Research Articles (Production Animal Studies)

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One Health Economics approach to prevention and control of zoonotic and animal diseases - considerations for South Africa
(BioMed Central, 2025-05) Mamabolo, Manana; Machalaba, Catherine; Zantsi, Siphe; Rostal, Melinda K.; Karesh, William B.; Thompson, P.N. (Peter N.); Chaminuka, Petronella
Outbreaks of animal and zoonotic diseases in South Africa are costly and raise concerns about national biosecurity. The interconnectedness of humans, livestock, wildlife and their social and ecological environment necessitates a holistic approach to prevention, preparedness and response to zoonotic and animal diseases. One Health is an increasingly accepted approach in contemporary science and policy spheres, but with limited consideration for economic dimensions. To more fully estimate costs of animal and zoonotic diseases in the country and to explore further scope for applying a One Health economics lens, the Agricultural Research Council of South Africa, in collaboration with partners, held a One Health Economics mini-congress to provide a platform where multidisciplinary stakeholders discussed practical examples, primarily from the Southern African region. Discussions at the mini-congress centred around One Health economics and opportunities, economic insights on prevention and control of Rift Valley fever (RVF), avian influenza and other zoonotic diseases, return on investment for One Health approaches, and insights from the natural resources and animal and human health sectors. Regional and international perspectives on multi-sectoral economic analysis and financing were also shared. Key recommendations from the mini-congress included promoting coordination, co-creation and co-implemented efforts to minimize effects of One Health challenges, and including economic aspects of multi-sectoral engagement to identify and reduce trade-offs and maximize co-benefits of strategies and programmes. Integration of economics in One Health fora, research and collaboration, and promotion of communities of practice and applied training to enhance learning and knowledge exchange were also identified as important.
Seven infectious bronchitis virus genotypes including South American-origin G1-11 and Asian-origin GVI-1 circulated in southern African poultry from 2010 to 2020
(Elsevier, 2025-05) Strydom, Christine; Abolnik, Celia; celia.abolnik@up.ac.za
Infectious bronchitis virus (IBV) affects the respiratory, urogenital and reproductive systems of chickens and causes major economic losses. Biosecurity and vaccinations are used to limit the disease's impact, and identifying the circulating strains is important for selecting appropriate vaccines. The partial spike (S1) genes of 364 IBVs, isolated from commercial chickens in Botswana, Eswatini, Namibia and South Africa from 2010 to 2020, were phylogenetically analyzed. Seven genotypes were identified: 184 viruses (50,5 %) were classified as genotype GI-19 (QX) and 78 (21,4 %) were GI-1 (Mass/H120). Thirty-nine (10,7 %) were genotype GI-13 (4/91), 29 (8,0 %) were GVI-1 (TC07–2), 19 (5,2 %) were GI-23 (Variant 2), and 13 (3,6 %) were GI-11 (UFMG/G-Brazil). Two (0.5 %) viruses belonged to the GIV-1 (DE/072/92) genotype. Genotype GI-11 had not been reported outside South America before but has evidently circulated in South Africa for at least a decade. Similarly, genotype GVI-1, previously thought to be restricted to Asia, has been present in southern Africa since at least 2010. Prior to 2013, only Mass and H120 vaccines were permitted to be used in South Africa, but since 2013 793/B (GI-13), QX (GI-19), 4–91 (GI-13) and Variant 2 (GI-23) live attenuated vaccines were permitted. Accordingly, the four IBV variants we identified were putative recombinants of genotypes G1–1 and G1–19, G1–13 and G1–19, or G1–13 and unknown IBV strains, but these variant viruses did not spread extensively or persist in the region. The phylogenetic evidence points to imported contaminated poultry and poultry products as the source of new IBV genotypes in southern Africa. HIGHLIGHTS • Seven IBV genotypes circulated in southern African poultry from 2010 to 2020. • Genotype GI-11, thought to be restricted to South America, was identified. • Genotype GVI-1, thought to be restricted to Asia, was identified. • Variant IBVs were recombinants of registered vaccines and field viruses. • Imported poultry and poultry products are the likely source of IBVs.
Factors affecting in vitro oocyte maturation in Southern white rhinoceros (Ceratotherium simum simum)
(Medpharm Publications, 2025-05) Smuts, Mario P.; De Bruin, P.R.; Fosgate, Geoffrey Theodore; Vorster, L.; De la Rey, Marlene; Lichtenberg, C.; Young, C.; Durrant, B.S.; Meyer, Leith Carl Rodney; Holm, Dietmar Erik; mario.smuts@up.ac.za
BACKGROUND : Population numbers of free-roaming rhinoceros are dwindling while natural breeding in captive populations is challenged by sub-optimal fertility. When natural breeding programmes fail and population numbers continue to decline, the use of assisted reproduction technologies (ART) as a conservation tool to save wildlife species from extinction is imperative. Assisted breeding programmes in rhinoceros are challenging and attempts to develop species-specific ART beyond artificial insemination have been limited. This study evaluates various ex- and in-situ factors that could potentially affect in vitro oocyte maturation (IVM) in the Southern white rhinoceros (SWR). OBJECTIVES : To identify predictors of oocyte maturation following ovum pick-up (OPU) procedures performed on a large number of rhinoceros under different management conditions. METHODS : Data from 85 OPU procedures between November 2018 and June 2023 were obtained for this study. A total of 23 factors (three animal, four environmental, 16 laboratory) were evaluated as potentially affecting IVM success. RESULTS : Of the 85 procedures performed on 59 SWR, a total of 265 oocytes were collected with a median of two oocytes (range 0–18) per OPU. Eighteen (18) of the procedures yielded 0 oocytes. The overall maturation rate was 30% (80/265), and six identified factors had significant univariate associations with maturation outcome, of which three remained in the multivariable model. CONCLUSION : Farming system, season and oocyte density in maturation medium (> 100 ul/oocyte) were independently associated with improved maturation success (p < 0.05).
Effect of different dietary fibre raw material sources on production and gut development in fast-growing broilers
(South African Society for Animal Science, 2024-05-29) Fourie, Andries Benjamin; Wandrag, D.B.R. (Daniel)
Many studies have been published recently about the beneficial effect of different fibre sources in a broiler diet. To assess the effects of raw material sources available in southern Africa, a trial was done with four treatments: control diet, 2% sunflower hulls, 2% malt culms, and 0.8% of a commercial lignocellulose product. Using a completely randomised block design, each treatment had 24 repetitions (96 pens in total), with 48 birds per pen. The effects were measured weekly by assessing production parameters, gut development, and the humoral immune response. Production parameters were measured per pen, gut measurements were done on 12 birds per treatment each week, and humoral immune response on 24 birds per treatment at 32 days. The promising responses seen in previous studies on fibre sources such as sugar beet pulp and oat hulls were not fully repeated here with the local fibre sources. There were no statistical differences from the control group based on production parameters. Sunflower hulls produced a substantial improvement over the control group with regards to caecal and overall intestinal lengths at 7 d. There was a numerical improvement in gizzard weights at 7 d for the malt culms group. No marked differences were detected in serology. The results indicate that there could be merit in including sunflower hulls in the pre-starter period (days 0-7), although it did not translate to production advantages here. Different inclusion levels should be investigated.
Seasonal effects of Searsia lancea, Celtis africana and concentrate supplementation on weight changes, serum and urine metabolites in South African Nguni goats
(Springer, 2025-06) Phiri, France; Kanengoni, Arnold Tapera
This study evaluated the seasonal impact of different dietary supplements on male Nguni goats' health, focusing on serum and urine metabolite concentrations. Twenty male Nguni goats (15 ± 1.6 kg) were arranged in a 2 × 4 (season × diet) factorial design using a randomized complete block arrangement with five goats per treatment. All goats received a basal diet of Eragrostis hay supplemented with one of four treatments: T1) Searsia lancea (SLA), T2) Celtis africana (CAF), T3) a 1:1 combination of SLA and CAF (LAC), or T4) a control diet with concentrate. During the wet season, goats fed CAF or SLA showed higher average daily gain (ADG) and average dry matter intake (ADMI) than those on LAC. Significant season × diet interactions were observed for urobilinogen (URO), urine bilirubin (UBIL), urine protein (UPRO), and urine calcium (UCAL). Goats on the control diet exhibited higher URO and UBIL values (P < 0.05) than those on browse forages during both seasons. In the wet season, goats on SLA had higher UPRO (P < 0.05) than those on LAC. Across seasons, goats on CAF showed higher blood serum gamma-glutamyltransferase (GGT) than those on control or LAC diets (P < 0.05). Diet significantly affected (P < 0.05) serum GGT, albumin, alkaline phosphatase, urea nitrogen, creatinine, cholesterol, glucose, and inorganic phosphate levels regardless of season. Urinalysis revealed diet-related kidney dysfunction and imbalanced serum metabolites. The study concluded that CAF and SLA supplementation negatively affected renal and hepatic health in goats, warranting further investigation.
A multi-modal investigation into the prevalence and diagnostic evaluation of vector-borne pathogens and retroviruses in domestic cats throughout Namibia
(Elsevier, 2025-08) De Villiers, Lourens; Penzhorn, Barend Louis; Schoeman, Johan P.; Molini, Umberto; De Villiers, Mari; Byaruhanga, Charles; Makgabo, Sekgota Marcus; Collins, Nicola E.; Zealand, Samantha; Baines, Ian J.M.; Stoltsz, Wilhelm Heinrich; Thompson, P.N. (Peter N.); Oosthuizen, Marinda C.
Neglected, but economically significant, tropical diseases may be prevalent in domestic cats of Namibia. A multi-centre prevalence field study was conducted across Namibia to assess the distribution of vector-borne pathogens and retroviruses from domestic cats. Samples of blood and serum from 280 cats in 15 towns across eight regions (22–51 cats per region) were analysed. Screening for Ehrlichia, Anaplasma, Babesia, and Hepatozoon species, as well as feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV), was conducted using light microscopy, point-of-care serology, and quantitative real-time polymerase chain reaction (qPCR) assays. Haematology and serum biochemistry analyses were also performed. Several pathogens were identified in Namibian cats using these diagnostic tools. Comparatively, pathogen detection rates varied by modality, namely light microscopy (5 %), serology (42 %), and qPCR (27 %). More specifically, microscopy revealed an overall prevalence (3 %) for inclusions resembling large Babesia parasites, serology indicated a seroprevalence for FIV antibodies (4 %) and FeLV antigen (40 %), and an overall prevalence determined by qPCR for E. canis (2 %) and H. canis (26 %). The investigation also demonstrated the associations between tick presence, pathogen infection, and disease manifestations in Namibian cats. A particular significant positive association was found between H. canis infection and FeLV antigen seroprevalence (P = 0.005). Overall, the study highlighted the difference of various diagnostic tools for detecting pathogen prevalence in cats. Appropriate diagnostic testing - informed by known associations with disease manifestation - should be key in guiding responsible treatment strategies and evaluating potential zoonotic risks linked to domestic cats of Namibia. HIGHLIGHTS • First comprehensive survey of vector-borne diseases and retroviruses in domestic cats across several Namibian regions. • First confirmed detection of Ehrlichia canis and Hepatozoon canis in domestic feline blood across several regions of Namibia. • Demonstrated significant associations between pathogen infection, tick presence, and disease manifestation.
Efficacy, safety and interval from end of treatment to estrus in cats treated with an ultra-low dose megestrol acetate protocol for suppression of reproductive activity
(Elsevier, 2025-10) Pereira, Maria; Grassi, Anna; Pipan, Maja Zakosek; Contato, Giulia; Dal Ponte, Giada; Ghezzo, Anna; De Cramer, Kurt Guido Mireille; Romagnoli, Stefano
Cat breeders need safe, predictable and fully reversible temporary control of reproduction in queens. Megestrol acetate (MA), a short-acting progestogen was investigated in this study designed to determine whether low-dose treatment is both effective and safe in cats for periods up to 6 months. Twenty-eight queens were treated orally with 11.5 μg/kg/day of MA for one to six months. A physical examination, vaginal cytology, and reproductive ultrasound were performed before, during and after treatment, whilst urinalysis and hematological/biochemical tests, including progesterone assay, were performed before and after treatment. MA suppressed reproductive function effectively in 27/28 queens. Transient mammary and uterine hyperplasia were detected in four (14 %) and three (11 %) queens, respectively, treated for more than four months, without associated clinical signs. Pyometra was observed in only one queen following her first estrus cycle post-treatment. Significant but reversible weight gain was observed in 85 % of the animals. The resumption of cyclicity occurred on average 6 weeks after the end of treatment but was influenced by the duration of treatment and seasonality. An ultra-low dose MA treatment was effective in suppressing estrus in queens treated up to 6 months. Close monitoring should be paid to queens treated for longer than 4 months as the incidence of side effects, albeit minor and manageable, increases thereafter. Mammary gland assessment and progesterone assay are indispensable before treatment. Fertility is preserved, making MA a valuable option for temporary control of reproductive activity in queens, who otherwise cycle continuously leading to both unwanted behavior and pregnancies. HIGHLIGHTS • Megestrol acetate (11.5 μg/kg/day) is safe and effective for suppression of reproductive activity in queens up to 4 months. • Mammary gland health assessment and a progesterone assay < 2 ng/ml are necessary before initiating treatment. • Queens increase body weight during treatment, but return to pre-treatment weight shortly after the end treatment. • Reproductive activity resumes on average in 6 weeks but is influenced by the duration of treatment and seasonality.
Accidental intravenous overdose of meloxicam in a Cape Vulture (Gyps coprotheres)
(Medpharm Publications, 2025-02) Gazendam, Bart Adriaan Theodorus; Koeppel, Katja Natalie
Many species of vulture are under threat from man-made inventions; this has led to wounded and sick vultures presenting for veterinary treatment and in need of pain management. Following the devastating effect of diclofenac on vultures in South Asia, meloxicam was found to be very safe for vultures, as a treatment as well as through ingestion of meat from treated animals. Many studies investigated the safety of meloxicam, and all found it to be safe up to 2 mg/kg, which was deemed the maximum likely exposure through treated carcasses. All studies exposed the birds either through oral dosing, treated meat or intramuscular administration, no instances of toxicity where recorded and all birds remained healthy. In this case the bird was exposed to a single dose of 2 mg/kg, intravenously, with no signs of toxicity. This appears to be the first recorded instance of accidental intravenous administration of meloxicam in a vulture.
Vaccines in the fight against antimicrobial resistance – perspectives from South Africa
(South African Medical Association, 2024-09) Brink, A.; Kagasi, A.; Musyoki, A.; Kagina, B.; Feldman, C.; Reddy, D..; Du Toit, E.; Kalanxhi, E.; Meyer, J.; Impalli, I.; Schonfeldt, M.; Sibanda, M.; Schellack, Natalie; Skosana, Phumzile; Essack, S.; Dlamini, S.; Ramsamy, Y.
Antimicrobial resistance (AMR), in which microbes adapt to and resist current therapies, is a well-recognised global problem that threatens to reverse gains made by modern medicine in the last decades. AMR is a complex issue; however, at its core, it is driven by the overuse and inappropriate use of antimicrobials. Socioeconomic factors have been identified as significant contributors to the emergence and exacerbation of AMR, especially in populations facing inadequate access to healthcare, poor sanitation services and high morbidity and mortality rates. Weak healthcare systems and water, sanitation and hygiene have been highlighted as fundamental risk factors for AMR emergence and transmission. Behavioural factors, such as purchasing antibiotics without a prescription from a registered healthcare professional, not completing the prescribed course or overly prolonged courses of antibiotics, using antibiotics to treat viral infections, lack of access to quality antibiotics, and the proliferation of substandard or falsified (SF) drugs, have also been identified as significant contributors to AMR. Low- and middle-income countries have a higher incidence of antibiotics being dispensed without a prescription than higher-income countries.
Seasonality, social structure and age predict conspecific aggression in captive breeding southern ground-hornbills (Bucorvus leadbeateri)
(Wiley, 2025-03) Koeppel, Katja Natalie; Lubbe, Nevanya; Donaldson, Ashleigh Claire; Kemp, Lucy Valeska; katja.koeppel@up.ac.za
Southern Ground-hornbills (SGHs) are listed as Vulnerable globally, and Endangered in South Africa, Namibia and Swaziland, due to poisoning, habitat loss and persecution. Successful conservation breeding and rearing of redundant second-hatched chick protocol has been established to supplement natural SGH populations in an attempt mitigate a declining population. However, captive rearing is costly and susceptible to loss of birds through conspecific aggression. Maximising the efficacy of reproductive output in captive settings and ensuring successful reintroductions of captive-reared birds to wild populations is of paramount importance if this species is to persist. Therefore, it is important to untangle the predictors of what drives mortalities in captive birds, particularly, through conspecific aggression. Using a database of captive SGH mortalities collected over 46 years we investigated whether variables such as season, age, relatedness, sex and husbandry predicted the occurrence of conspecific aggression in SGH. Aggression among adult, non-related birds particularly during SGH breeding season (austral spring) was the most predictable form of conspecific aggression. It was inferred that aggression is normally directed at non-related birds outside of already established social groups or at younger, related birds that are not dispersing from groups when reaching sexual maturity. Variables such as season, age, relatedness and husbandry were therefore all useful for predicting the potential and avoidable occurrence of an aggression event. Male birds were most often the aggressors. Making use of such variables to manage birds in a captive setting, move birds before sexual maturity and maintaining birds in known and accepted social structures could greatly improve management in SGH breeding facilities and optimise the efforts for re-establishing natural SGH populations. SUMMARY: Conspecific trauma accounted for approximately 7.80% of all recorded Southern Ground-hornbill (SGH) mortalities. Seasonality significantly influenced aggression, with more attacks in austral spring compared to autumn. Breeding status did not affect aggression frequency; non-breeding individuals were more often involved. Males were not significantly more aggressive than females or pairs, but non-breeding individuals were most aggressive in austral winter and spring. Victim sex or attacker sex did not predict aggression likelihood. Age and sex determined onset of attacks with majority of attacks been adult birds and females (8.8 ± 8.3 years) been attacked earlier then male (9.1 ± 8.9 years). Group size did not significantly influence attack frequency. Moon phase did not affect aggression occurrence.
The role of smallholder pig farmers in the biosecurity of pig diseases in the Eastern Cape Province of South Africa
(Wiley, 2025-05) Simbizi, Vincent; Moerane, Rebone; Gummow, Bruce
Biosecurity forms an important component of preventing disease transmission. However, data on the demographics and practices of smallholder pig farmers in Southern Africa are scant, and little is published on the biosecurity related to these farms. A questionnaire survey was, therefore, carried out in the Eastern Cape Province of South Africa to describe the demographics and practices of smallholder pig farmers and to understand their role in the biosecurity and prevention of pig diseases. Females represented 52% of pig farmers and reflect the cultural importance of pig farming in Xhosa culture. All the farmers who were interviewed had poor biosecurity measures on their farms. A low level of education, lack of training and reliance on remedies to treat and prevent pig diseases were key findings for the majority of farmers. Farmers had a poor knowledge of correct antibiotic use, which could contribute to antimicrobial resistance (AMR). Smallholder farms were found to frequently involve free-ranging pigs, swill feeding and informal trading, practices known to contribute to the spread of communicable pig diseases such as foot and mouth disease and African swine fever. Smallholder pig farms are, therefore, a potential risk for disease incursion and spread of communicable diseases within a region. Cost-effective biosecurity measures and marketing opportunities will help to prevent pig diseases, while a continuing education programme will modernise the rural pig industry and reduce the impact of AMR.
A cross-sectional study of keratoconjunctivitis among dairy cattle farms subject to Mediterranean climatic conditions
(Springer, 2025-03) Maartens, Louis Henning; Thompson, P.N. (Peter N.); Grewar, John Duncan; Picard, Jacqueline; Gummow, Bruce
The epidemiology of bovine keratoconjunctivitis (BK) is complex and involves several conjunctival microbiota as well as host and environmental factors. Data about BK in dairy cattle are scarce, and even scarcer for dairy cattle in Mediterranean climates. We determined the BK prevalence among dairy cattle in Southern Africa’s Mediterranean climatic zone by examining 1,675 dairy cattle across 28 herds. Conjunctival swabs were analysed using real-time PCR. Risk factor data were collected by questionnaire and evaluated by multivariable logistic regression. The BK prevalence was 19.4%, (95% CI: 15.0 – 24.8%). Mesomycoplasma bovoculi was demonstrated in 75.7% of the sampled eyes (95% CI: 62.8 – 85.2%) across all farms. Moraxella bovis (18.3%, 95% CI: 11.9 – 27.0%) and Moraxella bovoculi (8.6%, 95% CI: 4.6 – 15.6%) were detected on 89% and 64% of the farms, respectively. Mycoplasmopsis bovis was rarely encountered. Moraxella bovoculi was significantly associated with BK (OR: 2.7, 95% CI: 1.3 – 5.6, Wald P: 0.01). Prevalence varied significantly by age and breed. Shade availability (OR: 2.5, 95% CI: 1.4 – 4.4, Wald P < 0.01), sanitation frequency, (OR: 0.4, 95% CI: 0.2 – 1.0, Wald P: 0.05), fly burden (OR: 2.1, 95% CI: 1.3 – 3.6, Wald P < 0.01) and introduced cattle (OR: 2.0, 95% CI: 1.1 – 3.5, Wald P: 0.02) were significantly associated with the prevalence of BK. Closed herds with proper biosecurity, fly control via sound management practices, and access to shade are recommended for preventing BK in dairy herds farmed in a Mediterranean climate.
Meeting report : CEPI workshop on Rift Valley fever epidemiology and modeling to inform human vaccine development, Nairobi, 4–5 June 2024
(Elsevier, 2025-04) Gharpure, Radhika; Vegvari, Carolin; Abdissa, Alemseged; Alimi, Yewande; Anyamba, Assaf; Auerbach, Jochen; Bett, Bernard; Bird, Brian H.; Bob, Ndeye Sakha; Breugelmans, J. Gabrielle; Clark, Jessica; Cleaveland, Sarah; Cramer, Jakob; Dawa, Jeanette; Fay, Petra C.; Formenty, Pierre; Gerdts, Volker; Gerken, Keli N.; Gitonga, John; Groschup, Martin; Heighway, James; Johnson, Sherry Ama Mawuko; Juma, John; Kading, Rebekah C.; Kamau, Maureen; Kerama, Samuel; Lubisi, Baratang Alison; Lutwama, Julius; Luyimbazi, Dick; Marami, Dadi; Moore, Sean M.; Muturi, Mathew; Mwangoka, Grace; Ndiu, Angela; Njenga, M. Kariuki; Njouom, Richard; Nyakarahuka, Luke; Nzietchueng, Serge; Oloo, Paul; Otiende, Mark; Oyola, Samuel; Paganini, Lodovico Samuele; Pandit, Pranav S.; Punt, Carine; Samy, Abdallah M.; Situma, Silvia; Sneddon, Heidi; Ten Bosch, Quirine A.; Tezcan-Ulger, Seda; Thompson, P.N. (Peter N.); Tildesley, Mike; Tinto, Bachirou; Vesga, Juan F.; Schreur, Paul P. Wichgers; Hart, Peter
Rift Valley fever (RVF) is a zoonotic viral disease that causes epidemics and epizootics among humans and livestock, resulting in substantial health and socioeconomic consequences. Currently, there are no RVF vaccines licensed for humans, but several candidates show promise in early-stage development. Existing gaps in RVF epidemiological data and challenges associated with predicting RVF outbreak risk complicate the planning of efficacy studies, making the pathway to licensure for promising candidates unclear. In June 2024, the Coalition for Epidemic Preparedness Innovations (CEPI) convened a two-day workshop in Nairobi, Kenya, to discuss RVF epidemiology, modeling priorities, and specific gaps relevant to human RVF vaccine development. The workshop included representatives from multiple RVF-endemic countries, key global collaborators, and international health organizations. Workshop participants identified five key priorities: (1) Looking beyond outbreaks: There is a need to better characterize the complex One Health epidemiology of RVF and understand interepidemic persistence of the virus; (2) Better data for better models: Epidemiological modeling is crucial for research, prediction, and planning, but it requires accurate and representative data; (3) New, improved and accessible diagnostics and serological assays: These are needed to inform epidemiology and case definitions, without which RVF research will continue to suffer due to paucity of data and challenges in determining infection and exposure; (4) Defining use cases, regulatory pathways, and implementation strategies for human vaccines: Clarity on these topics will facilitate licensure and effective use of RVF vaccines; and (5) People-centered approaches: Community engagement and involvement of social and behavioral scientists are key to the success of human vaccine research and development and implementation, particularly as the virus impacts livestock and livelihoods. Workshop participants welcomed a renewed focus for RVF epidemiology and modeling, and expressed enthusiasm for continued multidisciplinary collaborations to support enabling sciences for human RVF vaccine research and development.
Precision feeding of feedlot calves based on phenotypic production profiles I. The effect on economic important production parameters
(MDPI, 2025-05) Hentzen, Andreas H.R.; Holm, Dietmar Erik; andreas.hentzen@up.ac.za
Precision feeding feeder calves according to their production potential could improve economically important production traits. We report two experiments, in two separate locations where feeder calves were categorized into previously established production profiles (PP 1, PP 2, and PP 3). These production-profiled calves were then randomly allocated to a high-producing diet (HPD), medium-producing diet (MPD), or a low-producing diet (LPD). The findings of experiment 1 (n = 430) were used to adjust the formulation of the diets in experiment 2 (n = 104). The mixed modelling of economically important feedlot carcass growth traits was performed in order to evaluate the interactions between PP classification and diet. PP 3 was repeatedly outperformed in all production parameters (p < 0.01) by PP 1 and PP 2, irrespective of the diet. In experiment 1, PP 1 calves outperformed PP 2 and PP 3 calves; however, the HPD was insufficiently matched to their growth potential. In experiment 2 where the metabolizable energy was increased, PP 1 calves gained 23.0 kg more carcass (p = 0.05), at an improved carcass feed conversion of 0.91 kg/kg (p = 0.06), when compared to PP 2 calves on MPD. This is the first report demonstrating the feasibility of precision livestock feeding based on the predicted growth needs of incoming feeder calves as determined by production profiling.
Strategic challenges in the global control of high pathogenicity avian influenza
(Office International des Epizooties, 2024-12) Swayne, D.E.; Sims, L.D.; Brown, R.; Harder, T.; Stegeman, A.; Abolnik, Celia; Delgado, M.; Awada, L.; Pavade, G.; Torres, G.
H5Nx A/Goose/Guangdong/1/96 Eurasian lineage high pathogenicity avian influenza (HPAI) viruses have been the main HPAI strains detected globally since 2005. These have spread around the world, causing a panzootic that has spanned six continents, with continual threat to not only wild and captive birds and poultry, but also wild, captive and domestic mammals and humans. The viruses' ecology and epidemiology - especially the 2.3.4.4b clade - have changed, with over 489 species of birds infected and spreading the virus over migratory routes. This results in the death of many birds, including endangered species, and serves as a source of transmission to poultry and mammals. Improved surveillance and sharing of HPAI virus sequences, metadata and viruses across the veterinary, public health, wildlife and environment sectors are needed to elucidate the population dynamics of the infections, which is crucial to addressing this complex One Health issue. The development of appropriate mitigation strategies or changes in husbandry, production and selling practices can reduce the risk of viruses being introduced into farms, as well as their amplification and viral evolution, and any spill-back to wild birds. Approaches to prevention and control of HPAI in countries where these 2.3.4.4b viruses remain entrenched in poultry, or places at risk of virus introduction via wild bird populations, involve measures to reduce the effects of the disease in poultry (including enhanced farm bio-security, vaccination, zoning and compartmentalisation). Their uptake reflects the difficulties encountered in relying solely on biosecurity for disease prevention and on stamping out alone for virus control and elimination. The World Organisation for Animal Health's Terrestrial Animal Health Code allows use of vaccination of poultry under specific conditions and without negatively impacting HPAI-free status if appropriate surveillance is conducted, thus supporting safe trade in poultry and poultry products. Nevertheless, concerns regarding loss of valuable export markets still interfere with greater utilisation of vaccination.
A One Health approach to reducing livestock disease prevalence in developing countries : advances, challenges, and prospects
(Annual Reviews, 2025-02) Lane, Jennifer K.; Kelly, Terra; Bird, Brian; Chenais, Erika; Roug, Annette; Vidal, Gema; Gallardo, Rodrigo; Zhou, Huaijun; Vanhoy, Grace; Smith, Woutrina
Challenges in livestock production in developing countries are often linked to a high disease prevalence and may be related to poor husbandry, feeding, and nutrition practices, as well as to inadequate access to preventive veterinary care. Structural barriers including chronic poverty, gender roles, inadequate supply chains, and limitations in surveillance infrastructure further complicate progress. Despite many challenges, the livestock sector substantially contributes to agricultural GDP, and reducing livestock disease prevalence is a goal for many countries. One Health initiatives that work across disciplines and sectors to reduce livestock diseases are underway around the world and use integrated approaches that consider the connections between humans, animals, and their shared environments. The growing recognition of the role livestock play in sustainability and livelihoods, as well as their involvement in zoonotic disease transmission and global health security, has highlighted the need for disease reduction strategies as described in this review.
The potential of various phenotypic traits to predict feedlot production in cattle - a systematic review
(CSIRO Publishing, 2025-05) Hentzen, Andreas H.R.; Holm, Dietmar Erik; dietmar.holm@up.ac.za
CONTEXT : Visual evaluation of phenotypic traits is an old and still practiced management tool in the beef industry. Beef production has improved because of the constant visual re-evaluation of phenotypic traits that are associated with production. Current data exposed the need to put all existing knowledge together in context. AIMS : This literature review is to determine the value of individual predictor variables based on existing knowledge, with the view of further improving, expanding, and refining the measured traits. METHODS : This systematic literature review focused on phenotypic traits and their potential associations with production. The traits needed to be predictive in nature. We particularly focused on studies involving intensive production systems, such as feedlots. A search of keywords related to the topic was performed on published articles and textbooks. This included textbooks from the seed stock industry. KEY RESULTS : Several, but not all, studies have demonstrated a positive association between phenotypic cattle traits and subsequent feedlot performance. The sensitivity of the measurement varied. The phenotypic traits investigated were either visually appraised and/or linearly measured. Studies focused on muscle and skeletal development because of their contribution to growth. Specific phenotypic traits were investigated, rather than a more holistic approach and/or combination thereof. For example, two different studies evaluated the predictive ability of dimensions of the cannon bone: one investigating the circumference and another the length. CONCLUSION : The consulted literature revealed limited evidence that phenotypic traits of incoming feeder calves can predict feedlot production. The current information needs more structure and refinement in measurement and reporting to find its application in a beef feedlot operation. IMPLICATIONS : A structured phenotypic evaluation before onset of the feeding phase in beef feedlots carries numerous advantages in beef production. The potential of precision feeding calves to phenotypically established production-related profiles can result from this study.
Vaccination and surveillance for high pathogenicity avian influenza in poultry-current situation and perspectives
(Elsevier, 2025-08) Sajjadi, Nancy C.; Abolnik, Celia; Baldinelli, Francesca; Brown, Ian; Cameron, Angus; De Wit, Sjaak; Dhingra, Madhur; Espeisse, Olivier; Guerrin, Jean Luc; Harder, Timm; Ho, Jeremy; Chua, Tze-Hoong; Hussein, Khaled; Lyons, Nicholas; Monne, Isabella; Okamuro, Yukitake; Pacheco, Damian Tago; Pavade, Gounalan; Poncon, Nicolas; Prajitno, Teguh Yodiantara; Rojas, Jose Gonzales; Swayne, David; Stegeman, Arjan
The International Alliance for Biological Standardization (IABS), in collaboration with the World Organization for Animal Health (WOAH) convened a hybrid meeting on 22–23 October 2024 at the WOAH Headquarters (HQ) in Paris, France to discuss the global state of vaccination and surveillance for high pathogenicity avian influenza (HPAI) in poultry. The primary objective of the meeting was to advance vaccination acceptance to both control virus spread and reduce disease. Vaccination is increasingly recognized as a tool to complement biosecurity, movement controls and stamping-out of infected flocks. However, concerns persist regarding the risk of undetected, sustained transmission (silent infection) in vaccinated flocks as a result of inadequate surveillance. This has contributed to both vaccination hesitancy and trade barriers. The meeting aimed to assess the current state of the art regarding HPAI surveillance programs in vaccinated populations and their effectiveness. Representatives of multiple stakeholders were invited to share their experiences and perspectives on the use of vaccination and accompanying surveillance to control the growing H5N1 panzootic and its global impact. Several conclusions and recommendations emerged as essential to advancing the acceptance of vaccination strategies. These included (1) the utility of quantitative reverse transcriptase polymerase chain reaction (RT-qPCR) as a sensitive, specific and economical tool to detect virus in vaccinated populations, (2) regular testing of dead birds within a flock as a highly effective method for early detection of outbreaks in vaccinated flocks and demonstrating freedom from infection and, (3) the importance of collecting information on circulating field strains in the selection of candidate vaccine antigens to ensure adequate efficacy. Testing sentinel birds was deemed less effective for surveillance and serological testing of vaccinated birds was considered more useful for assessing immunity levels than for determining the infection status of a flock. There was broad agreement on the need to standardize surveillance outcomes in terms of accepted confidence levels to promote safe and fair trade. However, it was acknowledged that context and pragmatic considerations will shape the development of situation specific plans, which must be statistically valid, scientifically sound, economically feasible and operationally sustainable for both governments and industry. Concomitantly, it was recommended that trade policies tied to vaccination and surveillance should be based solely on science and risks. To this end, enforcement of existing international rules and resolution of disputes are considered a shared responsibility. Peer reviewed publications were proposed as a central mechanism for developing the stronger guidelines needed to facilitate fair trade agreements and enable implementation of global vaccination programs. Rapid dissemination of information, consistent messaging and exchange of virus isolates were also seen as critical for coordinating an effective global response to controlling HPAI.
WSAVA guidelines for the control of reproduction in dogs and cats
(World Small Animal Veterinary Association (WSAVA), 2024-07) Romagnoli, S.; Krekeler, N.; De Cramer, Kurt Guido Mireille; Kutzler, M.; McCarthy, R.; Schaefer-Somi, S.
No abstract available.
Evidence-based guidelines for the post-fire assessment of domestic ruminants : a scoping review
(BioMed Central, 2025-03) Cardoso, Claudia L.; May, Catherine Edith; Leask, Rhoda; claudia.cardosocamaiti@up.ac.za
Wildfires globally impact farmers, with risk expected to rise in the next thirty years. Beyond fatalities, wildfires impair the reproductive capabilities of surviving livestock due to smoke exposure. Effective interventions require considering animal welfare, prognosis, and costs. Enhanced clinical assessment is crucial. There is a paucity of data concerning decision-making processes regarding burn injuries in livestock. This study establishes evidence-based guidelines for wildfire-affected ruminants in field settings. The goal is categorizing scientific evidence to create prognostic guidelines. English and Spanish publications from Web of Science, Medline, and Google Scholar were searched using keywords related to burn injuries, disaster management, and animal welfare. A research matrix was populated based on inclusion criteria and evidence strength, leading to the development of visual triage guidelines for sheep and cattle. Most evidence comprises case reports (expert opinion) and observational trials. Ovine controlled trials in the 80 s and 90 s significantly advanced burn injury understanding in humans and animals. Key clinical factors determining burn severity include burn extent and depth, anatomic location, and smoke inhalation. Core non-clinical factors implicated in decision-making include feed, water, and shelter, amongst others. Animal categorization by burn severity creates a model for prioritising resources towards animals with the best recovery chances, protecting animal welfare.

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