TUT DIGITAL OPEN REPOSITORY

Recent Submissions

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    A systematic review on the prospects of X- and Y-sexed semen in ruminant livestock: Implications for conservation, a South African perspective
    (Frontiers Media, 2024-04-09) Ngcobo, Jabulani Nkululeko; Nedambale, Tshimangadzo Lucky; Sithole, Sindisiwe Mbali; Mtileni, Bohani; Mpofu, Takalani Judas; Ramukhithi, Fhulufhelo Vincent; Chokoe, Tlou Caswel; Nephawe, Khathutshelo Agree
    (Nguni Pedi, Zulu, and Namaqua Afrikaner, Afrino, Africander, Bezuidenhout Africander, Damara, Dorper, Döhne Merino, Meat Master, South African Merino, South African Mutton Merino, Van Rooy, and Dorper), goat (SA veld, Tankwa, Imbuzi, Bantu, Boer, and Savanna) and cattle (Afrigus, Afrikaner, Bolowana, Bonsmara, Bovelder, Drakensberger, South African Angus, South African Dairy Swiss, South African Friesland, South African Red, and Veld Master) animals. These breeds require less veterinary service, feed, management e􀀀orts, provide income to rural and or poor owners. However, most of the mare under extinction risks and some with unknown status, hence, require immediate conservation intervention. To allow faster genetic progress on the endangered animals, it is important to generate productive animals while reducing wastages and this can be achieved through sex-sorted semen. Therefore, this systematic review is aimed to evaluate the prospects of X and Y-sexed semen in ruminant livestock and some solutions that can be used to address poor sex-sorted semen and its fertility. This review was incorporated through gathering and assessing relevant articles and through the data from the DAD-IS database. The keywords that were used to search articles online were pre-gender selection, indigenous ecotypes, fertility, flow cytometry, artificial insemination, conservation, and improving sexed semen. Following a careful review of all articles, PRISMA guidelines were used to find the articles that are suitable to address the aim of this review. N Sex-sorted semen is a recently introduced technology gaining more attention M from researchers particularly, in the conservation programs. Preselection of semen based on the sex chromosomes (X- and or Y-bearing chromosomes) is of paramount importance to obtain desired sex of the offspring and avoid animal wastage as much as possible. However, diverse factors can affect quality Mof semen of different animal species especially after sex-sorting. Flow cytometry is a common method used to select male and female sperm cells and discard dead and abnormal sperm cells during the process. Thus, sperm sexing is a good advanced reproductive technology (ART) however, it is associated with the production of oxidative stress (OS) and DNA fragmentation (SDF). These findings, therefore, necessitates more innovation studies to come up with a sexing technology that will protect sperm cell injuries during sorting in frozen thawed.
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    Selective laser melting: Evaluation of the effectiveness and reliability of multi-scale multiphysics simulation environments
    (Elsevier Ltd., 2024-01-31) Mukalay, Thierry Abedi; Trimble, John Alfred; Mpofu, Khumbulani; Muvunzi, Rumbidzai
    This study evaluates the effectiveness and reliability of Multi-scale Multiphysics Selective Laser Melting (SLM) Simulation Environments. A literature review and bibliometric analysis were conducted to identify the most widely used SLM Simulation Environments. The effectiveness of simulation environments was assessed through a SWOT analysis enhanced by an Analytic Network Process (ANP). The reliability of simulation environments was analysed through a design of experiment (DoE). The DoE solely assessed the ability of these environments to accurately predict part distortion. The results showed that the most robust SLM process simulation modelling systems are Ansys Additive Print, Comsol, Simufact Additive, Netfabb, and Simulia.
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    Effect of agro-ecological zone, season of birth and sex on pre-weaning performance of Nguni calves in Limpopo Province, South Africa.
    (Springer, 2016-11-04) Mpofu, T. J.; Ginindza, M.M.; Siwendu, N.A.; Nephawe, K.A.; MTILENI, B. J.
    The study was conducted to determine the effect of agro-ecological zone, season of birth and sex on Nguni calves’ pre-weaning performance. Production indices such as birth weight (BW), weaning weight (WW), pre-weaning average daily gain (P-ADG) and pre-weaning gain (P-WG) were assessed in the different agro-ecological zones. Herd records on performance of 826 Nguni calves from nine Nguni herds representing different agro-ecological zones: arid zone (n = 217); semi-arid zone (n = 296); dry sub-humid zone (n = 118) and humid zone (n = 195) were used for the analysis of pre-weaning calf performance. General linear model (GLM) procedure of SAS (2013) was used to analyse data, whereas mean separation was conducted using Tukey’s HSD test. Agro-ecological zone had a great influence (P < 0.01) on performance levels arising from pasture conditions which were dependent on rain, temperature, topography and soil type. Fluctuations in WW, P-ADG and P-WG performance across agro-ecological zones depicted the sensitivity of Nguni calves to postnatal stress. Calves in humid zone had higher performance with 121.21 kg for WW, 96.83 kg for PWG and 0.477 kg/day for P-ADG. The lowest WW (114.51 kg), P-WG (89.98 kg) and P-ADG (0.438 kg/day) were observed in arid zone. Male calves were heavier at weaning (128.18 kg), P-ADG (0.503 kg/day) and total gain (103.03 kg); however, similar BW of 25 kg was observed for both male and female calves. Season had a significant (P < 0.05) effect on BW, P-ADG and P-WG. The P-ADG was 0.461 kg/day for calves born in summer and 0.449 kg/ day for calves born in winter season. Calves born in summer gained 94.69 kg and calves born in winter gained 92.10 kg. Summer calves gained 2.59 kg more than winter calves. Summer heifer calves performed poorly whilst summer male calves outperformed heifer calves in terms of WW, P-W Gand P-ADG. Pre-weaned calves in humid zone outperformed all calves in other agro-ecological zones. It was concluded that acceptable levels of growth are achievable from Nguni cattle under the different agro-ecological zones of Limpopo province, South Africa
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    Influence of male–male competition on reproductive performance and mortality of broiler breeders following intra-spiking.
    (Poultry Science Association Inc., 2019-05-02) Mphepya, Lesiba C.; Van Rensburg, Willie J.; Mpofu, Takalani J.; Mtileni, Bohani J.
    The study was conducted to determine the influence of male–male competition on reproductive performance and male mortality of Cobb 500 broiler breeder flocks following double intra-spiking. Broiler breeders were housed in 3 open-sided houses each accommodating 8,200 females and 820 males. Males of the same age on the same farm were exchanged between the houses (intra-spiking) to stimulate competition thereby changing the social hierarchy of each house. Intra-spiking was performed by replacing 25, 35, and 45% of males between the houses at 40 and 48 weeks of age (WOA), respectively. Eggs were collected from 36 to 55 WOA, when egg fertility and male mortality were recorded. Data was analyzed using repeated measures techniques of SAS 9.4, modeling the covariance structure of the observed data. Male–male competition (intra-spiking), age and their interaction significantly (P < 0.05) influenced egg fertility, hatchability, and male mortality. Average fertility and hatchability were increased in the 45% intra-spiked flocks (P < 0.05) (95.89 and 85.83%) compared with the 35% (95.13 and 86.30%) and 25% (94.42 and 0.23%) intra-spiked flocks. Fertility and hatchability with the 45% double intraspiked flocks was consistently higher (P < 0.05) over time than the other double intra-spiked flocks. Male mortality was lower (P < 0.05) in the 45% intra-spiked flock (0.23%) than in the 35% (0.40%) and 25% (0.44%) intra-spiked flocks. After double intra-spiking, the male mortality in the 25 and 35% double intra-spiked flocks significantly increased (P < 0.05), whereas that of 45% intra-spiked flocks remained relatively low. Male mortality in the 45% intra-spiked flocks was consistently low over time than other double intra-spike levels from 45 WOA until the end of the trial. Noteworthy, egg fertility and hatchability gradually decreased, and mortality increased with increasing flock age toward the end of the productive life cycle. High level of male–male competition (45%) showed great promise as a tool to slow down the decrease in egg fertility and hatchability and reduce male mortality in aging broiler breeder flocks.
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    Prevalence of gastrointestinal parasites in communal goats from different agro-ecological zones of South Africa.
    (Veterinary World, 2020-01-04) Mpofu, Takalani J.; Nephawe, Khathutshelo A.; Mtileni, Bohani
    Aim: A longitudinal study was conducted to assess the epidemiology of common gastrointestinal parasite (GIP) infections affecting goats in South Africa as influenced by agro-ecological zone (AEZ), sampling season, and the age and sex of animals. Materials and Methods: A total of 288 goats (101 male and 187 female) were randomly sampled during winter and summer in areas representing four AEZs (arid: 80; semi-arid: 76; humid: 62; and dry sub-humid: 70) of South Africa. Fecal samples from each animal were collected from the rectum, and the presence of GIP eggs was determined using a modified McMaster technique. A sample was considered positive when a minimum of one GIP egg was detected under the microscope. Fecal cultures were prepared, and infective larvae were collected and identified. The data were analyzed by MiniTab17 (2017) using the FREQ procedure, and the association between the independent factors and the prevalence of various GIPs were evaluated using the Pearson Chi-square test (p<0.05). Results: The overall prevalence of GIP in the present study was 37.1%, with a mean prevalence of 30.0, 26.4, 31.1, 36.6, and 59.6% for Eimeria spp., Trichuris, Strongyloides papillosus, Moniezia spp., and strongyles, respectively. There was a significant (p<0.05) association between the prevalence of strongyles, Trichuris, Moniezia spp., and AEZs, whereas an insignificant (p>0.05) association was observed for the prevalence of Eimeria spp. and S. papillosus. A significant (p<0.05) association between goat age and prevalence of all GIPs was observed, where the prevalence was higher in young goats, followed by adults, and then by suckling goats. The prevalence of various GIPs was similar between male and female goats. The percentage of infection with Eimeria spp., Trichuris, S. papillosus, and strongyle parasitic infections was marginally higher in males than in females, whereas that of the Moniezia spp. was higher in females. A significant (p<0.05) association between the prevalence of Eimeria spp. and sampling season was observed, and there was an insignificant (p>0.05) association between the other GIPs and sampling season. The prevalence of Eimeria spp. infection was higher in winter (34.0%) than in summer (26.0%). Conclusion: AEZs and goat age are the most important risk factors influencing GIP infections in South African communal goats. These epidemiological parameters are important for outlining effective parasite control management systems against these GIPs in goats.