Research Articles (Animal and Wildlife Sciences)

Permanent URI for this collectionhttp://hdl.handle.net/2263/1748

This collection contains some of the full text peer-reviewed/ refereed articles published by researchers from the Department of Animal and Wildlife Sciences

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Shifting the focus from animal species to livestock production systems : an interactive tool for evaluating food contributions relative to environmental impacts
(Oxford University Press, 2025-02) De Lange, Elna; Du Toit, Cornelius Jacobus Lindeque; Fletcher, Andrew; Iliushyk, Taras; Kalinovska, Bohdana; Lupton, Naomi; Maree, Enrike; Ederer, Peer
IMPLICATIONS : The Animal Production System Evaluator tool for evaluating and comparing livestock production systems illustrates the contribution they can make to nationally adjusted protein food baskets in relation to different environmental impact indicators. There is value in creating interactive tools for stakeholders, which facilitate informed decision-making in order to optimize productivity and sustainability in livestock production. The Animal Production System Evaluator tool builds on data sources from the Food and Agriculture Organization, the Global Livestock Environmental Assessment Model, and the PLANET Food System Explorer. The tool aims to satisfy the following characteristics: Multifaceted Assessment: Evaluations of livestock production systems are required for integrating both nutritional contributions and environmental impacts to promote sustainable practices. Tailored Solutions: Region-specific solutions that account for the diverse conditions across different areas are needed, moving away from a one-size-fits-all approach. Systemic Focus: It is important to focus on entire production systems, rather than on animals, to ensure effective resource management and to mitigate environmental impacts. Global Relevance: Livestock production’s dual role in providing nutrients and managing environmental impacts is essential for achieving sustainable development goals.
Ruminant livestock farmers and industry are leading innovation to deliver human nutrition and improved environmental outcomes through sector lifecycle collaboration : a review of case studies
(Oxford University Press, 2025-02) Maree, Enrike; Blignaut, James; Gilliland, John; Lee, Michael R.F.; Manzano, Pablo; McCosker, Terry; Du Toit,; Du Toit, Cornelius Jacobus Lindeque; Truter, Wayne; Weinheimer, Ben; Polkinghorne, Rod
IMPLICATIONS : Well-managed systems like adaptive grazing and silvopasture enhance soil health, biodiversity, and water retention while reducing greenhouse gas emissions. Intensive feeding practices, from supplementation to feedlots, increase meat production and manage emissions effectively through controlled feeding and manure strategies. Combining sustainable grazing with intensive systems balances land use, nutrition, and emissions reduction, addressing global food demand. Livestock’s up-cycling efficiency converts inedible grasses and by-products into nutrient-dense food, critical for food security. Farmers and industry leaders, through innovation and life-cycle analysis, use data-driven decisions to optimize sustainability, showcasing livestock’s essential role in achieving environmental and nutritional goals in agriculture.
Effect of Vachellia tortilis leaf meal and sunflower oil Inclusion in supplementary diets of lambs on in vitro short-chain fatty acid and gas production and in vivo growth performance
(MDPI, 2025-03) Serumula, Mahlogonolo Daniel; Pepeta, Bulelani Nangamso; Moyo, Mehluli; Suinyuy, Terence Nkwanwir; Nsahlai, Ignatius Verla
This study examined the effect of dietary Vachellia tortilis leaf meal and sunflower oil inclusion in supplementary diets on in vitro short-chain fatty acid (SCFA) and gas production and the in vivo growth performance of lambs. Four concentrate dietary treatments comprising control (CL), Vachellia tortilis leaf meal (VT), sunflower oil (SFO), and Vachellia tortilis leaf meal sunflower oil (VSFO) were formulated. Eight Merino lambs were blocked into two live weight blocks where animals within each block were randomly assigned to dietary treatments, making two animals per treatment. Lambs were offered a concentrate diet of 480 g/day per head, with urea-treated hay fed as a basal diet. Dietary effects were evaluated for in vitro short-chain fatty acid and gas production and 28-day growth performance of lambs over three study periods. The inclusion of VT and SFO showed no statistically significant effect on total SCFAs, acetate to propionate (A:P) ratio, methane (CH4), and carbon dioxide (CO2) production (p > 0.05), which might be attributable to low experimental units. The hourly A:P ratio and CH4 yield were the highest (p < 0.05) at 16 h of incubation. The inclusion of VT showed no statistically significant effect on growth performance and gas production due to the small sample size. Therefore, VT can be explored as a supplementary protein source in lamb diets given the impression of not showing any causative adverse effects on growth performance and in vitro gas production, although further research with larger sample sizes is needed to confirm these findings.
Calcium and phosphorus digestibility in broilers as affected by varying phytate concentrations from corn
(Elsevier, 2024-11) Venter, Kyle M.; Li, W.; Angel, R.; Plumstead, P.W.; Proszkowiec-Weglarz, M.; Enting, H.; Ellestad, L.E.
Dietary phytate P (PP) concentration impacts Ca and P digestibility in broilers. Research was conducted to determine the impact of increasing concentration of dietary PP, with and without phytase, on broiler standardized ileal digestibility (SID) of Ca and P. Digestible (Dig) Ca and P were calculated by multiplying SID and the analyzed dietary Ca and P concentrations. The experiment was a factorial arrangement of 2 phytase (0 and 1,000 U/kg) and 4 PP (0.16, 0.23, 0.29, and 0.34%) concentrations. Treatments were fed for 36 h from 20 to 22 d of age (4 b/pen, n ≥ 7 replicate pens/treatment). Different ratios of corn and corn germ were used to achieve the desired PP concentrations. A limestone with 800 µm geometric mean diameter was used as the sole Ca source to achieve 0.7% Ca in the final diets (96% Ca from limestone). An additional diet was fed that was N, Ca- and P-free, for the determination of endogenous losses of each nutrient. Distal ileal digesta were pooled from all birds in a pen. There were no interactions between PP and phytase on SID Ca or Dig Ca from limestone. Irrespective of phytase inclusion, increasing PP from 0.16 to 0.34% decreased SID Ca from 53.8 to 38.1% (P < 0.05). The SID Ca averaged 41.5 and 51.4% in diets containing 0 and 1000 U phytase/kg, respectively, across all PP concentrations (P < 0.05). Interactions were seen between PP and phytase on SID and Dig P (P < 0.05) with SID P of 31.1, 24.0, 20.1, and 16.3% for broilers fed 0.16, 0.23, 0.29, and 0.34% PP diets without phytase, respectively. When phytase was included at 1000 U/kg, SID P was 89.9, 87.5, 73.9 and 60.4% for diets containing 0.16, 0.23, 0.29 and 0.34% PP, respectively (P < 0.05). Overall, phytase improved SID Ca and P independent of PP concentration. However, with increasing PP concentration, both SID Ca and P were negatively affected.
Digestible calcium in broiler production
(Plaas Media, 2025-01) Jacobs, Kean; u19167424@tuks.co.za
The broiler industry is facing a severe problem related to the increased incidence of skeletal abnormalities. This not only raises concerns for animal health and welfare, but impacts growth performance and subsequently broiler operation profitability.
Behaviour of commercial layer hens in enriched cages and floor systems examined using human and video-based observations
(South African Society for Animal Science, 2025-06) Chilemba, Timothy.; Van Marle-Koster, Este; Masenge, Andries; Cromhout, M.; Nkukwana, Thobela T.; evm.koster@up.ac.za
There is considerable pressure to eliminate the use of conventional cages in commercial layer hen production systems. However, the assessment of alternative systems that can ensure the hen's ability to perform natural behaviours, while simultaneously enhancing farm productivity and economic efficiency, remains incomplete. This study assessed layer behaviour in a floor system and in enriched cages on a commercial layer farm using human and video-based observations. The study focused on dust bathing, nesting, feather pecking, and perching behaviours, and on the formation of mud balls on the feet. A large proportion (72.9%) of the hens exhibited dust-bathing behaviour, with an average duration of 22.63 minutes. Feather pecking was exhibited by 35.4% of layers in the enriched cages, compared to 58.3% of layers in the floor system. Overall, feather pecking was the least observed behaviour. Layers in enriched cages used perches more (47%) than layers in the floor system (27%), and a negative association was found between body weight and perching in layers in the floor system. At the end of the six-week trial period, 41.67% of the hens had developed mud balls on their toes that exceeded 3 cm in length. The results of this study provide evidence of the relationships between poultry behaviour, welfare, and production. Video-based observations confirmed that farm managers may not be able to identify certain welfare-related behavioural aspects unless they are closely monitored. The results of this study may be used to inform stakeholders about behaviour and welfare considerations in the management of commercial layers.
Implementation of a digestible calcium system : why is it needed and where are we?
(Elsevier, 2025-06) Venter, Kyle M.; Angel, R.; Korver, D.R.; Cunha, M.; Plumstead, P.W.
The regulation of blood calcium (Ca) and phosphorus (P) levels are closely intertwined, requiring that their metabolically available supply in the diet be carefully balanced. The majority of the P in plant-based feed ingredients is stored as phytate, which is poorly digestible by broilers, while inorganic P sources also show significant variability in digestibility. For decades, poultry nutritionists have incorporated available P in diet formulation, recognizing that the digestibility of P in feedstuffs is highly variable. In contrast, poultry diets are still formulated on a total Ca (tCa) basis, overlooking the variable digestibility of Ca from different dietary sources. Incorrect assumptions regarding the digestibility of Ca can lead to Ca imbalances, which negatively affect both broiler health and overall performance. Furthermore, the influence of Ca and limestone on phytase efficacy, which plays a critical role in enhancing P availability by breaking down phytate, is highlighted. As the poultry industry moves towards implementing a digestible Ca (dCa) system, the development of accurate prediction equations for limestone digestibility becomes essential. Such an approach not only improves the precision of diet formulation but also enhances overall broiler performance by ensuring a more balanced and metabolically available supply of both Ca and P. Transitioning to a dCa system, in conjunction with phytase use, represents a critical step in optimizing nutrient efficiency and improving sustainability in modern poultry production.
Feeding for fertility : how early-life nutrition impacts dairy herds
(Plaas Publishing, 2025-03) Schultz, Cilé-Mari
The Guinness World Record holder cow for lifetime milk production, Smurf from Ontario in Canada, achieved an average daily milk output of 35,4ℓ. Meanwhile, Marília FIV Teatro de Naylo, a cow from Brazil, holds the record for the largest milk yield in 24 hours, producing an astonishing 123,61ℓ through mechanical milking.
Influence of tannin-rich extract from commercial Acacia mearnsii and gallocatechin on ovine cryopreserved semen viability
(Taylor and Francis, 2025) Liman, Mohammed S.; Hassen, Abubeker; Smuts, Mario P.; Biraima, Ahmed D.A.; Sutovsky, Peter; McGaw, Lyndy Joy; Holm, Dietmar Erik; dietmar.holm@up.ac.za
The objective of this study was to evaluate the effect of a tannin-rich extract from commercial Acacia mearnsii (MTE_0), and gallocatechin, a flavonoid compound derived from Acacia mearnsii, on the long-term viability and motility of cryopreserved ovine semen. Six fresh ejaculates obtained from six adult merino rams twice per week for three weeks were allocated to five aliquots (0, 12.5, 25, 50, and 100 µM gallocatechin added into the Optidyl™ extender) before cooling and cryopreservation. Effects of MTE_0 and gallocatechin on post-thawed motility characteristics were analyzed using computer-assisted semen analysis (CASA), and viability (LIVE/DEAD® kit, Molecular Invitrogen, Waltham, MA), oxidative stress (2,7-dichlorodihydrofluorescein diacetate (H2DCFDA, Thermo Fisher®, Waltham, MA)) for reactive oxygen species (ROS), mitochondrial membrane potential (JC-1 MitoTracker, Molecular Invitrogen, Waltham, MA), acrosomal integrity (lectin PNA), and capacitation using merocyanine 540 (M540) and YO-PRO-1 dyes in flow cytometry. Data were analyzed using one-way ANOVA (IBM SPSS 21.0 for Windows, Armonk, NY). Gallocatechin at 25 µM positively affected (p ≤ .001) kinematic parameters including average path velocity (VAP), progressive velocity (VSL), and beat cross frequency (BCF) of cryopreserved semen. Similarly, gallocatechin at 25 µM- improved sperm motility (live 21.99 ± 2.06%), reduced ROS levels (26.45 ± 1.10%), and mitigated premature capacitation (viable and stable 20.08 ± 1.48%) compared to other treatments. Gallocatechin addition to semen resulted in a significant (p ≤ .001) positive effect compared with the MTE_0 extract. It is concluded that gallocatechin inclusion at 25 µM significantly reduces semen deterioration following cryopreservation. This study is the first to introduce gallocatechin as an efficient antioxidant additive to ovine semen to improve its quality during storage. Our findings will help improve post-thaw ovine semen quality and longevity. Future studies to elucidate the mechanism of anti-oxidative stress action of gallocatechin and its derivatives on semen motility and longevity are recommended.
Thermal properties of rhinoceros ovum pick-up probes : possible effects of temperature shock on oocyte maturation potential
(Medpharm Publications, 2024-11) Vorster, L.; De Bruin, Phillippus Rudolf; Smuts, M.P. (Mario); De la Rey, M.; Herbst, C.; Durrant, B.S.; Holm, Dietmar Erik
BACKGROUND: The implementation of assisted reproductive techniques and use of in vitro embryo production has highlighted their potential in attempts to prevent the extinction of the northern white rhinoceros (Ceratotherium simum cottoni). However, in vitro embryo production has proved challenging. Transrectal ovum pick-up (OPU), while done successfully with custom-made aspiration probes (AP), may expose oocytes to detrimental temperature shock OBJECTIVE: This study compares the temperature regulation properties between two AP, made from different materials and used during OPU in southern white rhinoceros (C. s. simum METHODS: The initial PVC plastic AP, produced using a computer numerical control machine, was compared to a modified aluminium AP. A rhinoceros model was constructed using a 210 L water container fitted with heating elements and a water pump. Water was warmed to 37.5-38.5 °C to simulate rhinoceros body temperature. The AP was equilibrated to room temperature (22 simulating summer) or in a walk-in fridge (4 simulating winter) overnight. Temperature loggers were placed inside and on the outside of the AP RESULTS: The aluminium AP equilibrated to the model water temperature within 15 minutes of submersion in the model, while the temperature of the PVC AP remained significantly lower during the three-hour period. The inside of the PVC AP remained significantly colder compared to outside during both winter and summer (33.23 ± 4.28°C vs. 36.51 ± 2.13 °C and 36.04 ± 1.69 °C vs. 37.22 ± 0.92 °C, respectively). There was no significant difference between the inside temperature of the aluminium AP compared to the outside temperature during both the winter and summer simulations (36.75 ± 0.49 °C vs. 37.83 ± 0.40 °C and 37.86 ± 0.16 °C vs. 38.04 ± 0.11 °C, respectively CONCLUSION: This research highlights the importance of using material with good thermal properties during assisted reproductive procedures. It also contributes to further advancement during the establishment of a successful in vitro embryo production protocol for rhinoceros in South Africa
Selection signatures associated with adaptation in South African Drakensberger, Nguni, and Tuli beef breeds
(Springer, 2025) Maxman, Gomo; Van Marle-Koster, Este; Lashmar, Simon Frederick; Visser, Carina; u22608053@tuks.co.za
In the present study 1,709 cattle, including 1,118 Drakensberger (DRB), 377 Nguni (NGI), and 214 Tuli (TUL), were genotyped using the GeneSeek® Genomic Profiler™ 150 K bovine SNP panel. A genomic data set of 122,632 quality-filtered single nucleotide polymorphisms (SNPs) were used to identify selection signatures within breeds based on conserved runs of homozygosity (ROH) and heterozygosity (ROHet) estimated with the detectRUNS R package. The mean number of ROH per animal varied across breeds ranging from 36.09 ± 12.82 (NGI) to 51.82 ± 21.01 (DRB), and the mean ROH length per breed ranged between 2.31 Mb (NGI) and 3.90 Mb (DRB). The smallest length categories i.e., ROH < 4 Mb were most frequent, indicating historic inbreeding effects for all breeds. The ROH based inbreeding coefficients (FROH) ranged between 0.033 ± 0.024 (NGI) and 0.081 ± 0.046 (DRB). Genes mapped to candidate regions were associated with immunity (ADAMTS12, LY96, WDPCP) and adaptation (FKBP4, CBFA2T3, TUBB3) in cattle and genes previously only reported for immunity in mice and human (EXOC3L1, MYO1G). The present study contributes to the understanding of the genetic mechanisms of adaptation, providing information for potential molecular application in genetic evaluation and selection programs.
Determination of calcium and phosphorus digestibility of individual feed ingredients as affected by limestone, in the presence and absence of phytase in broilers
(MDPI, 2024-12-02) Venter, Kyle M.; Angel, Roselina; Fourie, Jamie; Plumstead, P.W. (Peter); Li, Wenting; Enting, Henk; Dersjant-Li, Yueming; Jansen van Rensburg, Christine; christinejvr@up.ac.za
To begin formulating broiler diets on a digestible calcium (Ca) basis, robust Ca digestibility values for ingredients and factors affecting this digestibility are needed. This study had three main objectives: (1) determine the standardized ileal digestibility (SID) of Ca and phosphorus (P) for seven plant-based feed ingredients in broilers, (2) assess the impact of phytate source on SID Ca from limestone (LS), and (3) evaluate the effect of phytase on SID Ca and P for the different ingredients. Two experiments were conducted to satisfy these objectives. In Experiment 1, a 4 × 2 × 2 factorial design was used, with four plant-based feed ingredients (corn, wheat, sorghum, and full-fat soybean meal (FFS)), two LS inclusions in the diet (absence of LS and the inclusion of LS required to achieve 0.65% Ca in the final diet), and two phytase doses (0 and 1000 FTU/kg diet). Experiment 2 utilized a 3 × 2 × 2 factorial design with three plant-based ingredients (soybean meal (SBM), rapeseed meal (RSM), and sunflower meal (SFM)), two LS inclusions in the diet (absence of LS and the inclusion of LS required to achieve 0.65% Ca in the final diet), and two phytase doses (0 and 1000 FTU/kg diet). The trial had eight replicate pens (6 broilers/replicate) per treatment. Data were analyzed using a factorial analysis in JMP Pro 16.0 with means separation performed when p < 0.05, using Tukey HSD. The SID Ca in the absence of phytase for wheat (72.9%) and FFS (69.9%) was higher (p < 0.05) than for sorghum (54.5%) and corn (46.3%). In Experiment 2, the SID Ca in the absence of phytase from SFM (61.0%) was higher (p < 0.01) than RSM (42.7%) and SBM (46.8%). The SID Ca from added LS was affected by the ingredient, with diets containing wheat and FFS resulting in the lowest (p < 0.05) SID Ca versus those containing corn and sorghum irrespective of phytase dose in Experiment 1, and the lowest (p < 0.05) for SBM and RSM vs. SFM in the absence of phytase in Experiment 2. Phytase supplementation increased (p < 0.01) SID Ca and SID P across all feed ingredients compared to non-supplemented diets. There was a two-way interaction (p < 0.01) of LS addition and ingredient on SID P in both experiments. The results of this study provide SID Ca and SID P values from the selected ingredients and show that phytate from different ingredients reacts differently with Ca from LS and should be considered when developing SID coefficients of Ca and P for use in commercial broiler feed formulation. The SID coefficients of Ca and P for the individual feed ingredients evaluated in this study will allow for the further development and transition towards dCa and dP in commercial feed formulation.
Low-cost uncrewed aerial vehicles (UAVs) as a novel tool for welfare assessments on open pen commercial crocodile farms
(Medpharm Publications, 2024-03) Myburgh, Albert; Viljoen, Devon M.; Myburgh, Jan G.; Downs, C.T.; Webb, E.C. (Edward Cottington); Woodborne, S.; albert.myburgh@up.ac.za
BACKGROUND : The welfare of crocodiles on commercial farms in southern Africa requires precise assessment, focusing on stocking densities and pen conditions. However, disputes between animal welfare groups and farm owners persist due to inadequate methodologies for quantifying these factors. OBJECTIVES : This study aimed to address these disputes and enhance crocodile welfare assessment by introducing a novel technique using a low-cost consumer uncrewed aerial vehicle (UAV) and open-source photogrammetry software. The objective was to quantify key welfare parameters accurately and efficiently. METHOD : The study involved applying the UAV-based technique to two large Nile crocodile (Crocodylus niloticus) farms in South Africa. The approach enabled the mapping and surveying of crocodile pens, facilitating the determination of stocking densities, biomass indicators, and other pen-related attributes. Comparisons were made between UAV-derived crocodile counts and farmer estimates. RESULTS : The UAV-based crocodile counts significantly differed from the estimates provided by farmers, underscoring the need for a more precise assessment method. The technique’s cost-effectiveness was evident, with implementation expenses totalling less than R10 000, a fraction of the cost associated with commercial UAV surveys. CONCLUSIONS : The introduced UAV-based technique offers a valuable solution to the ongoing debates regarding crocodile welfare on commercial farms. By quantifying key parameters accurately and economically, it empowers farmers and animal welfare groups to make informed decisions. The method’s ease of adoption, demonstrated through its use by some Southern African crocodile farmers, signifies its potential for widespread application, ultimately contributing to improved crocodile welfare.
The effect of a warmed enema during ovum pick-up on subsequent in vitro oocyte maturation in southern white rhinoceros (Ceratotherium simum simum)
(Medpharm Publications, 2024-08) Vorster, L.; De Bruin, Phillippus Rudolf; Smuts, M.P. (Mario); Durrant, B.S.; De la Rey, M.; Herbst, C.; Holm, Dietmar Erik
BACKGROUND : Rhinoceros are currently one of the most threatened mammal species globally. Slow population growth, increased poaching and habitat destruction have led to increased conservation efforts for each species. Assisted reproductive technologies (ART) have been implemented in an attempt to aid reproductive outputs for the conservation of these endangered species. Developing species-specific ART programmes for wildlife have been challenging. Temperature control during oocyte recovery is essential for ensuring in vitro success. OBJECTIVE : This study is the first to investigate the effect of enema warming prior to trans-rectal ovum pick-up (OPU) on in vitro oocyte maturation in Southern white rhinoceros (Ceratotherium simum simum). METHODS : OPUs were performed on 20 rhinoceros cows from three different game farms in South Africa; oocytes were transported to one of two in vitro fertilisation laboratories for culture. The enema fluid was either warmed to 32 °C or not warmed prior to the OPU. Location of the farm, the different laboratories, ambient temperature, season, aspiration probe temperature, media type and enema temperature were investigated as predictor variables for oocyte maturation success. RESULTS : After considering all other potential covariates, warming of the enema fluid was the only independent predictor of in vitro oocyte maturation success during this study. CONCLUSION : Oocytes retrieved from rhinoceros cows that received an enema warmed to 32 °C were 2.3 times more likely to mature in vitro compared to oocytes from cows that received an unwarmed enema; the findings can be implemented in other rhinoceros ART programmes and in conservation efforts of other endangered mammalian species.
The potential effect of Garlium GEM HCTM as a tick control agent in cattle
(Medpharm Publications, 2024-03) Hagg, Francois Marius; Erasmus, Lourens Jacobus; Stoltsz, Wilhelm Heinrich
As resistance to chemical acaricides increases amongst tick populations, investigations of natural remedies that have acaricidal or tick-repellent effects have become essential in the search for alternatives for sustainable tick control. Garlium GEM HC (Garlium), a natural concentrated garlic product, was supplemented in-feed to beef cattle to determine if it could assist in reducing the number of attached ticks on cattle. Two grams of Garlium was supplemented daily to eight Bonsmara steers over 43 days. A second group of eight steers served as controls. All animals were infested with a similar number of Rhipicephalus appendiculatus adults and Rhipicephalus microplus larvae. Subsequently, the number of attached engorged ticks and the hatchability of the tick eggs were determined. Blood samples were collected from the steers for whole blood analyses. The results were analysed using a twosample t-test procedure. Due to large standard deviations observed, most of the tick parameters were only numerically improved. Although not significant, the number of larvae produced by female R. appendiculatus ticks per host was reduced by 23%. Estimated number of R. microplus larvae produced from ticks harvested from Garlium supplemented cattle were reduced by 42.3% (p = 0.10). No adverse effect was observed on haematocrits or haemoglobin concentrations. Garlium reduced segmented neutrophil count in the treatment group, suggesting that the immune system was less challenged. Although not statistically significant, the effect of reducing the number of larvae produced per host for the two tick species by approximately 20% and 40% respectively, may be of economic benefit to commercial cattle farmers.
Copper (Cu) metabolism in domestic herbivores as guide to criteria for predicting the Cu nutritional status of wild ruminants in southern Africa
(Medpharm Publications, 2024-03) Van Ryssen, J.B.J.; Bath, Gareth
In southern Africa game farming has become an effective way of using underutilised resources and a valuable method of preserving and increasing wildlife numbers. However, little is known about the mineral requirements of wild animal species or the assessment of the mineral nutritional status of these species. To establish criteria for estimating the copper (Cu) nutritional status of wildlife, current knowledge about Cu metabolism and criteria for domestic animals has been used. Since the Cu metabolism of ruminants differs substantially from that of non-ruminants, Cu metabolism in domestic species such as cattle and sheep representing wild ruminants, and pigs and horses as non-ruminant species, has been scrutinised to propose criteria for wild bovids in southern Africa. In the adequate range of dietary Cu intakes, literature suggests that hepatic Cu concentrations in ruminants increase linearly with an increase in Cu intake, allowing a relatively reliable measure of sufficiency. In non-ruminants, hepatic Cu concentrations follow a lag phase during which hepatic Cu concentrations remain relatively constant with increasing dietary Cu intakes of more that 25 times their requirements. A consequence is that non-ruminants can tolerate much higher dietary levels of Cu compared to ruminants. It is proposed that at liver Cu concentrations of < 20 mg/kg dry matter (DM), a wild ruminant could benefit from Cu supplementation; liver Cu concentrations of between 20 and 300 mg Cu/kg DM suggest an adequate Cu intake; concentrations of 300 to 500 mg/kg DM indicate a potentially unhealthy accumulation of Cu, while liver Cu concentrations of > 500 mg/kg DM indicate that the animal probably consumed more Cu than required and might be at risk of developing Cu toxicosis.
Effect of rainfall interception and resting period on the soil seed bank
(Frontiers Media, 2024-07) Magandana, Thabo Patrick; Hassen, Abubeker; Tesfamariam, Eyob Habte
The ecosystems across the world are affected by diverse impacts of climate change. Climate change will also affect soil seed bank as the seed bank is determined by the plants that are above the ground. This study was conducted to determine whether rainfall interception and resting period will affect the soil seed bank or not. Rainfall interception was employed as main plot treatment at four different levels—namely, 15%, 30%, 60%, and 0%—and the main plot treatments were each replicated five times using the rainout shelters arranged as main plot treatments in a split-plot experimental design. The main plots are 49 m2 (7 m × 7 m) in size and were covered by metal frame structures with Vshaped clear acrylic bands on top without ultraviolet filter, and these plots were sub-divided into two sub-plots to determine the effect of resting periods (70 and 90 days). The soil samples were 8 cm in diameter and 20 cm in depth (1,005 cm3 ). We used seed emergence method rather than seed separation method to determine the soil seed bank due to the very small size of some seeds for some species. The 60% rainfall interception resulted in significantly high forb densities at both resting periods. The forb densities decreased by 32 and 35% at 15% and 30%, while they increased by 195% at 60% rainfall interception compared to 0% rainfall interception at 70-day resting period. Resting period significantly affected grass densities at 60% rainfall as the densities were higher at 70- than 90-day resting period. At 90-day resting period, grass densities were significantly higher at 0% rainfall interception than the rest of the treatments, while the grass densities were significantly lower at 60% rainfall interception. The 60% rainfall interception resulted in significantly (p< 0.05) higher total densities (forbs and grass) in both resting periods. Total density increased by 2.9% and 143.48% at 15% and 60% rainfall interception, respectively. Our results show that drought has a negative effect on grass soil seed bank, while it improves the forbs soil seed bank. Furthermore, the resting period has no significant effects on soil seed bank in grasslands.
Effects of dietary supplementation with Acaciamearnsii tannin extract on carcass characteristics and meat quality of lambs
(BMC, 2024-08) Venter, Megan; Hassen, Abubeker; Pophiwa, Pamela; Webb, E.C. (Edward Cottington); abubeker.hasssen@up.ac.za
BACKGROUND: Plant extracts are used as possible methane mitigants and to replace antibiotic feed supplements previously used prophylactically to improve the adaptation of lambs in intensive feeding systems. This study investigated the effects of Acacia mearnsii tannin extract used as anti-methanogenic feed additives on carcass and meat quality of lambs. METHODS: Forty Dohne Merino lambs, with an initial mass between 23.90 kg and 37.40 kg, were first stratified according to their initial body weight and thereafter one of the eight lambs with similar body weight were randomly assigned to four treatment groups (n=10 lambs/treatment). The lambs were fed ad libitum with a basal total mixed ration. Four experimental diets were formulated: TMR diet (control); TMR diet with Rumensin® at a dosage of 75 mg/ kg of DM feed (Monensin; Positive control); TMR diet with raw condensed Acacia tannin at 20 g/kg of DM feed (Crude tannin); TMR with addition of encapsulated condensed Acacia tannin at 20 g/kg of DM feed (Encapsulated condensed tannins). The lambs were slaughtered at a live mass of about 50 kg after a 19 week trial period. RESULTS: Dietary tannin additives did not affect the carcass composition or colour aspects of lamb meat. However, there were minor changes in fatty acid profiles, particularly in the intramuscular adipose tissue. The addition of encapsulated tannin extract resulted in a higher proportion of C18:2n6t (0.15%±0.03 vs. 0.19%±0.03; p<0.05), C18.3n3 (0.24%±0.04 vs. 0.29%±0.04; p<0.05), C22:6n3 (0.02±0.01 vs. 0.05±0.03; p<0.05), in comparison to monensin. This improvement in fatty acid profiles is presumably beneficial for human health, but it could affect the sensory quality of meat. CONCLUSION: Our results suggest that Acacia mearnsii tannin extracts can be included as anti-methanogenic feed additives in lamb diets without compromising product quality.
The impact of myostatin variants on growth traits in South African Bonsmara beef cattle
(Springer, 2024-11) Madula, Rendani Asnath; Visser, Carina; Van Marle-Koster, Este; carina.visser@up.ac.za
Double muscling occurs when the myostatin (MSTN) gene is deactivated due to a series of mutations, leading to uncontrolled muscle growth and excessive muscle fiber accumulation, as the gene can no longer effectively regulate muscle development. This study aimed to assess the impact of MSTN variants and their combinations on growth traits, namely direct birth weight (BWDIR), direct weaning weight (WWDIR), average daily gain (ADG) and feed conversion ratio (FCR) in the South African (SA) Bonsmara. Genomically enhanced estimated breeding value (GEBVs) for traits of interest, and MTSN genotypes for SA Bonsmara animals were available for the study. Thirteen MSTN variants (Nt821, Q204X, F94L, E226X, E291X, C313Y, Nt419, S105C, D182N, Nt414, Nt324, Nt267, and Nt748) were routinely genotyped using the IDBv3 SNP array. Genotypic frequencies of MSTN variants ranged from 1.18% for Q204X to 35.02% for Nt748. No association was observed between the Nt267 variant and any growth traits, while both Nt748 and Nt414 variants affected WWDIR, ADG and FCR (p < 0.05). The results of the effect of multiple variants on growth traits indicated that there was an additive effect when more than one MSTN variant was present in an individual. This study is the first study to report the impact of MSTN variants on traits of economic importance in the SA Bonsmara breed.
Risk factors underlining reproductive performance in smallholder beef cattle herds of South Africa
(Springer, 2024-11) Nkadimeng, Marble; Van Marle-Koster, Este; Nengovhela, Nkhanedzeni B.; Ramukhithi, Fhulufhelo V.; Mphaphathi, Masindi L.; Rust, Johannes M.; Makgahlela, Mahlako L.
Improving the historically low reproductive performance of beef cattle in smallholder systems is essential for its productivity and profitability. Therefore, identifying and addressing risk factors associated with low performance in this system present an opportunity for improvement. The study aimed to evaluate the effect of animal and management risk factors on pregnancy rate (PR), fetal and calf loss (FC), calving interval (CI) and days open (DO) in smallholder beef cattle farms. A multi-stage selection approach was conducted in five provinces of South Africa. Cow records (3694) collected from 40 smallholder herds over two years (2018–2019) were analysed. Data on animal and herd management factors including body condition score (BCS), cow age class, breed type, lactation status, culling old/non-productive cows, record-keeping, and breeding and calving seasons were recorded. The GLIMMIX procedure was computed to determine risk factors associated with performance indicators (PR, FC, CI and DO). Risk factors highly associated with performance were breed type, BCS, cow-age class and breeding/calving season (P ≤ 0.05). Indicators FC, DO and CI increased with decreased BCS, autumn calving seasons, and in first calvers and aged cows. Whereas, PR increased with increasing odds of BCS and breeding seasons between December-March, November-February and January-March. Optimizing reproductive performance in smallholder beef cattle herds may involve managing cow body condition, breeding with adapted genotypes and synchronizing breeding with favourable seasons. Therefore, record keeping and regular monitoring of herd nutrition, climate and breed performance may be significant in improving reproductive performance in smallholder herds.

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