Fernanda Castillo-Alcala

Mycoplasma bovis in Respiratory Disease of Feedlot Cattle

Mycoplasma bovis has recently emerged as an important cause of chronic caseonecrotic bronchopneumonia, arthritis, and tenosynovitis in beef cattle. Mycoplasma bovis can act as a primary pathogen, yet many cases are coinfected with other bacteria or viruses, and evidence suggests that M. bovis colonizes and perpetuates lung lesions that were initiated by other bacteria, such as M. haemolytica. Mycoplasma bovis elicits a robust humoral immune response, but the resulting antibodies are not protective because of the variable surface proteins, and vaccines have not yet been shown to prevent disease. Mycoplasma bovis infections are responsible for a high proportion of the chronic disease occurring in feedlots, and the welfare of such animals is an important aspect of feedlot health management.

Leptospirosis in farmed deer in New Zealand: A review

Abstract Current knowledge of leptospirosis in farmed deer in New Zealand is reviewed. Over the past 25 years, leptospirosis has been reported to occur in individual cases as well as in herd outbreaks in farmed deer and in human cases linked to farmed deer. Serological studies and evidence from bacterial culture suggest infection is widespread. Mixing of young stock from several sources appears to be a significant risk factor for outbreaks. The culture of Leptospira interrogans Hardjobovis, Pomona and Copenhageni has been reported. Infection with serovar Hardjobovis had the highest prevalence, either individually or mixed with serovar Pomona. Infection with serovar Copenhageni appears uncommon and its pathogenicity in deer is unproven. Titres to serovars Australis, Ballum, Balcanica and Tarassovi have been reported. Deer appear to be maintenance hosts for serovar Hardjobovis, incidental or accidental hosts and probably a maintenance population for serovar Pomona, since some infections persist for several months, and accidental hosts for serovar Copenhageni. Serovar Pomona appears to produce clinical and probably subclinical disease, whereas serovar Hardjobovis appears to cause only subclinical disease, although the relative risk of disease causation has not been determined. Clinical disease is usually manifested by haemolysis, jaundice, renal lesions, haemoglobinuria and often by sudden death. Renal lesions are commonly observed at slaughter and many are associated with leptospiral infections. Occupationally, slaughterhouse workers appear to beat greatest risk of contracting the disease from deer. Vaccination produces serological responses, but its effectiveness in protecting against disease, and prevention or reduction of shedding in urine, has not yet been confirmed in deer. More robust knowledge of the epidemiology of leptospiral infections in deer, and the effectiveness of vaccines and vaccination regimes, is needed to assist the deer industry to develop a strategy to manage this disease.

Regional seroprevalence of leptospirosis on deer farms in New Zealand

Abstract AIM: To undertake a seroprevalence survey to estimate the distribution of infection by Leptospira spp. serovars Hardjobovis, Pomona and Copenhageni in farmed deer herds regionally throughout New Zealand. METHODS: Between March 2003 and February 2005, 111 red and red x wapiti deer herds not using a leptospiral vaccine were selected from nine regions from Northland to Southland. Eighty-three herds were selected for on-farm collection of 12– 20 blood samples from hinds predominantly 9–30 months of age, by jugular venepuncture, while similar numbers, predominantly males9–30 months of age, per farm were collected from 28 herds at sticking at deer slaughter premises (DSP). Serum was stored frozen until analysed using the microscopic agglutination test (MAT). Titre cut-points of 1:24 for serovar Hardjobovis and 1:48 for serovars Pomona and Copenhageni were considered positive at the individual animal level. Herds were considered seropositive if there were at least three animals per herd seropositive to any serovar. RESULTS: Eighty-one percent of herds were seropositive for Leptospira spp. Hardjobovis was the predominant serovar at the herd (78%) and individual animal (60.8%) levels. The seroprevalence of Pomona was 20% and 8.4% at the herd and animal levels, respectively. Dual seroreactivity to both Hardjobovis and Pomona was observed in 16% of herds and 6.6% of individuals; within-herd seroprevalence for both serovars ranged from 0 to 100%.No herds and 1.2% of animals were seropositive for serovar Copenhageni. There was a regional difference in the prevalence of herds seropositive to both Hardjobovis and Pomona (p=0.02), but no difference between regions in the prevalence of herds seropositive to either Hardjobovis or Pomona alone. CONCLUSION: The seroprevalence of Leptospira spp. serovars is high, and distributed in farmed deer herds throughout New Zealand. CLINICAL SIGNIFICANCE: Results confirm the risk of disease and potential loss of production in deer, and exposure of infection to humans and other livestock from deer is widespread, demonstrating that control of the disease needs to be considered at a national rather than regional level.

Prevalence and genotype of Mycoplasma bovis in beef cattle after arrival at a feedlot

OBJECTIVE To determine the prevalence of Mycoplasma bovis infection in the lungs of cattle at various times after arrival at a feedlot, to measure the relationship between clinical disease status and the concentration and genotype of M bovis within the lungs, and to investigate changes in the genotype of M bovis over time. SAMPLE Bronchoalveolar lavage fluid (BALF) from 328 healthy or pneumonic beef cattle and 20 M bovis isolates obtained from postmortem samples. PROCEDURES The concentration of M bovis in BALF was determined via real-time PCR assays, and M bovis isolates from BALF were genotyped via amplified fragment length polymorphism (AFLP) analysis. RESULTS Prevalence of M bovis in BALF was 1 of 60 (1.7%) at arrival to a feedlot and 26 of 36 (72.2%) and 36 of 42 (85.7%) at ≤ 15 days and 55 days after arrival, respectively. Neither the concentration nor the AFLP type of M bovis in BALF was correlated with clinical disease status. The M bovis AFLP type differed between early and later sampling periods in 14 of 17 cattle. CONCLUSIONS AND CLINICAL RELEVANCE The findings implied spread of M bovis among calves and suggested that host factors and copathogens may determine disease outcomes in infected calves. Chronic pulmonary infection with M bovis may represent a dynamic situation of bacterial clearance and reinfection with strains of different AFLP type, rather than continuous infection with a single clone. These findings impact our understanding of why cattle with chronic pneumonia and polyarthritis syndrome inadequately respond to antimicrobial treatment.

Molecular and immunohistochemical diagnosis of Francisella noatunensis subsp. orientalis from formalin-fixed, paraffin-embedded tissues

Members of the genus Francisella (viz., F. noatunensis subsp. orientalis [Fno] and F. noatunensis subsp. noatunensis) have been described as causative agents of chronic granulomatous and pyogranulomatous lesions in wild and cultured fish species. In the present study, 68 archived formalin-fixed, paraffin-embedded (FFPE) tissues from several fish species, collected at different geographical locations from 2000 to 2011, were analyzed using a real-time polymerase chain reaction assay for the detection of the Fno intracellular growth loci C (iglC) gene and by immunohistochemistry for the demonstration of Fno antigens. The results revealed a high correlation between these 2 diagnostic techniques validating their use for the diagnosis of Fno infection in archived FFPE tissues and confirming the presence of Fno in fish species from the Cari y years of the present century.

Amounts and distribution of mineral elements associated with liveweight gains of grazing red deer (Cervus elaphus)

Abstract Fourteen red deer with liveweights ranging from 9.0 to 94.8 kg which had died from natural causes or were killed by barbiturate overdose were dissected, and the brain, lungs, heart, spleen, liver, kidney, pancreas, stomach, small intestine, hind gut, muscle, bone, skin and blood weighed and subsampled for mineral element determinations carried out by inductively coupled emission spectrometry. Total mineral element composition associated with each tissue was determined from the weight of tissue and its mineral concentration. Bone and muscle content were estimated using published equations derived from sheep. Data are presented on the concentrations and amounts of Ca, P, Mg, Na, K, Cu, Zn, Fe and Mn present in the organs, digestive tract, offal, muscle, bone and skin. Expressed as a percent of total mineral based on the empty body weight, bone contained 99% Ca, 88% P, 59% Na and 59% Mg; muscle contained 82% K, 62% Zn and 38% Fe. Soft tissues and organs usually contained less than 6% of a mineral element. In the case of Cu, the distribution between the liver, muscle and bone was 77, 8 and 3% for the neonatal calf and 24, 59 and 2% for the young adult. Each kilogram gain in liveweight was associated with 13.9 gCa, 10.7 gP, 0.53 gMg, 1.0 g Na, 2.4 g K, 0.91 mg Cu, 25.4 mg Zn, 43.0 mg Fe and 0.44 mg Mn.

Branchial cysts in two Amazon parrots (Amazona species).

Abstract A 37-year-old yellow-crowned Amazon parrot (Amazona ochrocephala) and a 20-year-old red-lored Amazon parrot (Amazona autumnalis) each presented with a large mass localized on the lateral neck. With the first bird, there was no evidence of signs of pain or discomfort, and the bird prehended and swallowed food normally. The second bird showed signs of mild upper-gastrointestinal discomfort. Results of an ultrasound examination and aspiration of the mass on each bird revealed a cystic structure. A computed tomography performed on the second bird revealed a large polycystic mass connected to the pharynx by a lateral tract. During surgical resection, both masses were found to originate from the subpharyngeal area. Based on topography and the histopathologic and immunohistochemical results, the masses were determined to be a second branchial cleft cyst for the first case and a second branchial pouch cyst for the second case. In addition, a carcinoma was present in situ within the epithelium of case 1, and the cyst in case 2 was secondarily infected. Branchial cysts are uncommonly diagnosed in veterinary and human medicine. These 2 cases are the first documented in parrots and appear similar to second branchial cysts reported in adult humans.

Sedative and mechanical hypoalgesic effects of butorphanol in xylazine-premedicated donkeys

REASONS FOR PERFORMING STUDY Combinations of α2 -adrenoceptor and opioid agonists are commonly used in equids, but little scientific information is available on donkeys. OBJECTIVES To compare the sedative and hypoalgesic effects of xylazine alone or in combination with different dosages of butorphanol in donkeys. STUDY DESIGN Placebo-controlled, operator-blinded, randomised, crossover, Latin square study. METHODS Six donkeys received intravenous normal saline and normal saline (NS-NS); xylazine (0.5 mg/kg bwt) and normal saline (X-NS); xylazine and 10 μg/kg bwt butorphanol (X-B10); xylazine and 20 μg/kg bwt butorphanol (X-B20); xylazine and 30 μg/kg bwt butorphanol (X-B30); and xylazine and 40 μg/kg bwt butorphanol (X-B40). Sedation scores (SS), head height above ground (HHAG) and mechanical nociceptive thresholds (MNT) were assessed before and for 120 min after treatment. Areas under the curve (AUC) values for 0-30, 30-60 and 60-120 min were computed for SS, HHAG and MNT. As appropriate, differences between treatments were analysed using the Friedman test followed by Dunns test and a repeated measures one-way analysis of variance followed by Tukeys test; significance was set at P<0.05. RESULTS All treatments apart from NS-NS induced sedation. Butorphanol treatments induced significantly larger SS-AUC0 -30 values than those for NS-NS (P<0.05). Compared to corresponding NS-NS values, HHAG-AUC0 -30 values were significantly smaller for all other treatments (P<0.001) and HHAG-AUC30-60 values were significantly smaller for X-B40 (P<0.05). Compared to NS-NS, all treatments induced mechanical hypoalgesia and yielded significantly larger MNT-AUC0-30 values (P<0.001). Treatment X-NS yielded significantly smaller MNT-AUC0 -30 values than those for X-B30 and X-B40 (P<0.05). Only MNT-AUC30 -60 values for X-B30 and X-B40 were significantly larger than those for NS-NS and X-NS (P<0.05). CONCLUSIONS Sedation and mechanical hypoalgesia induced by xylazine were enhanced by butorphanol at 40 μg/kg bwt. This drug combination may be suitable for chemical restraint of donkeys undergoing certain clinical procedures.

Sedation and mechanical antinociception after intravenous administration of detomidine in donkeys: a dosage–effect study

There is limited, useful, scientific information on detomidine in donkeys. This study compared the effects of intravenous saline, detomidine (10, 13.5, 17 and 20 μg/kg) and acepromazine (50 μg/kg) in donkeys by computing areas under the curve for 0–30, 30–60 and 60–120 minutes (AUC0–30, AUC30–60 and AUC60–120) for sedation scores, head heights and mechanical nociceptive thresholds (MNTs). For sedation scores, all detomidine treatments, except 10 μg/kg, increased AUC0–30 values compared with saline, and AUC0–30 values were larger for 17 μg/kg detomidine than for acepromazine. All head height AUC values were lower for detomidine than for saline (except AUC60–120 for 10 μg/kg detomidine) and acepromazine (except AUC0–30 for 10 and 20 μg/kg detomidine, and AUC60–120 for 10 μg/kg detomidine). For MNTs, all detomidine treatments increased AUC0–30 and AUC30–60 values compared with saline and acepromazine; AUC30–60 values were smaller for 10 μg/kg than for 17 and 20 μg/kg detomidine. MNT AUC60–120 values were larger for 20 μg/kg detomidine than for saline, 10 μg/kg detomidine and acepromazine. Detomidine induced sedation and antinociception, but only antinociception was dosage dependent. Selection of detomidine dosage for donkeys may depend on the required duration of sedation and/or degree of analgesia.

A survey of anthelmintic use and internal parasite control in farmed deer in New Zealand.

Abstract AIM: To survey parasite control programmes and anthelmintic usage over a 12-month period on deer farms in New Zealand. METHODS: A questionnaire of general farm data, policy and procedures for anthelmintic use, anthelmintic programmes for weaner and older deer, general information and understanding of parasite management practices was posted to 500 deer farmers in November 2004. RESULTS: Two hundred and twenty-seven (45.4%) replies were received, and 198 (39.6%) were suitable for analysis. Ninety-four percent of respondents used anthelmintics at least once in the 12-month period; 53% treated all classes of deer and 22% treated only weaners. Seventy-four percent based anthelmintic dose on weight of the heaviest animal, and 36% used a weigh scale. Weaner deer (n=175 farms) were treated 1–13 (mean 3.2) times in their first 12 months, at the earliest commencing in January and at the latest in November. The mean interval between treatments ranged from 41 to 46 days. Yearling and adult hinds and stags were treated at least once (range 1–7 times) on 55–64% of farms, depending on class of animal. Moxidectin was the anthelmintic most commonly used (46–58%, depending on class of animal), followed by abamectin, eprinomectin, oxfendazole, ivermectin, albendazole, levamisole and doramectin. Perceived efficacy was the most common reason for choosing a type of anthelmintic. Weight gain and body condition were the most common measures used for monitoring parasitism in weaners and older deer, respectively, and few respondents used faecal egg and/or larval counts. Coughing and/or scouring were associated with parasitism in weaners on 13–14% of farms, and deaths associated with lungworm and gastrointestinal parasites were recorded on 5% and 3% of farms, respectively. Veterinary input to diagnosis was involved in 23% of events. Production losses and/or death of yearling and/or adult deer due to parasitism were reported by 27% of respondents. When planning anthelmintic treatment programmes, 63% of respondents followed advice from veterinarians. Thirty-four percent always placed deer on clean or spelled pastures after treatment, while 32% did that often. Fifteen percent had incorporated forages and/or herbs with assumed anthelmintic properties into their parasite control programme. Forty-four percent were very confident of a return on investment when using anthelmintics for their deer. Respondents stated that their knowledge of the life cycle of the major parasites of deer was very good (8%), reasonably good (61%), poor (28%), or nil (3%). CONCLUSION: Anthelmintics are used on almost all deer farms, and practices and programmes vary considerably. Opportunities exist for veterinarians to assist deer farmer clients to improve their parasite control programmes.