South African Journal of Animal Science
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Addition of neem seeds (Azadirachta indica A. Juss) to fattening pig diets
Get PDFNeem products are biologically and pharmacologically active and could therefore serve as alternatives to antibiotics in pig feed. This study evaluated the effects of adding ground neem seeds (GNS) to the diets of fattening pigs on growth performance, carcass characteristics, and the physicochemical properties of the meat. In the growing and finishing I phases, 32 and 31 pigs, respectively, were used to evaluate five dietary treatments: control diet (T1), control diet + antibiotic (oxytetracycline, T2), control diet + 0.1% GNS (T3), control diet + 0.2% GNS (T4), and control diet + 0.3% GNS (T5). In the finishing II phase, 13 pigs were used to evaluate T1, T2, and T3, and the physicochemical properties of the meat from these pigs were determined. The study used a completely randomised, unbalanced experimental design. In growing pigs, 0.2% GNS reduced feed intake, while the other growth performance variables and carcass characteristics were not affected by the level of GNS inclusion. In the finishing I phase, 0.3% GNS reduced feed intake and the feed-to-gain ratio; however, there were no significant effects on the other measured variables. In finishing II pigs, GNS supplementation did not modify growth performance; however, 0.1% GNS modified the meat pH, L*, and a* values. Ground neem seeds at higher inclusion levels may improve the feed efficiency of pigs, but may also have a negative effect on some meat quality parameters.
(Submitted 17 November 2022; Accepted 25 August 2025; Published 30 September 2025
The effect of a phytogenic-based feed additive on concurrent Lawsonia intracellularis and Brachyspira hyodysenteriae infections in pigs
Get PDFThis study investigated the efficacy of a commercial phytogenic-based premixed feed additive (PFA) in treating combined Lawsonia intracellularis and Brachyspira hyodysenteriae infections in finishing pigs, with tiamulin/lincomycin treatment as the control. Pigs aged 20 weeks were allocated to PFA treatment (11 pens, 45 pigs per pen) and control (7 pens, 43 pigs per pen) groups for a seven-week experimental period. Floor faecal samples and rectal swabs were collected weekly, and the percentage of pigs per pen with diarrhoea was recorded weekly. The bacterial contents of the samples were determined using real-time polymerase chain reaction, and at the end of the experiment, histological changes in ileal samples were examined. There was an intermittent decrease in L. intracellularis in the control group (from 4.85 to 0.82 DNA log10 copies/μl) and a continuous reduction in L. intracellularis in the PFA group (from 5.69 to 0.64 DNA log10 copies/μl) over a six-week period. B. hyodysenteriae was not detected in rectal swabs from the control group at week six, and an intermittent decrease in B. hyodysenteriae, from 3.04 to 0.26 DNA log10 copies/μl, was observed in the PFA group. Bacterial DNA in the floor faecal samples declined during the seven-week experimental period, as found for the rectal swabs. There were no cases of diarrhoea from week two onwards in the control group and week three onwards in the PFA group. The results of this study indicate that a PFA rich in essential oils has a therapeutic effect comparable to that of tiamulin/lincomycin in pigs with proliferative enteropathy and swine dysentery.
Submitted 11 July 2023; Accepted 9 January 2024; Published February 2025
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Significance of research to South African science
This study is significant for South African science as it provides field-based evidence that a phytogenic feed additive can effectively reduce infections caused by Lawsonia intracellularis and Brachyspira hyodysenteriae in pigs - two pathogens that severely impact pig health and productivity. By demonstrating an alternative to antibiotics, the research supports efforts to combat antimicrobial resistance and promotes more sustainable farming practices. It contributes to innovation in animal nutrition and aligns with national priorities in animal health, biosecurity, and One Health
An HPLC-MS/MS method for the quantification of heat stress-related milk metabolites in milk from Holstein-Friesian cross-bred cows in Tanzania
Get PDFThe main objective of this study was to develop and validate a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for the determination and quantification of three metabolites in raw milk samples: creatinine, citrate, and β-hydroxybutyrate (3-BHB). The effect of the temperature-humidity index (THI) on the concentrations of these metabolites was also investigated. The study used 29 Holstein-Friesian × Tanzanian Shorthorn Zebu cross-bred cows of two genotypes from the Tanzania Livestock Research Institute in Tanga, Tanzania. The cows were in their second or third parity and their second or third month of lactation. Chromatographic separation of the three metabolites was performed using a Supelco column (150 × 2.1 mm, 3 µm), with a mobile phase consisting of 1% formic acid and 10 mM ammonium formate in high-performance liquid chromatography (HPLC) water, and 1% formic acid in methanol. Creatinine, citrate, and 3-BHB were measured at 2.13, 2.33, and 2.48 minutes of run time, respectively. The calibration curves were linear and ranged from 0.0025 to 0.64 µg/mL for creatinine, 1.25 to 3.20 µg/mL for citrate, and 0.25 to1.28 µg/mL for 3-BHB. The creatinine (8.44–5.40 µg/mL), citrate (36.54–33.93 µg/mL), and 3-BHB (12.07–8.96 µg/mL) concentrations decreased with an increase in THI from 77 to 83. However, these results were complicated by significant interactions between the THI and the genotype, parity, and months in lactation. In conclusion, this study demonstrates the potential of an HPLC-MS/MS method to estimate creatinine, citrate, and 3-BHB concentrations in milk samples, and shows that heat stress affects the concentrations of these milk metabolites.
Submitted 5 November 2024; Accepted 5 February 2025; Published March 2025
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Significance of research to South African science
The article represents a significant advancement for food safety science and veterinary pharmacology in South Africa. By developing and validating a rapid, sensitive, and cost-effective method for detecting fluoroquinolone residues in poultry meat, the study directly supports the country\u27s capacity to monitor antibiotic residues and enforce maximum residue limits (MRLs). This is critical for protecting public health, ensuring compliance with international export standards, and addressing antimicrobial resistance (AMR) - a growing concern in both human and animal health. The locally relevant methodology also strengthens South Africa’s analytical infrastructure and contributes to regional leadership in residue analysis and food quality assurance
Effects of propylene glycol and organic chromium on milk production and blood parameters in early lactation dairy cows
Get PDFThis study assessed the effects of supplementing organic chromium (Cr), alone and in combination with propylene glycol (PG), on milk yield and blood chemistry in early lactation dairy cows. Thirty multiparous Holstein cows were randomly assigned to three treatments: control (CONT), Cr (1 g Cr/day), and Cr with PG (CrPG, 1 g Cr/day plus 125 mL liquid PG/day). The study started at calving and continued for three weeks postpartum. Drenching dairy cows with Cr and PG significantly improved fertility, with a decrease in the number of days to fall pregnant and a shorter calving interval. Cows administered CrPG had lower serum concentrations of urea, non-esterified fatty acids, beta-hydroxybutyric acid, alanine aminotransferase, and aspartate aminotransferase. Serum triglyceride and very-low-density lipoprotein levels were higher in the CrPG and Cr groups from day 12 after calving onwards, whereas high-density lipoprotein concentrations were higher in the CrPG and Cr groups from day nine onwards. Insulin levels were significantly higher in the CrPG and Cr groups than in the CONT group from the day of parturition to the ninth day postpartum, whereas from the 12th day onwards, insulin levels were significantly lower in the CrPG group. Gamma-glutamyl transferase levels only showed significant variation between the treatment groups on the third day after calving. Dietary supplementation with CrPG during early lactation improved fertility parameters and positively influenced energy metabolism by reducing non-esterified fatty acid and beta-hydroxybutyric acid concentrations and increasing insulin concentrations, thus protecting the dairy cows from subclinical metabolic disorders.
Submitted 14 October 2024; Accepted 26 March 2025; Published April 2025
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Significance of research to South African science
The article by Uyarlar et al. (2025) offers practical relevance for South Africa’s dairy science and livestock nutrition sectors. Although conducted internationally, the study’s findings are significant for local scientists and producers seeking strategies to manage metabolic stress in dairy cows during the critical transition period. By demonstrating the potential of propylene glycol and organic chromium to improve energy balance and milk yield without adverse effects, the research contributes to efforts to enhance animal health, productivity, and welfare in commercial dairy systems. These insights are especially valuable for adapting nutrition-based interventions to South Africa’s diverse farming conditions and for supporting evidence-based herd management practices
Effects of wood vinegar supplementation on the performance, carcass yield, intestinal histomorphology, and immune status of broiler chickens
Get PDFThis study aimed to determine the effects of the addition of wood vinegar (WV) to drinking water on the production performance, intestinal histomorphology, and immune response of broiler chickens. In total, 432 one-day-old chicks were allocated to six groups (T1–T6), with six replicates of 12 chicks each (72 chicks per treatment group), and raised for 35 days. Group T1 (0.0% WV) served as a negative control, group T2 (0.02% oxytetracycline) as a positive control, and groups T3 to T6 as experimental groups that received WV in their drinking water at 0.1%, 0.2%, 0.5%, and 1.0%, respectively. Data were analysed using a general linear model, and the significance of differences between the treatment groups was determined using Duncan’s multiple range test. The results demonstrated that the addition of WV to drinking water enhanced the feed conversion ratio, cumulative weight gain, and final body weight, while the abdominal fat yield was significantly decreased in the WV treatment groups. Compared to the negative control and antibiotic-treated groups, WV improved the ileum and jejunum villus height, as well as increasing plasma immunoglobulin A and M concentrations and the expression of the insulin-like growth factor-1 and growth hormone receptor genes in all the treated groups. Collectively, these results demonstrate that WV is a suitable replacement for antibiotics in broiler production, with no adverse effects on growth performance.
Submitted 18 December 2024; Accepted 21 July 2025; Published 31 July 202
Assessment of heavy metal contamination in faeces of cattle grazing in wastewater treatment plants in Limpopo Province, South Africa
Get PDFIn Limpopo Province, South Africa, livestock commonly graze freely around wastewater treatment plants (WWTPs), raising contamination concerns and prompting the assessment of heavy metal levels in palatable grasses, sludge liquors, and cow faeces. Twenty-one cow faecal samples were collected from two WWTPs and a control farm, while 12 palatable grass samples and 16 sludge liquor samples were collected from two WWTPs. Samples were collected from February to March 2024 and analysed for heavy metals using inductively coupled plasma-mass spectrometry. Heavy metal concentrations in the grass samples were within the maximum tolerable limits for cattle feed and in the order aluminium > zinc > copper > chromium > strontium > nickel > arsenic > selenium > cadmium. In the sludge liquor, metals such as aluminium, copper, mercury, and lead exceeded permissible limits for livestock drinking water, posing a health risk for both the animals and the consumers of the animal products. The mean concentrations in the faecal samples were in the order aluminium > zinc > strontium > copper > chromium > nickel > lead > arsenic > selenium > cadmium; in most cases, the control farm faecal samples contained significantly higher concentrations than the WWTP faecal samples. The strong correlations found between the heavy metal concentrations in the faeces, grass, and sludge liquor samples suggest that the grass and sludge liquor are contaminating the animal tissue. These findings indicate that livestock should be prevented from grazing near WWTPs and that heavy metal concentrations in animal products from the study area need regular monitoring.
(Submitted 20 February 2025; Accepted 27 June 2025; Published 22 August 2025
Evaluation of ground maize grain silage rehydrated with water or whey: A sustainable storage option
Get PDFThe aim of this study was to assess the quality of ground maize grain silage rehydrated with varying proportions of whey, in comparison with silage rehydrated with water, to determine the potential of using whey during silage production as a strategy to enhance process sustainability. The treatments included four different rehydration methods for the ground maize, with the control treatment adding 30% water to the maize grain, and whey being used to rehydrate the maize at three different rehydration levels (20%, 30%, and 40% whey). The highest effluent losses were observed in the treatment with 40% whey rehydration (7.86 kg/t fresh matter), and the pH was highest in the control treatment (5.51). The silage rehydrated with water contained the fewest lactic acid bacteria (0.90 log colony-forming units/g) and the lowest lactic acid concentration (2.71 g/kg dry matter). Stability loss occurred fastest in the silage rehydrated with water (41.6 hours), followed by the silage rehydrated with 40% whey (46.4 hours). Rehydration with whey enhanced the quality of the ground maize silage, promoting greater sustainability in both the processing and production of grain silage.
(Submitted 20 February 2025; Accepted 5 August 2025; Published 27 August 2025
Effects of postpartum energy balance, body condition score, and insemination time on conception rates of Bonsmara cows bred using timed artificial insemination
Get PDFFertility management of extensively farmed beef cattle in South Africa is essential to ensure the economic viability of such production systems. However, the success of timed artificial insemination (TAI) programmes varies, affecting cattle farmers\u27 adoption of this reproductive technique. This study investigated the effects of postpartum energy balance (∆M), body condition score (BCS), time of artificial insemination (morning or afternoon), and any interactions on the conception rates of Bonsmara cows (N = 72, second to ninth parity, BCS ≥2.25) in the Limpopo Province of South Africa. The cows were synchronised in the morning or afternoon using the seven-day CO-Synch synchronisation protocol. Cow live weight and BCS were recorded at synchronisation, TAI, and pregnancy determination, and the data were used to calculate the ∆M. Cows that did not conceive from TAI were naturally mated, and the number of cows that did not conceive was recorded. The average conception rate of cows bred by both TAI and natural mating was 76.7 ± 5.60%. The ∆M and time of artificial insemination did not influence the conception rate. The BCS and duration of the postpartum period influenced the conception rates of cows bred by TAI and cows bred by combined TAI and natural mating. Cows that conceived from TAI tended to have higher estimated breeding values for fertility than those that conceived from natural mating or did not conceive. Cows with a BCS of 3.00–3.75 had the highest conception rates, followed by those with a BCS >3.75, with cows with a BCS <2.75 having the lowest rates.
(Submitted 4 August 2025; Accepted 19 August 2025; Published 10 October 2025
Breeding practices and trait preferences of sheep farmers from two villages in Lepelle-Nkumpi municipality, Limpopo Province, South Africa
Get PDFDespite the large genetic diversity within South Africa\u27s sheep population, average productivity on smallholdings remains low. This study therefore aimed to identify the breeding practices and trait preferences of sheep farmers in the Makurung and Lenting villages, Limpopo Province, for use in the development of a community-based breeding programme. Data were collected from 70 purposively sampled farmers in the two villages using a questionnaire survey method. Descriptive analysis, significance testing, and index ranks using SPSS software were employed to describe and analyse the collected data. Most (48.8%) of the sheep farmers in both villages kept sheep for savings and investment, and meat production purposes. The overwhelming majority (90.0%) of sheep farmers in both villages practised uncontrolled mating, but a significant difference in breeding practices was observed between the villages. Knowledge of castration and culling practices did not significantly differ between the villages. The sheep farmers\u27 preferred traits for breeding rams were mating ability (0.3), body size (0.3), and growth rate (0.2), while for breeding ewes they were twinning ability (0.3), mothering ability (0.2), and lambing interval (0.2). We conclude that farmers should focus more on ewe reproductive anatomy traits (such as udder size and shape, and teat size and placement), and ram reproductive anatomy traits (such as scrotal size and circumference, and testicular size and weight), as these can have an impact on long-term flock productivity. These findings could guide interventions such as the establishment of sustainable community-based breeding schemes to improve sheep production in the study area.
Submitted 6 May 2024; Accepted 4 January 2025; Published February 2025
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Significance of research to South African science
This study provides empirical insights into the breeding practices, trait preferences, and socio-economic conditions of smallholder sheep farmers in Limpopo. It highlights that despite a wealth of genetic diversity in South Africa’s sheep populations, productivity remains low—primarily due to limited breeding knowledge and uncontrolled mating practices. The research identifies key traits preferred by farmers (such as mating ability, body size, and twinning ability) and underscores the potential of community-based breeding programmes (CBBPs) to improve productivity in smallholder systems.
By documenting the real-world needs and practices of farmers, the study lays the groundwork for locally relevant, participatory genetic improvement programmes that can enhance food security, rural livelihoods, and sustainable agriculture. It aligns with national development goals by supporting evidence-based policy and extension services, particularly in under-resourced rural areas. This makes it a valuable resource for researchers, policymakers, and extension officers working to strengthen South Africa’s small ruminant sector
Human counting versus artificial intelligence for assessing medullation in mohair fibres
Get PDFThe fleeces of mammals with dense coats, such as the mohair fleeces of Angora goats, usually include medullated fibres. These fibres constitute a problem for the textile industry because of their structural characteristics. Three experiments were conducted in this study, with the aim of comparing human image analysis to digital image analysis and artificial intelligence (AI), in terms of their ability to determine the incidence of medullation in mohair samples. The experiments entailed determining the incidences of industry non-objectionable medullated (NOB) fibres and objectionable medullated (SME) fibres, as percentages of the non-medullated fibres. In each experiment, a set of samples was analysed by both laboratory personnel and by different AI models using a Smart Fiber Medullometer. Laboratory personnel showed better coincidence and higher correlations with the AI models when counting SME fibres (r = 0.64–0.97) than when counting NOB fibres (r = 0.57–0.87). This could be the result of the more clearly defined characteristics of SME fibres, in relation to NOB fibres. The results of this study indicate a great advance in the automatic detection of SME and NOB fibres in mohair samples. However, further adjustments of the AI models are required for counting NOB fibres.
Submitted 12 June 2024; Accepted 8 April 2025; Published May 2025
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Significance of research to South African science
The article holds notable significance for South African science, particularly within the textile and agricultural sectors. Mohair is a valuable fibre in South Africa, which is one of the world’s leading producers. The study compares human assessment with artificial intelligence (AI) methods for detecting medullated fibres in mohair, a critical quality determinant for the textile industry. The findings demonstrate the growing potential of AI technologies to enhance the accuracy and efficiency of fibre quality analysis, offering a pathway to modernising mohair processing and improving global competitiveness. This aligns with South Africa\u27s strategic focus on smart agriculture, innovation, and adding value to animal fibre production