Journal of the South African Veterinary Association

A new era for the Journal of the South African Veterinary Association

Temporally specific adrenocorticotropic hormone reference intervals for horses in South Africa

An endogenous adrenocorticotropic hormone (ACTH) concentration above the reference interval (RI) is commonly used as means for diagnosing equine pituitary pars intermedia dysfunction (PPID). Basal ACTH concentrations are highly dependent on photoperiod and RIs should be month- and location-specific. To date, no ACTH RIs have been specifically established for South Africa. This study aimed to determine geographically and seasonally relevant RIs for equine ACTH in the Gauteng province of South Africa. A longitudinal prospective study was conducted over twelve months to determine ACTH RIs for a representative population of healthy South African horses in the Gauteng province. Eighty clinically healthy horses under 12 years of age were recruited for monthly venous blood sample collection, from July 2019 to June 2020. ACTH was measured using a chemiluminescent assay. RIs were constructed for each month of the year. This South African population showed similar temporal changes in ACTH concentrations to those previously observed in other locations. Upper reference limits were at their lowest in early summer (21.4 pg/ml, 90% CI 20.8-21.7) with a pronounced increase in autumn (60.6 pg/ml, 90% CI 53.1-62.7), and tapered off in winter (22.3 pg/ml, 90% CI 19.9-23.2). The month-specific ACTH RIs generated in this study will improve the accuracy of diagnosis and monitoring of PPID in the local equine population. These results highlighted the previously recommended need for seasonal and location-specific RIs.

The potential effects and interactions of oxidative stress and trace minerals on fresh and frozen semen in bulls - a review

Reproduction is one of the most important factors determining successful cattle farming systems. Management practices, such as nutritional supplementation, can influence the reproductive performance of cattle. The objective of this literature review is to determine the potential value of injectable trace mineral administration on fresh and cryopreserved semen quality of bulls. A search of keywords related to the topic was performed on published articles and textbooks. The search was narrowed to the 40 most relevant references. Several studies have demonstrated a positive association between trace mineral supplementation and bull semen quality. Moderate amounts of reactive oxygen species (ROS) play an important role in normal spermatogenesis, but oxidative stress (OS), as experienced with adverse environmental conditions or disease, can contribute to idiopathic male infertility by negatively impacting spermatogenesis. Trace minerals such as selenium, copper, zinc, and manganese have been demonstrated to have antioxidant effects in mammals. Due to the complexity of oral ingested trace mineral bioavailability, injectable trace mineral supplementation prior to physiological periods with known deficiencies or increased requirement can benefit the animal. The potential benefits of injectable trace mineral supplementation to minimise oxidative damage to spermatogenesis in breeding bulls need further investigation. Positive results from such studies can lead to the implementation of injectable trace mineral supplementation strategies prior to the breeding season to minimise the detrimental effects of OS and can improve semen quality.

Molecular detection of zoonotic pathogens causing gastroenteritis in humans: Salmonella spp., Shigella spp. and Escherichia coli isolated from Rattus species inhabiting chicken farms in North West Province, South Africa

Rodents are key carriers and reservoirs of various pathogens of public health importance to both human and animal diseases. This research was carried out in order to identify the selected pathogens, namely, Shigella spp., Salmonella spp. and Escherichia coli from rats that inhabit the poultry houses. A total of 154 samples from captured rats were examined for the zoonotic bacterial pathogens, of which 3.3%, 29.9% and 20.7% were harbouring Shigella spp., Salmonella spp., and E. coli, respectively. A total of 14 Shigella isolates expressed presence of ipaH gene, of which eight and five were positive for S. sonnei and S. boydii, respectively. For Salmonella, 68 isolates were positive for invA and other genes including spy with 26 (38%), sdf\ 2 (18%), spvC 14 (20%), hilA 28 (41%), misL 43 (63%), orfL 31 (46%) and spiC 38 (56%). For E. coli, the aggR gene was the most prevalent (62 [42%]), followed by the eae gene, which was only detected in 21 (14%) isolates, while stx gene was not detected in any of the samples. This study shows that zoonotic pathogens with virulence genes are circulating in rodents from selected chicken farms in the North West Province of South Africa. Rodents must therefore be regarded as important carriers of zoonotic pathogens that can potentially infect both humans and animals.

The effect of different dietary flavourants and salt levels on feed intake of juvenile ostriches

Yearly the ostrich industry loses up to 40% of newly-hatched chicks, partly due to insufficient feed intake. This study was conducted to determine whether the inclusion of various feed flavourants would improve feed intake in ostrich chicks (Trial 1). Ninety-six day-old ostrich chicks were raised in groups of 12 at a Western Cape research farm until 28 days of age. These chicks were provided with free-choice access to a variety of flavoured diets, namely sweet, sour, bitter, salt or an unflavoured control diet. Chicks were found to prefer salty feed, as the salt-flavoured diet had the highest daily feed intake (34% of total) throughout the trial. Subsequently Trial 2 was conducted to determine the preferred level of dietary salt (Experiment 1) as well as the influence dietary salt had on various production parameters (Experiment 2). In Experiment 1, three groups of seven chicks each were offered ad libitum access to diets containing 4 g/kg, 14 g/kg, 24 g/kg, and 34 g/kg of salt respectively. Experiment 1 found that chicks preferred the diet containing 14 g salt/kg (36.4% of total daily feed consumed). For Experiment 2, 56 birds were divided into eight groups of seven. Conversely to the current conventional inclusion of 4 g salt/kg, Experiment 2 showed that chicks reared on a diet containing 14 g salt/kg had a 41.7% higher average daily gain than the group consuming 4 g salt/kg. It can therefore be concluded that ostriches prefer diets with a higher dietary salt level than current conventional diets provide (14 g/kg vs 4 g/kg).

What is in a name? Scientific name changes of potentially poisonous plants and fungi in South Africa

Changes over the past five decades in the scientific names of some potentially poisonous plants and toxigenic fungi in South Africa are briefly reviewed. Some of the reasons why taxonomists change names are highlighted. In recent years, DNA sequencing data have contributed considerably towards establishing phylogenetic relationships among plants, often resulting in changes in generic circumscription and, consequently, the names of species. Philosophical differences between the phylogenetic and the evolutionary schools of plant classification are briefly explained as these may manifest as different classifications for the same group of plants. Although choice of classification remains the prerogative of the end-user of plant names, in this review, the classifications for plants currently adopted by the South African National Biodiversity Institute (SANBI) in its online database, Plants of Southern Africa (POSA), were followed. Noteworthy generic changes include Pachystigma to Vangueria, Homeria to Moraea, and Urginia to Drimia. Following much controversy, the species native to southern Africa that were formerly treated as Acacia are now classified in either Vachellia or Senegalia, with the genus name Acacia being retained for the mainly Australian members of the group, the latter commonly known as wattles. Former southern African members of Acacia implicated in poisoning include Vachellia erioloba (camel thorn), Vachellia sieberiana var. woodii (paperbark thorn), and Senegalia caffra (common hook thorn).

Spatiotemporal analysis of African swine fever outbreaks on South African smallholder farms, 1993-2018

African swine fever (ASF) is a contagious viral disease of swine worldwide. ASF in South Africa has for many years been confined to a controlled area in the northeast of the country that was proclaimed in 1935. Since 2012, outbreaks are more likely to occur in the historically ASF-free area. This study aimed to analyse the spatial and spatiotemporal structure of ASF outbreaks in South Africa between 1993 and 2018. Global space-time clustering of ASF outbreaks was investigated by the Diggle space-time K-function while Kulldorff's spatial scan statistic was applied to detect local cluster of ASF outbreaks. Globally, ASF outbreaks exhibit statistically significant spatial clustering. They have shown a significant negative space-time interaction at month scale (p = 0.003) but no significant space-time interaction at year scale (p = 0.577), revealing strong evidence that ASF cases that are close in space occur in months which are close and vice versa. In studying local area space-time clustering at both month and year scale, three significant local clusters associated with high-rate were detected. These clusters are localised in both the ASF-controlled area and outside the controlled area with radius varying from 60.84 km up to 271.43 km and risk ratio varying from 6.61 up to 17.70. At month scale, clusters with more outbreaks were observed between June 2017 and August 2017 and involved 22 outbreaks followed by the cluster that involved 13 outbreaks in January 2012. These results show the need to maintain high biosecurity standards on pig farms in both inside and outside the ASF-controlled areas.

Knowledge, attitudes, and practices of veterinarians on antibiotic use and resistance and its containment in South Africa

The inappropriate use of antibiotics in the veterinary sector has contributed to antibiotic resistance (ABR), which negatively impacts animal health and welfare. Understanding the knowledge, attitudes, and practices (KAP) on antibiotic use, ABR, and its containment amongst veterinarians is critical to optimise antibiotic use and contain resistance. A quantitative questionnaire-based online survey was conducted amongst members of professional veterinary associations. The questionnaire consisted of four sections focusing on socio-demographic characteristics, KAP of participants on antibiotic use, ABR, and its containment in the South African veterinary sector. The Independent t-test, analysis of variance (ANOVA), and chi-square test were used to establish associations among selected socio-demographic variables and selected KAP parameters. A total of 130 responses were received from 2 178 animal health professionals, yielding a response rate of six per cent, with 102 complete responses constituting the final sample size. Self-reported knowledge on antibiotic stewardship, ABR mechanisms, and pharmacology was good at 96 (94.1%), 91 (89.2%), and 70 (68.6%), respectively. Notably, most of the veterinarians (61; 59.8%) lacked an antibiotic stewardship programme at their practice. Place of practice was significantly associated (p = 0.004) with possession of knowledge about ABR. Veterinarians in urban practice were more knowledgeable about ABR than those in rural practice. Antibiotic stewardship programmes need to be implemented in veterinary practice. Such programmes might encourage the frequent use of consensus guidelines for the appropriate use of antibiotics and microbiology-informed therapy.

**The effects of feeding and transport length on the welfare of white rhinoceroses (Ceratotherium simum simum) during long-distance translocations: a preliminary study**

Translocation is a valuable conservation tool, but poses significant risks for the transported rhinoceroses. Interventions reducing these risks are required to ensure positive welfare during transportation. The aim of this study was to evaluate the effect of journey duration and feeding during the transport of white rhinoceroses (Ceratotherium simum simum). A total of 32 animals were transported by road during two events, five days apart. Fifteen rhinoceroses in the first transport event (37.0 ± 2.4 hr duration) were not fed, while 17 rhinoceroses in the second event (32.2 ± 1.5 hr duration) were offered lucerne. Blood samples were collected at capture and after transport for the evaluation of changes in serum clinical chemistry analytes. The Wilcoxon rank-sum test was used to compare differences between the groups. In all rhinoceroses, transport resulted in changes in serum electrolyte, metabolite and enzyme concentrations, indicating a loss in total body water, nutritional shifts, stress and fatigue. Fed rhinoceroses, transported over a shorter time, displayed greater changes in osmolality (p < 0.006), serum sodium and chloride concentrations (p = 0.005 and = 0.001, respectively) indicating a greater degree of total body water loss than non-fed rhinoceroses. Feeding and a shorter transport duration reduced, but did not prevent, nutritional challenges. A greater increase in the muscle enzymes CK and AST (p = 0.027 and = 0.001, respectively), indicated greater fatigue in non-fed rhinoceroses transported over a longer time. Further work to distinguish the effects of feeding and journey duration is required to better understand the role feeding may play in mitigating welfare challenges during rhinoceros translocation.

Sources of error in acid-base analysis from a blood gas analyser result: a narrative review

Preservation of blood pH within a narrow range is essential to optimal physiological function. This narrow pH range is maintained via the interactions of various buffer systems. Blood gas analysis is thus essential in the diagnosis and management of disorders affecting blood pH. Common methods of acid-base interpretation in veterinary science are the traditional approach, the physicochemical approach and the semiquantitative approach. However, blood gas analysis is prone to error during the pre-analytical, analytical and post-analytical phases of the laboratory process. The pre-analytical phase incorporates steps in obtaining the sample, thus sources of pre-analytical error are related to operator technique. Most errors occur during the pre-analytical phase. Pre-analytical errors include entrainment of air bubbles into the sample and delays between sampling and analysis, both of which cause inaccurate measurement of oxygen and carbon dioxide tensions. The analytical phase outlines processes within the analyser. Common analytical errors are related to substances confounding analyte measurements. The post-analytical phase mainly describes interpretation of the results. Some of the approaches to acid-base interpretation require extensive post-analytical calculations, thus lending themselves to error. Errors occurring during the prior phases will be amplified. Errors in the measurement of the carbon dioxide tension (from which bicarbonate concentration and base excess are calculated) will introduce error into all three methods of acid-base interpretation. Furthermore, errors occurring in the measurements of electrolytes and lactate will result in incorrect interpretations if the physicochemical and semiquantitative approaches are applied. The potential sources of error during the various phases are reviewed.

**Resolution of feline Mycobacterium panniculitis despite protracted treatment with methylprednisolone acetate**

Saprophytic or non-tuberculous mycobacteria are ubiquitous in the environment. They can cause opportunistic infections when the skin is broken and typically manifest with draining sinus tracts or cutaneous nodules. This report details the first confirmed Mycobacterium smegmatis panniculitis in a cat in South Africa. Despite repeated treatment with methylprednisolone acetate for six months prior to diagnosis, the cat made an uneventful recovery once switched to doxycycline and marbofloxacin.

Successful treatment of a South African cat with effusive feline infectious peritonitis with remdesivir

Historically, feline infectious peritonitis (FIP) has been considered almost invariably fatal. The recent COVID-19 pandemic has fuelled research in coronavirus pathophysiology and treatment. An unintended consequence is that we now have an effective treatment accessible for FIP. This paper reports on the successful resolution of immunohistochemistry-confirmed effusive FIP in an adolescent cat in South Africa following monotherapy with remdesivir at 4.9-5.6 mg/kg daily for 80 days.

Successful treatment of babesiosis in a south-western black rhinoceros (Diceros bicornis bicornis)

Under stressful conditions, black rhinoceroses that are sub-clinical carriers of Babesia bicornis can succumb to babesiosis. After 16 days in captivity, a five-year-old female black rhino captured for relocation presented with inappetence, abdominal discomfort and constipation. After chemical immobilisation, dry faecal balls were removed from the rectum, peripheral blood smears were made and blood collected into EDTA tubes. She was treated prophylactically for colic with flunixin meglumine, penicillin and doramectin. Piroplasms were seen on fixed and stained peripheral blood smears. Overnight she developed severe haemoglobinuria, a sign consistent with babesiosis. Subsequently, DNA extracted from a blood specimen reacted with the B. bicornis probe on Reverse Line Blot (RLB) assay, confirming the diagnosis of babesiosis. Specific treatment consisted of 14 ml imidocarb dipropionate (dosage 2.4 mg/kg) administered intramuscularly by pole syringe. Fifteen days later the patient was still moderately anaemic, with the red blood cell (RBC) count, haematocrit and haemoglobin concentration within normal ranges but on microscopic examination there was a marked RBC macrocytosis and polychromasia indicative of a regenerative anaemia. DNA extracted from blood collected at that time did not react with the B. bicornis probe on RLB assay, indicating that treatment with imidocarb had been effective. Once the patient's appetite improved, she started gaining weight. After 82 days in captivity and 65 days after babesiosis had been diagnosed, she was released at the site where she had been captured.

Lung lobe torsion in association with a pulmonary papillary carcinoma in a dog

Lung lobe torsion (LLT) is an uncommon condition in dogs reported to be most commonly idiopathic or secondary to trauma, pleural effusion, lung lobectomy or thoracic neoplasia. Carcinomas are the most common primary lung tumours in dogs, but only a few cases have been reported in association with LLT in veterinary medicine. This case describes an adult male neutered Labrador, which presented with lethargy, weight loss and pleural effusion. Computed tomography (CT), cytology of the lung, thoracocentesis and fluid analysis were performed. CT revealed pleural effusion and torsion of the left cranial lung lobe with no evidence of a pulmonary mass or metastatic disease. Thoracotomy and left cranial lung lobectomy were performed. Intraoperatively there was no macroscopic evidence of pulmonary neoplasia. Histopathology of the lobar tissue confirmed grade 2 pulmonary papillary carcinoma. It is possible that early detection and surgical management might help to prevent the morbidity and mortality associated with LLT. However, as in this case, the underlying cause for the LLT will ultimately determine the patient's prognosis. The final diagnosis of papillary carcinoma in this case, was only made via histopathological assessment of the pulmonary tissue as it was unclear on the advanced imaging and macroscopic intraoperative evaluation of the lungs. This case highlights the importance of considering pulmonary neoplasia as a differential for LLT even in the absence of a macroscopic mass, and therefore the value of performing histopathology on the excised lung tissue.

The first caesarean operation on a mare in South Africa

Prevalence of radiographic changes in forelimb digits and metacarpophalangeal joints of South African endurance racehorses

If the number of events alone is considered, endurance riding is the fastest growing and the second-most popular Federation Equestre Internationale (FEI) discipline. Lameness is the most common cause of elimination from endurance races worldwide. To the authors' knowledge, no studies have been published investigating the prevalence of radiographic changes in the forelimb digits and metacarpophalangeal joints (MCP) of endurance racehorses in South Africa. The study aimed to investigate the prevalence of radiographic changes in the forelimb digits and MCP joints of South African endurance racehorses. One hundred endurance racehorses registered with ERASA were volunteered by their owners to partake in the current study. Radiographs were obtained from horses competing in endurance races during the 2018-2019 endurance racing season. Radiographs included seven standard views of each distal forelimb. Radiographic images were independently evaluated by three observers, point prevalence and inter-rater reliability (IRR) was calculated. Data analysis of the forelimb digits revealed a large proportion of horses with bilateral signs of dorsopalmar hoof imbalance (95%); a diversion from a straight digital axis (91%), with an extended (broken back) proximal interphalangeal joint (67%) being the most common abnormality. Osteoarthritis of the proximal (16%) and distal (7%) interphalangeal joints was only observed in a low percentage of horses. Interestingly, the hoof-distal-phalanx-ratio of the majority (86%) of horses was more than 25% but none of these horses showed any other signs of chronic laminitis, indicating that hoof-distal-phalanx-ratio might not be a reliable indicator of chronic laminitis in this population of horses. Ossification of the ungular cartilages was observed in the majority (69%) of horses, either affecting one or both distal phalanges. Descriptive data analysis of the MCP joints showed that a large proportion of horses displayed radiological signs of MCP joint osteoarthritis (28%), with 10% being bilateral. The current study provides insight into radiographic changes and their prevalence in the distal front limbs of South African endurance racehorses. Knowledge about the prevalence of specific radiographic changes would enable equine practitioners to better evaluate and manage horses that are affected. Although no correlations were made with age, speed or number of competitive kilometres competed, the current study may serve as a basis for future research.

Predictors of foaling outcomes in barren and maiden Thoroughbred mares in South Africa

Population demographics and reproductive performance of Thoroughbred populations have been described, but the most recent assessment of the South African Thoroughbred population was reported two decades ago. Objectives of this study were to report demographic data for selected Thoroughbred breeding populations and to analyse selected mare-level variables in association with foaling outcomes, as predictors of reproductive performance. The National Horseracing Authority of Southern Africa's stud health scheme requires annual screening of Thoroughbred stallions, maiden and barren mares for venereal pathogens prior to breeding. In 2018 and 2019, 1 065 and 1 207 horses were sampled, respectively. Demographic data were sourced from laboratory sample submission forms that accompanied samples and supplemented by data gathered from the annual Thoroughbred foal identification programme. Univariate analysis of candidate predictors of successful foaling outcomes was performed followed by assessment in a multivariable model. Median ages of mares and stallions tested in 2018 and 2019 were nine and 11 years, respectively. Nearly twice the number of barren compared to maiden mares were tested in each year, and failure to conceive was the most common reported reason for classification as barren. Of mares tested in 2018 and 2019, 68.1% (95% CI 65.1-70.9) and 63.3% (95% CI 60.4-66.1), respectively, subsequently produced foals that were presented for identification. Mare age, rather than reproductive status, was a significant predictor of having a foal presented for identification. In conclusion, novel demographic data were described for South African Thoroughbred populations. Seasonal foaling rate as the selected measure of reproductive performance for sampled mares ranged from 63.3% to 68.1% and declined with increasing mare age.

The clinical presentation and management of a naturally occurring Bluetongue virus infection in a pregnant Rottweiler dog

Few reports of clinical Bluetongue virus (BTV) infections have been described in dogs. Most cases were linked to inoculation with a BTV-contaminated canine modified live vaccine. In dogs, cases have only been described in pregnant females with clinical signs of fever and abortion followed by severe dyspnoea and death. A pregnant Rottweiler dog was presented with a three-day history of progressive lethargy and anorexia. The patient was a guard dog living in an enclosure where sheep were kept at night. High mortalities had been experienced in the sheep but had not been investigated. On presentation, the major clinical findings were dyspnoea and hypoxia. Clinicopathological tests showed hypoxia and systemic inflammation. Radiological findings were consistent with non-cardiogenic pulmonary oedema. The patient was treated symptomatically and recovered but did not retain the pregnancy. BTV was identified in the patient's blood using BTV RT-PCR (Ct value 24.7). At a follow-up farm visit, an ongoing BTV outbreak in the sheep was diagnosed with affected sheep testing positive for BTV on RT-PCR. This report describes the clinical presentation, diagnostic investigations and successful treatment of a dog with BTV infection. This is the first case report of a naturally occurring clinical BTV infection in a dog. Possible routes of infection were direct contact, midge-borne, or ingestion of infected afterbirth or abortus from sheep.

Intra- and inter-operator variability of refractometric total proteins measurement of canine plasma

Refractometric total proteins are commonly used in practice as a quick and inexpensive way to measure total protein concentration in bodily fluids. Little information is available about how the operator performing the measurement affects the results. The aim of our study was to determine the inter- and intra-operator variability of refractometric total proteins measured on canine plasma using a temperature-compensated handheld refractometer. A pooled sample of canine lithium-heparin plasma was created using leftover samples from dogs presented to our hospital. The sample was then divided into three aliquots. Total proteins of these aliquots were measured by veterinary nurses, interns, residents and specialists working at our hospital. Statistical analysis revealed excellent inter-operator (ICC 0.99, CI 95% 0.971-1.00) and intra-operator (ICC 0.997, CI 95% 0.9900.999) variability. Having different operators measuring refractometric total plasma proteins in practice should not affect the results. This suggests different operators can be used when monitoring total plasma proteins of a patient over time and when designing a study that involves this test.