trypanosomes. Pendant les 21 mois de l'étude, la trypanosomose a été la maladie la plus fréquemment rencontrée dans le groupe traité au Bérénil avec en moyenne 5,5 réinfections. L'espèce trypanosomienne prédominante étaitT. vivax et le vecteur le plus importantGlossina palpalis gambiensis. Les résultats montrent que, bien que le coût direct des médicaments dans les deux régimes de maintien ait été presque identique, l'emploi du Trypamidium a engendré un gain de poids annuel significativement plus grand, a prévenu les mortalités dues à la trypanosomose et conduit à un troupeau de valeur marchande plus élevée.

     

Characterization of some parameters of non-specific immunity in beef cattle (II)

Serum protein, immunoglobulins, complement, lysozyme, serum bactericidal activity and blast transformation of peripheral blood lymphocytes were tested in beef cattle in different herds and age groups. These parameters were evaluated in their time-kinetics, in comparison with age-matched groups of dairy cattle. Like dairy calves, beef calves up to 4 months of age were shown to have low levels of serum bactericidal activity and haemolytic complement; besides, a worse profile was detected in serum protein and gamma 2 globulin levels. Al(OH)3 and oil-adjuvanted vaccines had a favourable influence on immunoglobulin and lysozyme synthesis. An acute stressing event like transportation was shown to decrease mitogen-driven lymphocyte stimulation for at least 10 days after arrival.     

Optic neuropathy in a herd of beef cattle in Alberta associated with consumption of moldy corn

A group of beef cattle in eastern Alberta was investigated due to sudden onset of blindness after grazing on standing corn in mid-winter. Fumonisin-producing Fusarium spp. were isolated from the corn. Blindness was due to an optic nerve degeneration suspected to be secondary to fumonisin mycotoxin.     

Investigation of bovine viral diarrhea virus infections in a range beef cattle herd

Bovine viral diarrhea virus (BVDV) infections resulting in clinical disease developed in calves, despite vaccination of dams and high maternal BVDV antibody titers in calves. Eight persistently infected (PI) calves born to immunocompetent dams were identified in the herd. Neutralizing BVDV antibody titers of PI calves had decreased greatly by the time the calves were 1 to 2 months old. Antibody titers of PI calves decreased more rapidly than antibody titers of calves that were not PI. Reduced antibody titers in PI calves allowed detection of BVDV in serum specimens of all PI calves by the time they were 8 weeks old. Persistent infection in suspect calves was detectable serologically and was confirmed by virologic examination of serum specimens 4 months after weaning, when the calves were 9 months old. Growth rates were reduced in viremic calves.     

Transmission and control of leptospiral infection in a beef cattle herd in southern alberta

Leptospiral antibodies were detected in unvaccinated cattle on a 17 000 hectare ranch in the arid southeast region of Alberta. Antibody to serovar hardjo was present before the breeding season in 7% of 42 yearling bulls, 86% of 29 two year old bulls and 5% of 519 cows. Pomona antibody was confined to 3.7% of the cows. Bulls were treated once with dihydrostreptomycin, 25 mg/kg. Bulls and cows were vaccinated twice at a six week interval, with pomona-hardjo-gripptotyphosa bacterin before breeding and cows were revaccinated the next year. Leptospires were demonstrated in urine, kidney and spinal fluid of vaccinated and treated cattle. New infections occurred on range in vaccinates. Eighteen months after the last vaccination, hardjo and pomona antibody prevalences in cows were 3.6 and 3.2% respectively. A group of 250 seronegative cows on the same ranch were not vaccinated. They remained seronegative throughout the 2.5 years of the study. These cows, in contrast to infected groups, were excluded from pastures adjacent to perimeter herds and grazing leases, and they were bred by artificial inseminstion. Rotation through pastures in common with infected groups, and exposure to seropositive heat detector bulls, did not result in seroconversion in these cows. The study showed the potential of range bulls to amplify and transmit hardjo infection, limitations to the value of treatment and vaccination with available agents, and the potential of management practices to maintain an uninfected herd in close proximity to cattle carrying hardjo infection.     

Seasonal distribution of bovine coccidia in beef cattle herd in the university farm

Fecal samples (2,019) from cattle in the university farm, Tohoku University, were examined for coccidian oocysts from April 1986 to January 1987, and 19.3% of them was positive for Eimeria spp. Thirteen Eimeria species were identified. Eimeria bovis (25.7%) was the most dominant species, followed by E. auburnensis (17.6%), E. canadensis (14.5%), E. alabamensis (9.7%), E. ellipsoidalis (8.1%), E. zuernii (7.0%), E. bukidnonensis (5.4%), E. brasiliensis (3.9%), E. cylindrica (1.3%), E. illinoiensis (0.4%), and E. pellita (0.2%). Fecal samples positive for coccidial oocysts amounted to 12.9% and 26.7% on average during grazing on pasture and loose housing, respectively.     

Simulation analysis of the effect of herd immunity and age structure on infection of a cattle herd with bluetongue viruses in Queensland, Australia

A state-transition model based on Leslie matrix formulation was used to investigate the effects of herd immunity and age structure on the infection of a simulated cattle herd with bluetongue viruses under Australian climatic conditions. Increasing duration of immunity decreased the prevalence of infection. A duration of immunity of 33 months was consistent with prevalence estimates made from previous serological studies of bluetongue virus. Herd prevalence displayed slowly dampening cyclical variation over time (most pronounced when a short duration of immunity was simulated). Increasing calving and mortality risk rates in the simulated herd increased prevalence, whereas increasing age at first calving decreased prevalence. Manipulation of calving rates had the greatest effect on the predicted prevalence of infection in the herd. Simulation of a number of herd-management scenarios suggested that management systems in which cattle are bred early and where high calving rates are achieved are likely to contribute to high levels of infection with bluetongue viruses. Results confirm the importance of management factors in influencing the prevalence of infectious diseases in animal populations.     

Onion toxicosis in a herd of beef cows.

A herd consumed approximately 20 kg onions/cow/day for 6 weeks. Five cows died and two aborted. Onion toxicosis results in methemoglobinemia and hemolytic anemia. These changes can cause secondary organ damage and death, if enough onions are consumed.     

Factors associated with ELISA scores for paratuberculosis in an Angus-Brahman multibreed herd of beef cattle

Cow and calf genetic and environmental factors were evaluated for their association with ELISA scores for paratuberculosis in a multibreed population of beef cattle. The ELISA scores are a measure of the presence or absence of antibodies against Mycobacterium avium subsp. paratuberculosis in bovine serum. The linear mixed-model analysis used 352 ELISA scores from 238 cows: 51 Angus (A); 34 Brahman (B); 41 (3/4 A 1/4 B); 45 (1/2 A 1/2 B); 34 (1/4 A 3/4 B); and 33 Brangus (5/8 A 3/8 B). Cows were assumed to be unrelated. Year affected (P < 0.001) ELISA scores, but age of cow did not, which was expected to be significant because of the chronic progressive nature of this disease. Important regressions on fixed effects associated with cows were 1) a positive estimate of cow B breed effect (0.59 +/- 0.24; P < 0.017), indicating an upward trend of ELISA scores toward 100% B cows; 2) a negative estimate for weight change from before calving (late November) to the date of the blood sample in May (-0.0062 +/- 0.0019 score/kg; P < 0.002), indicating that poorer maintenance of cow weights was associated with higher ELISA scores; and 3) a positive estimate for days in lactation of cow on the date of the blood sample (0.0086 +/- 0.0034 score/d; P < 0.021), indicating the production of larger amounts of antibodies against Mycobacterium avium subsp. paratuberculosis as lactation progressed. Relevant regressions on fixed effects associated with calves were 1) calf birth weight (-0.022 +/- 0.010 score/kg; P < 0.035), and 2) calf gain from birth to the date of the cow blood sample (-0.0092 +/- 0.0027 score/kg; P < 0.001). These estimates indicate that cows that produced lighter calves at birth and/or calves with slower preweaning growth tended to have greater ELISA scores. Although the sensitivity (percentage of infected animals detected) of ELISA was only 50%, these results suggest that subclinical paratuberculosis may be negatively affecting cows and their offspring. Factors identified as associated with ELISA scores could help producers with culling decisions related to paratuberculosis control and eradication in beef cattle.