Journal of the South African Veterinary Association

**Cooking and drying as effective mechanisms in limiting the zoonotic effect of Mycobacterium bovis in beef**

For this study 48 non-infected muscle, lymphatic and visceral bovine tissue samples were collected from an approved red meat abattoir and spiked with 8 x10(7)cfu/ml of M. bovis. The different spiked samples were subjected to cooking and drying (drying through the process of biltong-making) processes in a controlled laboratory environment. Mycobacterial isolates confirmed as M. bovis by means of polymerase chain reaction (PCR) were observed in 17 of a total of 576 samples that were exposed to the secondary processing method of cooking. The study showed that not only can M. bovis survive the cooking process but the survival of the bacterium will be determined by its unique adaptive changes to the surrounding composition of the environment. The results for the samples exposed to the drying process (n = 96) did not show any growth, suggesting that the process of biltong production as used in this study is likely to render infected meat safe for human consumption.

**Assessment of viability and acrosomal status of Asian elephant (Elephas maximus) sperm after treatment with calcium ionophore and heparin**

Knowledge about the acrosomal status of Asian elephant (Elephas maximus) sperm is extremely limited. The objective of this study was to evaluate the viability and acrosomal status of Asian elephant sperm following induction by calcium ionophore and heparin using propidium iodide (PI) and fluorescein isothiocyanate conjugated peanut agglutinin (FITC-PNA). Semen samples were collected from elephant bulls by manual stimulation. Semen was diluted with extender, cooled to 4 °C and transported to a laboratory for the experiment. Sperm cells were incubated in modified Tyrode's medium containing either 1 mM calcium ionophore or 10 mg/ml heparin for 5 h at 39°C. Sperm recovered at the onset (0 h), 1, 2, 3,4and5hof incubation were simultaneously assessed for the viability and acrosomal status using dual staining of FITC-PNA and PI. Results were confirmed by transmission electron microscopy. A progressive increase in the proportion of live-acrosome reacted sperm was observed within3hofincubation in both treatment groups which slightly decreased at 4 to5hof incubation. At 1 to3hof incubation, the percentage of live-acrosome reacted sperm induced by calcium ionophore was higher (P < 0.05) than those induced by heparin and the control. However, there were no statistical differences at 4 to 5 h of incubation. A progressive reduction of the percentage of motile sperm was observed in the control as well as both treatment groups. Sperm motility decreased sharply when they were incubated in calcium ionophore compared with incubation in heparin and control groups. These results indicate that the occurrence of live-acrosome reacted sperm in the Asian elephant was induced by calcium ionophore at a rate higher than that induced by heparin.

**The epidemiology of lion lentivirus infection among a population of free-ranging lions (Panthera leo) in the Kruger National Park, South Africa**

Feline immunodeficiency virus is a lentivirus of domestic cats that causes significant lifelong infection. Infection with this or similar lentiviruses has been detected in several nondomestic feline species, including African lions (Panthera leo). Although lion lentivirus (FIVple) infection is endemic in certain lion populations in eastern and southern Africa, little is known about its pathogenic effects or its epidemiological impact in free-ranging lions. This report describes the epidemiological investigation of lentivirus positivity of free-ranging lions in the Kruger National Park, South Africa. A nested polymerase chain reaction assay for virus detection was performed on all whole blood samples collected. In addition, serum samples were tested for cross-reactive antibodies to domestic feline lentivirus antigens and to puma lentivirus synthetic envelope peptide antigen. The results were analysed in conjunction with epidemiological data to provide a descriptive epidemiological study on lion lentivirus infection in a free-ranging population of lions. The overall prevalence of lentivirus infection was 69 %, with a prevalence of 41 % in the north of the park, and 80 % in the south. Adult males had the highest prevalence when combining the factors of sex and age: 94 %. The lowest prevalences were found among juveniles, with male juveniles at 29 %. Adults were 5.58 times more likely to test positive for FIVple than juveniles, with adult males being 35 times more likely to be test positive for FIVple compared with juvenile males. This research represents the 1st epidemiological study of the lion lentivirus among free-ranging lions in the Kruger National Park.

Economic assessment of the performance of trypanotolerant cattle breeds in a pastoral production system in Kenya

Cattle are the major source of food security and income for pastoral farmers in sub-Saharan Africa. However, infectious and parasitic diseases remain a major constraint to improved cattle productivity in the region. The use of animal health economics to support decision-making on cost-effective disease control options is increasingly becoming important in the developing world. Trypanotolerant indigenous Orma/zebu cattle in a trypanosomosis-endemic area of Kenya were evaluated for economic performance using gross-margin analysis and partial-farm budgeting. Orma/zebu and Sahiwal/zebu cross-bred cattle were exposed to similar husbandry practices and monitored for growth rate, incidence of common infections (trypanosomosis, anaplasmosis, babesiosis, East Coast Fever and helminthosis) and the cost of treatment assessed. Interview questionnaires were also used to assess the preference rating of the 2 breeds. Results indicated that incidence of infection was trypanosomosis 3 %, anaplasmosis 58 %, babesiosis 11 %, East Coast Fever 22 % and helminthosis 28 %, with no significant difference between breeds. The Orma/zebu and Sahiwal/zebu breeds had comparable economic benefits, hence a pastoralist in Magadi division is likely to get similar returns from both breeds. This study therefore recommends adoption of not only the Sahiwal/zebu but also the Orma/zebu breed for cattle improvement in trypanosomosis endemic areas and conservation of indigenous genetic resources.

Prevalence of clinical and subclinical mastitis and quality of milk on smallholder dairy farms in Tanzania

A cross sectional study was conducted during October and November 2006 on 69 smallholder dairy farms with lactating cows in Mvomero and Njombe districts Tanzania, to determine the prevalence of mastitis and to assess the milk quality on the study farms. Clinical mastitis was investigated using clinical changes of udder and milk at animal level. Cow-side California Mastitis Test (CMT) and microbiological cultures were used to assess subclinical mastitis at quarter level. Milk quality was determined on bulk milk samples at herd level using alcohol and acidity tests, butter fat content, total solids, ash content as well as Delvotest® for antimicrobial residues. Overall prevalence of clinical mastitis at herd level in both districts was 21.7 % (n = 69). Based on CMT, prevalence of subclinical mastitis at animal level was 51.6 % (n = 91). Prevalence of bacterial isolates at animal level was 35.2 % (n = 91) while for fungal it was 16.7 % (n = 90). Based on CMT results, prevalence of subclinical mastitis at quarter level was 30 % (n = 353), while for bacteria and fungi it was 16% and 6 % respectively. Contamination of milk with antimicrobial residues was 4.5 % (n = 67). The milk quality parameters for most of the milk samples were within acceptable levels. Findings in this study have demonstrated high prevalence of subclinical mastitis that may contribute to low productivity of dairy cattle in both districts. About 20 % of CMT subclinical cases had no involvement of microbial pathogens that suggested the need for minimal interventions with antimicrobial agents. These findings call for use of udder disinfectants and improved milking hygiene as intervention strategies to control mastitis on the smallholder dairy farms in Tanzania.

After-hours equine emergency admissions at a university referral hospital (1998-2007): Causes and interventions

Medical records of equine after-hours admissions from 1998 to 2007 are reviewed. Data extracted from the medical records included signalment, reason for admission, pre-admission treatment, clinical presentation, procedures performed, final diagnoses, complications occurring in hospital, length of stay and outcome. Eight hundred and twenty after-hours admissions were available of which 75 % were classified as emergencies. Most horses originated from Gauteng province (82 %), with Thoroughbred, Arabian, and Warmbloods representing 46 %, 10 % and 7 % of horses. Horses had a median age of 7 years and were predominantly male (60 %). Gastrointestinal (64 %) and musculoskeletal (19 %) disorders were the primary reasons for admission. Anti-inflammatories, sedation and antibiotics were given in 51 %, 20 % and 15 % of cases respectively prior to referral. On admission, 23 % of horses had surgical intervention. Intravenous catheterisation (64 %), rectal examination (61 %), nasogastric intubation (56 %), abdominocentesis (33 %) and ultrasonography (19 %) were the procedures performed most frequently. Surgical and medical colics constituted 28 % and 27 % respectively of the overall diagnoses, while piroplasmosis was diagnosed in5%ofhorses. Post-admission complications occurred in <2 % of horses. The median length of stay was 4 days (95 % CI: 1 to 21 days). Overall survival to discharge was 74 %. This study demonstrates that the majority of after-hours equine admissions to a university referral hospital required medical intervention and were mostly due to gastrointestinal disorders. Information obtained from this study can be used in emergency referral planning.

Efficacy of a genotype 2 Newcastle disease vaccine (Avinew^®) against challenge with highly virulent genotypes 5d and 3d

Since 2002, following its introduction, the lineage 5d Newcastle disease virus (so-called Goose paramyxovirus - GPMV) strain has caused numerous disease outbreaks among commercial and backyard poultry in South Africa, raising questions about the ability of commercially available Newcastle disease vaccines to fully protect poultry against the strain. This study aimed to determine whether there are differences in the level of protection offered by Avinew® Newcastle disease vaccine against GPMV virus as compared with a 3d Newcastle disease virus isolated in South Africa in 1993 (Rainbow challenge virus - RCV) strain. Six groups of 10-day-old, specific pathogen-free chickens were vaccinated with doses of 10(3.0), 10(4.5) and 10(6.0) EID50 of Avinew® vaccine and challenged at 4 weeks of age intramuscularly at a dose of 10(5.3) EID50/ 0.2 mi/bird of GPMV and RCV No statistically significant difference could be found in the protection offered by Avinew® vaccine against GPMV as compared to RCV challenge. The protection offered against the ND challenge was found to be dose dependent. At the recommended field dose of 10(6.0) EID50 the vaccine gave 100 % protection from mortality against both the challenge viruses, but not against infection and replication of the viruses, as gross lesions were evident even in apparently healthy birds that survived the challenge. The protective dose (PD90) of the Avinew® vaccine against GPMV challenge was calculated at 10(4.38) and against that of RCV at 10(4.43).

The effects of firocoxib (Previcox™) in geriatric dogs over a period of 90 days

The long-term use of non-steroidal anti-inflammatory agents in geriatric dogs with osteoarthritis has not been well studied in veterinary medicine. This study evaluated the effects of firocoxib administered to dogs over 7 years of age for 90 days. Pain and lameness scores were evaluated by the owner weekly for the 1st month and then biweekly through to the end of the study, the veterinarian evaluated the dogs monthly. Serum chemistry, including urea, creatinine, alanine transferase, aspartate transaminase, bile acids and bilirubin, urine specific gravity and a urine dipstick, were performed at monthly intervals. Forty-five dogs were enrolled into the treatment group and 9 into the control group. A total of 33 dogs completed the trial in the treatment group and 8 in the control group. Lameness and pain scores were found to be significantly lower in the treated group from day 30 for most parameters evaluated. Bile acids (although not comparable to controls, with higher mean value and a high standard deviation in the control group; in addition the control group had increased bile acids at day 0) and urea (within normal reference range provided (WNL)) were significantly different in the treatment group between days 0 and 90. Urea (WNL) on days 30 and 90 and creatinine (WNL) on day 90 were significantly different between the control group and the treatment group. The most common adverse events reported were diarrhoea, vomition, dark faeces and anorexia. This study showed that firocoxib was effective in managing pain associated with osteoarthritis for 90 days. Despite the geriatric high-risk population used for this study, minimal biochemical changes were seen and adverse drug events seen were in agreement with those previously reported.

Preliminary assessment of the AAI Index^® during isoflurane anaesthesia in dogs undergoing clinical procedures

The auditory evoked potential (AEP) is correlated to anaesthetic depth. The AEP has been used in rats, pigs, dogs and humans to assess anaesthetic depth. This study was undertaken to determine whether the AAI Index® derived from the AEP correlated with changes in end tidal isoflurane concentration in dogs. The average AAI Index was 21.8 ± 10.5 and isoflurane concentration was 1.7 ± 0.4 %. Data were divided into 0.5 % intervals of end tidal anaesthetic agent concentration (ETAA). When ETAA values were higher than 2.5 % the AAI values were 2.1-2.5 %, 1.6-2.0 % and 1.1-1.5 % higher than AAI values although not statistically different. The 2.1-2.5 % interval was statistically different from the 1.1-1.5 % and <1.1 % interval. The 1.6-2.0 % interval was statistically different from the 1.1-1.5 % and the <1.1 % intervals. The 1.1-1.5 % interval was statistically different from the <1.1 % interval. The correlation between the AAI Index and isoflurane was -0.176 and was statistically significant (P = 0.0009). A linear regression between the AAI Index and isoflurane revealed the following relationship: AAI = 29.074 - (4.2755 x isoflurane) with a power of 0.913. The polynomial regression relationship was AAI = 53.334 - (35.715 x isoflurane) + (10.322 x isoflurane²) - (0.43646 x isoflurane³) with a power of 0.999. The AAI Index was found to correlate with changes in isoflurane concentration.

A survey of ectoparasites, cestodes and management of free-range indigenous chickens in rural Zimbabwe

A survey of ectoparasites, cestodes and husbandry aspects of indigenous free-range chickens was carried out in selected districts from the highveld and lowveld of rural Zimbabwe. The survey recorded infection with 4 species from the order Phthiraptera (lice), 1 species from the order Siphonaptera (fleas), 6 species from the order Acarina (ticks and mites) and 9 species of cestodes. Among the ectoparasites, the most prevalent was Menacanthus stramineus (87.7 %) followed by Echidinophaga gallinacea (71.9 %). Chickens in the Mazowe district had the highest number of ectoparasites species (10 of 11) followed by Goromonzi district (9 of 11) both these districts are situated in the highveld of Zimbabwe. The most prevalent cestode species was Raillietina tetragona (84.4 %), followed by Raillletina echinobothrida (32.2 %). Chickens in the Goromonzi district had the highest number of cestode species (7 of 9), followed by Mazowe district (one subgenus and 5 of 9). In all the districts sampled the main purpose of keeping free-range chickens was for meat for the household, with few households using the birds as a source of income. The majority of households kept their birds extensively with barely any appropriate housing, and supplementary feeding was only occasionally practised.

Causes of gastrointestinal colic at an equine referral hospital in South Africa (1998-2007)

The most common causes of gastrointestinal colic at an equine referral hospital in South Africa were determined following retrieval of the medical records of horses admitted during a 10-year study period. The study included 935 horses of which 28 % were admitted after hours. Most horses were Thoroughbreds (54 %), male (57 %), with a mean age of 8.2 years and originated from the Gauteng Province (81 %). Heart rate (98 %), mucous membrane colour (95 %) and auscultation of the abdomen (91 %) were the clinical data commonly obtained at admission. Packed cell volume, total serum protein and white cell count were recorded in 78 %, 75 % and 44 % of horses respectively. Transrectal palpation (93 %), nasogastric intubation (84 %), intravenous catheterisation (74 %) and abdominocentesis (53 %) were the most frequently performed procedures. Medical intervention was performed in 558 horses (60 %). The common causes of medical colic were impactions (39 %), tympany (7 %) and displacement of the large colon (6 %). An exploratory laparotomy was performed in 331 horses (36 %). The common causes of surgical colic were displacement (29 %), impaction (22 %) and small intestinal strangulating lesions (18 %). Death occurred in 3 % of horses, while euthanasia before medical intervention was performed in 4 %. Overall, medical intervention was successful in 93 % of horses and 67 % in horses managed surgically. In conclusion, 55 % of all the equine admissions responded to medical intervention and the recovery rate for horses receiving both medical and surgical intervention was comparable to that reported in other studies.

Urinary bladder botryoid rhabdomyosarcoma with widespread metastases in an 8-month-old Labrador cross dog

An 8-month-old crossbred Labrador retriever was presented with a history and clinical signs suggestive of lower urinary tract obstruction. Laboratory results revealed azotaemia and hyperphosphataemia. Ultrasonographic evaluation of the urinary tract showed a mass at the bladder trigone, hydronephrosis, hyrodureter, and suspected metastases to lymph nodes and the liver. Pulmonary metastasis was identified on thoracic radiographs. A post mortem confirmed metastases to the liver, lungs and regional lymph nodes, as well as to the mesenteric lymph nodes, mediastinum, heart, subcutaneous tissue and several muscle groups. A histopathological diagnosis of metastatic botryoid rhabdomyosarcoma (sarcoma botryoides) was made. A review of the literature shows that, although the bladder trigone is a well documented location for this tumour, this case was unique with its widespread metastases to previously undocumented organs. The incidence, embryology, ultra-sonographic appearance and treatment of this tumour are discussed.