Epidemiological Observations in a Corriedale Flock affected by Brucella ovis

Brucellosis in sheep, caused by Brucella ovis, is primarily a chronic infectious disease of rams with epididymitis as its most characteristic lesion. Six hundred rams from an infected farm were clinically and serologically examined once a year, over a 3-year period. An increase from 2.1% to 6.3% in the prevalence of animals serologically positive to B. ovis occurred over the 3 years. However, the prevalence of rams with lesions in the reproductive tract declined from 14.2% to 6.5% in the third year following one year of strict culling of clinically affected and rams that were serologically positive for B. ovis. Clinical lesions found in the 179 affected rams fell into two main categories: rams with epididymitis and rams with affected lymph nodes. These results suggest that the prevalence of the disease relates mainly to the sexual activity of the animal and not to age in itself. A single cull based on the results of clinical examination and serological test results was unable to decrease the prevalence of B. ovis in an extensive Corriedale sheep flock.     

Transmission of Brucella ovis from rams to red deer stags

AIM: To determine whether B. ovis will transmit from infected rams to non-infected red deer stags (Cervus elaphus) grazing together in the same paddock. METHODS: Six rams artificially infected with B. ovis were grazed with six non-infected 14-month-old red deer stags for a four and a half month period from March 4 to July 20, 1999. Stags were blood sampled at one- to six-weekly intervals to test for B. ovis antibodies using a complement fixation test. Stags that seroconverted were semen sampled to test for B. ovis infection by bacteriological culture. RESULTS: Between day 92 and day 124 of grazing together (June 4 and July 6), sera from five of the six stags became positive in the B. ovis complement fixation test. B. ovis was cultured from semen samples from four of the seropositive stags. CONCLUSIONS: Brucella ovis can be transmitted from infected rams to non-infected stags grazing in the same paddock, suggesting that B. ovis infection in farmed deer in New Zealand initially came from infected rams. Whether transmission occurs from direct contact between rams or stags, or indirectly by environmental contamination needs to be established.     

Dictyocaulus infection in farmed red deer (Cervus elaphus)

Post mortem examination of red deer calves on a deer farm situated on hill ground in north-east Scotland revealed infection by a lungworm morphologically similar to Dictyocaulus viviparus. Trials were conducted to monitor the natural development of D viviparus infection in red deer, to investigate the value of a commercial lungworm vaccine and to evaluate methods of treating clinical cases. The findings indicate that the syndrome may be less apparent in red deer than it is in cattle, protection might be gained by vaccination and that housing and medication provide useful therapy. The extent of clinical disease is likely to depend on the general health, bodily condition and nutritional status of the animals versus the weight of infection acquired from the pasture. However, various factors can affect both sides in this confrontation.     

Effects of Brucella ovis infection on semen characteristics of 16-month-old red deer stags

AIM: To determine the effects of Brucella ovis infection on semen characteristics of 16-month-old red deer stags (Cervus elaphus). METHODS: At monthly intervals during March, April and May, semen was collected using electro-ejaculation from 9 yearling red deer stags that had been artificially infected with B. ovis 3 months previously. In March, semen was also collected from 6 non-infected stags from the same peer group for comparison. Semen was evaluated for gross appearance, percentage of sperm showing forward motility, sperm morphology and sperm density/ml of semen, and the presence of white blood cells was determined. In addition, at the time of semen collection, the epididymes of each stag were palpated and lesions recorded. RESULTS: Grossly visible purulent material was present in semen from 6/9 infected stags and the percentage of sperm showing forward motility did not exceed 20% in any of these samples. Increased numbers of white blood cells and cellular debris were evident in semen from 8/9 infected stags. Compared with non-infected stags, sperm motility in semen from infected stags was significantly reduced (p<0.05). There were no differences in percentage of morphologically normal sperm between groups, but infected stags had more detached sperm heads present in semen than non-infected stags (p<0.05). Only 2 of the infected stags had lesions of epididymitis evident on scrotal palpation. CONCLUSIONS: B. ovis infection is likely to have a detrimental effect on stag semen quality. While there was variation between individual animals, overall sperm motility was decreased and semen from infected stags had increased numbers of white blood cells and detached sperm heads. CLINICAL RELEVANCE: The fertility of breeding stags may be reduced if they are infected with B. ovis and this possibility should be considered when investigating reproductive problems of deer.     

Experimental tuberculosis in red deer (Cervus elaphus)

This study was designed to investigate experimental Mycobacterium bovis infection of red deer (Cervus elaphus). Three intravenously inoculated deer (dose 10 microg-1000 microg) developed miliary tuberculosis of the lungs and all died within 28 days of being infected. No clinical illnesses were observed in four subcutaneously (dose 1 microg-1000 microg) and three intratracheally (dose 10 microg-100 microg) inoculated deer. At the conclusion of the experiment six weeks post inoculation, these seven animals reacted to 2 mg/ml of bovine purified protein derivative. The principal lesions in the intravenously inoculated deer were in the lungs which had multiple foci of necrosis containing very large numbers of acid fast bacilli. A gradation of changes was seen in the subcutaneously inoculated deer. The animal receiving the 1 microg dose only had lesions at the injection site and the draining prescapular lymph node. Deer receiving higher doses also had histopathological changes in the lungs and liver. Microscopic changes in the intratracheally infected animals were restricted to the thoracic cavity. The ability of the deer to controlled infection was related to the route of inoculation.     

Tuberculosis in imported red deer (Cervus elaphus)

An outbreak of tuberculosis due to Mycobacterium bovis in farmed red deer imported from an eastern European country is described. Twenty-six of the 106 deer examined at autopsy were found to be infected and 19 had visible lesions of tuberculosis. Single comparative intradermal tuberculin tests on 51 deer showed that the test had a specificity of 61.3 per cent and a sensitivity of 80 per cent relative to subsequent biological and cultural tests on tissues taken at autopsy. Three hundred and seventy eight culled fallow and sika deer which had been running in a park in contact with some of the infected animals were found to be free of tuberculosis.     

Experimental tuberculosis in red deer (Cervus elaphus)

This study was designed to investigate experimental Mycobacterium bovis infection of red deer (Cervus elaphus). Three intravenously inoculated deer (dose 10µg–1000µg) developed miliary tuberculosis of the lungs and all died within 28 days of being infected. No clinical illnesses were observed in four subcutaneously (dose 1 uµg–100uµg) and three intratracheally (dose lµg–100µg) inoculated deer. At the conclusion of the experiment six weeks post inoculation, these seven animals reacted to 2 mg/ml of bovine purified protein derivative. The principal lesions in the intravenously inoculated deer were in the lungs which had multiple foci of necrosis containing very large numbers of acid fast bacilli. A gradation of changes was seen in the subcutaneously inoculated deer. The animal receiving the 1µg dose only had lesions at the injection site and the draining prescapular lymph node. Deer receiving higher doses also had histopathological changes in the lungs and liver. Microscopic changes in the intratracheally infected animals were restricted to the thoracic cavity. The ability of the deer to control infection was related to the route of inoculation.     

Persistence, serodiagnosis and effects on semen characteristics of artificial Brucella ovis infection in red deer stags

AIMS: To investigate the persistence of infection and serum antibody titres after infection of red deer (Cervus elaphus) stags with Brucella ovis, and compare these with those of rams. To assess the effects of recent and chronic infection on semen characteristics of stags. METHODS: Fourteen stags and eight rams were artificially infected with B. ovis by intravenous inoculation. Semen and blood samples were collected at approximately monthly intervals for 649 days. Semen samples were subjected to bacterial culture, and sera were tested for B. ovis antibodies using a complement fixation test (CFT) and an enzyme-linked immunosorbent assay (ELISA). At the end of the study, animals were slaughtered and reproductive organs subjected to bacterial culture. During the first and second breeding seasons, three and five semen samples, respectively, were evaluated from each stag for sperm motility and morphology. RESULTS: Twelve of 14 (86%) stags and 6/8 (75%) rams developed a patent B. ovis infection and shed the organism in semen. All six infected rams continued to shed B. ovis in semen throughout the 649-day study period, and at slaughter B. ovis was isolated from the reproductive tract and urinary bladder. In contrast, 10/12 (83%) infected stags stopped shedding B. ovis in semen 103-342 days after inoculation, and the organism could not be isolated from their reproductive tracts at slaughter. The remaining two infected stags shed B. ovis in semen throughout the study period and the organism was isolated from their reproductive tracts at slaughter. All inoculated animals initially developed serum antibody titres detectable using the B. ovis CFT and ELISA. For infected stags, the diagnostic sensitivity of these tests was 100% for the first 166 days, but decreased to 50-90% after this. The diagnostic sensitivity for the infected rams was 100% throughout the study period. Infection in stags resulted in variable effects on semen characteristics. Eight of 12 (67%) infected stags had a mean sperm motility of < 50%, and < 60% mean normal sperm in the first year of infection. Seven of these stags had resolved the infection by the following breeding season, and there was a significant improvement in sperm motility and morphology. CONCLUSIONS: Stags are as susceptible as rams to experimental B. ovis infection. However, the majority of infected stags resolved the infection within a year, whereas rams remained infected for at least 649 days (22 months). Serology, using CFT and ELISA, was effective at detecting infection during the first 166 days in both species, but after this time was less effective at detecting infection in stags than in rams. Infection with B. ovis had variable but generally deleterious effects on the semen characteristics of stags, which resolved following resolution of the infection. Differences in the characteristics of the disease in stags compared with rams mean that different control methods are warranted for the two species. CLINICAL RELEVANCE: Most stags infected with B. ovis are likely to resolve the infection within a year, and semen characteristics return to levels acceptable for breeding. Serology is useful for detection of infection in the early stages of the disease, but once disease has been present in the herd for some time false-negative reactions are likely to occur in individual stags.     

Electrical stunning of red deer (Cervus elaphus)

Eighteen of 23 red deer (Cervus elaphus) at a deer slaughtering premises were successfully stunned with an apparatus modified from that normally used to stun sheep. The five unsuccessful electrical stuns were associated with poor head restraint and poor head contact by the electrodes. The median stunning current was 0.9 A, and in the majority of cases the duration of stunning was less than 1 second. The signs of the electrically induced epileptiform seizures in the deer were dissimilar to those seen in sheep, cattle and pigs, in that the initial tonic phase was less marked, and of shorter duration. A similar shorter and less obvious tonic phase was noted in four deer shot with a captive bolt pistol. Two animals which were electrically stunned, and bled within 10 seconds, showed no signs of recovery while bleeding. The electroencephalograms of four deer stunned with currents of 1.3 A for a duration of either 0.5 or 1.0 seconds were recorded under more controlled conditions. All four animals developed electroencephalograms typical of an epileptiform seizure. The animals exhibited behavioural reactions similar to the other 18 animals in the trial at the deer slaughtering premises and were rendered unconscious for between 54 and 122 seconds. The electroencephalogram activity amplitude was greater than that recorded immediately before stunning and took between 6 and 9 seconds to build up to maximum value. It is concluded that, providing the heads of deer are adequately restrained, head-only electrical stunning can be incorporated into a humane method of slaughter for deer.     

Atypical symptoms in a case of sleepy foal disease (Actinobacillus equuli infection)

Extract

It was reported that a maiden thoroughbred marc was unwilling to feed her foal in spite of persistent efforts by the foal during the first eight hours after birth.     

Pharmacokinetics of ceftiofur in red deer (Cervus elaphus)

Twelve adult female red deer (Cervus elaphus) were given 250 mg of ceftiofur sodium by intramuscular injection (i.m.) and ballistic implant in a crossover design. Blood samples were taken from an in-dwelling jugular catheter prior to drug administration and at 0.25, 0.5, 1, 2, 4, 8, 12, 24, 36, 48, and 72 h postadministration of the drug. Samples were centrifuged and plasma kept frozen at -70 degrees C until analysis for ceftiofur and active metabolites using an HPLC method. The pharmacokinetics of ceftiofur and metabolites after i.m. dosing and following ballistic implant were quite different. Absorption after i.m. injection was rapid; whereas following ballistic implant there was a lag-time until concentrations were detectable in plasma. The maximum concentration reached in plasma was higher following injection compared with ballistic implant, however the AUC calculated after ballistic implant was almost identical to the mean AUC found after i.m. dosing. The results indicate that i.m. administration of ceftiofur maintains adequate plasma levels for most susceptible bacterial pathogens for at least 12 h; therefore twice daily administration is needed in red deer. Ballistic implants produced plasma concentrations above the MIC for most bacterial pathogens from 4 to 24 h in most animals after administration; however, absorption of the drug was variable and some did not maintain effective concentrations for more than a few hours. Ceftiofur is a useful drug in red deer and twice daily i.m. administration dosing should allow treatment for susceptible bacterial pathogens.     

Congenital nutritional myodegeneration (white muscle disease) in a red deer (Cervus elaphus) calf

CASE HISTORY A 5-day-old red deer calf was submitted with tachypnoea and dyspnoea, and was reluctant to move.

CLINICAL FINDINGS: Muscular damage was established via elevated creatinine phosphokinase (CPK) activities (5,000 U/L), while concentrations of Se in whole blood were low (24.8 nmol/L). The animal died despite treatment with penicillin-streptomycin and 0.1 mg/kg Se/vitamin E administered by S/C injection.

DIAGNOSIS: Necropsy and histological examination of cardiac and skeletal muscle confirmed the presumptive diagnosis of congenital white muscle disease (WMD). Prophylactic administration of a Se/vitamin E commercial preparation (as above) to another calf born in the same herd one month later was associated with good health and apparently normal growth and development.

CLINICAL RELEVANCE: Congenital WMD due to Se deficiency can be fatal in red deer calves. However, prophylactic administration of Se and vitamin E to neonatal calves may be beneficial for neonatal red deer calves.     

Pharmacokinetics of oxfendazole in red deer (Cervus elaphus)

The pharmacokinetics of oxfendazole (OFZ) in red deer (Cervus elaphus) was examined. OFZ, administered per os at 4.53 mg kg-1, was extracted in ether from plasma and identified and concentrations estimated by high pressure liquid chromatography. Irrespective of whether the animals were fed concentrates indoors as pellets or grass while on pasture, OFZ was absorbed rapidly. Concentrations of OFZ in plasma reached maxima within 20 hours (0.83 and 1.005 mg litre-1 respectively) and were undetectable 36 hours after administration. Fenbendazole was not detected at any time in the chromatograms. Metabolism of OFZ occurred rapidly producing the sulphone metabolite. In comparison with published data for OFZ in sheep, red deer appear to metabolise OFZ and excrete OFZ sulphone at much faster rates. Consequently, anthelmintic efficacy is likely to vary from species to species.     

Babesias of red deer (Cervus elaphus) in Ireland

ABSTRACT: Blood samples were obtained from 38 wild red deer (Cervus elaphus) at two sites in Ireland and subjected to PCR analysis of the 18S rRNA gene followed by sequencing. Two fragments of the 18S rRNA gene were generated by two different PCR protocols and subsequent sequencing suggested that at least six of the deer were infected by a babesia that, in those loci, is indistinguishable from Babesia divergens, an important tick-borne pathogen of cattle and of zoonotic significance. Additionally, a B. odocoilei-like parasite was detected in three samples and a babesia that did not match any sequences in the GenBank database was found in five samples. Neither B. capreoli nor B. venatorum (EU1) were found. There have been several reports of B. divergens occurring in deer species, including red deer, roe deer (Capreolus capreolus) and reindeer (Rangifer tarandus). However, in view of recent re-sequencing of bovine-origin samples deposited previously in GenBank, it is unlikely that any of these sequences from deer are B. divergens. The present study describes the only deer piroplasm detected so far that shows complete identity with B. divergens, in just over half of the 18S rRNA gene. The entire gene of this deer parasite should be analysed and transmission experiments undertaken before the infectivity of B. divergens for red deer can be confirmed.     

Influence of winter feed restriction and summer compensation on skeletal development in red deer stags (Cervus elaphus)

The influence of two planes of nutrition (unrestricted and 70 per cent restricted during the winter) on skeletal development as illustrated by the metacarpus was studied in 12 red deer stag calves. At approximately three-monthly intervals from January 1978 when the stags were seven months old, until August 1979 when the stags were 26 months old, radiographs of the right metacarpus were taken. From the resultant radiographs, diaphyseal length, diaphyseal breadth, breadth of mineralised bone, cortical bone index and area of mineralised bone were measured. Growth in length was complete by August 1978. There were no differences in length between the unrestricted and restricted stags at that time. Differences in breadth, area and cortical bone index were maintained throughout the study although differences in area of mineralised bone were the only measure significantly different throughout the study. It is considered that the major influence of plane of nutrition on this index of skeletal development in deer is on breadth and thickness of cortical bone, resulting in a weaker bone of the same length in the winter restricted stags.