https://ir.unisa.ac.za/handle/10500/30871 2026-05-12T18:26:36Z https://ir.unisa.ac.za/handle/10500/32369 Beach and dune erosion along the coast of Richards Bay, South Africa and implications for the management of shoreline change Alakram, Suvana Sandy beaches are dynamic in nature and are subject to natural and anthropogenic processes that influence its evolution. One of the key drivers of coastal evolution is the erosion of the coastline. Sandy beaches are more susceptible to erosion because its fine sand is easily erodible. Since approximately 80% of South Africa’s coastline consists of sandy beaches, including environmentally sensitive dune systems, the impetus is to improve our knowledge and understanding of processes taking place at the coastal zone to aid in coastal zone management and planning for future hazards. This research integrated the use of geographical information systems (GIS), remote sensing, and modelling techniques to contribute knowledge on the interrelationships between the spatial and temporal dynamics of shoreline changes along the coast of Richards Bay, South Africa. Shoreline change rates were quantified over a 45 year period between 1977 and 2022 using the United States Geological Survey’s Digital Shoreline Analysis System. The historical data was then used to estimate future shoreline positions 10 and 20 years into the future. The results of the shoreline analysis revealed consistent erosion north of the Richards Bay harbour with a net shoreline movement of 167.80 m in some areas. The beaches south of the harbour recorded an accretional trend with a net shoreline movement of 98.90 m in some areas. The study verified that the development of the port breakwaters has caused an interruption the longshore sediment transport pattern, resulting in accretion on the updrift side (South), and erosion on the downdrift (North). The shoreline change rate statistics were used to predict future shoreline positions using the Extrapolated Linear Regression method 10 and 20 years into the future. In the context of climate change and associated sea level rise, model based approaches in ArcGIS Pro were used to assess the vulnerability of the study area to inundations caused by storm surges. The inundation screening was initated for four different surge levels using a high resolution DEM as input. The results indicated that during a 9 and 10 m storm surge, 60 and 68% of the study area respectively was inundated which serves as important baseline information for disaster risk assessments. This dissertation also explored possible pathways to coastal resilience and proposed strategies to mitigate coastal erosion and flooding in a changing environment.; Strande is dinamies en onderhewig aan natuurlike en antropogeniese prosesse wat die evolusie daarvan beïnvloed. Een van die belangrikste dryfkragte van kusevolusie is erosie van die kuslyn. Strande is meer vatbaar vir erosie omdat fyn sand maklik erodeerbaar is. Ongeveer 80% van Suid-Afrika se kuslyn bestaan uit hoofsaaklik sand dominante strande wat omgewings belangrikke duinstelsels behels. Dus is die doel van hierdie projek om ons kennis en begrip van kussoonprosesse te verbeter asook om te help met kussonebestuur en beplanning vir toekomstige gevare. Hierdie navorsing maak gebruik van ‘n metode wat geografiese inligtingstelsels (GIS), afstandswaarneming en modelleringstegnieke behels. Met die doel om die onderliggende verband tussen die ruimtelike en temporale dinamika van kuslynveranderinge langs die kus van Richardsbaai, Suid-Afrika, beter te verstaan. Die kuslynveranderingstempo's is oor 'n tydperk van 45 jaar, tussen 1977 en 2022, gekwantifiseer met behulp van die Verenigde State se Geologiese Opname se Digitale Kuslynanalisestelsel (DSAS). Hierdie historiese data was gebruik om die toekomstige kuslynposisies te skat oor 10 en 20 jaar. In sommige gebiede het die studie erosie noord van die Richardsbaai-hawe uitgewys met 'n totale kuslynbeweging van 167.80 m. Strande suid van die hawe het 'n akkresionele tendens vertoon met 'n netto kuslynbeweging van 98.90 m in sommige gebiede. Met klimaatverandering en stygende seevlaktes ingedagte, was ArcGIS Pro gebruik om die kwesbaarheid van die studiegebied vir stormvloede te modeleer en assesseer. Vier verskillende stormvloed scenarios was getoets met behulp van hoë resolusie DEMs. Die resultate wys dat 60 of 68 persent van die studiegebied sal vloed met ‘n 9 of 10 m stormvloed scenario en dien as ‘n belangrikke basislyn for toekomstige ramp en risikoassesering. Verder, ondersoek hierdie navorsing opsies om kusveerkragtigheid te verbeter en stel strategië voor om die impak van kuserosie en vloede te versag in ‘n area wat klimaatverandering ondervind. Abstracts in English and Afrikaans 2026-01-26T00:00:00Z https://ir.unisa.ac.za/handle/10500/31878 A phylogenetic study of the genus Dianthus L. (Caryophyllaceae) in South Africa Mnxati, Edward Sifiso This study addresses the phylogenetic relationships within the genus Dianthus in South Africa, employing molecular analysis approach and the distribution pattern of the genus. We extracted DNA and sequenced South African taxa which were then added into other Dianthus sequence data including Petrorhagia species (outgroup) from GenBank. A robust phylogenetic tree comprising of three plastids (trnH-psbA, trnK-matK and trnK-psbA) and ITS nuclear region was assembled based on 94 taxa of Dianthus species and Petrorhagia using Mr Bayes analysis. Furthermore, we generated the distribution map for each Dianthus species using QGIS, points extracted from BRAHMS database. Our results have revealed Dianthus as monophyletic when Petrorhagia was used as an outgroup (s). Four strongly supported clades were identified (Africa Lineage, Eurasian radiation, Section Verruculosi and Section Armerium), indicating geographical distinctions. We identified potential discrepancies, notably in the placement of D. mooiensis and D. namaensis. An unexpected relationship between D. thunbergii and D. bolusii was also highlighted, challenging current morphological classifications. Defined clades were further observed within African Dianthus (Ethiopia & Northern African species; BS/100), and Western & Eastern region of South Africa; BS/100), while two subclades (BS/100 & BS/72) were observed within the South African clade. Additionally, ITS generated unsupported and unresolved trees independently, as did the three plastids (trnH-psbA, trnK-matK, and trnK-psbA). The identified clades and unresolved species placements warrant further investigation, possibly through additional molecular gene markers or broader taxon sampling. This study sets the groundwork for future research aimed at resolving the taxonomic revision of Dianthus in South Africa. 2024-02-28T00:00:00Z https://ir.unisa.ac.za/handle/10500/31877 African horse sickness Epidemiology: Culicoides spp. diversity, vectors and overwintering of the virus in Eastern Cape Province, South Africa Mtyapi, Ayanda Patrick African horse sickness (AHS) is a devastating, non-contagious viral disease of equids. However, zebra are resistant to the disease. Previously it was accepted that outbreaks of AHS would start in the northern parts of South Africa and gradually move southwards as the season progressed. This stemmed from the belief that the large population of zebras in the Kruger National Park, acted as the source of the virus. In outbreaks that have occurred over the past 25 years, it has become evident that this was not true, as outbreaks would persist for two or more seasons in the south of the country, with the same AHS serotype causing the first outbreak being the only one recorded in that area in subsequent years. Therefore, it is possible that the virus overwinters in the area. However, the overwintering mechanism of the African horse sickness virus (AHSV) is not fully understood. It has been suggested that the AHSV overwinters in adult Culicoides populations, at low levels of viremia in natural hosts, or in other vertebrate or invertebrate hosts such as dogs and ticks, respectively. The aim of this study was to investigate how the AHSV overwinters in the study area, and the role dogs and ticks play in this process and to determine the diversity for both Culicoides and tick species in the study area. This study was undertaken in the Sarah Baartman district in the Eastern Cape Province of South Africa. A total of 28 sites were recruited for collection of Culicoides and tick species, and blood samples from dogs. A 220 V down draught-UV light trap was used to collect Culicoides specimens, while ticks were collected directly from live hosts. Blood samples were drawn from dogs using the cephalic vein. All these samples were sent to the Agricultural Research Council – Onderstepoort Veterinary Research (ARC-OVR) for analysis. Over the survey period 918 collections of Culicoides were made, and 44,850 Culicoides specimens, comprising of 49 Culicoides species were recovered. A total of 1,260 tick specimens comprising of 10 species from three genera were collected and identified during the survey. Over a period of one year, blood samples were collected from 100 dogs. Each dog was sampled four times, once every season. Blood samples were analysed using an AHS indirect ELISA to test for the presence of IgG antibodies. Culicoides and tick samples were first tested for the presence of AHSV using an inhouse PCR. All samples that tested positive on the inhouse PCR were subjected to the WOAH (accredited and validated) test. Only samples that tested positive with the WOAH test were considered AHSV positive. While five Culicoides pools tested positive with the inhouse PCR, only two pools of these pools tested positive for the virus on the WOAH PCR test. Furthermore, of the two pools that tested positive: one was from Site 1 and consisted of two specimens of C. bolitinos and the other pool was from Site 7 and consisted of six specimens of C. tuttifrutti. This study provides an insight into the diversity of both Culicoides and tick species in the study area. Findings reported here demonstrated that dogs are not preferred hosts for Culicoides species given that none of the dogs tested positive for AHSV antibodies. Based on the results from this study, only Culicoides species have the potential to play a role in the overwintering of AHSV in the area. However, additional tick species and other possible vertebrate hosts should also be investigated. Further research is needed to investigate the role of C. tuttifrutti and other blood feeding flies in the transmission of AHSV and other orbiviruses.; Afrika-perdesiekte (APS) is ’n verwoestende, nie-aansteeklike virale siekte van perdagtiges. Sebras is egter bestand teen die siekte. Voorheen is aanvaar dat uitbrekings van APS in die noordelike dele van Suid-Afrika sou begin en geleidelik suidwaarts sou beweeg soos die seisoen vorder. Dit het gespruit uit die oortuiging dat die groot bevolking sebras in die Krugerwildtuin die bron van die virus was. In uitbrekings die afgelope 25 jaar, het dit duidelik geword dat dit nie waar is nie, aangesien uitbrekings vir twee of meer seisoene in die suide van die land sou voortduur, met die APS-serotipe wat die eerste uitbreking veroorsaak het die enigste een wat in die daaropvolgende jare aangeteken is. Daarom is dit moontlik dat die virus in die gebied oorwinter. Daar is egter nie voldoende begrip van die oorwinteringsmeganisme van die Afrika-perdesiektevirus (APSV) nie. Daar is voorgestel dat die APSV oorwinter in volwasse Culicoides-bevolkings, teen lae vlakke van viremie in natuurlike gashere, of in ander werweldiere of ongewerwelde diere soos honde en bosluise, onderskeidelik. Die doel van hierdie studie was om te ondersoek hoe die APSV in die studiegebied oorwinter, die rol wat honde en bosluise in hierdie proses speel, en om die diversiteit van beide Culicoides- en bosluis spesies in die studiegebied te bepaal. Hierdie studie is in die Sarah Baartman distrik in die Oos-Kaap provinsie van Suid-Afrika onderneem. Altesaam 28 terreine is besoek vir die insameling van Culicoides- en bosluis spesies, en vir bloedmonsters van honde. ’n 220 V-intreklug-UV-ligval is gebruik om die Culicoides-monsters te versamel terwyl bosluise direk van lewende gashere ingesamel is. Bloedmonsters is uit die kefaliese aar by honde getrek. Al hierdie monsters is na die Landbounavorsingsraad-Onderstepoort Veterinêre Navorsing (LNR-OVN) gestuur vir analise. Tydens die opname tydperk is 918 insamelings van Culicoides gemaak, en 44,850 Culicoides-monsters bestaande uit 49 Culicoides spesies is opgespoor. ’n Totaal van 1,260 bosluis-monsters bestaande uit 10 spesies uit drie genera is tydens die opname ingesamel en geïdentifiseer. Tydens ’n tydperk van een jaar is bloedmonsters by 100 honde ingesamel. Bloedmonsters is vier keer, een keer per seisoen, by elke hond ingesamel. Bloedmonsters is ontleed met behulp van ’n APS indirekte ensiemgekoppelde immunosorbenttoets (ELISA) vir die teenwoordigheid van IgG-teenliggame. Culicoides- en bosluismonsters is eers getoets vir die teenwoordigheid van APSV met behulp van ’n interne PKR. Alle monsters wat positief getoets het met die interne PKR is aan die Wêreld organisasie vir Dieregesondheid (WOAH) se geakkrediteerde en geldige toets onderwerp. Slegs monsters wat positief getoets het met die WOAH-toets is as APSV-positief beskou. Alhoewel vyf Culicoides-poele positief getoets het met die interne Polimerase kettingreaksie (PKR), het slegs twee poele van hierdie poele positief getoets vir hierdie virus met die WOAH-PKR-toets. Verder, van die twee poele wat positief getoets het, was een van Terrein 1 en het bestaan uit twee monsters van C. bolitinos, en die ander poel was van Terrein 7 en het bestaan uit ses monsters van C. tuttifrutti. Hierdie studie bied insig in die diversiteit van beide Culicoides- en bosluis spesies in die studiegebied. Die bevindinge wat hier gerapporteer is, het getoon dat honde nie voorkeur gashere vir Culicoides-spesies is nie, aangesien geen honde positief getoets het vir APSV-teenliggame nie. Op grond van die resultate van hierdie studie het slegs Culicoides spesies die potensiaal om ’n rol te speel in die oorwintering van APSV in die gebied. Addisionele bosluis spesies en ander moontlike gewerwelde gashere moet egter ook ondersoek word. Verdere navorsing is nodig om die rol van C. tuttifrutti en ander bloed voedende vlieë in die oordrag van APSV en ander orbivirusse te ondersoek.; Isifo samahashe iAfrican horse sickness (iAHS) sisifo esitshabalalisayo, esingosuleliyo. Nangona kunjalo, amaqwarhashe ayaxhathisa kwesi sifo. Ngaphambili kwakusamkelwa ukuba uqhambuko lweAHS luza kuqala kwiindawo ezisemantla oMzantsi Afrika luze ngokuthe chu lunwenwe ukuya emazantsi ngokuhamba kwexesha lonyaka. Oku kubangelwa yinkolelo yokuba uninzi lwamaqwarhashe eKruger National Park, lusebenza njengemvelaphi yale ntsholongwane. Kuqhambuko oluye lwenzeka kule minyaka ingama 25 adlulileyo, kuye kwacaca ukuba oku bekungeyonyani, nanjengoko ukuqhambuka bekuye kuqhubeke kangangezihlandlo ezibini okanye ngaphezulu ngexesha lonyaka kumazantsi eli lizwe, kunye neAHS efanayo ebangele ukuqhambuka kokuqala ibekuphela kwako ekubhalwe phantsi kule ndawo kwiminyaka elandelayo. Ngoko ke, kunokwenzeka ukuba le ntsholongwane inwenwa ubusika bonke kwindawo leyo. Nangona kunjalo, indlela yokunwenwa ubusika bonke kwentsholongwane yokugula kwamahashe iAfrika horse sickness virus (iAHSV) ayiqondwa ngokupheleleyo. Kuye kwacetyiswa ukuba iAHSV inwenwa ubusika bonke kwiimbuzane (Culicoides) ezindala, kumanqanaba aphantsi kokubakho kweentsholongwane egazini kumakhaya endalo, okanye kwamanye amakhaya ezilwanyane ezinethambo lomqolo okanye izilwanyana ezingenathambo lomqolo ezifana nezinja kunye namakhalane, ngokulandelanayo. Olu phando lwenziwe kwisithili iSarah Baartman kwiPhondo leMpuma Koloni eMzantsi Afrika. Kukhangelwe iindawo ezingama28 zizonke ukuze kuqokelelwe iintlobo zeembuzane, namakhalane, kunye neesampuli zegazi ezinjeni. Kusetyenziswe isibane sokuthiyisela/sokubamba izinambuzane i220 V down draught-UV ukuqokelela iisampuli zeembuzane, ngelixa amakhalane aqokelelwa ngokuthe ngqo kwizilwanyane eziphilayo. Iisampuli zegazi zitsalwe kwizinja kusetyenziswa umthambo osemkhonweni. Zonke ezi sampuli ziye zathunyelwa kwiAgricultural Research Council – Onderstepoort Veterinary Research (iARC-OVR) ukuze zixilongwe. Ngexesha lophando kwenziwa ingqokelela yeembuzane ezingama 918, kunye neesampuli zeembuzane ezingama 44,850, ezibandakanya iintlobo zeembuzane ezingama49 ezafunyanwayo. Zizonke ziisampuli zamakhalane ali 1,260 eziquka iintlobo ezili10 ezivela kumaqela amathathu afanayo ezithe zaqokelelwa zaze zachongwa ngexesha lovavanyo. Kwisithuba esingangonyaka, iisampuli zegazi zaqokelelwa kwizinja ezili100. Kwathathwa iisampuli zegazi kane kwinja nganye, kanye ngexesha lonyaka. Iisampuli zegazi zaxilongwa kusetyenziswa iAHS indirect ELISA ukuvavanya ubukho bezithintelintsholongwane zeIgG. Iisampuli zeembuzane nezamakhalane zavavanywa kuqala ukujonga ubukho beAHSV kusetyenziswa iPCR yangaphakathi. Zonke iisampuli eziye zafunyaniswa zinentsholongwane kwiPCR yangaphakathi zifakwe kuvavanyo lweWOAH (oluvunyiweyo noluqinisekisiweyo). Ziisampuli kuphela eziye zafunyaniswa zinentsholongwane ngovavanyo lweWOAH eziye zathathwa ngokuba zineAHSV. Ngelixa amagcuntswana amahlanu eembuzane afunyaniswa enentsholongwane ngePCR yangaphakathi, ngamagcuntswana amabini kuphela kula magcuntswana afunyaniswe enentsholongwane kuvavanyo lweWOAH PCR. Ngaphaya koko, kumagcuntswana amabini afunyaniswe ukuba anayo le ntsholongwane: elinye belisuka kuSite 1 kwaye lineesampuli ezimbini ze C. bolitinos, elinye igcunstwana belisuka kuSite 7 kwaye lineesampuli ezintandathu ze C. tuttifrutti. Olu phando lunikeza ulwazi ngentlobo ntlobo zeembuzane kwakunye neentlobo ntlobo zamakhalane kwindawo uphando ebelubanjwe kuyo. Iziphumo ezixelwe apha zibonise ukuba izinja azikhethwa ziintlobo zeembuzane kuba akukho nanye kwizinja ezivavanyiweyo efunyaniswe inezithintelintsholongwane zeAHSV. Ngokusekelwe kwiziphumo zolu phando, ziintlobo zeembuzane kuphela ezinokuthi zidlale indima yokunwenwa ubusika bonke kweAHSV kwindawo. Nangona kunjalo, iintlobo zamakhalane ezongezelelweyo kunye nezinye izilwanyane ezinethambo lomqolo ezinokubakho kufuneka ziphandwe nazo. Uphando olongezelelweyo luyafuneka ukuphanda indima ye C. tuttifrutti nezinye izinambuzane ezifunxa igazi ekusasazeni iAHSV kunye nezinye iintsholongwane ezisuleleka ngenxa yezinambuzane (i-orbiviruses).; Lefu la Dipere la Afrika (AHS) ke lefu le sithabetsang, le sa tshwaetsaneng la kokwana-hloko ya mefuta e anyesang ya dipere. Leha ho le jwalo, diqwaha ha di be le lefu lena. Pele ho ne ho amohelwa hore ho qhoma ha AHS ho tla qala dikarolong tse ka Leboya la Afrika Borwa mme butle-butle le lebe dikarolong tse borwa ha nako ya selemo e ntse e tswela pele. Sena se ne se bakwa ke tumelo ya hore palo e ngata ya diqwaha tse Kruger National Park, e sebetsa e le mohlodi wa kokwana-hloko. Ho qhoma ho etsahetseng dilemong tse 25 tse fetileng, ho bonahetse hore sena e ne e se nnete, kaha mafu a sewa a ne a tla tswela pele ka dinako tse pedi kapa ho feta tsa selemo karolong e borwa ho naha, ka mokgwa wa ho bokella disele kapa dikokwana-hloko, o tshwanang wa AHS e bakang sewa sa pele e le sona feela se tlalehilweng sebakeng seo dilemong tse latelang. Ka hona, ho ka etsahala hore kokwana-hloko e phele nakong yohle ya mariha sebakeng seo. Leha ho le jwalo, ho phela nakong yohle ya mariha ha kokwana-hloko ya lefu la dipere tsa Afrika (AHSV) ha ho so utlwisiswe ka botlalo. Ho ile ha etswa tlhahiso ya hore AHSV e phela nakong yohle ya mariha ho di-Culicoide tse kgolo, ka maemo a tlase a boteng ba vaerase mading ho baamohedi ba tlhaho, kapa ho dihlopha tse ding tsa diphoofolo tse nang le mokokotlo kapa tse se nang mokokotlo tse kang dintja le diboseleise, ka ho latellana. Sepheo sa phuputso ena e ne e le ho batlisisa hore na AHSV e phela mariha oohle jwang sebakeng sa phuputso, le karolo eo dintja le diboseleise di e bapalang tshebetsong ena le ho fumana hore na mefuta ya di-Culicoide le diboseleise e na le mofuta ofe sebakeng sa phuputso. Phuputso ena e entswe seterekeng sa Sarah Baartman Porofenseng ya Kapa Botjhabela Afrika Borwa. Kakaretso ya dibaka tse 28 e ile ya ngodiswa bakeng sa pokello ya mefuta ya di-Culicoide le diboseleise, le disampole tsa madi a dintja. Sefi sa lebone sa 220 V down draught-UV se ile sa sebediswa ho bokella mehlala ya di-Culicoide, ha diboseleise di ne di bokellwa ka ho toba ho baamohedi ba phelang. Ho ile ha nkuwa disampole tsa madi ho dintja ho sebediswa mothapo wa cephalic. Disampole tsena kaofela di ile tsa romellwa Lekgotleng la Dipatlisiso tsa Temo - Onderstepoort Veterinary Research (ARC-OVR) bakeng sa tlhahlobo. Nakong ya phuputsi ho ile ha etswa dipokello tse 918 tsa di-Culicoide, mme mefuta e 44,850 ya di-Culicoides, e nang le mefuta e 49 ya di-Culicoides e ile ya fumanwa. Kakaretso ya mehlala ya diboseleise tse 1,260 tse nang le mefuta e 10 ho tswa melokong e meraro e ile ya bokellwa le ho tsejwa nakong ya dipatlisiso. Ka nako ya selemo se le seng, ho ile ha bokellwa disampole tsa madi ho dintja tse 100. Ntja ka nngwe e ile ya etswa disampole ka makgetlo a mane, hanngwe ka nako ya selemo. Disampole tsa madi di ile tsa hlahlojwa ho sebediswa ELISA e sa tobang ya AHS ho etsa tlhahlobo ya boteng ba disele tse sireletsang mmele mafung tsa IgG. Di-Culicoide le disampole tsa dibosoleise di ile tsa lekwa pele bakeng sa boteng ba AHSV ho sebediswa PCR e teng. Disampole tsohle tse fumanweng di na le AHSV ho PCR e teng di ile tsa etswa tlhahlobo ya WOAH (e amohelehang le e tiisitsweng). Ke feela disampole tse fumanweng di na le AHSV ka tlhahlobo ya WOAH di ileng tsa nkuwa di na le AHSV. Le hoja matamo a mahlano a di-Culicoide a ile a fumanwa a e na le PCR ya kahare, ke matamo a mabedi feela a matamo ana a ileng a fumanwa a e na le kokwana-hloko tekong ya WOAH PCR. Ho feta moo, ho matamo a mabedi a ileng a fumanwa a e na le AHSV: le leng le ne le tswa Setsing sa 1 mme le ne le na le mehlala e mmedi ya C. bolitinos le letamo le leng le ne le tswa Setsing sa 7 mme le ne le na le mehlala e tsheletseng ya C. tuttifrutti. Phuputso ena e fana ka temohisiso ka mefuta-futa ya mefuta ya di-Culicoide le diboseleise sebakeng sa phuputso. Diphumano tse tlalehilweng mona di bontshitse hore dintja ha di ratehe bakeng sa mefuta ya di-Culicoid kaha ha ho le e nngwe ya dintja tse fumanweng di na le disele tse sireletsang mmeleng mafung tsa AHSV. Ho ipapisitswe le diphetho ho tswa phuputsong ena, ke mefuta ya di-Culicoide feela e nang le monyetla wa ho bapala karolo ya ho phela mariha oohle wa AHSV sebakeng seo. Leha ho le jwalo, mefuta e meng ya diboseleise le diphoofolo tse ding tse nang le lesapo la mokokotlo le tsona di lokela ho etswa dipatlisiso. Ho hlokahala dipatlisiso tse ding ho batlisisa karolo ya C. tuttifrutti le ditshintsi tse ding tse fepang madi phetisong ya AHSV le dikokwana-hloko tse ding tsa orbivirus. Abstracts in English, Afrikaans, Xhosa and Sesotho 2024-02-28T00:00:00Z https://ir.unisa.ac.za/handle/10500/31478 The farm gate carbon and water footprint of diverse beef cattle genotypes in South Africa and its environmental impact Chabalala, Nelly Thuli The aim of this study is to estimate the current farm-gate carbon and blue water footprint of the major beef breeds in South Africa that is representative of the different breed types e.g. Sanga (indigenous), Sanga derived, Zebu, Zebu derived, British and European breeds. A simulation programme was used to simulate the methane production (expressed as methane intensity) and blue water footprint of a weaner calf production system for 9 diverse beef cattle genotypes. The chosen genotypes were based on the number of animals and the availability of data. The breeds involved were: Afrikaner, Nguni, Bonsmara, Angus, Hereford, Brahman, Brangus, Charolais and Simmentaler. The simulation study also involved a farm size of 1200 hectares (ha), with a carrying capacity of 6 hectares per Large Stock Unit (LSU) which could carry 200 LSU’s. Frame size specific equations were used to estimate cow LSU units. The Tier 2 Intergovernmental Panel on Climate Change (IPCC) approach for the methane (CH4) emission values, as already published in the literature was used. Through this approach it was estimated that the enteric methane emissions factor (MEFenteric) of a LSU was equivalent/equal to 94kg methane/year. Furthermore, a 15% replacement rate, 2% pre-weaning mortality, 2% post weaning mortality and a 4% use of breeding bulls were assumed. The blue water use intensity can be estimated in the same way, and it was assumed that for every kg of dry matter intake, a ruminant animal needs 4 litres (L) of water, but it can be increased by 50 % when it is hot. Therefore, an average of 5 litres water intake was used. A LSU needs 9kg dry matter per day and therefore 45 litres of water per day. It was thus estimated that the litres of blue water consumed on the farm was 16 425 litres/year/LSU multiplied by 200 LSU’s which was equal to 3 285 kilolitres. Actual published production values (weaning weight, cow weight, fertility) for each breed was used. For the small frame Afrikaner and Nguni breeds, it was estimated that the methane intensity (kg methane per kg live weight leaving the farm) was 0.60kg and 0.68 kg, respectively. For the medium frame Bonsmara, Angus, Hereford, Brahman and Brangus, the methane intensity was 0.59kg, 0.59kg, 0.64kg, 0.61kg and 0.62kg, respectively. Lastly, for the large frame Charolais and Simmentaler, the methane intensity was 0.85kg and 0.73kg, respectively. The methane intensity varied from 0.59kg CH4 to 0.85kg CH4, which represents a 44% difference. However, when comparing different size breeds, assuming a 10% improvement in each trait, the methane intensity varied from 0.55kg to 0.75kg, vi respectively and a 55% difference was then observed. Moreover, when estimating the water use intensity, it varied from 103 to 148 kilolitres from small to large frame breeds and when a 10% improvement was applied it then ranged from 96 to 131 kilolitres per kg live weight leaving the farm. It was surprising that the Nguni had a medium methane and water intensity, since it is the most fertile breed. However, it should be taken into account that the Nguni was the smallest breed and 147 cows with calves could be kept on the 1 200ha farm. These cows and calves produce large quantities of methane and utilizes large/high water quantities as compared to some of the other breeds. The Afrikaner, Bonsmara, Angus, Brahman and Brangus breeds have low methane and water use intensities and can be regarded as environmentally friendly. The Nguni and Hereford breeds have medium methane and water use intensities while the Charolais and Simmentaler breeds have higher methane and water use intensities. This information can be used to develop a model that can estimate the farm-gate methane emission and water use intensity for different breed types, production levels and systems. Such a model will be valuable in the event that carbon taxes are introduced and total life cycle of water use can be fully analysed.; Xikongomelo xa phurojeke leyi i ku pima khaboni ya sweswi ya farm-gate na mati ya blue water footprint ya tinxaka letikulu ta nyama ya homu e Afrika Dzonga leswi yimelaka tinxaka to hambana ta tinxaka xikombiso Sanga (indigenous), Sanga derived, Zebu, Zebu derived, British na Tinxaka ta le Yuropa. Dyondzo yitirhisiwile ku tekelela vuhumelerisi bya methane (leswi kombisiwaka tani hi matimba ya methane) na blue water footprint ya weaner calf production system eka 9 wa ti genotypes to hambana hambana ta tihomu ta homu. Ti genotypes leti hlawuriweke ati seketeriwile eka nhlayo ya swifuwo xikan’we naku kumeka ka data. Tinxaka leti katsekaka akuri: Afrikaner, Nguni, Bonsmara, Angus, Hereford, Brahman, Brangus, Charolais na Simmentaler. Dyondzo ya simulation yitlhele yi katsa vukulu bya purasi ra 1200 wa ti hectares (ha), laha kungana vuswikoti byo rhwala bya 6 wa ti hectares hi Large Stock Unit (LSU) leyinga rhwala 200 wa ti LSU’s. Kutani ku tirhisiwile ti equations to hlawuleka ta vukulu bya furemu ku ringanyeta tiyuniti ta LSU ta tihomu. Endlelo ra Tier 2 ra Phanele ya le Xikarhi ka Mfumo eka ku Cinca ka Maxelo (IPCC) eka mimpimo ya ku humesiwa ka methane (CH4), tanihilaha se swi kandziyisiweke hakona eka matsalwa. Hiku tirhisa endlelo leri ku ringanyetiwe leswaku enteric methane emissions factor (MEFenteric) ya LSU ayi ringana/ringana na 94kg methane/lembe. Kuya emahlweni, 15% wa nhlayo ya ku cinciwa, 2% wa ku fa ka le mahlweni ka ku lumuriwa, 2% wa ku fa endzhaku ka ku lumuriwa na 4% wa ku tirhisiwa ka tinkunzi leti fuyiwaka swi tekiwile. Kutala ka matirhiselo ya mati ya wasi yanga ringanyetiwa hindlela leyi fanaka, naswona aku ehleketiwile leswaku eka kg yin’wana na yin’wana ya swakudya swo oma leswi dyiwaka xifuwo lexi dyaka swilava 4 wa tilitara (L) ta mati, kambe xinga engeteriwa hi 50 % loko xi hisa. Hikokwalaho, ku tirhisiwile xiringaniso xa 5 wa tilitara ta mati lawa ya dyiwaka. LSU yilava 9kg ya swakudya swo oma hi siku naswona hikokwalaho ka sweswo 45 wa tilitara ta mati hi siku. Xisweswo swiringanyetiwile leswaku tilitara ta mati ya wasi lawa ya tirhisiwaka e purasini akuri 16 425 wa tilitara/lembe/LSU ku andzisiwa hi 200 wa ti LSU leswi ringanaka na 3 285 wa tikhilolitara. Mimpimo ya xiviri ya vuhumelerisi leyi kandziyisiweke (ndzilo wa ku lumuriwa, ntiko wa tihomu, ku veleka) eka muxaka wun’wana na wun’wana wutirhisiwile. Eka tinxaka letintsongo ta frame, Afrikaner na Nguni, aku ringanyetiwa leswaku matimba ya methane (kg methane hi kg ya ntiko lowu hanyaka lowu humaka viii e purasini) akuri 0.60kg na 0.68 kg, hiku landzelelana. Eka furemu yale xikarhi, ya Bonsmara, Angus, Hereford, Brahman, Brangus, matimba ya methane akuri 0.59kg, 0.59kg, 0.64kg, 0.61kg, 0.62kg, hiku landzelelana. Naswona eka furemu leyikulu, Charolais na Simmentaler, matimba ya methane akuri 0.85kg na 0.73kg, hiku landzelelana. Nhlayo ya methane ayi hambana kusuka eka 0.59kg CH4 kuya eka 0.85kg CH4, leswi yimelaka ku hambana ka 44%. Hambiswiritano, loko ku pimanyisiwa tinxaka tohambana hambana ta vukulu, hiku tekela enhlokweni ku cinca ka 10% eka mfanelo yin’wana na yin’wana, matimba ya methane ya hambana kusuka eka 0.55kg kuya eka 0.75kg, hiku landzelelana. Naswona kwalomu ka 55% wa ku hambana ku tlhele ku voniwa. Ku tlula kwalaho, loko ku ringanyetiwa matimba ya matirhiselo ya mati, ya hambana kusuka eka 103 kuya eka 148 kilolitres kusuka eka tinxaka letintsongo kuya eka letikulu ta furemu naswona loko 10% wa ku cinca ku cheriwa kutani akuri kusuka eka 96 kuya eka 131 kilolitres hi ntiko lowu hanyaka lowu humaka e purasini. A swi hlamarisa kuva va Nguni ayiri na methane yale xikarhi xikan’we na mati yotala, tani hileswi kunga muxaka lowu noneke swinene. Hambiswiritano, swifanele ku tekeriwa enhlokweni leswaku Nguni akuri muxaka lowuntsongo swinene naswona 147 wa tihomu letingana marhole tinga hlayisiwa eka purasi ra 1 200ha. Tihomu leti na marhole ya humesa nhlayo leyikulu ya methane naswona ya tirhisa mati lamakulu/yale henhla loko ku pimanyisiwa na tinxaka ta Afrikaner, Bonsmara, Angus, Brahman na Brangus. Tinxaka ta Afrikaner, Bonsmara, Angus, Brahman na Brangus tina methane yale hansi na matirhiselo ya mati naswona tinga tekiwa tani hi letinga onhi mbango. Tinxaka ta Nguni na Hereford tina methane yale xikarhi xikan’we na matirhiselo ya mati kasi tinxaka ta Charolais na Simmentaler tina methane yale henhla xikan’we na matirhiselo ya mati. Mahungu lawa yanga tirhisiwa ku tumbuluxa modele lowu nga ringanyetaka ku humesiwa ka methane ya le purasini xikan’we na matimba ya matirhiselo ya mati eka tinxaka tohambana hambana ta tinxaka, swiyimo swa vuhumelerisi na tisisiteme. Modele wo tano wu ta va wa nkoka loko ko tshuka ku nghenisiwa swibalo swa khaboni naswona xirhendzevutani xa vutomi hinkwabyo xa matirhiselo ya mati xi ta xopaxopiwa hi ku hetiseka. Abstracts in English and Tsonga 2024-01-01T00:00:00Z