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PubMed1985

Heavy metals in tissues of cattle exposed to sludge-treated pastures for eight years.

Cattle allowed to graze pastures variously treated with anaerobically digested sludge (ADS) for up to 8 years, contained higher concentrations of heavy metals and organic compounds in some tissues than did cattle not exposed to ADS. Chemical analyses were made on heart, diaphragm, liver, kidney, brain, and bone to determine the amount of Zn, Cu, Cd, Cr, Ni, Pb, Fe, and Hg. Determinations for organic compounds (polychlorinated-biphenyls, dieldrin, and heptachlor/epoxide) were made on visceral fat. Cadmium was the only metal to accumulate consistently in increased amounts. Amounts of Cd accumulated in kidneys and livers were higher in cattle exposed to ADS than in cattle not exposed to ADS. Although the amounts were higher in cattle exposed to ADS, none of the cattle had detectable evidence of disease or pathologic conditions. The mean amount of Cd in kidneys of cattle exposed to ADS was 44 vs 9 mg/kg dry weight. Amounts of other heavy metals in the body tissues were generally not unusual and were similar in both groups of cattle. Polychlorinated-biphenyl concentrations were higher in the visceral fat of cattle exposed to ADS. All cattle in both herds remained healthy, and pathologic changes that could be attributed to association with ADS were not detected. Seemingly, ADS can be used safely to produce cattle forage without endangering the health of cattle.

Adipose Tissue↗
PubMed1998

Tuberculosis in adult beef cattle of Mexican origin shipped direct-to-slaughter into Texas.

OBJECTIVE: To evaluate differences in prevalence of tuberculosis (TB) in adult beef cattle that originated from different states in Mexico and were shipped direct-to-slaughter into Texas in 1995. DESIGN: Epidemiologic survey. ANIMALS: Approximately 65,000 adult beef cattle. PROCEDURES: Postmortem examinations of carcasses for detection of Mycobacterium bovis infection were conducted at slaughter plants in Texas. Specimens were collected from cattle with granulomatous lesions, stored in neutral-buffered 10% formalin or saturated sodium borate solution, and processed for histologic and bacteriologic diagnosis. Prevalence and 95% confidence intervals were estimated by state of origin. Difference between prevalences for different states was tested for significance (P < 0.05), using the proportion test. RESULTS: Overall prevalence of TB at slaughter in adult beef cattle that originated from Mexico was approximately 0.5/1,000 (34/65,233). Prevalence of TB in cattle that originated from Chihuahua (0.07) was significantly lower than that in cattle from Coahuila (0.80), Nuevo Leon (1.27), and Tamaulipas (1.81). CLINICAL IMPLICATIONS: Prevalence of M bovis infection in adult beef cattle may be significantly different between states in the northern border region of Mexico. On the basis of disease prevalence and numbers of exported cattle and provided safeguards such as TB testing are continued, cattle from Chihuahua may pose a lower risk of TB transmission to Texas cattle than do cattle from Coahuila, Nuevo Leon, and Tamaulipas. To allow interstate/international movement of cattle from northern border states of Mexico, TB testing requirements should be continued. In the context of international trade, southern border states of the United States should continue collaborating with northern border states of Mexico to control and eradicate this disease.

Abattoirs↗
PubMed1998

Genetic test for myophosphorylase deficiency in Charolais cattle.

OBJECTIVE: To develop a simple test for the determination of genetic susceptibility to myophosphorylase deficiency in Charolais cattle. ANIMALS: 48 adult Charolais cattle and 233 calves from one herd and 3 Charolais cattle from 2 other herds. Sixty Piedmontese and 34 Saler cattle provided negative-control samples. PROCEDURE: Cattle were from a Charolais herd in which myophosphorylase deficiency was identified and 2 other herds in which cattle had signs compatible with the disease. Genomic DNA was isolated from heparinized blood samples. A segment of the myophosphorylase gene containing the mutation site was amplified by polymerase chain reaction assays, and the genotype (normal vs affected allele) was determined by using restriction enzyme and agarose gel electrophoretic analysis. RESULTS: The 3 myophosphorylase genotypes (homozygous normal, homozygous affected, and heterozygous) could be readily identified. Segregation of the affected allele could be determined in an extended pedigree, and all clinically affected cattle were homozygous for this allele. Determination of the distribution of normal and affected alleles in a large population did not indicate a strong selective advantage for heterozygous carriers in this herd. Heterozygotes were also identified in Charolais cattle from the 2 other herds. CONCLUSIONS: Breeders of Charolais cattle can use this genetic test to perform marker-assisted selection and remove cattle with the mutant myophosphorylase allele from the breeding population. Alternatively, they could more accurately determine selective advantages and disadvantages for cattle with the affected allele. CLINICAL RELEVANCE: Development of this test enables rapid genetic screening of Charolais and related breeds of cattle for detection of the mutation responsible for myophosphorylase deficiency.

Animals↗
PubMed1990

Population growth rates for Amblyomma americanum (Acari: Ixodidae) on Bos indicus, B. taurus and B. indicus x B. taurus cattle.

Densities of Amblyomma americanum (L.) on Bos indicus, B. taurus and B. indicus X B. taurus cattle are compared over a 3-year period, and the growth rate (rate of increase or decrease) of parasitic tick populations on each cattle genotype is estimated. Average log10 densities of parasitic A. americanum larvae are significantly (P = 0.05) lower on B. indicus cattle than on B. taurus and B. indicus XB. taurus cattle. Average log densities of nymphal and adult ticks on B. taurus cattle are significantly higher than on B. indicus cattle but neither cattle genotype differs in this regard from B. indicus X B. taurus cattle. Estimated annual tick population growth rates (log10) for parasitic A. americanum are positive on B. taurus cattle (+0.84 larvae, +0.09 nymphs, +0.22 adults calf-1 year-1), but are negative on B. indicus (-0.18 nymphs, -0.14 adults calf-1 year-1) and B. indicus X B. taurus cattle (-0.45 larvae, -0.24 nymphs, -0.14 adults calf-1 year-1). Populations of parasitic larvae were not detected on B. indicus cattle.

Animals↗
PubMed2006

Danofloxacin (Advocin) reduces the spread of contagious bovine pleuropneumonia to healthy in-contact cattle.

Contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides subsp. mycoides SC (MmmSC), is one of the most important diseases of cattle in Sub-Saharan Africa. The live T1/44 vaccine is normally used for its control but produces only transient protection and gives rise to adverse reactions. The present study evaluated the efficacy of danofloxacin (2.5% Advocintrade mark, Pfizer Ltd.) for the treatment of naturally infected cattle and in the prevention of CBPP transmission to in-contact cattle. Adult cattle, taken from a natural outbreak, were placed into two groups of 10 animals and kept on a research farm in paddocks 50m apart. One group was treated with 2.5mg/kg danofloxacin on days 0, 1 and 2; the other group were saline treated. On day 2, 10 CBPP-free, seronegative cattle were placed in contact with each of the two groups. All cattle were monitored for 3.5 months. No differences were seen in clinical improvement of the CBPP-affected cattle treated with danofloxacin compared with the untreated CBPP-affected cattle with approximately half of each group being withdrawn because of CBPP or showing CBPP lesions at post mortem examination. Clinical scores of the two groups were also similar. However cattle kept in contact with the danofloxacin-treated CBPP-affected animals showed significantly fewer lesions, less mortality and fewer animals were seropositive (P<0.02) and had reduced clinical scores (P<0.001) compared to cattle kept in contact with untreated CBPP-affected cattle. MmmSC was also isolated from fewer contact controls kept with the treated group. These findings could have important implications for the control of CBPP in Africa.

Animals↗
PubMed2004

Persistence of the protective immunity to Schistosoma japonicum in Chinese yellow cattle induced by recombinant 26kDa glutathione-S-transferase (reSjc26GST).

To observe the long lasting effect of the recombinant Sj26GST sub-unit vaccine against Schistosoma japonicum in cattle, animals aged from 5 to 12 months were vaccinated with reSjc26GST, and were challenged by natural infection 6 months or 12 months after vaccination. Worm burdens per cattle and egg burden in tissue (per gram) of cattle with or without vaccination were compared. The results showed that anti-reSjc26GST antibodies were produced in vaccinated cattle. Following natural infection, the vaccinated and the control non-vaccinated cattle were all found to be infected with S. japonicum. A 30% reduction in worm number was observed in the vaccinated cattle when compared with the control cattle. The anti-fecundity effect was characterized by an average of 60% decrease in eggs deposited in the liver of vaccinated cattle; such a decrease is obviously very significant. In addition to the anti-fecundity effect induced in the vaccinated cattle, the number of miracidum hatched per 50 g faeces and the number of eggs released in intestinal tissues per gram were reduced or decreased. Results suggested that the immune responses induced by reSjc26GST in cattle were similar to that in buffaloes and in pigs. In addition, our result demonstrated that the lasting effect of immunity to S. japonicum induced in cattle after vaccination with reSjc 26 GST could persist at least 12 months.

Animals↗
PubMed2005

Seroprevalence of Neospora caninum in dairy and beef cattle with reproductive disorders in Japan.

Serum samples from 145 dairy and 65 beef cattle with reproductive disorders and 54 normally calving dairy cattle (controls) in Japan were tested for presence of Neospora caninum antibodies by use of an indirect fluorescent antibody test (IFAT, titer 1:200). Overall, seroprevalence of N. caninum was significantly higher (P < 0.001) in dairy cattle (20.0%, 29/145) than in beef cattle (1.5%, 1/65). In cattle which aborted, seroprevalence of N. caninum was significantly higher (P = 0.041) in dairy cattle (26.1%, 23/88, compared with controls (3.7%, 2/54)) than in beef cattle (5.0%, 1/20), indicating that neosporosis might be a more common problem in dairy cattle than in beef cattle in Japan. Seropositive cattle were 9.2 times more likely to abort compared to seronegative cows. Abortions associated with N. caninum seropositivity in this study were most frequently observed in the second trimester, and the mean gestational age of the fetuses aborted from seropositive dams was 5.7 months. In conclusions, N. caninum seems to be causing serious economic losses in the dairy industry in Japan. This is the first report on an objective comparison of seroprevalence of dairy and beef cattle with reproductive disorders in Asia.

Abortion, Veterinary↗
PubMed1994

Integrated management strategies for Amblyomma americanum (Acari: Ixodidae) on pastured beef cattle.

Data on tick control and knowledge of the damage caused to beef cattle by tick feeding were incorporated into a computerized dynamic life table model (LSTSIM) for Amblyomma americanum (L.). Simulations were made to determine economically feasible, 5-yr integrated pest management (IPM) strategies for A. americanum in forage areas utilized by Bos taurus, Bos indicus, and crossbred cattle (B. taurus x B. indicus). The effects of host resistance, pasture rotation, habitat conversion, topical acaricides, systemic acaricides, and the area-wide application of acaricides to pastures on populations of parasitic female ticks were simulated as individual control technologies and as components of multiple-factor IPM strategies. The most effective, single-factor control strategy for A. americanum in beef cattle forage areas is the use of tick-resistant B. indicus cattle. Pasture rotation combined with area-wide acaricide applications was the only economically feasible IPM strategy for B. indicus cattle and reduced tick densities by 89% after 5 yr. Thirteen economically feasible IPM strategies were identified for use with B. taurus cattle. Of these, the most efficacious was pasture rotation in May combined with systemic or topical acaricide applications. Other strategies included systemic acaricides with area-wide acaricide applications to pastures, topical acaricides with area-wide acaricide applications, pasture rotation with habitat conversion and topical acaricides, and pasture rotation with habitat conversion, topical acaricides, and area-wide acaricide applications. Each technology reduced tick densities on B. taurus cattle by > 80% over a 5-yr period. Nine IPM strategies were economically feasible for use with crossbred cattle. Of these, pasture rotation combined with systemic or topical acaricide applications reduced the number of female ticks on cattle by > 84%; pasture rotation combined with habitat conversion reduced tick numbers by 77%. The most effective nonacaricide-based IPM strategy for B. taurus and crossbred cattle was pasture rotation combined with habitat conversion. No acaricide-free IPM strategy was economically feasible for use with B. indicus cattle.

Animals↗
PubMed2004

Effect of mass medication with antibiotics at feedlot entry on the health and growth rate of cattle destined for the Australian domestic market.

OBJECTIVE: To examine the effectiveness of mass medication with long acting antibiotics at feedlot entry on lot-fed Australian domestic cattle during a period of high risk for bovine respiratory disease (BRD). DESIGN: Systematic allocation at feedlot entry of tilmicosin, long acting oxytetracycline or no antibiotic treatment, to cattle lot fed for the Australian domestic market. Comparisons of growth rate, disease occurrence and mortality were made between the groups at the conclusion of the feeding period. RESULTS: Cattle medicated with tilmicosin at 10 mg/kg body weight on entry to the feedlot grew 0.08 kg/d faster than cattle medicated with oxytetracycline at 20 mg/kg body weight and non-medicated cattle. There was no significant difference in growth rate between oxytetracycline medicated cattle and cattle not medicated with antibiotic at feedlot entry. Cattle medicated with tilmicosin at feedlot entry had 8 fewer cases of disease per 100 animals compared with cattle not medicated with antibiotic at feedlot entry. There was no significant difference in disease occurrence between oxytetracycline medicated cattle and those not medicated with antibiotic at feedlot entry. CONCLUSION: Mass medication with tilmicosin at feedlot entry of cattle destined for the Australian domestic market may be used to reduce disease occurrence and increase growth rate during periods of high risk for BRD.

Animals↗
PubMed1992

Disseminated mycoses in cattle. A study on nine autopsy cases.

Nine cases affected with disseminated mucormycosis (1.3% of all autopsy cases and 20.0% of systemic mycosis) were found among bovine systemic mycosis examined from 1975 to 1985. The disseminated lesions were found in the lungs (3 cattle), heart (2 cattle), liver (2 cattle), spleen (1 beef cattle), kidneys (1 cattle), central nervous system (1 cattle) and lymph node (1 cattle). Histological examination revealed granulomatous lesions, necrotic foci including infarcts, and thromboangiitis with the hyphae of a member of the Zygomycetes and neutrophil reaction. Granulomatous lesions with asteroid bodies were found in the liver. Metastatic foci were established from the primary lesions found in the alimentary organ (4 from the forestomach or abomasum and 1 from the tongue). One case resulted from uterine mucormycosis, and no primary lesion was found in the other 3 cattle. Complicated infection with respiratory aspergillosis occurred in 4 cases with alimentary mucormycosis. All of the 9 cattle had predisposing disorders. Six cattle had been manifested with prolonged debilitating conditions. Anemia was present in 4, leukopenia in 2 and lymphopenia in 1 cattle.

Animals↗
PubMed2005

Detection of respiratory and enteric shedding of bovine coronaviruses in cattle in Northwestern Turkey.

Bovine coronavirus (BCoV) is an important cause of diarrhoea in calves, winter dysentery in adult cattle and respiratory tract disease in feedlot cattle. Serum, faecal and nasal swab samples were collected from a total of 96 cattle with clinical signs in 29 barns of 23 villages in Northwestern Turkey. The cattle were subdivided into 3 distinct age groups (0-30 days old, 4-12 months old and 2-7 years old). An indirect antigen-capture ELISA and an antibody-detection ELISA as well as geometric mean BCoV antibody titres were used to detect BoCV shed in the faeces and in the nasal secretions, respectively. Relationships between BCoV shedding and age group, seroconversion and clinical signs in cattle were also analysed. The rate of faecal shedding of BoCV was 37.1% (13/35) in 0-30 days old calves, 25.6% (10/39) in 4-12 months old feedlot cattle and 18.2% (4/22) in 2-7 years old cows. The overall rate of BCoV faecal shedding was 28.1% (27/96) in the cattle examined. Only one animal in the 4-12 months old age group was found to shed BoCV nasally. The analysis showed that there was a significant difference (P < 0.0001) with respect to faecal shedding between the clinical signs and the age groups. BCoV antibody titre in 50% of all cattle was < or =100 as detected by ELISA while 27.1% of the cattle had high titres ranging between 1,600 and 25,600. The seroconversion rate was 7.3% (7/96) in animals shedding BoCV in the faeces and 42.7% (41/96) in cattle negative for faecal shedding as detected by ELISA, and 20.8% of cattle with no seroconversion shed BCoV in the faeces. There was no statistically significant association between seroconversion and nasal or faecal BCoV shedding. These findings confirm the presence of BCoV infections in Turkey. Further studies are needed to isolate BCoV strains in Turkey and to investigate their antigenic and genetic properties.

Age Factors↗
PubMed2000

Prevalence of papillomatous digital dermatitis among culled adult cattle in the southeastern United States.

OBJECTIVE: To determine prevalence of papillomatous digital dermatitis (PDD) among culled adult dairy and beef cattle in the southeastern United States. ANIMALS: 815 cattle examined during 4 visits to a slaughterhouse. PROCEDURE: The left hind foot of each animal was examined for gross lesions of PDD. Breed and sex of the animals were recorded. Lesions were examined histologically for pathologic changes and bacteria, especially spirochetes. RESULTS: 22 of 76 (29%) dairy cattle and 29 of 739 (4%) beef cattle had gross lesions of PDD. Detection of lesions was not associated with sex of dairy cattle, but male beef cattle were more likely to have lesions of PDD than were female beef cattle. Histologically, acute and chronic lesions were seen; the most severe changes were localized to the stratum corneum. Spirochetes were seen in lesions from 31 of 51 (61%) cattle. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that PDD is common among culled adult cattle. Prevalence was higher in culled adult dairy cattle than in culled adult beef cattle.

Abattoirs↗
PubMed2006

Prevalence of vesivirus in a laboratory-based set of serum samples obtained from dairy and beef cattle.

OBJECTIVE: To examine sera obtained from dairy and beef cattle to detect antibodies against vesivirus and compare seroprevalence among cattle within the sample population. SAMPLE POPULATION: Cattle sera from 8 western states and Maryland submitted to the Washington Animal Disease Diagnostic Laboratory during 1999 and 2000. PROCEDURE: Sera were analyzed for vesivirus-specific antibodies by use of a recombinant vesivirus-San Miguel sea lion virus serotype 5-capsid peptide antigen in an indirect ELISA. RESULTS: Overall, 693 sera were tested and 105 (15.2%) had positive results. Seropositive cattle were from 7 states (all cattle from Montana and Maryland 10 and 4, respectively were seronegative). Overall seroprevalence for antivesivirus antibody in herds ranged between 0% and 80% (median, 14%). Higher antibody prevalence was significantly associated with older age, dairy rather than beef cattle, and reasons for submission. Logistic regression of factors (abortion, respiratory tract disease, and all other reasons for sample submission) revealed that older age and other reasons were independently associated with higher seroprevalence. Higher seropositive optical density values for the ELISA were observed among older cattle and cattle that aborted, compared with values for cattle with respiratory tract disease or other reasons for submission. CONCLUSIONS AND CLINICAL RELEVANCE: This laboratory-based surveillance sample provided a point estimate of seroprevalence against vesivirus among cattle in 9 US states. This suggests that vesivirus infection is widespread with high prevalence in some herds. Risk factors associated with vesivirus seroprevalence in beef and dairy cattle should be confirmed in population-based studies.

Animals↗
PubMed2000

Osseous sequestration in cattle: 110 cases (1987-1997).

OBJECTIVE: To determine risk factors for development of sequestra in cattle and identify factors associated with a successful outcome. DESIGN: Retrospective study. ANIMALS: 110 cattle. PROCEDURE: Medical records of cattle treated at veterinary teaching hospitals in North America were reviewed. To determine risk factors for osseous sequestration, breed, age, and sex of cattle with osseous sequestration were compared with breed, age, and sex of all other cattle admitted during the study period. RESULTS: 110 cattle were included in the study. Three had 2 sequestra; thus, 113 lesions were identified. Most sequestra were associated with the bones of the extremities, most commonly the third metacarpal or third metatarsal bone. Ninety-two animals were treated surgically (i.e., sequestrectomy), 7 were treated medically, 3 were initially treated medically and were then treated surgically, and 8 were not treated. Follow-up information was available for 65 animals treated surgically and 6 animals treated medically. Fifty-one (78%) animals treated surgically and 5 animals treated medically had a successful outcome. Cattle that were 6 months to 2 years old had a significantly increased risk of developing a sequestrum, compared with cattle < 6 months old. Cattle in which sequestrectomy was performed with the aid of local anesthesia were significantly more likely to undergo 2 or more surgical procedures than were cattle in which sequestrectomy was performed with the aid of general anesthesia. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that sequestrectomy will result in a successful outcome for most cattle with osseous sequestration.

Age Factors↗
PubMed2006

Obstruction of the small intestine by a trichobezoar in cattle: 15 cases (1992-2002).

OBJECTIVE: To determine historical and clinical findings, treatment, and outcome for cattle with small intestinal obstruction caused by a trichobezoar. DESIGN: Retrospective case series. ANIMALS: 15 cattle. PROCEDURES: Medical records of cattle with a diagnosis of small intestinal obstruction by a trichobezoar from 1992 to 2002 were reviewed. Information pertaining to various aspects of diagnosis, treatment, and outcome was collected from records. RESULTS: Trichobezoars were more common in young cattle, and affected cattle did not deteriorate clinically as rapidly as cattle with other types of intestinal obstruction. The most common initial owner complaints included decreased or absent fecal output, inappetance, abdominal distension, and signs of abdominal pain. Common clinical findings were dehydration, decreased or absent rumen motility, signs of depression, splashing sounds during succussion of the abdomen, and a pinging sound on percussion of the abdomen. The jejunum was obstructed in 10 cattle. Hypochloremic metabolic alkalosis and chronic inflammation were common laboratory findings. All 4 cattle that underwent abdominocentesis had peritonitis. The obstructing trichobezoar was removed surgically in 9 cattle, of which 7 survived and 2 died. The 6 cattle treated medically died or were euthanized. CONCLUSIONS AND CLINICAL RELEVANCE: Obstruction of the small intestine by a trichobezoar is uncommon, but it should be considered as a differential diagnosis in cattle with signs of intestinal obstruction, particularly if they are younger than 4 years of age and have a history of nonacute signs of intestinal obstruction. Surgical removal appears to be a favorable method of treatment and should be considered when this condition is suspected.

Animals↗
PubMed1992

Risk factors for abomasal volvulus and left abomasal displacement in cattle.

A hospital-based case-control study was conducted to evaluate and compare risk factors for abomasal volvulus (AV) and left displaced abomasum (LDA) in cattle. Medical record abstracts were derived from 17 North American veterinary schools by the Veterinary Medical Data Program for all cattle admitted between Jan 1, 1977 and Dec 31, 1986, and for those with a diagnosis of AV or LDA. From a total of 108,956 individual cattle records, 1,036 cases of AV and 7,695 cases of LDA were identified, with a ratio of LDA to AV cases of 7.4 to 1. In-hospital mortality was 23.5% for AV and 5.6% for LDA. Age, breed, gender, and season each had significant (P less than 0.05) effects on risk for AV and LDA. Risk for AV and LDA increased with increasing age, with greater risk in cattle aged 4 to 7 years. Dairy cattle were at higher risk of developing AV (adjusted odds ratio, 36.4) and LDA (adjusted odds ratio, 95.2) than were beef cattle. The odds of AV in Brown Swiss cattle were significantly (P less than 0.0001) lower, and the odds of LDA in Guernsey cattle were significantly (P less than 0.0001) higher than those in Holstein cattle. Female cattle were also at higher risk of developing AV (adjusted odds ratio, 3.3) and LDA (adjusted odds ratio, 29.1) than were male cattle. The odds of AV and LDA varied considerably throughout the year, with the lowest number of cases observed in autumn. Seasonal development of AV differed significantly (P less than 0.0001) from that of LDA, with the odds of AV and LDA being highest in January and March, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Abomasum↗
PubMed1988

Radioimmunoassay for Anaplasma marginale antibodies in cattle.

A radioimmunoassay is described for use in the detection of Anaplasma marginale antibodies in cattle sera. Optimal sensitivity and specificity were obtained by using 2 antigens, an A marginale antigen and a RBC antigen (obtained before infection was established) from the same calf. In addition, sera were preabsorbed with RBC from healthy cattle and with sonicated Babesia bovis. Of 86 sera obtained from cattle with A marginale infection (as determined by blood smear examination or by results of subinoculation of blood from such infected cattle into splenectomized calves), 85 had positive results by use of this test. Of 100 sera obtained from cattle raised in an anaplasmosis-free area, 98 yielded negative results, and sera obtained from 35 cattle (97 sera) infected with B bigemina and from 18 cattle infected with Theileria orientalis yielded negative results. By use of this test, 99 of 100 sera obtained from cattle with B bovis infection were negative for A marginale. Anaplasma marginale antibodies were detected in 18 cattle that had been pastured in a Boophilus microplus-free area for 2 years after natural infection. After 3 years, 16 of these cattle were still seropositive for A marginale. Sixteen cattle pastured in a Bo microplus-infested area had detectable antibody against A marginale 27 months after initial infection with A marginale. Sensitivity and specificity of the test were assessed as 98.8% for each.

Anaplasma↗
PubMed1984

Infestation potential of Psoroptes ovis (Hering) from cattle injected with ivermectin.

Cattle scabies mites, Psoroptes ovis (Hering), surviving on cattle injected subcutaneously with ivermectin were capable of infesting to unprotected cattle 3, 5, 7, and 9 days after injection. All recipient cattle exposed to mites from vehicle-injected cattle developed reproductive colonies in 5 weeks. All recipient cattle exposed to mites from ivermectin-injected cattle at 3 and 5 days after injection developed reproductive colonies in 5 weeks. By 8 weeks, 3 of 4 and 2 of 4 recipient cattle exposed to mites from ivermectin-injected cattle 7 and 9 days after injection, respectively, developed reproductive colonies. To prevent the spread of mites, injected cattle should be isolated from uninfested cattle for longer than 9 days.

Animals↗