Effects of arrival medication with tilmicosin phosphate on health and performance of newly received beef cattle

Three trials were conducted to evaluate the use of tilmicosin phosphate (Micotil) as a prophylactic medication for newly received, stressed beef cattle. In Trial 1, 57 beef calves (average initial BW = 170 kg) were shipped to the research feedlot from Tennessee and either given no antibiotic at processing or treated with Micotil at 10 mg of tilmicosin phosphate/kg of BW. During a 28-d receiving period, treatment at processing with Micotil did not affect daily gain (P < .17) or DMI (P < .22) compared to control calves. Prophylactic treatment with Micotil decreased (P < .01) the percentage of calves treated for symptoms of bovine respiratory disease from 46.4 to 0%. In Trial 2, 117 calves (average initial BW = 191 kg) were shipped from Tennessee and allotted randomly to the same two treatments as in Trial 1. All calves grazed a 24-ha pasture of irrigated winter wheat during the 28-d receiving period. Treatment of calves with Micotil at the time of arrival processing did not affect (P > .50) daily gain during the trial; however, as in Trial 1, mass treatment with Micotil decreased (P < .01) the percentage of calves treated for respiratory disease from 32.8% to 12.1%. In Trial 3, two truckloads of beef calves (183 total; average initial BW = 232 kg) shipped from Tennessee were allotted randomly to the same two treatments used in Trials 1 and 2 or to a third treatment that consisted of administration of Micotil at arrival processing if the rectal temperature of the calf was > or = 39.7 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of the effect of the fenbendazole sustained-release intraruminal device on the immunity of calves to lungworm

Each of 10 set-stocked calves was given a fenbendazole sustained-release intraruminal bolus at turnout for the control of parasitic bronchitis while a group of 10 similar calves was left untreated. The respiratory rates of the control calves were not greatly increased during the grazing season, but persistent coughing was evident from early July when they all had patent lungworm infections. Only occasional coughing was reported from the bolus-treated calves except for a transient increase in its frequency in late September. In mid-August, one of the treated calves was passing lungworm larvae and when they were housed six of the 10 had patent infections. In August tracer calves picked up an average of 23.5 lungworms per day from the control paddock but only 2.1 from the paddock grazed by the treated calves. In September the corresponding figures were 7.6 and 19.2 lungworms per day, respectively, from the control and 'treated' paddocks. After housing, the post mortem worm counts after an experimental challenge with Dictyocaulus viviparus larvae were reduced by 99.2 and 98.7 per cent (P < 0.0001), respectively, for the control and bolus-treated calves in comparison with weight-matched parasite-naive calves. Thus, despite a relatively low level of challenge during the grazing season, the treated animals had developed a considerable degree of protective immunity.     

Prophylactic efficacy of tilmicosin for bovine respiratory tract disease

The prophylactic administration of injectable tilmicosin for pneumonia in weaned beef calves was investigated in 1,806 animals. Comparisons were made among calves receiving an "on-arrival" injection of tilmicosin, calves receiving a single injection of long-acting oxytetracycline, and calves receiving no prophylaxis. Morbidity and mortality attributable to pneumonia, morbidity and mortality attributable to all causes, and case fatality were significantly lower in the group of calves that received tilmicosin, compared with calves that received long-acting oxytetracycline and calves that received no prophylactic antibiotic. Mean time to initial pneumonia treatment was significantly extended in calves that received prophylaxis, compared with those that received no antibiotic on arrival at the feedlot. Calves that received tilmicosin gained significantly more weight than calves that received oxytetracycline. Calves that were not treated for pneumonia during the trial period gained significantly more weight than did those calves that were treated for pneumonia regardless of experimental group. The majority of mortalities were attributable to fibrinous pneumonia (31/34). Important bacterial isolates (Pasteurella spp, Haemophilus somnus, Actinomyces pyogenes) obtained at necropsy did not have resistance to tilmicosin in association with administration of tilmicosin as prophylaxis for pneumonia. However, bacterial resistance to trimethoprim/sulfonamide and to oxytetracycline were commonly found in these postmortem isolates.     

Gas bubble disease in farmed fish in Saudi Arabia

Four outbreaks of gas bubble disease were encountered among farmed fish in Saudi Arabia. Two of them occurred among subadult (52.5 g) saltwater tilapia (Oreochromis spilurus), the first affecting about 50 per cent of the stock and resulting in about 30 per cent mortality, and the second affecting about 25 per cent of the population with about 5 per cent mortality. Another outbreak occurred among adult (270 g) brackish water (0.5 per cent salinity) tilapia (Oreochromis niloticus), affecting about 40 per cent of the population with about 25 per cent mortality. The fourth outbreak occurred among three-month-old (15 g) grouper (Epinephelus fuscogutiatus) and resulted in 10 per cent mortality. In all cases the total water gas pressure ranged between 111.2 and 113.4 per cent saturation and nitrogen was supersaturated while oxygen was undersaturated. The outbreaks were alleviated by reducing the gas pressure by splashing the source water or by switching to a source of water with lower gas pressure. However, in O niloticus the conditions of gas supersaturation resulted in a heavy infection by monogenetic trematodes which was treated with formalin at 40 mg/litre for seven hours on five successive days.     

Physical and chemical properties of DMP 504, a polyalkylammonium-based bile acid sequestrant

In an open, controlled, multi-centre clinical field trial, seven 'naturally occurring' outbreaks of acute febrile (rectal temperature > or = 39.5 degrees C) respiratory disease in housed calves were treated with a single antimicrobial agent, and either the non-steroidal anti-inflammatory drug (NSAID) carprofen (n = 95) or flunixin meglumine (n = 92) on an alternate basis. Carprofen was administered as a single subcutaneous injection at a mean dosage of 1.4 mg kg-1 (range 1.2 to 1.9 mg kg-1) body weight on the first day and flunixin meglumine by intravenous injection at a mean dosage of 2.0 mg kg-1 (range 1.2 to 2.6 mg kg-1) body weight on the first 3 consecutive days. All calves were examined clinically immediately prior to initial treatment and on three occasions up to 1 week after the end of treatment. There were no statically significant differences between NSAID groups in reduction of clinical parameters between examinations, or in overall efficacy. This trial demonstrated that a single dose of carprofen was equally effective as three daily doses of flunixin meglumine as adjunctive therapy to antimicrobial treatment in acute respiratory disease in calves.     

Manifestation of the Wolff-Parkinson-White syndrome during isoprenaline infusion and carotid sinus massage

Fully susceptible cross-bred calves, six to nine months of age, were immunised by tick-induced Theileria annulata infection treated with chlortetracycline at 16 mg/kg body weight for four, eight or 16 days. The infections were induced with 10 ticks (Hyalomma anatolicum anatolicum) or 30 ticks (H dromedarii). The recovered calves were tested for immunity to homologous severe challenge, 50 or 73 days after the first infection. The reaction of the calves to infections was evaluated by noting the prepatent period, symptoms, degree of anaemia, rate of parasitisation of lymphocytes and erythrocytes. It was observed that untreated calves developed acute theileriasis characterised by typical symptoms and lesions and 56 to 66 per cent mortality. The medicated calves, however, developed a mild form of the disease. Calves which recovered from treated or untreated infections were solidly resistant to subsequent severe homologous infection. Judged from the severity of anaemia in the infected calves, eight day and 16 day medication provided slightly better protection than four day medication. It was concluded that eight day medication afforded adequate protection against the severe immunising infection, and allowed the development of solid resistance to severe homologous challenge.     

Association of excess sulfur intake and an increase in hydrogen sulfide concentrations in the ruminal gas cap of recently weaned beef calves with polioencephalomalacia

During a 2-week period, 16 of 150 recently weaned calves developed signs of polioencephalomalacia (PEM). One calf was examined and treated at our veterinary teaching hospital and a necropsy was performed on a calf that died. During the peak of the outbreak, clinicians visited the ranch. Ruminal hydrogen sulfide (H2S) and blood thiamine concentrations were measured in 10 clinically normal penmates of PEM-affected calves. Ruminal H2S concentrations were high (> 0.695 mg/L [> 500 ppm]) in all cattle (mean, 12.19 mg/L [8,770 ppm]). All blood thiamine values were within the reference range. Within 12 hours after measurement of blood thiamine concentrations, 2 of the calves from which samples were obtained developed clinical signs of PEM. Dietary analysis revealed an estimated sulfur intake of 0.9% per calf on a dry-matter basis. Hay contributed most of this sulfur. In the investigation reported here, an outbreak of PEM was associated with high ruminal H2S concentrations and excess sulfur intake without evidence of thiamine deficiency.     

Mycoplasmas and ovine keratoconjunctivitis

The clinical course of an outbreak of keratoconjunctivitis in housed lambs and their dams was followed. Signs were transient generally and became severe in only a small proportion of lambs. The outbreak became most obvious when the lambs were 46 to 55 days old, when 46.9 per cent were affected. Mycoplasma conjunctivae isolations, confirmed by comparison with the type strain by biochemical and serological reactions, increased to 62.1 per cent of all eyes swabbed, but no correlation could be demonstrated between presence of the organism and clinical status. The reasons for this are discussed. Mycoplasma ovipneumoniae was also recovered from the eyes of a small number of lambs. Instillation of a broth culture of M conjunctivae into the conjunctival sacs of four hoggs produced a transient keratoconjunctivitis similar to that observed in the field, but no effect was observed in animals inoculated intravenously. M conjunctivae may therefore be the aetiological agent of non-follicular infectious ovine keratoconjunctivitis, although further work in gnotobiotic or specific pathogen free lambs is required to establish the fact beyond doubt.     

Immune response of calves experimentally infected with non-cell-culture-passaged bovine respiratory syncytial virus

The immune response of calves was studied following infection with non-cell-passaged Bovine respiratory syncytial virus (BRSV). Two groups of 6 specific pathogen free (SPF) calves were housed in separate isolation rooms. One group was inoculated intranasally with a non-cell-passaged BRSV strain and the control group was mock-infected. A BRSV specific antibody response was observed for all the BRSV infected calves. These antibodies were shown to have neutralizing activity. No lymphocyte proliferation response was detected in the mock-infected group whereas three animals in the infected group were positive three weeks after the infection. All BRSV-infected calves, except one, produced interferon-gamma (IFN-gamma) one week post-infection and IFN-gamma was observed in all six infected calves after three weeks. The control group showed no IFN-gamma synthesis. In spite of the limits of the BRSV infection model, humoral and cellular immune responses were actively developed by all the calves against this pathogen.     

Effects of supplemental shade on thermoregulatory response of calves to heat challenge in a hutch environment

Holstein (n = 12) and Guernsey (n = 6) calves, housed in hutches, were used to evaluate the complex relationships among external environment, housing microclimate, and thermal status of calves. The study was conducted during the summer; 9 calves were housed in hutches under supplemental shade, and 9 calves were maintained in hutches under direct sunlight. Environmental and calf temperatures were measured twice daily at 0700 and 1500 h, which included determinations of air temperature, inner and outer surface temperatures of the hutch, rectal and skin temperatures of the calf, and respiration rate. Outer and inner surface temperatures of the hutch were lower under supplemental shade. Hutch air temperature was highly correlated with inner surface temperature and therefore was lower in the shaded environment. During the p.m. period, when heat stress was highest, calves housed in a shaded hutch environment had lower skin temperatures and respiration rates than did unshaded calves. Body temperature and respiration rates increased less for calves in shade than for calves in sun. These data define the relationship between the calf and the environment. Supplemental shade diminished the severity of heat stress experienced by calves that were housed in hutches during the summer.     

Pathological and epidemiological aspects of the coexistence of maedi-visna and sheep pulmonary adenomatosis

Between 1982 and 1991, 159 sheep suffering from chronic respiratory disease were subjected to clinical, pathological, histopathological and serological examination. Maedi was diagnosed in 82 sheep and sheep pulmonary adenomatosis (SPA) in another 59. Forty-one of the latter (69.5 per cent) were seropositive for maedi-visna (MV) virus infection, but only six (10.2 per cent) showed concurrent lung lesions of maedi. Even disregarding the MV seronegative sheep and those younger than two years old, the rate of concurrent maedi lesions did not exceed 18 per cent. During a similar period, 5060 sheep from 161 flocks (86 of which also provided the 159 affected animals) were tested for antibodies to MV virus. The average seroprevalence of MV virus infection among flocks in which SPA was detected was 66.4 per cent, whereas in those in which SPA could not be demonstrated, and in those in which necropsies were not performed, the levels of MV virus infection were 55.1 per cent and 43.6 per cent, respectively. The effect of SPA on the seroprevalence of MV virus infection was independent of other factors, such as breed of sheep or the size of the flocks. These results provide evidence that SPA plays a role in the spread of MV virus infection, although a synergistic effect of the simultaneous infection on the expression of concurrent lesions does not seem to occur.     

Mortality following elective infrarenal aortic reconstruction: a Joint Vascular Research Group study

BACKGROUND: This study aimed to define the cause of death in patients undergoing elective infrarenal aortic reconstruction. METHODS: Members of the Joint Vascular Research Group who had collected details prospectively of patients undergoing elective aortic reconstruction provided information on those who died. RESULTS: Details of 3786 patients were obtained. Some 171 patients died (133 following abdominal aortic aneurysm (AAA) and 38 after aortofemoral bifurcation graft (AFBG) for occlusive disease). The mortality rate following AAA repair was 4.8 per cent, rising to 16 per cent if repair was combined with either renal or distal reconstruction (P < 0.001). Similar results were obtained with AFBG (3.4 and 11 per cent respectively, P < 0.001). The first major complication encountered was cardiac (39.8 per cent), followed by bleeding (20.5 per cent), respiratory (13.5), and gut (5.3 per cent), or limb ischaemia (6.4 per cent). Bleeding was commoner following reconstruction for aneurysm compared with that for occlusive disease (P < 0.05). Eighty-six patients (50.3 per cent) died from the first major complication. Of the remainder, 45 (53 per cent) developed multisystem organ failure (MSOF). The most commonly involved systems were cardiac, respiratory and renal. CONCLUSION: Cardiac problems were the major cause of death following infrarenal aortic reconstruction. MSOF is the 'final common pathway' in about half of the patients who survive the initial complication.     

Intracellular accumulation, subcellular distribution, and efflux of tilmicosin in chicken phagocytes

Tilmicosin is a semi-synthetic macrolide antibiotic, currently approved for veterinary use in cattle and swine respiratory disease, and is in development for use in poultry mycoplasma air sacculitis. In order to provide an understanding of clinical efficacy, the in vitro interaction of tilmicosin with three types of chicken phagocytes (MQ-NCSU macrophages, monocyte-macrophages, and heterophils) was evaluated. After incubation with radiolabeled tilmicosin, uptake was determined and expressed as the ratio of the cellular (Cc) to the extracellular (Ce) drug concentration (Cc:Ce). Tilmicosin was avidly accumulated by heterophils (Cc: Ce 138 at 4 h incubation vs 32 and 66, respectively, in MQ-NCSU and monocyte-macrophages) with 61 to 88% localized in the lysosomes. Uptake was dependent on cell viability, temperature, and pH, but was not influenced by metabolic inhibitors. However, phagocytosis of Pasteurella multocida and lipopolysaccharide exposure increased tilmicosin uptake by the chicken phagocytes. Upon removal of extracellular tilmicosin, 50% of the intracellular tilmicosin was effluxed within the first 30 min, but after 4 h of incubation in antibiotic-free medium, 30% remained cell-associated. Opsonized P. multocida significantly enhanced the release of tilmicosin from all three types of chicken phagocytes. Tilmicosin uptake was observed to increase lysosomal enzyme (acid phosphatase, lysozyme, avidin, and beta-glucuronidase) production. Finally, neutrophils were shown to transport and efflux bioactive tilmicosin in a test system measuring both neutrophil chemotaxis under agarose and a bioassay measuring inhibition of bacterial growth in the presence of antibiotic in agar. These in vitro observations of cellular pharmacology suggest a complex interaction between phagocytes and tilmicosin that contribute to clinical efficacy.     

Welfare implications of identification of cattle by ear tags

The damage caused by ear tags used for identification was studied by examining the ears of normal beef cattle and cull cows after slaughter, and by comparing the effects of metal and polyurethane ear tags in calves which had been double-tagged in the same ear. Metal tags were associated with more damage to the ears than polyurethane tags, the difference being most marked in the young calves, in which slight changes were found in 36.6 per cent and severe changes in 9.8 per cent of ears. There was a high incidence of blood around the point of insertion of the metal tags at three weeks old, but with the polyurethane tags only one calf showed slight evidence of blood around the point of insertion. In the beef cattle fitted with metal tags, a slight reaction was recorded in 40 per cent, a moderate reaction in 17 per cent and significant changes were found in 12 per cent of ears. By comparison, 16 per cent of ears with polyurethane tags showed only a slight reaction, and 80 per cent of the polyurethane tags were considered to be a good fit, compared with 37 per cent of metal tags. More changes were observed in the ears of the cull cows, with 23.5 per cent of ears with polyurethane tags being free from damage, compared with only 2.9 per cent of ears with metal tags.     

An evaluation of the effect of an alpha hydroxy acid-blend skin cream in the cosmetic improvement of symptoms of moderate to severe xerosis, epidermolytic hyperkeratosis, and ichthyosis

It has been observed that the occurrence of respiratory complications and diarrhoea among measles cases has changed over time but this change has not been quantified. A study was carried out in the city of Gweru, Zimbabwe, to quantify these changes. Rates of respiratory complications and diarrhoea among measles cases were determined in each year for the period 1968-89. It was found that mean rates of respiratory complications and diarrhoea during 1968-78 were 17.2 per cent (95 per cent CI = 11.6-22.8) and 5.2 per cent (95 per cent CI = 0-11) respectively while during 1979-89, mean rates of respiratory complications and diarrhoea were 6.5 per cent (95 per cent CI = 1-12.1) and 16.4 per cent (95 per cent CI = 10.1-22.0) respectively. Analysis of variance (ANOVA) to determine the main effects and the interaction showed that the main effects were not statistically significant (F = 0.01, d.f.1,2 = 1,40, p = 0.935; and F = 0.13, d.f.1,2 = 1,40, p = 0.725 respectively) Meanwhile the interaction term of complications and period was statistically significant (F = 15.7, d.f.1,2 = 1,40, p < 0.001). It was concluded that a change in rates of respiratory complications and diarrhoea had occurred among measles cases. It is suggested that the increase in vaccination coverage in 1979-89 and the shift in age at infection to older age groups in the same period may have brought about this change through selective suppression of respiratory complications among measles cases.     

Detection of peste des petits ruminants virus antigen in conjunctival smears of goats by indirect immunofluorescence

Peste des petits ruminants virus (PPRV) antigen was detected in conjunctival epithelial cells obtained from goats in the early or late stage of the disease by the use of a specific monoclonal antibody (mAb) to PPRV in an immunofluorescent antibody test (IFAT). The affected goats were sampled during an outbreak of peste des petits ruminants in Eritrea. Syncytia were also observed in some smears, consistent with a morbillivirus infection, but the IFAT was more sensitive than staining for syncytia in the detection of viral antigen, the two tests giving 63 per cent and 40 per cent of animals, respectively, with positive tests. Positive immunofluorescence was observed in samples from goats in the early and late stages of the disease, but was not observed with a specific rinderpest mAb or with conjunctival smears from uninfected animals. It is concluded that preparation of conjunctival smears for staining for syncytia is a simple procedure which can be applied in the field, and by use of a specific mAb PPRV infection can be rapidly confirmed and differentiated from rinderpest.     

Pharmacokinetics and pharmacodynamics of tilmicosin in sheep and cattle

Tilmicosin is a long-acting macrolide antibiotic currently approved for treatment of bovine respiratory disease in the USA. Serum pharmacokinetics of tilmicosin were compared between cattle (major species) and sheep (minor species) after subcutaneous injection in order to evaluate a new potential application of the drug in currently nonapproved species. There were no significant differences in the elimination rates, maximum serum concentrations, half-lives (t1/2), areas under the curve (AUC), areas under the first-moment curve (AUMC), and mean residence times. Volume of distribution (Vd(area)) and clearance (Cl), when normalized by body weight, were also similar. The only significantly different parameter was time at which maximum drug concentration was reached (tmax), with sheep having the tmax of 3.9 h, compared to 0.5 h in cattle. Although macrolides are considered to be one of the safest anti-infective drugs, adverse cardiovascular effects of several macrolides have been reported. The cardiopulmonary effects of tilmicosin were monitored in healthy adult sheep after receiving a single subcutaneous (s.c.) injection of tilmicosin at the dose of 10 mg/kg, and no significant changes were found. The study indicates that tilmicosin can be used safely and effectively in sheep at the given dose, with no adverse cardiopulmonary effects.     

Anaemia in housed lambs

Anaemia was detected in housed lambs by clinical and haematological investigation. Conjunctival pallor was used as a clinical test for anaemia and the results indicate that this has high specificity (91 per cent to 95 per cent) and low sensitivity (53 per cent to 55 per cent). The haematological results indicated a non-regenerative anaemia with low packed cell volume, red blood cell count and haemoglobin. In a subset of lambs examined biochemically, anaemia was associated with low serum iron concentration and low serum iron binding: cobalt levels were within normal ranges and blood copper levels were slightly raised. At present it is unclear whether this is a primary or secondary iron deficiency.     

A 1957 outbreak of Legionnaires' disease associated with a meat packing plant

Retrospective study shows that a 1957 outbreak of pneumonia in Austin, Minnesota, was Legionnaires' disease. Between June 7 and August 9, 1957, 78 persons were hospitalized with acute respiratory disease of unknown cause. Most had fever, headache, cough, and pneumonitis; two died. Ages ranged from 14-83 years; half of the patients were aged 55 years or older. Eighty-seven per cent were men. There were no secondary cases. Forty-six (59%) of the 78 patients were employees at a local meat packing plant, in distinction to the area's total working population (32%). Serosurvey of 15 of the 1957 outbreak cases and 30 controls matched for age, sex, and either occupation or residence was carried out in 1979. Antibody titers were determined for Legionella pneumophila serogroups 1-4 by means of indirect immunofluorescence. Twelve (80%) of the 15 cases and 13 (43%) of the 30 controls had antibody titers of 1:64 or greater to one or more of the L. pneumophila serogroups. Significant differences in L. pneumophila antibody titers (prevalence and level) were found between cases and control groups matched for residence (serogroups 1-3) or occupation (serogroups 2 and 3). Only three of 20 Austin residents with pneumonia diagnosed between 1978 and 1980 had L. pneumophila antibody titers of 1:128 or greater (p less than 0.001), in comparison to cases. These serologic data and the 1957 clinical and epidemiologic observations support the contention that this is the earliest documented outbreak of Legionnaires' disease.     

Primary carcinoma of the gallbladder. The role of adjunctive therapy in its treatment

Of forty-three patients with carcinoma of the gallbladder discovered ih a twenty-five year period (during which 10,349 patients were diagnosed as having cholelithiasis), eighteen patients (42 per cent) had no obvious tumor outside of the gallbladder at the time of operation, nineteen patients (44 per cent) had local spread of the disease, and six patients (14 per cent) had abdominal carcinomatosis or distant metastasis. In the twenty-one patients who underwent surgical therapy for cure of their disease, the five year survival rate was 33 per cent. The more extensive surgical procedures (other than cholecystectomy alone) did not significantly increase survival. Neither the duration of the symptoms nor the pathologic type of the tumor altered the eventual outcome. No patients with tumor outside the gallbladder at the time of operation survived longer than two years. Compared to those who did not receive it, the fifteen patients treated postoperatively with adjunctive therapy (radiation therapy or chemotherapy or both) lived longer and also were significantly better palliated when tumor outside of the gallbladder was found at the time of operation. From these findings, the routine use of adjunctive therapy is recommended in all patients with disease outside of the gallbladder and serious consideration should be given to its use in all patients found to have carcinoma of the gallbladder.