Research Articles (Production Animal Studies)

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Efficacy of three weed species against bovine mastitis-causing bacteria, and their anti-inflammatory, antioxidant and cytotoxic activities
Erhabor, Rosemary Chinelo; Dzoyem, Jean Paul; Petzer, Inge-Marie; McGaw, Lyndy Joy (Elsevier, 2025-11)
Bovine mastitis is a significant infectious disease in the dairy industry, and it tends to re-occur owing to antibiotic resistance. Management of the condition using complementary treatments could reduce the economic burden caused by the disease. Different extracts (methanol, ethanol, acetone, dichloromethane: methanol, hot and cold water) of three species commonly growing as weeds in South Africa (Leonotis leonurus, L. nepetifolia and Tithonia rotundifolia) were investigated. The plants are reported to be used traditionally to treat breast swelling, inflammation, abscesses, wounds, pains, fever, and muscular cramps. The antibacterial, antibiofilm, quorum quenching, anti-inflammatory, antioxidant activity and cytotoxicity of the different extracts were investigated. The antibacterial activity against six Staphylococcus aureus species isolated from clinical cases of bovine mastitis, and two Staphylococcus reference strains (S. aureus ATCC 29213 and S. epidermidis ATCC 35984) was tested. Quorum quenching activity using Chromobacterium violaceum as a model was conducted. At the same time, antibiofilm assays were carried out using crystal violet and 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl-2H-tetrazolium (INT) assays to determine the antiadhesion and biofilm inhibitory activity, as well as the viability of bacterial cells after treatment with the plant extracts. The antioxidant activity was investigated using in vitro chemical assays. Inhibition of the 15-lipoxygenase enzyme (15-LOX) and nitric oxide (NO) release from activated macrophages was used to determine the anti-inflammatory potential of the extracts. The cytotoxicity of the extracts was assessed via a tetrazolium-based colorimetric reduction assay against Vero African green monkey kidney and bovine dermis cell lines. The extracts showed moderate to good inhibition of bacterial growth with minimum inhibitory concentration (MIC) values ranging between 0.02 and 2.5 mg/mL. The extracts of Leonotis leonurus had the best anti-adhesion and biofilm inhibitory activity against the pathogens. They inhibited the metabolic activity of the bacterial cells at different times, with the most active resulting in 100 % inhibition. Eight extracts had excellent anti-quorum sensing ability with violacein inhibition ≥50 % at all concentrations (IC50 = 0.08 to 2.5 mg/mL). Most of the extracts had excellent activity against the 15-LOX enzyme compared with the positive controls, as well as good to moderate NO inhibition. The extracts were less toxic to the bovine dermis cells than to the Vero cells. The antibacterial effects, little to no cytotoxicity at low concentrations and the promising antibiofilm and quorum quenching results in this study provide motivation for further investigation of the extracts as potential candidates for development of a novel therapy for the management of pathogenic traits in organisms implicated in causing mastitis.
Possible factors affecting the bioavailability of copper and the copper requirements of wild, free-ranging African herbivores : a review
Van Ryssen, J.B.J.; Bath, Gareth F. (South African Society for Animal Science, 2025-11-12)
Free-ranging wild herbivores in Africa comprise 78 species of ruminants and several species of monogastric hindgut fermenters, and are classified as grazers, mixed feeders, and browsers. The objective of this review is to provide guidance to wildlife nutrition advisers by outlining key metabolic principles relevant to assessing copper nutrition in herbivores. In domestic species, copper bioavailability is influenced by dietary copper antagonists, copper solubility at absorption sites, and the homeostatic regulation of copper metabolism. Differences in the homeostatic control of copper absorption and metabolism in the liver between ruminants and monogastric species have a major effect on their tolerance to excessive copper exposure. As some elements in the diet are antagonistic to copper solubility in the digestive tract, dietary copper concentration alone has limited diagnostic value for assessing the potential copper nutrition status of a ruminant. Dietary copper is most soluble in acidic environments and factors influencing rumen pH, such as the effect of diet type on rumination and saliva flow, could thus influence copper solubility. In monogastric species, the solubility of dietary copper in the stomach can be high (up to 80% in vitro) because of the acidic environment of the stomach. Consequently, in domestic species, the bioavailability of copper varies from 1% to 10% in mature ruminants, compared with an estimated >30% for non-ruminants. This suggests that for wild species with similar body weights and diets, dietary copper requirements per kilogram of feed intake for maintenance should be substantially lower for monogastric species than for ruminants.
Unveiling brucellosis risks in breeding herds : case study on diagnostic failures and control gaps in South Africa
Mazwi, Koketso Desiree; Lita, Emmanuel P.; Hassim, Ayesha; Seakamela, Emmanuel; Matle, Itumeleng; Abdool-Khader, Farah; Scheepers, Gerhardus S.; Ngoshe, Yusuf Bitrus; Van Heerden, Henriette (AOSIS, 2026-07-31)
Brucellosis is a zoonotic pathogen of livestock, wildlife and humans, with significant implications for reproductive losses and public health. The movement and introduction of breeding animals with unknown status into previously Brucella-negative herds pose a risk for disease introduction and sustained transmission. This case study documents two independent brucellosis outbreaks integrating epidemiological observations with serial serological testing, bacteriological culture and molecular confirmatory assays following abortion events. Diagnostic tests were performed, including serology, PCR and culture from diverse samples. On a cattle farm, animals previously certified as brucellosis-negative demonstrated progressive seroconversion from 2024 onwards. Brucella abortus was detected in the blood clots of tested animals using abortus-melitensis-ovis-suis PCR (AMOS-PCR), including a suspect bull that later tested seronegative on follow-up serology. A Brucella-positive human case occurred following direct exposure to the infected cattle farm, underscoring the zoonotic risk. On the sable antelope farm, B. abortus was detected in two seropositive females through culture of lymph nodes and amniotic fluid, while B. abortus was also isolated from the semen of a seronegative breeding bull, suggesting that the bull was a carrier and posing a transmission risk to the herd. The findings demonstrate that infected breeding males may remain seronegative while actively harbouring and shedding B. abortus. This study indicates that seronegative breeding males can undermine brucellosis control programmes, may act as undetected reservoirs of infection, thereby challenging current surveillance strategies. The findings highlight the diagnostic limitations of relying solely on serological tests, particularly in chronically infected cattle and wildlife, and support the integration of more sensitive assays, such as iELISA, alongside PCR methods, into diagnostic strategies on brucellosis-affected farms to improve detection and support eradication efforts. CONTRIBUTION : Strengthened biosecurity, systematic testing of breeding males, and comprehensive vaccination programmes are critical to preventing ongoing spillover among livestock, wildlife, and humans in South Africa.
Mechanisms of anti-inflammatory and antioxidant activity of extracts of selected South African Celastraceae and Crassulaceae plant species with known efficacy against bovine mastitis bacterial pathogens
Ogbuadike, Eucharia Chika; Nkadimeng, Sanah Malomile; Khunoana, Edward Thato; Igwe, Chima C.; Qekwana, Daniel Nenene; Petzer, Inge-Marie; McGaw, Lyndy Joy (Wiley, 2026-02-23)
Inflammation, a complicated reaction to microbial infection or injury, promotes healing under normal circumstances. However, when it becomes uncontrolled, it can result in cell damage or even death. Inflammation is a major feature of infectious mastitis in cattle as well as in humans, with substantial health, welfare and financial challenges. Uncontrolled inflammation is commonly accompanied by excess reactive oxygen species (ROS), which may be harmful. Ethanol and acetone leaf extracts of Bryophyllum pinnatum (Lam.) Oken (synonym: Kalanchoe pinnata (Lam.) Pers.), Kalanchoe gunniae Gideon F. Sm. and Figueiredo, Maytenus undata (Thunb.) Blakelock and Maurocenia frangula Mill. were investigated for their antioxidant and anti-inflammatory activities. In previous work, these plant species had promising antimicrobial activity against mastitis-causing bacteria. In this study, anti-inflammatory activity of the extracts was investigated in terms of their ability to inhibit the action of the enzymes implicated in inflammation, namely 15-lipoxygenase (15-LOX) and cyclooxygenase (COX). Their ability to inhibit the production of nitric oxide (NO) by lipopolysaccharide (LPS)-activated RAW 264.7 macrophages was also tested. Using ELISA kits, the effect of the plant extracts on the regulation of cytokine production was determined. Evaluation of antioxidant activity was done using electron reducing 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and radical scavenging 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assays. The best 15-LOX inhibitory activity with IC50 values of 1.25 and 2.03 μg/mL for acetone and ethanol extracts, respectively, was observed with K. gunniae extracts. The best NO inhibition of 80.48% and cell viability of 96.75% was produced by the acetone extract of B. pinnatum at the highest concentration (100 μg/mL). Significant inhibition of COX-2 was observed with both extracts of K. gunniae and B. pinnatum. In this study, the highest inhibitory activity against proinflammatory cytokines and enhanced production of anti-inflammatory cytokines were observed with extracts of B. pinnatum. Kalanchoe gunniae extracts had the best antioxidant activity with IC50 values ranging from 0.06 to 0.42 μg/mL. This research highlights the therapeutic potential of the selected plant species in managing inflammation and oxidative stress associated with bacterial mastitis.
In vitro bioactivity of leaf extract fractions and Quercetin-3-O-rhamnoside from Combretum elaeagnoides against Staphylococcus species implicated in causing bovine mastitis
Erhabor, Rosemary Chinelo; Dzoyem, Jean Paul; Petzer, Inge-Marie; Abdalla, Muna A.; McGaw, Lyndy Joy (MDPI, 2026-02)
Globally, antibiotic resistance is a growing concern, motivating the search for alternatives. Bovine mastitis is an inflammatory disease of the udder caused by various microorganisms, many of which are resistant to various antibiotics, impacting the quality of dairy products and farmer income. In this study, the in vitro bioactivity of the methanol leaf extract, fractions (ethyl acetate (CeEtOAc), butanol (CeBuOH), hexane (CeHx), dichloromethane CeDCM), and water (CeAq), and a purified compound, quercetin-3-O-rhamnoside isolated from the CeEtOAc fraction of Combretum elaeagnoides Klotzsch, were investigated against six Staphylococcus aureus (S. aureus) strains isolated from clinical cases of bovine mastitis and two reference ATCC strains (S. aureus ATCC 29213 and S. epidermidis ATCC 35984). Methods used for assessing bioactivity included serial microdilution for antibacterial efficacy, crystal violet staining and p-iodonitrotetrazolium (INT) metabolic assays for anti-biofilm activity, and a microdilution assay for anti-quorum-sensing potential. The anti-inflammatory assays included 15-lipoxygenase enzyme inhibition and nitric oxide assays. Cytotoxicity screening was conducted using a tetrazolium-based colorimetric assay against bovine dermis cells. The extracts and fractions exhibited moderate to good antibacterial activity with minimum inhibitory concentration (MIC) values ranging from 0.07 to 1.04 mg/mL, with the ethyl acetate fraction being the most effective. The anti-biofilm activity of the extract, fractions, and isolated compound (quercetin-3-O-rhamnoside) varied at time zero (T0), with inhibition ranging from 3% to 100%. The CeDCM and CeEtOAc fractions exhibited the most potent anti-biofilm effects after 24 h, with inhibition ranging from 24% to 91%. The extracts and fractions exhibited significant inhibition (>50%) of biofilm within the incubation times (T0–T48), and quercetin-3-O-rhamnoside alone had >60% inhibition at 48 h. The CeEtOAc fraction had the most significant anti-quorum-sensing activity (IC50 < 0.08 mg/mL). The methanol extract and fractions exhibited significant anti-inflammatory activity, inhibiting nitric oxide production (IC50: 7–26 µg/mL). In contrast, the CeAq, CeHx, and CeDCM fractions showed the best inhibitory activity against the 15-lipoxygenase enzyme (IC50 = 3–4 µg/mL). The extracts and fractions were non-cytotoxic to bovine dermis cells (LC50 = 0.88–1 mg/mL). Combretum elaeagnoides extract and its fractions are recommended for further investigation as potential herbal treatments for the management of mastitis and its symptoms.
Clinical management of testicular tumors in dogs
Pereira, Maria; Tekin , Koray; Perez, Malena; De Cramer, Kurt Guido Mireille; Romagnoli, Stefano (MDPI, 2026-04-15)
Testicular tumors are the most common neoplasms of the canine male reproductive tract, corresponding to approximately 25% of all tumors in intact males. A large percentage of cases are characterized by one of three main tumor types: seminomas, interstitial Leydig cell tumors, or Sertoli cell tumors. Clinical importance is primarily associated with endocrine activity rather than malignant behavior; orchiectomy is the treatment of choice for most canine testicular cancers. Endocrine activity, particularly estrogen secretion, may result in feminization syndrome and, in severe cases, bone marrow suppression. The diagnostic approach combines physical examination, ultrasonography with hormonal assessment using endocrine testing (testosterone, estradiol, and T:E ratio), and/or tissue level evidence of the estrogen effect (preputial cytology). Management is centered on orchiectomy; unilateral surgery may be considered when the contralateral testis is clinically and ultrasonographically normal and when preservation of reproductive capacity or working ability is still a priority. Dogs with hormonally active tumors benefit from postoperative hematologic and endocrine monitoring. Recent advances in immunohistochemistry (IHC), such as Ki-67 and inhibin-α markers, and imaging techniques are improving tumor characterization and individualized clinical decision making.
Benefits of a tuberculin skin testing refresher training programme for veterinary field technicians in the Bushbuckridge Municipality, South Africa
Rikhotso, Boetie Oupa; Pretorius, Oonagh; Thompson, P.N. (Peter N.); Michel, Anita Luise (Medpharm Publications, 2026-03)
Bovine tuberculosis (bTB) is an economically important global zoonotic disease affecting all mammalian species, caused by Mycobacterium bovis. The diagnostic test prescribed by the South African National Bovine Tuberculosis Control Scheme and required for international trade in live cattle is the intradermal tuberculin test. Theoretical and practical learning of tuberculin skin testing should be done simultaneously during student training. The study aimed to assess the training programme of Veterinary Field Technicians (VFTs) on tuberculin skin testing in cattle and its impact on their performance. Twenty-five VFTs, between the ages of 22 and 61, were enrolled for bovine tuberculosis (bTB) testing refresher training, which covered both theoretical and practical aspects of the tuberculin skin test. Twenty-three VFTs participated in both the pre-training and the post-training written assessment, while two VFTs each missed one of the assessments. The mean (± SD) pre-training score was 39% (±14%), and only 4/23 VFTs (17%) achieved the pass score of 50%. The mean post-training score was 55% (± 15%), and 16 (70%) passed the posttraining test. The mean difference (post-training – pre-training) was 16% (95% CI: 12, 19%; p < 0.001), with a large effect size (Hedges’ gav = 1.07; 95% CI: 0.90, 1.25). VFTs in the age group 51–61 years performed poorly in the assessments compared to those aged between 22 and 50 years old. Adjusting for pre-training score, there was an inverse association between age and post-training score (b = -0.46; 95% CI: -0.75, -0.17; p = 0.004). It was concluded from this study that VFTs employed by the State were not allocated sufficient time for theoretical and practical re-training on tuberculin skin testing of cattle in Bushbuckridge local municipality, Mpumalanga province. The refresher training course was a useful intervention to effectively improve the theoretical and practical TB testing skills of VFTs.
Uterine squamous cell carcinoma in a 10-year-old Vietnamese pot-bellied pig (Sus scrofa domesticus)
Janse van Rensburg, Le-lani; Tagwireyi, Whatmore Munetsi; Magadu, Rungano; Grobler, Miemie; Avenant, Lida; Brown, Geoffrey James; Hoepner, Nicolene (BioMed Central, 2026-05)
A 10-year-old intact female Vietnamese Pot-bellied pet pig (Sus scrofa domesticus) presented to the Production Animal Clinic at the Onderstepoort Veterinary Academic Hospital in South Africa (OVAH) with recurrent vaginal bleeding as the primary complaint. Clinical examination, vaginoscopy with vaginal cytology and abdominal ultrasound localised the haemorrhage to the reproductive tract and initially revealed a pyometra. After the failure of medical treatment with a luteolytic agent, anti-inflammatory and antibiotics, an exploratory laparotomy was performed, during which two macroscopical uterine lesions were observed. Histopathology identified the lesions as a squamous cell carcinoma infiltrating the endo- and myometrium and a focal endometrial polyp. An ovariohysterectomy resulted in a full recovery. No evidence of pulmonary metastases was found.
Occurrence of antimicrobial-resistant Listeria monocytogenes and Listeria spp. recovered from cattle farms and the factors associated with their distribution in Mpumalanga and North West Provinces in South Africa
Moabelo, Khomotso Confidence; Mtshali, Nduduzo C.; Moerane, Rebone; Gcebe, Nomakorinte; Ngoshe, Yusuf Bitrus; Adesiyun, Abiodun Adewale (Wiley, 2026-05-31)
Two cross-sectional studies determined the prevalence of antimicrobial resistance (AMR) in Listeria monocytogenes and Listeria spp. isolated from cattle farms in Mpumalanga and North West provinces in South Africa. A total of 100 isolates comprise 12 and 44 of L. monocytogenes and Listeria spp., respectively, from Mpumalanga province and 3 and 41 from North West province. The disc diffusion method was used to determine the isolates' resistance to 16 antimicrobial agents. The studies also investigated the factors (district, farm type, and sample type) associated with AMR. All 100 isolates tested were resistant to at least one antimicrobial agent. Among the isolates of L. monocytogenes from Mpumalanga province, the prevalence of resistance ranged from 41.7% (doxycycline) to 100% (cefotaxime, kanamycin, streptomycin, and nalidixic acid), compared to from 33.3% (kanamycin, tetracycline, doxycycline, nalidixic acid, and enrofloxacin) to 100% (streptomycin, nalidixic acid, and ampicillin) in the North West province. Across both provinces, the prevalence of resistance varied significantly for amoxicillin-clavulanate (p = 0.0110), kanamycin (p = 0.0286), and azithromycin (p = 0.0022). Among the Listeria spp., resistance ranged from 2.3% (cefotaxime) to 100% (nalidixic acid) in Mpumalanga province, compared to from 14.6% (sulfamethoxazole-trimethoprim, SXT) to 100% (nalidixic acid) in North West. For L. monocytogenes and Listeria spp. from both provinces, resistance to antimicrobial class was low for SXT (6.0%) and β-lactams (9.7%) but comparatively high for lincosamides (50%) and fluoroquinolone (62.3%) (p < 0.00001). Of the three factors (district, farm type, and sample type) investigated for their association with the prevalence of resistance in L. monocytogenes and Listeria spp. in both provinces, the district location of the farm was the only factor that statistically significantly (p = 0.0455) affected the prevalence of resistance in L. monocytogenes to ciprofloxacin in only Mpumalanga province. Notably, on a larger geographic scale, Mpumalanga and North West provinces showed significant (p < 0.05) differences in the prevalence of ampicillin resistance. The high prevalence of resistance to multiple antimicrobial agents across sources and the two provinces may pose therapeutic challenges for treating listeriosis on cattle farms.
Knowledge, attitudes and practices regarding Rift Valley Fever among livestock traders in the Alaotra Mangoro Region, Madagascar
Alain, Félix; Miraimila, Botovola; Chevalier, Veronique; Thompson, P.N. (Peter N.) (MDPI, 2026-05-16)
Rift Valley fever (RVF) is a viral zoonosis endemic in Madagascar, threatening human and animal health as well as the economy. Trade-related livestock movements are a major factor in the spread of RVF virus. While previous RVF research in Madagascar has focused on farmers or general ecology, this study is the first to specifically target livestock traders, the primary drivers for long-distance viral spread, in the Alaotra Mangoro endemic hotspot. This study aimed to assess the level of knowledge, prevailing attitudes and current practices regarding RVF among people engaged in livestock trade in the Alaotra Mangoro region, as well as the factors associated with these KAPs. A descriptive and analytical cross-sectional survey was conducted among 406 livestock traders in five districts of the Alaotra Mangoro region, using a structured questionnaire. A multi-stage sampling approach was employed, utilising purposive selection of markets followed by snowball sampling to reach informal traders often missed by traditional surveys. Generalised linear mixed models were used to analyse factors associated with KAPs regarding RVF. Awareness of RVF was very low (only 18.5% respondents had heard of it), with significant regional disparities (0% in Anosibe An’Ala versus 51.6% in Moramanga). Veterinarians (15.5%), family (12.8%), radio (9.6%) and neighbours (9.6%) were the main sources of information. Understanding of symptoms and modes of transmission (particularly mosquito bites) was limited. Higher levels of education (OR = 181.6; 95% CI: 29.9–1123.7; p < 0.001) and older age (50–60 years) were associated with better knowledge. Proactive attitudes were scarce (21.4%), although more than half (53.4%) believed that RVF is a real disease. Perception of personal risk and the contribution of livestock trade to the spread of the disease was low. However, confidence in animal vaccination was relatively high (60.3%). Preventive practices were highly inadequate. The majority did not wear protective equipment when handling sick animals (94.6%) and rarely avoided touching aborted foetuses (12.6%). Less than half (48.3%) expressed a willingness to report sick or dead animals, and nearly half admitted to having sold or purchased sick livestock (49.5%). Cooking meat (95.1%) and using mosquito nets (74.1%) were the only well-established practices. More than half of respondents (57.9%) lived more than 5 km from veterinary services, and cost was the most frequently cited barrier to consultation. Participation in awareness campaigns was virtually non-existent (5.4%). Results revealed critical gaps in KAP that may contribute to the persistence of RVF. A “One Health” approach is imperative, integrating human, animal and environmental health.
Antimicrobial-resistant Listeria species isolated from beef and beef products sold in Mpumalanga Province, South Africa
Moabelo, Khomotso Confidence; Gana, James; Ngoshe, Yusuf Bitrus; Moerane, Rebone; Adesiyun, Abiodun Adewale (Elsevier, 2026-05)
This study determined the antimicrobial resistance profiles of L. monocytogenes and other Listeria spp. isolated from beef and beef products sold in retail outlets across Mpumalanga province, South Africa. A total of 153 isolates were obtained from 30 retail outlets. Standard bacteriological methods and PCR were used for isolation and confirmation, and disc diffusion was used to assess resistance to 16 antimicrobials. All isolates showed resistance to at least one antimicrobial, with MDR observed in 51.5% of L. monocytogenes and 47.5% of Listeria spp. All 33 isolates of L. monocytogenes were susceptible to five antimicrobial agents (penicillin, ampicillin, amoxicillin-clavulanic acid, gentamicin, and trimethoprim-sulfamethoxazole), which are commonly used in the treatment of listeriosis. Resistance prevalence ranged from 3.0% to 100% for L. monocytogenes and from 1.7% to 100% for Listeria spp., with all isolates showing resistance to nalidixic acid. The district location, outlet size, and types of beef and beef products significantly affected resistance patterns. Although all L. monocytogenes isolates were susceptible to five therapeutically important antimicrobials, the high prevalence of resistance, including MDR, in Listeria spp. remains a concern. This is because AMR-Listeria species can transfer resistance genes/plasmids to pathogenic L. monocytogenes, thereby posing both food safety and therapeutic implications. HIGHLIGHTS • Antimicrobial resistance (AMR) of Listeria monocytogenes and other Listeria spp. in beef products was determined. • All isolates of L. monocytogenes were susceptible to penicillin, ampicillin, amoxicillin-clavulanic acid, gentamycin, and trimethoprim-sulfamethoxazole. • The frequency of multidrug resistance (MDR) was 51.5% and 47.5% in L. monocytogenes and Listeria spp., respectively. • District location, retail outlet size, and types of beef affected AMR frequencies. • High AMR prevalence in L. monocytogenes isolates may pose food safety and therapeutic implications.
Effects of selenium and zinc supplementation on epididymal spermatozoa quality in indigenous Kolbroek and Large White boars
Netshirovha, Thivhilaheli Richard; Kanengoni, Arnold Tapera; Chimonyo, Michael (Elsevier, 2026-03)
This study investigated selenium (Se) and zinc (Zn) supplementation effects on epididymal spermatozoa quality in indigenous Kolbroek and commercial Large White × Landrace (LW × LR) boars. Forty-eight boars, 8 months old at evaluation, were allocated to a 2 × 2 × 2 factorial design with two Se levels (0.26 vs 0.65 mg/kg), two Zn levels (35 vs 74 mg/kg), and two genotypes over 16 weeks. Epididymal spermatozoa were evaluated for concentration, morphology, motility, mineral composition, and oxidative stress markers. The LW × LR boars achieved greater progressive motility with high Se+Zn supplementation (61.8%) versus low supplementation (39.5%; Cohen's d = 1.39), while Kolbroek boars performed optimally under low Se+Zn conditions (43.9% vs 39.7%; Cohen's d = -0.24). Treatment responsiveness was 5.4-fold greater in LW × LR (22.3% range) than Kolbroek (4.1% range). Significant genotype × treatment interactions occurred for live spermatozoa (P < 0.05) and sperm concentration (Se effect: P < 0.05). Sperm concentration showed the largest effect size (Cohen's d = 1.28) with antagonistic Se × Zn interaction tendencies (P = 0.069). Kolbroek boars demonstrated superior mineral retention (23.9% higher selenium) and genotype-dependent oxidative responses. Selenium reduced malondialdehyde by 7.1% in Kolbroek but minimally affected LW × LR, while zinc increased oxidative stress by 14.7% in LW × LR with negligible Kolbroek impact. These findings challenge universal supplementation protocols, showing that indigenous and commercial breeds require different strategies to optimize reproductive performance. The results support implementing breed-specific precision nutrition in pig breeding programs to enhance reproductive efficiency and lower costs. HIGHLIGHTS • Selenium and zinc supplementation improved spermatozoa motility in Large White boars, while Kolbroek boars performed optimally under low mineral supplementation. • Kolbroek boars retained more selenium and magnesium compared to Large White boars. • Selenium supplementation reduced oxidative stress in Kolbroek boars. • Genotype-specific mineral nutrition strategies should be developed to enhance boar semen quality.
A review of drivers of emerging infectious diseases within the wildlife-human-domestic animal interface in the West Pacific Tropics
Lastica-Ternura, Emilia A.; Horwood, Paul; Skerratt, Lee Francis; Gummow, Bruce (Elsevier, 2026-06)
The West Pacific Tropics (WPT) is a hotspot for disease emergence. Rich biodiversity, high species population density, susceptibility to climate change, rapid land use changes and high transboundary traffic, provide an ideal situation for disease spread, but their interaction in driving disease emergence is poorly understood. Studies related to drivers of emerging infectious diseases (EID) published between 2004 and 2024 were gathered through a document search using Web of Science, SCOPUS and MedLine. A PRISMA diagram was used to document the selection process, and track materials retrieved. A total of 23,235 articles were collated using EndNote™ (ver. 21.5) during the initial search. After removal of duplicates and grey literature, titles and abstracts of 16,442 articles were screened based on the exclusion and inclusion criteria, and 75 articles were sought for retrieval. Out of the 43 eligible reports for full paper review, 29 were excluded based on the exclusion criteria and 14 studies were included in the review. The small number of eligible studies was partially because documents chosen were limited to studies or topics within the WPT. Some territories were underrepresented which introduced some bias into the study. Included studies were analysed using a direct acyclic graph (DAG), which identified ten vectors that showed causal paths leading to EID. Socioeconomics and governance were key drivers of EID within wildlife-human-domestic animal transboundary interface in the WPT. By framing these interactions within a regional One Health systems perspective, the study shows that governance and socioeconomic factors act as cross-cutting determinants that influence multiple pathways of pathogen spillover and spread. Activities that promote increased proximity of wildlife to domestic animals and people serve to mediate disease transmission and spread. Harmonising wildlife trade regulation and strengthened territorial biosecurity measures through the adoption of regional best practices are recommended as key disease prevention strategies.
Knowledge, practice, and risk of exposure of abattoir workers to Mycobacterium spp. in abattoirs and non-abattoir environments in Gauteng province, South Africa
Mareledwane, Vuyokazi Epipodia; Hlokwe, Tiny Motlatso; Ngoshe, Yusuf Bitrus; Adesiyun, Abiodun Adewale (AOSIS, 2026-03-18)
Zoonotic tuberculosis (TB), caused by Mycobacterium bovis, a member of the Mycobacterium tuberculosis complex, remains a global public health hazard. Information based on knowledge, practices, and associated risks among high-risk occupations, such as veterinarians and abattoir workers, is crucial. A close-end questionnaire was used to interview 103 abattoir workers during sampling visits, and data on their knowledge, practices, and potential exposure to Mycobacterium spp. were collected. More males (87/103, 84.47%) participated in the study, with the majority (83/103, 80.58%) working in the abattoirs’ slaughter and meat processing sections. A high proportion (88.35%) of participants were knowledgeable about TB. A relatively low proportion of abattoir workers were aware that they could transmit TB to animals (44.6%) and that they could acquire the disease from animals (45.7%), suggesting that they may know about the disease but little about its mode of transmission. To reduce exposure to infectious bacteria, personal protective equipment (PPE) was worn when handling carcasses at abattoirs, with 95.15% (95% confidence interval [CI]: 90.92–99.37) reporting its use. Non-abattoir potential exposure to Mycobacterium spp. among abattoir workers included the consumption of undercooked meat (10.68%; 95% CI: 4.61–16.75), slaughtering of animals at home (47.57%; 95% CI: 37.76–57.38), and consuming raw milk (25.24%; 95% CI: 16.71–33.77). It is therefore not enough for abattoir workers to know about bovine TB; they must also understand other aspects of the disease, particularly its transmission. CONTRIBUTION : Our findings revealed a high proportion of workers following good PPE donning practices when handling carcasses, thereby minimising the transmission of zoonotic diseases such as TB. Consumption of raw milk and undercooked meat are significant risks associated with the transmission of zoonotic TB. Therefore, to reduce the risks and improve the overall well-being, awareness programmes regarding control and prevention are crucial.
Knowledge, attitudes, perceptions and practices of selected commercial dairy cattle farmers regarding neosporosis in South Africa
Tagwireyi, Whatmore Munetsi; Morar-Leather, Darshana; Thompson, P.N. (Peter N.); Neves, Luís C.B.G.; Alvarez-Garcia, Gema (AOSIS, 2026-03)
Neospora caninum is a cyst-forming coccidian protozoan with a broad host range and is maintained through a complex facultative heteroxenous life cycle involving definitive canid hosts and various warm-blooded intermediate hosts. In cattle, it is a major cause of infectious abortion, leading to significant losses in productivity and profitability worldwide. This study surveyed 48 commercial dairy farmers across seven milk-producing regions in South Africa to assess knowledge, attitudes, perceptions and practices regarding bovine neosporosis. Most respondents were commercial farmers (98%), managed mixed-breed cattle (48%), operated farms larger than 500 hectares (48%) and had cattle averaging 3-5 years in age (77%). Only 21% of farmers were aware of neosporosis. Despite limited knowledge, 77% demonstrated good disease management practices, and 52% had positive attitudes towards control efforts. Three variables were significantly associated with the odds of positive practice and positive attitude scores. Farms with herds over 500 animals were 41.7 times more likely (95% confidence interval: 1.5-5237.3) to exhibit good practices. Farms that used total mixed ration were associated with better practices, while the presence of wildlife was associated with poorer attitudes. Additionally, farms that reported the presence of wildlife were less likely to have a positive attitude score. No specific factors were found to be associated with increased disease knowledge. CONTRIBUTION : This study highlights the critical knowledge gap and the need for greater awareness and targeted biosecurity measures for bovine neosporosis. It also identified neosporosis as a neglected abortifacient in dairy cattle in South Africa.
Vaccination-challenge trials in beagle dogs using whole-cell Leptospira interrogans Serovar Copenhageni vaccine : prevention of clinical leptospirosis, serological, leptospiremia, leptospiruria, cytokines, hematological, and pathological changes
Noel, Teola; Suepaul, Rod; Adesiyun, Abiodun Adewale (MDPI, 2025-06-20)
A killed, whole-cell vaccine was produced to induce immunity in dogs against leptospirosis. The vaccine, containing serovar Copenhageni, was produced and administered to 12 beagle dogs at both 8 and 12 weeks of age. Ten unvaccinated dogs of the same age group served as the control group. A live, virulent inoculum of Leptospira (1.52 × 109-4.40 × 109 leptospires per dog) was used to challenge the dogs at 2 weeks (Study 1) and 14 months (Study 2) post-booster vaccination. At regular intervals, pre- and post-challenge (PC), the microscopic agglutination test (MAT) was performed to measure antibody titers. Leptospiremia and leptospiruria were determined via culture, and the cytokine, biochemical, and pathological profiles of vaccinates and controls were also assessed. A high antibody response was measurable after booster administration. In Study 1 (onset of immunity), acute leptospirosis was observed in five (100%) out of five unvaccinated dogs. In contrast, no acute clinical leptospirosis developed in vaccinated dogs, except in one (20%) dog with mild clinical signs. In Study 2 (duration of immunity), mild clinical signs were observed in two (40%) of the control dogs, while all vaccinated dogs remained clinically normal. The incidence of leptospiruria and leptospiremia PC was lower in the vaccinated dogs compared to the unvaccinated group. Severe thrombocytopenia occurred in 100% (5/5) of the unvaccinated dogs in Study 1 that exhibited acute severe leptospirosis, whereas 80% (4/5) of the unvaccinated dogs in Study 2 showed mild to moderate thrombocytopenia 3 days after challenge. Four out of five unvaccinated dogs (80%) in Study 1 exhibited icteric tissues and hemorrhages in the lungs and mucosal surfaces of the stomach and intestines. A high IL-10 to TNF-α ratio, observed in the control group of both studies, and severe thrombocytopenia observed in the control group of Study 1, indicative of acute leptospiral disease, were detected. The vaccine prevented acute clinical leptospirosis and reduced the renal carrier state in beagle dogs, and further investigation is required using a larger sample size.
Multiplex PCR for differentiating Ornithodoros tick vectors in South Africa : proof of concept
West, Susan; Van Emmenes, Juanita; Boshoff, Carin (AOSIS, 2025-10-27)
African swine fever (ASF) is a severe viral haemorrhagic disease affecting domestic pigs, maintained by ASF virus within an ancient sylvatic cycle involving Ornithodoros ticks that inhabit warthog burrows. This study aimed to develop and optimise a multiplex polymerase chain reaction (PCR) assay to differentiate three Ornithodoros species in South Africa - O. moubata, O. phacochoerus and O. waterbergensis, to enhance ASF vector identification and management. The final multiplex PCR effectively distinguished between species with specific amplicon sizes: 180 base pairs (bp) for O. moubata, 640 bp for O. phacochoerus and 1000 bp for O. waterbergensis. CONTRIBUTION : This refined multiplex PCR method demonstrates proof of concept as a reliable and rapid tool for distinguishing Ornithodoros species and correlating them with their geographical origins. This assay, based on amplification size, provides crucial information about the distribution of these species, which could enhance ASF control efforts.
Description of a new species of sucking louse Hoplopleura kuhnludwigi (Phthiraptera: Anoplura: Hoplopleuridae) from the Cape York rat Rattus leucopus cooktownensis (Rodentia: Muridae) in Australia using conventional methodology and novel epiflourescence microscopy
Constantinoiu, Constantin; Wang, Wei; Firth, Cadhla; Duffy, Richard; Picard, Jaqueline; Gummow, Bruce (Elsevier, 2025-06)
A new species of sucking louse, Hoplopleura kuhnludwigi (Phthiraptera: Hoplopleuridae), from the Cape York rat Rattus leucopus cooktownensis Tate, 1951 (Rodentia: Muridae) is described and illustrated with photos and drawings. The host rat(s) were trapped in Northeast Queensland, Australia and identified using morphological characters and DNA sequencing. Hoplopleura kuhnludwigi is the first louse species to be described on R. leucopus. The morphology of the new louse species is contrasted with the morphology of Hoplopleura spp. previously described in Australian murids and shown to be different from other louse species that infest Australian native murids. Both conventional lice processing and staining methodology and a novel method, based on autofluorescence of chitin, have been used to describe and illustrate the diagnostic characters of H. kuhnludwigi. Processing of H. kuhnludwigi for epifluorescence microscopy (EM) is fast and easy, and the examination of the lice processed by this method can improve the accuracy of the description and identification of the lice species from genus Hoplopleura and potentially other louse species.
Safe, sustainable, legal use and trade in wild species : testing a new five-dimensional sustainability assessment
Timoshyna, A.; Roe, D.; Aust, P.; Compton, J.; Hiller, C.; Kagembe, Q.; Long, N.; Natusch, D.; Taylor, William Andrew; Rock, K. (Elsevier, 2025-12)
The Kunming Montreal Global Biodiversity Framework, adopted by the UN Convention on Biological Diversity in 2022, sets ambitious targets to ensure that the use, harvesting and trade of wild species is sustainable, safe and legal. While the definition of ‘sustainable’ is traditionally inclusive of ecological, social, and economic dimensions, many practically applied standards and regulations often exclude non-ecological perspectives such as human health and animal welfare. Recognising the challenge of assessing sustainability in a comprehensive, but accessible, way, a five-dimensional sustainability assessment framework (5DSAF) was developed, explicitly focusing on social, ecological, economic, animal welfare, and human health dimensions of sustainability. This paper documents the experiences of applying and testing the 5DSAF in multiple species use examples: geographically, by different sectors, and socio-economically. Its application in the United Republic of Tanzania (game meat industry), in South Africa (game meat sector), in Indonesia (reticulated python skins), and in Zimbabwe (Nile crocodile) is discussed. It proposes the steps for the future adaptations, and application of 5DSAF beyond the initial case studies aiming to assist conservation practitioners, policymakers, as well as indigenous peoples and local communities and private sector actors to demonstrate that the use of wild animal species and products is safe, legal and sustainable and, meeting the objectives of One Health approach, and where it is not, to identify the necessary improvements that need to be made.
An evaluation of African animal trypanosomiasis control strategies in remote communities of Eastern Zambia
Mulenga, Gloria M.; Chilongo, Kalinga; Mubamba, Chrisborn; Gummow, Bruce (Cambridge University Press, 2024-10-30)
Communities living in African animal trypanosomiasis (AAT) endemic areas of Zambia use several control strategies to protect their livestock from the devastating effects of trypanosomiasis. Several studies have reported the effectiveness of trypanosomiasis control strategies based on retrospective data. In this study, we assessed incidence rates of AAT in cattle (n = 227) using a prospective cohort study comprising 4 treatment groups, i.e., Diminazene aceturate, Isometamidium chloride, Cyfluthrin pour-on and Cypermethrin treated targets. The study was conducted in Mambwe district in Eastern Zambia between February 2019 and March 2020. The endemic prevalence of AAT for each group was determined using ITS-PCR prior to application of treatments. High endemic trypanosome pre-treatment rates were found in all Groups (Diminazene aceturate (61%), Isometamidium chloride (48%), Cyfluthrin pour-on (87%) and Cypermethrin targets (72%)). The overall apparent prevalence for the Mambwe district was 67% (152/227) and true prevalence at 95%CI was 63–71%. Once treatments were implemented, 12 monthly follow-ups were conducted. The average monthly incidence rates without standardization recorded: Diminazene aceturate (67%) Isometamidium chloride (35%), Cyfluthrin pour-on (55%) and Cypermethrin targets (61%). Incidence rates were standardized considering the endemic level of disease for each Group and the average standardized monthly incidence rate in the Diminazene aceturate Group was 7%; the Isometamidium chloride Group −13%; the Cyfluthrin Group −26%; and the Cypermethrin target Group, −17%. All Groups showed a decrease in incidence of AAT over the period of the study with the Cyfluthrin group showing to be the most effective in reducing AAT incidence in cattle.

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