Dissertationen zum Thema „Sheep South Australia Breeding“

The South African sheep industry has experienced an increase in the price of meat and wool over the past several years. This has led to an interest in intensification of sheep production off planted pastures. Due to this phenomenon an economic viability study was done on the intensification of sheep production on cultivated pastures under irrigation. When intensifying sheep production, certain management practices need to be incorporated in order to enhance the output obtained per hectare and to overcome the higher input cost of production. Management practices that could be included are creep feeding, accelerated breeding and feedlotting of lambs after weaning. In order to determine the economic viability of such a system, certain production parameters need to be obtained for producing sheep intensively from cultivated pastures. Three studies were conducted to obtain the required production parameters; these were then followed by an economic evaluation incorporating the parameters obtained from the studies. All the studies were conducted at Kromme Rhee and Langgewens, two research farms of the Department of Agriculture in the Western Cape.

Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2009.
ENGLISH ABSTRACT: Fluctuations and a general decline in the ratio between wool and meat prices resulted in marked changes in the South African sheep industry. Commercial producers now exploit other mechanisms such as terminal crossbreeding of Merino-type with meat type breeds or dual-purpose breeds to attain short-term benefits resulting from price fluctuations between wool and mutton without compromising the wool-producing capacities of ewe flocks. Most components of lamb production have low heritability. However, heterosis can be achieved by mating wool-type breeds with specialist meat breed rams. Genetic improvement of livestock depends on defining breeding objectives, estimation of genetic parameters and accurately identifying the right animals to be used for future breeding. Genetic parameters for traits of economic importance in terminal sire sheep breeds that could be used on Merino-type ewes in commercial operations in South Africa had not been published for the national flock apart from a preliminary study having been conducted by Olivier et al. (2004). Selection objectives were poorly defined due to lack of parameter estimates for variance and covariance components. Against this background, this study obtained pedigree information and live weight data from the National Small Stock Improvement Scheme for the Dormer, Ile de France and Merino Landsheep and estimated non-genetic factors and genetic parameters influencing early growth traits. Genetic and phenotypic trends for early growth traits were constructed for the three breeds to monitor genetic progress. Non-genetic factors influencing early growth traits in the Dormer, Ile de France and Merino Landsheep were estimated using data obtained from the National Small Stock Improvement Scheme of South Africa. The original data sets for the Dormer, Ile de France and Merino Landsheep consisted of the following number of records respectively: 52 202, 35 553 and 7 772. However, pre-weaning weights were available for the Ile de France and Merino Landsheep breeds only and post-weaning weights were available only for the Dormer breed. The data sets were complicated to such an extent that smaller data sets had to be generated to analyse for fixed effects. The traits that were analysed were birth weight, pre-weaning weight, weaning weight and post-weaning weight. The fixed effects, identified as having a significant effect (P < 0.01) on early growth traits were sex of lamb, birth type, age of dam, contemporary groups, age at which the trait was recorded and month of birth and year of birth in the Merino Landsheep breed. Although some significant interactions were found, they were subsequently ignored owing to their very small effects. In all three breeds, male lambs were significantly (P < 0.001) heavier than female lambs and single-borne lambs were significantly heavier at birth than multiple borne lambs. The age of dam had a significant curvilinear regression on all early growth traits in all three terminal sire sheep breeds. It was concluded from the study that the influence of non-genetic factors on early growth traits should be adjusted for or eliminated statistically in genetic evaluations to get accurate genetic parameter estimations. (Co)variance estimates for birth weight, weaning weight and post-weaning weight were obtained for the Dormer breed using restricted maximum likelihood procedures (REML). Direct heritabilities (h2) in single-trait analyses were 0.21 ± 0.03, 0.23 ± 0.02 and 0.29 ± 0.05 for birth weight, weaning weight and post-weaning weight, respectively. Direct heritabilities of 0.28 ± 0.04, 0.55 ± 0.06 and 0.32 ± 0.02 for birth weight, weaning weight and post-weaning weight respectively were obtained using three-trait analysis. Direct maternal genetic effects (m2) were excluded from the analyses because of the failure to partition maternal effects into maternal genetic and maternal permanent environmental effects (m2 and c2). This culminated as a consequence of poor data and population structures emanating from the loss of genetic links across flocks due to the random entrance and exit of flocks from the recording scheme. Maternal permanent environment was estimated at 0.15 ± 0.02, 0.13 ± 0.02 and 0.20 ± 0.03 for birth weight, weaning weight and post-weaning weight respectively using single-trait analysis. The correlation between direct effects and maternal effects (ram) was excluded from the analyses due the structure of the data. Genetic, phenotypic and environmental correlations between early growth traits were low to moderate. The medium to high heritability estimates for early growth traits obtained in the study led to the conclusion that Dormer sheep can successfully be used in terminal crossbreeding programs to improve meat production characteristics. Direct heritability estimates were 0.31 ± 0.14, 0.09 ± 0.02 and 0.14 ± 0.003 for birth weight, pre-weaning weight and weaning weight respectively using single-trait analysis for the Ile de France breed. Maternal effects were significant for all the traits studied despite the failure to properly partition them into their components due to the loss of genetic linkages across generations emanating from poor data structure. Genetic, phenotypic and environmental correlations were estimated using three-trait analysis and were found to be low to moderate for early growth traits. Direct genetic and maternal permanent environmental ratios were also computed and they did not differ much from the results obtained using single-trait analyses. The reasonable genetic parameter estimates obtained in the study led to the conclusion that the Ile de France can be selected to use as sires in crossbreeding programs. Genetic parameters were estimated for early growth traits in the Merino Landsheep breed. REML estimates of birth weight, pre-weaning weight and weaning weight were obtained using animal models in single-trait analyses. The direct heritability estimate for birth weight was 0.23 ± 0.13 using an animal model with additive direct genetic effects and dam permanent environmental effects as the only random factors. The dam permanent environmental effect for birth weight amounted to 0.10 ± 0.07. Direct heritability for pre-weaning weight was 0.36 ± 0.05 and the dam permanent environmental effect 0.56 ± 0.03. Weaning weight was estimated using an animal model that contained direct additive effects and dam permanent environmental effects. The direct heritability estimate for weaning weight was 0.17 ± 0.03. Maternal genetic effects were estimated to be 0.02 ± 0.01. Genetic and phenotypic trends were constructed for early growth traits in the Dormer, Ile de France and Merino Landsheep breeds. The traits that were considered were birth weight, pre-weaning weight, weaning weight and post-weaning weight. However, pre-weaning weights were available for the Ile de France and Merino Landsheep breeds only and post-weaning weights were available only for the Dormer breed. The Dormer exhibited significant improvement in the phenotypic and genetic aspects of early growth traits during the 17 years of evaluation (1990-2007). The average predicted direct breeding values of birth weight decreased by 0.055 % during the evaluation period. The predicted direct breeding value for weaning weight increased by 0.12 % during the 17 year period. Post-weaning weight improved by 0.32 % per annum. The Ile de France registered an increase in the predicted breeding value of birth weight which amounted to 0.025 % per annum. Averaged direct breeding values for pre-weaning weight increased at an annual rate of 0.23 %. and that of weaning weight increased by 1.21 %. In the Merino Landsheep the predicted direct breeding value for birth weights decreased by 0.04 % per annum and pre-weaning and weaning weights increased by 0.36 % and 0.10 % respectively. The trends were obviously biased due to inconsistencies in data structure and very few records available for analysis in this breed. In conclusion, it was evident that the additive genetic variation was available for all the early growth traits in all the three breeds. Although adequate genetic variation for substantial genetic progress was available, only modest rates of progress were attained for all the traits in all three breeds. The only possible exception was weaning weight in the Ile de France breed, which improved at > 1 % per annum. At least all changes were in the desired direction. Breeders should be encouraged to record data consistently, as one of the major shortcomings in the data for all breeds were a lack of continuity in the submission of data to the NSIS. More informative analyses ought to be feasible if this requisite could be met.
AFRIKAANSE OPSOMMING: Die wisselende en algemene afname in die prysverhouding van wol tot vleis het merkbare veranderinge in die Suid-Afrikaanse skaapbedryf teweeggebring. Kommersïele produsente maak nou gebruik van ander metodes soos terminale kruisteling van Merino-tipe ooie met vleis tipe vaars of dubbel-doel rasse om korttermynvoordele uit die wisselende wol en vleis pryse te behaal, sonder om die wol-produksie potensiaal van die ooi-kudde te benadeel. Die meeste van die lamproduksie eienskappe het ‘n lae oorerflikheid. Nietemin, kan heterose wel behaal word deur die kruisteling van wol-tipe rasse met spesialis vleisramme. Genetiese verbetering van vee is afhanklik van die beskrywing van die teeltdoelwitte, die akkurate beraming van genetiese parameters en die noukeurige identifikasie van die geskikste diere vir toekomstige teling. Genetiese parameters vir ekonomies belangrike eienskappe van terminale ramrasse wat gebruik kan word op Merino-tipe ooie in die kommersiële skaapbedryf in Suid-Afrika is nog nie gepubliseer vir die nasionale kudde nie, behalwe vir ‘n voorlopige studie wat gedoen is deur Olivier et al. (2004). Seleksiedoelwitte is nie duidelik beskryf nie a.g.v ‘n tekort aan akkurate parameterberamings vir (ko)variansie komponente. Hierdie studie het dus stamboominligting en lewende gewig data verkry vanaf die Nasionele Kleinveeverbeteringsskema vir die Dormer-, Ile de France- en die Merino landskaaprasse en nie-genetiese faktore sowel genetiese parameters vir vroeë lamgewigte beraam. Genetiese en fenotipiese tendense vir vroeë lamgewigte is vervolgens opgestel vir drie rasse om genetiese vordering te evalueer. Die oorspronklike datastelle vir die Dormer, Ile de France en die Merino Landskaap het uit die volgende aantal rekords bestaan, onderskeidelik: 52 202, 35 553 en 7 772. Voor-speen gewigte was net beskikbaar vir die Ile de France- en die Merino Landskaaprasse, en na-speen gewigte was net beskikbaar vir die Dormerras. Die beperkings in die datastelle het genoodsaak dat dat kleiner datastelle ontwikkel moes word om die vaste effekte te analiseer. Die eienskappe wat ge-analiseer was, was geboortegewig, voor-speengewig, speengewig en naspeengewig. Die vaste effekte wat vroeë lamgewigte betekenisvol (P < 0.01) beïnvloed het, was geslag van die lam, geboortestatus, ouderdom van die ooi, kontemporêre groep, die ouderdom waarop die eienskap aangeteken is en (in sommige gevalle) die maand en jaar van geboorte. Alhoewel daar sommige betekenisvolle interaksies was, is dit nie in die finale modelle ingesluit nie, omdat dit min tot die verklaarde variasie bygedra het. In al die rasse het ramlammers swaarder (P < 0.001) geweeg as ooilammers. Enkelinge was ook swaarder (P<0.001) as meerlinge. Die ouderdom van die moer van die lam het ‘n beduidende kromlynige invloed op alle vroeë lamgewigte by al drie terminale ramrasse gehad. Die gevolgtrekking van hierdie studie is dat die invloed van nie-genetiese faktore op vroeë lamgewigte in ag geneem moet word, of dat dit moet statisies elimineer word in die genetiese evaluasie om akkurate genetiese beramings te verkry. (Ko)variansie beramings vir geboortegewig, speengewig en na-speengewig is deur gebruik te maak van die “restricted maximum likelihood procedures” (REML) vir die Dormerras verkry. Die direkte oorerflikheid (h2) wat verkry was deur die mees geskikste diere model in ‘n enkel-eienskap analise te gebruik was onderskeidelik 0.21 ±0.02, 0.23 ±0.02 en 0.29± 0.05 vir geboortegewig, speengewig en na-speengewig. Direkte ooreenstemende oorerflikheid wat uit die drie-eienskap analise was 0.28±0.04, 0.55±0.06 en 0.32±0.02 onderskeidelik vir geboortegewig, speengewig en na-speengewig. Direkte maternale genetiese effekte (m2) is uitgesluit vanaf die analise weens die onvermoë om die maternale effekte te verdeel in maternale genetiese effekte en maternale permanente omgewings effekte (m2 en c2). Dit was a.g.v onvolledige data en populasiestrukture wat gelei het tot die gebrek in genetiese bande oor kuddes, wat ontstaan het weens kuddes wat slegs tydelik data tot die skema bygedra het. Maternale permanente omgewingeffekte is geskat op onderskeidelik 0.15±0.02, 0.13±0.02 en 0.20±0.03 vir geboortegewig, speengewig en na-speengewig met die gebruik van die enkel-eienskap analise. Die korrelasie tussen direkte effekte en maternale effekte (ram) is uitgesluit a.g.v die gebrekkige struktuur van die data. Genetiese-, fenotipiese- en omgewingskorrelasies tussen die vroeë lamgewigte was laag tot matig. Die matige tot hoë oorerflikheidberamings vir vroeë lamgewigte uit hierdie studie het gelei tot die gevolgtrekking dat Dormer skape suksesvol gebruik kan word in terminale kruisteel programme om vleisproduksie te verbeter. Direkte oorerflikheid skattings was 0.31±0.14, 0.09±0.02 en 0.14±0.003 vir die geboorte gewig, voor-speen gewig en speen gewig onderskeidelik met die gebruik van ‘n enkel-faktor analise vir dir Ile de France skaap ras. Maternale effekte was beduidend vir al die eienskappe wat bestudeer was , ten spyte van die onvermoë om dit behoorlik te verdeel in hul komponente weens die verlies van genetiese bande dwarsoor die generasies wat uitvloei vanaf ‘n swak data struktuur. Genetiese, fenotipiese en omgewings korrelasies was geskat deur gebruik te maak van ‘n drie-faktor analise en was gevind om laag tot matig te wees vir die vroeë groei eienskappe. Direkte genetiese en maternale permanente omgewings ratios was bereken en dit het nie veel verskil van die resultate verkry deur die enkel-faktor analise. Die aanvaarbare genetiese parameter skattings verkry in hierdie studie het gelei tot die gevolgtrekking dat die Ile de France geselekteer kan word as teelramme in kruisteel programme. Genetiese parameters was geskat vir vroeë groei eienskappe in die Merino Landskaa ras. REML skattings van geboorte gewig, voor-speen gewig en speen gewig was verkry deur diere modelle in enkel-faktor analises. Die direkte oorerflikheid skatting vir geboorte gewig was 0.23±0.13 met die gebruik van die diere model met additiewe direkte genetiese effekte en ooi permanente omgewings faktore as die enigste ewekansige faktore. Die ooi permanente omewings effek vir geboorte gewig was 0.10±0.07. Direkte oorerflikheid vir voor-speen gewig was 0.36±0.05 en die ooi permanente omgewings effek 0.56±0.03. Speen gewig was geskat deur die gebruik van ‘n diere model wat die direkte additiewe effekte en die ooi permanente omgewings effekte bevat het. Die direkte oorerflikheids skatting vir speen gewig was 0.17±0.03. Maternale genetiese effekte was geskat as 0.02±0.01. Genetiese en fenotipiese tendense is verkry vir vroeë lamgewigte in die Dormer-, Ile de France- en Merino Landskaaprasse. Die eienskappe wat oorweeg is, was geboortegewig, voor-speengewig, speengewig en naspeengewig. Voor-speengewigte was net beskikbaar was vir die Ile de France- en die Merino Landskaap rasse en die na-speense gewigte net vir die Dormerras. Die Dormer het beduidende verbetering vertoon in die fenotipiese en genetiese aspekte vir vroeë lamgewigte gedurende die 17 jaar van evaluasie (1990-2007). Die gemiddelde voorspelde direkte teeltwaarde van speen gewig het met 0.12% per jaar gestyg gedurende die 17- jaar periode. Na-speen gewig het met 0.32% per jaar verbeter. By die Ile de France het ‘n toename in die voorspelde teelwaarde van geboortegewig (0.025% per jaar) voorgekom. Gemiddelde direkte teelwaardes vir voor-speengewig het toegeneem teen ‘n jaarlikse tempo van 0.23% en speengewig het met 1.21% per jaar toegeneem. In die Merino Landskaapras het die voorspelde direkte teelwaarde vir geboortegewig met 0.04% per jaar gedaal, terwyl voor-speen- en speengewigte met 0.36% en 0.10% onderskeidelik toegeneem het. Die tendense was ooglopend gekompromiteer weens probleme met die data struktuur, en a.g.v van die relatief min rekords wat beskikbaar was vir die analise in die ras. Dit was duidelik dat die additiewe genetiese variasie beskikbaar was vir al die vroeë groei eienskappe in al die drie rasse. Alhoewel voldoende genetiese variasie vir wesentlike genetiese vordering beskikbaar was, is daar slegs matige vordering verkry vir al die eienskappe in al drie rasse. Die enigste moontlike uitsondering was speengewig in die Ile de France ras, wat met 1.21 % per jaar gestyg het. Alle veranderinge was minstens in die gewensde rigting. Telers word versoek om data deurlopend en akkuraat aan te teken , aangesien een van die groot tekortkominge met die data van al die rasse ‘n tekort aan deurlopendheid in die indiening van die data aan die NISS was. ‘n Meer verteenwoordigende analise sal uitvoerbaar wees, as daar aan al die bogenoemde aanbeveling voldoen kan word.

Over the last 60 years, grass tetany has been recognised as a significant lethal condition in sheep and cattle.Outcomes from this study include documentation of the likely precursors to grass tetany, ways to recognise these precursors, and long term practices that will enable producers to minimise livestock deaths. The benefit of this research to beef producers is that the environmental circumstances thought to be associated with outbreaks of grass tetany have been identified, along with remedial action that can be taken to prevent deaths occurring.Recommendations to industry on best practice to be adopted by leading producers to minimise outbreaks of grass tetany are made.This study provides an alternate strategy for the management of grass tetany in beef cattle, to the more clinical approaches previously recommended. It is suggested that losses from this economically important metabolic disease can be minimised if management practices of beef cattle producers in eastern Australia can incorporate a more holistic approach to farm management, which takes account of the soil/plant/animal/climate inter-relationships.
Master of Science (Hons)

Thesis (PhD)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: Reproduction and robustness traits are integral in ensuring sustainable, efficient and profitable sheep farming. Increases in genetic gain of reproduction and robustness traits are however, hampered by low heritability coupled with the difficulty in quantification of these traits for traditional selective breeding strategies. The aim of the current study was therefore to identify genomic regions underlying variation in reproduction traits and elucidate quantitative trait loci (QTL) and/or genes associated with reproductive traits. The Elsenburg Merino flock has been divergently selected for the ability to raise multiple offspring and has resulted in a High and a Low line that differ markedly with regard to reproductive output and other robustness traits. The flock thus served as an ideal platform to identify genomic regions subject to selection for reproductive traits. To pinpoint genomic regions subject to selection, a whole-genome genotyping platform, the OvineSNP50 chip, was selected to determine the genotype of more than 50 000 SNPs spread evenly across the ovine genome. The utility of the OvineSNP50 chip was determined for the Elsenburg Merino flock as well as additional South African Merino samples and three other important South African sheep breeds, the Blackheaded Dorper, South African Mutton Merino (SAMM) and the Namaqua Afrikaner. Although genotyping analysis of the Elsenburg Merino flock indicated some signs of poor genotype quality, the overall utility of the genotype data were successfully demonstrated for the South African Merino and the other two commercial breeds, the Dorper and SAMM. Genotyping results of the Namaqua Afrikaner and possibly other indigenous African breeds may be influenced by SNP ascertainment bias due to the limited number of indigenous African breeds used during SNP discovery. Analysis of pedigree, phenotypic records and SNP genotype data of the Elsenburg Merino cohort used in the current study, confirmed that the lines are phenotypically as well as genetically distinct. Numerous putative genomic regions subject to selection were identified by either an FST outlier approach or a genomic scan for regions of homozygosity (ROH) in the High and Low lines. Although annotated genes with putative roles in reproduction were identified, the exact mechanism of involvement with variation in reproduction traits could not be determined for all regions and genes. Putative ROH overlapped with QTL for several reproduction, milk, production and parasite resistance traits, and sheds some light on the possible function of these regions. The overlap between QTL for production and parasite resistance with putative ROH may indicate that several, seemingly unrelated traits add to the net-reproduction and may have been indirectly selected in the Elsenburg Merino flock. A SNP genotyping panel based solely on reproduction traits may therefore be ineffective to capture the variation in all traits influencing reproduction and robustness traits. A holistic selection strategy taking several important traits, such as robustness, reproduction and production into account may as such be a more effective strategy to breed animals with the ability to produce and reproduce more efficiently and thereby ensure profitable and sustainable sheep farming in South Africa.
AFRIKAANSE OPSOMMING: Reproduksie- en gehardheids-eienskappe is noodsaaklik om volhoubare, doeltreffende en winsgewende skaapboerdery te verseker. ‘n Toename in genetiese vordering in reproduksie- en gehardheids-eienskappe word egter bemoeilik deur lae oorerflikhede tesame met die probleme in kwantifisering van hierdie eienskappe vir tradisionele selektiewe diereteelt strategieë. Die doel van die huidige studie was dus om gebiede in die genoom onderliggend tot variasie in reproduksie-eienskappe te identifiseer en die rol van verwante kwantitatiewe eienskap loki (KEL) en/of gene met reproduktiewe eienskappe te bepaal. Die Elsenburg Merinokudde is uiteenlopend geselekteer vir die vermoë om meerlinge groot te maak en het gelei tot 'n Hoë en 'n Lae lyn wat merkbaar verskil ten opsigte van reproduksie-uitsette en ander gehardheids-eienskappe. Die kudde het dus gedien as 'n ideale platform om genomiese areas onderhewig aan seleksie vir reproduksie-eienskappe te identifiseer. Om vas te stel waar genomiese areas onderhewig aan seleksie gevind kan word, is ‘n heel-genoom genotiperingsplatform, die OvineSNP50 skyfie, gekies om die genotipes van meer as 50 000 enkel nukleotied polimorfismes (ENPs) eweredig versprei oor die skaap genoom, te bepaal. Die nut van die OvineSNP50 skyfie is bepaal vir die Elsenburg Merinokudde sowel as addisionele Suid-Afrikaanse Merinos en drie ander belangrike Suid-Afrikaanse skaaprasse, die Swartkop Dorper, Suid-Afrikaanse Vleismerino (SAVM) en die Namakwa Afrikaner. Hoewel genotipe resultate van die Elsenburg Merino kudde sommige tekens van swak genotipe gehalte getoon het, kon die algehele nut van die genotipering resultate vir die Suid-Afrikaanse Merino en die ander twee kommersiële rasse, die Dorper en SAVM, bevestig word. Genotipering resultate van die Namakwa Afrikaner en moontlik ook ander inheemse Afrika rasse kan deur ENP vasstellingspartydigheid beïnvloed word as gevolg van die beperkte aantal inheemse Afrika rasse gebruik tydens ENP ontdekking. Ontleding van stamboom inligting, fenotipe rekords en ENP genotipe data van die Elsenburg Merino-kohort gebruik in die huidige studie, het bevestig dat die lyne fenotipies asook geneties verskil. Talle vermeende genomiese areas onderhewig aan seleksie is geïdentifiseer deur 'n FST uitskieter benadering of deur ‘n genomiese skandering vir gebiede van homogositeit (GVH) in die Hoë en Lae lyne. Hoewel geannoteerde gene met potensiële rolle in reproduksie geïdentifiseer is, kan die presiese meganisme van betrokkenheid by variasie in reproduksie-eienskappe nie bevestig word vir al die gebiede en gene nie. Vermeende GVH oorvleuel met KEL vir 'n paar reproduksie-, melk-, produksie- en parasietweerstand-eienskappe, en werp daarom lig op die moontlike funksie van hierdie gebiede. Die oorvleueling tussen KEL vir produksie en parasietweerstand met vermeende GVH kan daarop dui dat 'n hele paar, skynbaar onverwante, eienskappe bydrae tot net-reproduksie, wat indirek geselekteer mag wees in die Elsenburg Merino-kudde. ‘n ENP genotiperingspaneel uitsluitlik gebaseer op reproduksie-eienskappe mag daarom onvoldoende wees om die variasie in alle eienskappe wat betrekking het op reproduksie- en gehardheids-eienskappe, in te sluit. ‘n Holistiese seleksie strategie wat verskeie belangrike eienskappe, soos gehardheid, reproduksie en produksie in ag neem, mag ‘n meer effektiewe strategie wees om diere te teel met die vermoë om in 'n meer doeltreffende manier te produseer en reproduseer en om daardeur winsgewende en volhoubare skaapboerdery in Suid-Afrika te verseker.

In Graaff-Reinet, domestic livestock farming and springbuck ranching are similar in that they both rely on the rangeland for their sustainability. However, as a consequence of repeated monotonous domestic livestock farming, resulting in compromised biological productivity and diversity, the rangelands have disintegrated. This, unfortunately, has placed the future sustainability of these rangelands and the livelihoods of the local people in an indeterminate state. In recent years, there has been an increasing interest in springbuck ranching for meat production as an alternative to domestic livestock farming in the area following (a) fears of worsening environmental challenges; (b) declining profitability in commercial domestic livestock farming and; (c) growing calls for the sustainable use of these rangelands for the benefit of future generations. The springbuck has emerged as a credible alternative to utilising the rangelands - as opposed to sheep - because of its promise to addressing the above challenges. This is in an attempt to tap into the multitude of benefits that the springbuck possesses (by virtue of being part of the natural capital of the area) that have a potential towards restoring ecological integrity by extenuating some of the detrimental effects of sheep farming on the rangelands and presenting opportunities for diversifying incomes. Yet, despite the general increase in interest, a resistance towards the uptake of springbuck ranching for meat production exists. The main contention is that springbuck meat production cannot out-perform the economic returns of wool sheep farming. This study attempts to address these concerns by investigating the profitability and economic sustainability of converting a sheep farm into a springbuck ranch in Graaff-Reinet. The study uses stochastic simulation to estimate the probability distribution of some key output variables, namely: net cash income, ending cash balance, real net worth and the net present value (NPV) in evaluating the profitability of converting a 5 000ha sheep-dominated farm into a springbuck-dominated ranch under three alternative scenarios. The use of stochastic simulation allows for the incorporation of downside risk associated with the production and marketing of wool, mutton and springbuck meat. The study uses stochastic prices and yields to calculate net returns variability. Incorporating scenario analysis helped to evaluate how alternative wool sheep-dominated and springbuck-dominated combinations would perform based on the probable outcomes of different assumptions in the various scenarios. By applying stochastic efficiency with respect to a function (SERF) criterion to the simulated NPVs, this study compares the profitability of alternative scenarios based on various risk aversion coefficients. The study finds that converting a 5 000ha wool sheep dominated farm into a springbuck dominated ranch could potentially be a more profitable investment than wool sheep farming over a 15 year planning horizon, in Graaff-Reinet. The SERF results indicate that for all scenarios tested, the best strategy of converting a wool sheep dominated farm into a springbuck ranch would be one which comprise a combination of 70% springbuck, 20% mutton and 10% wool production as the likely profitable enterprise mix. Using economic sustainability analysis, the study reveals that because of low costs in springbuck ranching, springbuck meat production enterprises are most likely to be more financially sustainable than wool sheep-dominated enterprises. This suggests that rangeland owners may be better off converting their wool sheep-dominated farms into springbuck-dominated ranches. Thus, as the call for more environmentally benign rangeland utilising economic-ecological systems intensifies, rangeland owners in the Eastern Cape Karoo have a practicable option. At the very least, there exists an option to broaden their incomes whilst promoting ecological restoration with springbuck meat production.

"September 2002" Bibliography: leaves 77-85. Examines the persistence of the yellow-footed antechinus using live trapping in small, remnant patches and strips of forest, to document autecological sata and the investgate occurrence, breeding activity and inter-patch movements. Radio-tracking was conducted to compare home range properties of lactating females in restricted and unrestricted habitat.

The objective of this study was to determine sheep production practices, constraints, flock dynamics, body condition and weight variation in two ecologically different resource-poor communal farming systems of the Eastern Cape Province of South Africa. Mean sheep flock sizes per household were not significantly different between the two ecologically different areas (villages); Gaga (19.0±3.10) and Sompondo (18.3±3.10). Shortage of feed, disease and parasite were reported the most important constraints across the two villages. In both villages, sheep housing was poorly constructed using acacia brushwoods. Fewer farmers owned rams: the rams to ewes ratio for the two villages were 1:20, 1:19 for Gaga and Sompondo, respectively. The low ram: ewe ratios reported suggest that inbreeding might have been reducing productivity of their flocks. There was also uncontrolled breeding due to undefined and mating seasons. Gall sickness, heart water and footrot caused most of the sheep mortalities. Dohne Merinos were the common genotypes in the two villages. Total entrances for each flock were higher (p < 0.05) in hot-dry season and hot-wet season than in other seasons. Most of the entrances were lambs and were born in hot-dry season (September) and cool-dry season (June) for larger flocks (10.90 ± 3.02) and for small flocks (3.65 ± 3.02). High lamb mortalities were experienced in the post-rainy (April) and hot-wet (December) season. There was a significant interaction between season and flock size. Most of the sales occurred in the hot-wet season. Ecological area had significant effect on sheep production potential (p < 0.05) in both flock classes. The average sheep production efficiency (SPE) value for Gaga and Sompondo were 0.50 ± 0.116 and 0.50 ± 0.096 respectively. The SPE for large flock was higher (p < 0.05) by season and flock size. Large flocks had a higher (p < 0.05) SPE values and the SPE ranged from 1.11 ± 0.193 in April, a post-rainy season month to 1.55 ± 0.193 in December, a hot-wet season month. Lamb mortalities constituted the greater part of outflows. High lamb mortalities occurred in hot-wet (December), hot-dry (September) and post-rainy (April) seasons. There was a significant interaction between season and age of sheep on body weight of sheep. Highest (p < 0.05) body weights were recorded in the post-rainy and autumn season in both lambs and ewes. It is therefore very important to come up with affordable interventions which take into play ecological differences of the areas for improved nutritional status of sheep in communal areas which will lead to improved sheep productivity and the poor-resourced farmer human nutritional and livelihood.

Thesis (M. Tech. Agriculture) -- Central University of Technology, Free state, 2012
Low lifetime rearing success and high perinatal mortality have been associated with small pelvic areas of ewes. Ewes with small pelvic areas are more prone to experience dystocia during parturition and high perinatal mortality. It would thus make sense to include pelvic area as criterion in selecting breeding animals (rams) in an attempt to assure bigger pelvic areas in the female progeny as the heritability of pelvic area ranges between 50-60%. The aims of this study were to develop two instruments to accurately measure the pelvic area and rump slope in small stock, to investigate the hindquarter dimensions and to quantify the relationship between a number of easy to measure external body measurements and pelvic dimensions of Dorper sheep. The pelvic meter developed was pre-tested on 90 sheep prior to slaughtering at an abattoir and shortly after slaughter. The correlation between the pre- and post- slaughter measurements was highly significant (P <0.05; r = 0.85). In this study 272 Dorper and White Dorper rams (5-7 months of age) participating in the Northern Cape Veldram project and 332 young Dorper and White Dorper ewes (±12 months of age) from three different breeders were measured. The inside pelvic area was measured trans-rectally. The rams’ pelvic areas were measured five times transrectally, at 40 days intervals between the ages of 223 ± 41 and 385 ± 41 days of age. The height of the pelvis was obtained by measuring the distance between the dorsal pubic tubercle on the floor of the pelvis and the sacrum (spinal column) on the top. The width of the pelvis was measured as the widest distance, between the right and the left shafts of the ilium bones. The pelvic area was calculated using the π (PH/2)*(PW/2) formula. Other linear body measurements (body height, shoulder height, chest depth, forequarter width, hindquarter width, rump length) as well as body weight were taken. The rams’ rump slope was measured in degrees with an instrument that was developed for this purpose, and the ewes’ rump slope was visually scored on a scale from 1-5 with one being very flat and five being very droopy. The overall mean pelvic area of ewes 35.44 ± 4.89 cm2 and those of the rams 28.22 ± 3.21 cm2 differed with 7.22 cm2. Stud ewes recorded significantly larger (P <0.05) pelvic areas (37.38 ± 4.3 cm2) than commercial ewes (33.92 ± 3.77cm2). Results indicated that there are no significant correlations between pelvic dimensions and other body measurements considered in this study, indicating the need to measure pelvic area directly. Both the pelvic meter and rump slope meter, specially developed for this study, proved to be accurate and relatively practical to use in Dorper sheep.

This thesis reports an investigation of the double-nesting phenomenon, a unique pattern of anomalous, protracted breeding, reported in seabirds from mid-western and south-western Australia. In particular, it deals with the Crested Tern Sterna bergii Lichtenstein and the Silver Gull Larus novaehollandiae Stephens, two related lariform seabirds which nest in sympatry, and possibly associatively, in the Fremantle area of south-western Australia. Both species have protracted breeding seasons in the study area, superficially similar in timing and duration, and therefore provided useful subjects for a comparative study of their breeding biology. From 1979 to 1984, the reproductive cycles of the two species were examined in detail. Emphasis was placed on determining the timing and periodicity of breeding, both at the population and at the individual level, and on determining those factors involved in the ’proximate' control of the reproductive cycle. The results showed that, despite superficial similarities in breeding seasons, there were fundamental differences in biology between the two species, particularly with respect to the influence of environmental ‘proximate’ factors. These contrasts are interpreted primarily in terms of the different evolutionary origins of the two species, although the various constraints on the reproductive cycle, which are imposed by their differing nesting adaptations and feeding behaviour, are also discussed. Models of the reproductive cycle at the individual level, and of the breeding season(s) at the population level, are developed for both species. Using data for some other seabird species breeding in south-western Australia, the Crested Tern and Silver Gull models are incorporated in a general explanation of ‘double-nesting’. The views presented not only provide some insight into a unique, localised phenomenon but should also lead to a re-examination of conventional ideas about seabird breeding seasons generally.

From 1979 to 1982, a study was conducted in the Kojonup district of Western Australia on the provision of veterinary services to the sheep industry at the farm level. The objectives of the study were: (i) To examine and evaluate management and other factors affecting sheep enterprise productivity. (ii) To develop guidelines and methodologies for integrated health and production programmes applicable to sheep farms. (iii) To assess the economic impact of sheep health and production programmes over a number of years by reference to control properties. (iv) To examine in detail certain of the procedures incorporated into planned sheep health and production programmes. In the last two decades international consensus has been reached that veterinary services to the livestock industries are best provided by planned animal health and production programmes. The nature and development of these programmes was reviewed as well as the history and principles of farm management advisory services in Australia. As a result of this review, a model service for the sheep industry was planned. First a farm data base was created. This enabled the evaluation of the physical and financial effects of the health and production programmes and facilitated the identification of associations between inputs and outputs. By reference to data from 36 farms over 4 years, key factors associated with sheep enterprise profitability were identified. The sheep enterprise gross margin per hectare was found to be highly correlated (p < 0.01) with gross margin per dry sheep equivalent, livestock and wool income per hectare, percent of income derived from livestock profit, lamb marking percentage, adult sheep wool per head, wool per hectare and winter stocking rate. A significant degree of correlation (p < 0.05) was obtained with time of lambing (June or earlier compared with July or later) and percentage of sheep losses (negative correlation). Following a year of monitoring farm performance in 1979, a series of veterinary professional visits were instigated on 18 properties (the experimental group) during the period 1980 to 1982. The timing and content of these visits was based on health and production factors of economic importance identified and tailored to sheep management systems. The main professional inputs were as follows: November to February - examination of rams for breeding soundness, review of joining programme, monitoring and planning parasite control programme, budgeting of supplementary feed requirements and bodyweighing of sheep. March to July - sheep and pasture inspection and evaluation, bodyweight monitoring, collection of farm production data for comparative performance analysis, pregnancy diagnosis and monitoring of parasite control. August to October - assessment of pasture quality and quantity, analysis of lambing data, review of farm performance and planning for next season. The performance of the experimental farms over the years 1979-1982 was compared with that of a similar group of 18 control farms. The indices used in the comparison were derived from the farm data base, with the variable gross margin per hectare being used as the major indicator of sheep enterprise performance. From 1980 there was a divergence between the groups in favour of the experimental group, reaching significance (p < 0.05) in 1981. During the three years measured, the programmes yielded a mean benefit-cost ratio of 714 per cent, and when the difference between the groups was standardised for farm area, a mean benefit per farm attributable to the programmes was $3992.00. The mean increase in profitability over the three years measured was 8.6 per cent per farm. Considered areas of loss common to many farms at the commencement of the programmes were: below optimum soil fertility and stocking rate; inappropriate time of lambing; inaccurate selection of sheep for slaughter; lack of objectivity in selection of breeding stock; and inappropriate supplementary feeding. Consequently these were major areas of input in the programmes applied. Consequent upon the needs of the sheep enterprises involved, two specific technologies were developed as part of the project. A facility was designed to enable field application of ultrasound pregnancy testing, using the "Scanopreg" machine, and this technique compared with the use of harnessed rams to detect non-pregnant ewes. For 2691 ewes in 8 flocks, the harnessed rams detected on average 55.8 per cent of the ewes diagnosed as non-pregnant by the ultrasound technique. Other advantages of the ultrasound technique are discussed, and the economics of pregnancy testing by this method were evaluated. In the area of supplementary feeding, non-protein nitrogen was utilised to improve the value of oats as a supplement to sheep grazing wheat stubble and as an additive to oat straw in a total maintenance ration for sheep. Sheep grazing wheat stubble and receiving 200 grams per head per day of oat grain treated with 2 per cent urea, maintained bodyweight over a 6 week period compared with a weight loss of 2.9 kg in sheep receiving the same quantity of untreated oat grain. This difference was significant (p < 0. 05). When oat straw was fed ad lib. To weaner sheep in combination with 100 grams per head per day of oats, straw treatment with 2 per cent urea significantly reduced weight loss over 2 months from 2.9 kg to 0.4 kg (p< 0.01). The documented results and subsequent farmer acceptance of this model health and production programme indicate that a practical means of productivity improvement within the Australian sheep industry has been developed.

Assessment of trophic interactions between increasing populations of New Zealand fur seals (Arctocephalus forsteri) and fisheries in southern Australia is limited due to a lack of species specific demographic data and an understanding of the factors influencing population growth. To establish species specific demographic parameters a cross-sectional sample of New Zealand fur seal females (330) and males (100) were caught and individually-marked on Kangaroo Island, South Australia between 2000 and 2003. The seals were aged through examination of a postcanine tooth, which was removed from each animal to investigate age-specific life-history parameters. Annual formation of cementum layers was confirmed and accuracy in age estimation was determined by examination of teeth removed from individuals of known-age. Indirect methods of assessing reproductive maturity based on mammary teat characteristics indicated that females first gave birth between 4-8 years of age, with an average age at reproductive maturity of 5 years. Among reproductively mature females, age-specific reproductive rates increased rapidly between 4-7 years of age, reaching maximum rates of 70-81% between 8-13 years, and gradually decreased in older females. No females older than 22 years were recorded to pup. Age of first territory tenure in males ranged from 8-10 years. The oldest female and male were 25 and 19 years old, respectively. Post-weaning growth in females was monophasic, characterised by high growth rates in length and mass during the juvenile growth stage, followed by a gradual decline in growth rates after reproductive maturity. In contrast, growth in males was biphasic and displayed a secondary growth spurt in both length and mass, which coincided with sexual and social maturation, followed by a rapid decline in growth rates. Age-specific survival rates were high (0.823-0.953) among prime-age females (8-13 yrs of age) and declined in older females. Relative change in annual pup production was strongly correlated with reproductive rates of prime-age females and adult female survival between breeding seasons.

Bibliography: leaves 325-341. Skin and fleece measurements were recorded at different ages for both male and female sheep from the Turretfield Merino Resource Flock and used to estimate the heritability of each trait and the phenotypic and genetic correlations among and between the skin and fleece traits. Generally, the heritability of each trait was high, which indicates that both the fleece and skin traits should respond well to selection.

Includes bibliographical references (leaves 325-341).
xxvii, 341 leaves : ill. ; 30 cm.
Skin and fleece measurements were recorded at different ages for both male and female sheep from the Turretfield Merino Resource Flock and used to estimate the heritability of each trait and the phenotypic and genetic correlations among and between the skin and fleece traits. Generally, the heritability of each trait was high, which indicates that both the fleece and skin traits should respond well to selection.
Thesis (Ph.D.)--University of Adelaide, Dept. of Animal Science, 2001

Includes bibliographical references (leaves 143-165)
xiii, 168 leaves : ill. (some col.) ; 30 cm.
Reports on studies undertaken to examine the physiological basis of the known ability of lupin grain to increase ovulation rate in the ewe.
Thesis (Ph.D.)--University of Adelaide, Dept. of Animal Sciences, Waite Agricultural Research Institute, 1989

Bibliography: leaves 300-321.
xiii, 321 leaves [11] leaves of plates : ill. (some col.) ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
This thesis aims to extend knowledge and understanding of the seed-seedling dynamics and productivity of annual Medicago pastures. In particular this study concentrates on the impact of grazing by sheep on Medicago pasture herbage and seed production and sheep body weight gains.
Thesis (Ph.D.)--University of Adelaide, Depts. of Agronomy and Farming Systems and Plant Science, 1997

Bibliography: leaves 259-291.
xiii, 291 leaves, [8 leaves of col. plates] : ill. (some col.) ; 30 cm.
Thesis (Ph.D.)--University of Adelaide, Faculty of Agricultural and Natural Resource Sciences,1994

This study investigates early life stages of the southern sea garfish (Hyporhamphus melanochir) and their association with seagrass in Gulf St Vincent, South Australia. The overall aims were to identify and describe the early life stages of H. melanochir and to explore the possible relationship(s) between these life stages and seagrass habitat with the emphasis on seagrass as a requirement for spawning or as a food source. The reproductive biology of female H. melanochir from the commercial fishery was assessed by microscopic examination of ovaries, oocyte size distributions, gonadosomatic indices, and macroscopic ovarian stages. Five stages of oocyte development were identified and described: perinucleolar, yolk vesicle, yolk globule, migratory nucleus and hydrated. A coherence between histological and whole oocyte descriptions is demonstrated. Hyporhamphus melanochir are characterised as multiple spawners with group-synchronous oocyte development and indeterminate fecundity. A protracted spawning season from October to March was indicated by the occurrence of ripe ovaries and increases in gonadosomatic index. Females reach sexual maturity at 193 mm standard length, and batch fecundity ranged from 201-3044 oocytes depending on fish size. Spawning shoals are segregated by sex, as indicated by commercial samples, with a biased female-to-male ratio of 4.5:1 during the spawning season (1.2:1 during the non-spawning season). In addition, features of the oocyte surface were closely examined, which revealed that the filaments on the chorion of the hydrated oocyte are adhesive. These adhesive filaments presumably allow the fertilised egg to become attached to vegetative substrate by adhesion and/or entanglement. H. melanochir larvae were discriminated from another hemiramphid species, river garfish (H. regularis), which is also known to occur in the study area, based on species-specific amplification of part of the mitochondrial control region using a multiplex polymerase chain reaction (PCR) assay. The species were easily discerned by the number and distinct sizes of PCR products [H. melanochir, 443 bp; river garfish (H. regularis), 462 and 264 bp]. Although based on a single gene, this molecular method will correctly identify the species of individuals in at least 96% and 94% of tests for H. melanochir and H. regularis, respectively. Subsequent to verifying the identification of species by molecular discrimination, the larval development of H. melanochir and H. regularis were described. Larvae of H. melanochir and H. regularis had completed notochord flexion at hatching and are characterized by their elongate body with distinct rows of melanophores along the dorsal, lateral and ventral surfaces; small to moderate head; heavily pigmented, long straight gut; persistent preanal finfold; and extended lower jaw. Fin formation occurs in the sequence: caudal, dorsal and anal (almost simultaneously), pectoral, pelvic. Despite the similarities between both species and among hemiramphid larvae in general, H. melanochir larvae are distinguishable from H. regularis by: having 58-61 vertebrae (v. 51-54 for H. regularis); having 12-15 melanophore pairs in longitudinal rows along the dorsal margin between the head and origin of the dorsal fin (v. 19-22 for H. regularis); and the absence of a large ventral pigment blotch anteriorly on the gut and isthmus (present in H. regularis). A logistic regression analysis of body measurements also revealed interspecies differences in the combined measurements of eye diameter and pre-anal fin length. Both species can be distinguished from morphologically similar larvae found in southern Australia (other hemiramphids and a scomberosocid) by differences in meristic counts and pigmentation. Hyporhamphus melanochir larvae were successfully collected throughout Gulf St Vincent using a neuston net; however, attempts to sample eggs were unsuccessful. Abundances of larvae in the gulf averaged 4.8 and 12.3 larvae 1000⁻ ² of surface water in December 1998 and December 2000, respectively. Larvae exhibit fast growth, as indicated by otolith growth increments, with backcalculated spawning dates falling within the October-March spawning season. Spatial analysis of larval distributions revealed a positive spatial autocorrelation, i.e. non-randomness or clustering of similar abundance values. Most larvae were found in the upper region of the gulf, and the prevalence of seagrass habitat throughout this region supports the view that the demersal eggs of H. melanochir become attached to seagrass and/or algae following spawning. A gyre in waters of the upper gulf, influenced by prevailing southerly winds, the Coriolis effect, and land boundaries, may explain retention of larvae. The importance of seagrass beds to H. melanochir spawning is also supported by anecdotal evidence and available literature on eggs of other Beloniformes, which are also demersal and attach to marine plants. Dual stable isotope analysis (δ¹³ and δ¹⁵N) of larval, juvenile and adult H. melanochir and several potential food sources from the Bay of Shoals was carried out to estimate the importance of zosteracean seagrass towards the assimilated diet of H. melanochir. Although the diet of H. melanochir larvae is probably planktonivorous, their isotopic signatures partly reflect the parental diet due to the influence of pre–existing tissue in addition to growth. According to mixing model calculations, the signatures of juveniles can be explained by a diet consisting of 23–37% Zostera, 0–10% Halophila and the remainder zooplankton, whilst the diet of adults consists of 53–58% Zostera and the remainder zooplankton. These findings indicate an increasing dependence upon Zostera with growth of H. melanochir. The results of this study enhance the completeness of our understanding of the fisheries biology and ecology of H. melanochir. Significant contributions are provided in reproductive biology and larval biology, seagrass beds (in combination with mixed algae) are demonstrated to be an important habitat for spawning, and Zostera seagrass is shown to be a necessary food source in the diet of juveniles and adults.
Thesis (Ph.D.)-- University of Adelaide, School of Earth and Environmental Sciences, 2005.

This study investigates early life stages of the southern sea garfish (Hyporhamphus melanochir) and their association with seagrass in Gulf St Vincent, South Australia. The overall aims were to identify and describe the early life stages of H. melanochir and to explore the possible relationship(s) between these life stages and seagrass habitat with the emphasis on seagrass as a requirement for spawning or as a food source. The reproductive biology of female H. melanochir from the commercial fishery was assessed by microscopic examination of ovaries, oocyte size distributions, gonadosomatic indices, and macroscopic ovarian stages. Five stages of oocyte development were identified and described: perinucleolar, yolk vesicle, yolk globule, migratory nucleus and hydrated. A coherence between histological and whole oocyte descriptions is demonstrated. Hyporhamphus melanochir are characterised as multiple spawners with group-synchronous oocyte development and indeterminate fecundity. A protracted spawning season from October to March was indicated by the occurrence of ripe ovaries and increases in gonadosomatic index. Females reach sexual maturity at 193 mm standard length, and batch fecundity ranged from 201-3044 oocytes depending on fish size. Spawning shoals are segregated by sex, as indicated by commercial samples, with a biased female-to-male ratio of 4.5:1 during the spawning season (1.2:1 during the non-spawning season). In addition, features of the oocyte surface were closely examined, which revealed that the filaments on the chorion of the hydrated oocyte are adhesive. These adhesive filaments presumably allow the fertilised egg to become attached to vegetative substrate by adhesion and/or entanglement. H. melanochir larvae were discriminated from another hemiramphid species, river garfish (H. regularis), which is also known to occur in the study area, based on species-specific amplification of part of the mitochondrial control region using a multiplex polymerase chain reaction (PCR) assay. The species were easily discerned by the number and distinct sizes of PCR products [H. melanochir, 443 bp; river garfish (H. regularis), 462 and 264 bp]. Although based on a single gene, this molecular method will correctly identify the species of individuals in at least 96% and 94% of tests for H. melanochir and H. regularis, respectively. Subsequent to verifying the identification of species by molecular discrimination, the larval development of H. melanochir and H. regularis were described. Larvae of H. melanochir and H. regularis had completed notochord flexion at hatching and are characterized by their elongate body with distinct rows of melanophores along the dorsal, lateral and ventral surfaces; small to moderate head; heavily pigmented, long straight gut; persistent preanal finfold; and extended lower jaw. Fin formation occurs in the sequence: caudal, dorsal and anal (almost simultaneously), pectoral, pelvic. Despite the similarities between both species and among hemiramphid larvae in general, H. melanochir larvae are distinguishable from H. regularis by: having 58-61 vertebrae (v. 51-54 for H. regularis); having 12-15 melanophore pairs in longitudinal rows along the dorsal margin between the head and origin of the dorsal fin (v. 19-22 for H. regularis); and the absence of a large ventral pigment blotch anteriorly on the gut and isthmus (present in H. regularis). A logistic regression analysis of body measurements also revealed interspecies differences in the combined measurements of eye diameter and pre-anal fin length. Both species can be distinguished from morphologically similar larvae found in southern Australia (other hemiramphids and a scomberosocid) by differences in meristic counts and pigmentation. Hyporhamphus melanochir larvae were successfully collected throughout Gulf St Vincent using a neuston net; however, attempts to sample eggs were unsuccessful. Abundances of larvae in the gulf averaged 4.8 and 12.3 larvae 1000⁻ ² of surface water in December 1998 and December 2000, respectively. Larvae exhibit fast growth, as indicated by otolith growth increments, with backcalculated spawning dates falling within the October-March spawning season. Spatial analysis of larval distributions revealed a positive spatial autocorrelation, i.e. non-randomness or clustering of similar abundance values. Most larvae were found in the upper region of the gulf, and the prevalence of seagrass habitat throughout this region supports the view that the demersal eggs of H. melanochir become attached to seagrass and/or algae following spawning. A gyre in waters of the upper gulf, influenced by prevailing southerly winds, the Coriolis effect, and land boundaries, may explain retention of larvae. The importance of seagrass beds to H. melanochir spawning is also supported by anecdotal evidence and available literature on eggs of other Beloniformes, which are also demersal and attach to marine plants. Dual stable isotope analysis (δ¹³ and δ¹⁵N) of larval, juvenile and adult H. melanochir and several potential food sources from the Bay of Shoals was carried out to estimate the importance of zosteracean seagrass towards the assimilated diet of H. melanochir. Although the diet of H. melanochir larvae is probably planktonivorous, their isotopic signatures partly reflect the parental diet due to the influence of pre–existing tissue in addition to growth. According to mixing model calculations, the signatures of juveniles can be explained by a diet consisting of 23–37% Zostera, 0–10% Halophila and the remainder zooplankton, whilst the diet of adults consists of 53–58% Zostera and the remainder zooplankton. These findings indicate an increasing dependence upon Zostera with growth of H. melanochir. The results of this study enhance the completeness of our understanding of the fisheries biology and ecology of H. melanochir. Significant contributions are provided in reproductive biology and larval biology, seagrass beds (in combination with mixed algae) are demonstrated to be an important habitat for spawning, and Zostera seagrass is shown to be a necessary food source in the diet of juveniles and adults.
Thesis (Ph.D.)-- University of Adelaide, School of Earth and Environmental Sciences, 2005.

M.Sc.
The amount of allozyme variation within, and the extent of genetic differentiation between, 19 sheep breeds from southern Africa were determined by six enzyme coding loci. Another eight enzyme coding loci were analyzed for five breeds. Between 55 and 66.67% of the protein coding loci were polymorphic (95% criterion) in all the breeds, except for the Namaqua sheep that were less polymorphic (33.33%). Values of 1.67 to 2.5 were obtained for the mean number of alleles per locus and average heterozygosities per locus was between 16.6 to 35.9%. The allelic constitution particularly at the transferrin (TF) locus varied appreciably for the different breeds. For example, the TF*H allele was exclusively noted in the Dormer sheep and the TF*G allele was found in the Afiino, Van Rooy, Border Leicester, Blackhead Persian and Skilder-Persian breeds. The only polymorphic breeds at the albumin locus were the South African Mutton Merino and Van Rooy breeds. The allelic constitution at the other polymorphic loci was similar for the breeds, but the allele frequencies of the South African Merino differs from Merino breeds in other countries at the TF locus. Unbiased genetic distance values were the smallest between the Dorper and Dormer breeds and the largest between the Romenof and Blackhead Persian breeds, and the mean genetic distance between the 19 breeds was 0.067. The mean amount of differentiation among the breeds relative to ' the limiting amount under complete fixation (F st) was calculated at 0.123, which is an indication of small genetic differentiation between the breeds studied. However, this , statistic is not reflected by the allele distribution that was not identical for 25 breed pairs (15%) of the total (171) at all the genetic blood systems studied. None of the breed pairs showed identical allele distributions at all the loci studied for at least one locus differed at each breed pair compared. Random amplified polimorphic DNA's gave no consistent or repeatable results. The results of the allozyme study presents the first study of the current genetic characterization of the different southern African sheep breeds.

This thesis challenges the constitutive and taken-for-granted assumptions of the current dominant administrative rationalist discourse of wild dog management and control (WMDC) in New South Wales (NSW), Australia. It asks: To what extent can conflicts over WDMC in NSW be understood in terms of contending discourses and what does that imply for policy legitimacy? It isolates the storylines that emerged from substantial empirical research and examines, if and how, these storylines contributed to the dominant discourse of administrative rationalism. From the beginning of white settlement of NSW, the State and farm families worked in concert to achieve the eradication of wild dogs and dingoes. From the 1960s, however, a significant discursive turn occurred in WDMC. This occurred as a result of the contending discourses of environmentalism, ecological science, animal welfare and biosecurity. These discourses collectively afforded new meanings to dingoes, wild dogs and WDMC. Concurrently, the State drove this discursive turn through a discourse of administrative rationalism. From 1995 until 2011, a period of successive NSW Labor Governments, the State further consolidated this discursive approach. It reified 'experts' and legislatively empowered public land managers to inform, shape and promulgate the dominant discourse of WDMC through the promotion of a 'best practice' model. Within this model the individual knowledges and experiences of farm families of WDMC were subject to empirical measurement, the interpretations of public land managers and the corroboration of continuing ecological studies. The entry of new social actors closely linked to Government who actively promoted 'new' innovations and technologies in WDMC further distilled the dominance of the administrative rationalist discourse. However, the legitimacy of this approach was forcefully challenged by a growing sense of crisis in the 'Bush.' This was driven by farm families who were directly affected by the lack of WDMC on public lands, the increasing numbers of wild dogs and the devastating effect this was having on the lives of farm families. This reality was exploited mercilessly for its political capital by all political parties. Successive NSW Labor Governments consistently reiterated in storylines its financial largesse in WDMC to give legitimacy to its discursive approach. These storylines of financial expenditures in real terms however are difficult to substantiate. Ironically, the success of the administrative rationalist discourse was dependent on the continued involvement of farm families in a public planning process which pivoted on their acquiescence to a discourse that subordinated their concerns and, at the same time, relied on the widespread adoption of this model by farm families across NSW. This has proved deeply problematic. Overwhelmingly, at public WDMC meetings farm families rejected the State's reliance on administrative rationalism and a chorus of voices reflected the significant gap that existed between the political and policy rhetoric of WDMC and the lived reality. Nevertheless, successive attempts by farm families have so far failed to dislodge the dominant discourse of WDMC.

Examines the persistence of the yellow-footed antechinus using live trapping in small, remnant patches and strips of forest, to document autecological sata and the investgate occurrence, breeding activity and inter-patch movements. Radio-tracking was conducted to compare home range properties of lactating females in restricted and unrestricted habitat.
Thesis (M.App.Sc.) -- University of Adelaide, Dept. of Animal Science, 2002

After European settlement, Australian rangelands especially in South Australia underwent significant changes because of the main land use of pastoralism. Many studies have revealed that the plant communities are negatively effected by herbivory mainly by sheep. The main aim of this study is to separate the different effects of sheep, rabbits and kangaroos. This was examined by survey supported by experimental and modelling research. A 32,000 km² area previously surveyed by Tiver and Andrew (1997) in eastern South Australia was re-surveyed to monitor populations of perennial plant species at sites of various intensity of grazing by sheep, rabbits and kangaroos (goats populations are low in the study area), the most important vertebrate herbivores. Plant population data were collected in both sheep paddocks and historically ungrazed by sheep (road reserves) by using the Random Walk method and analyzed using Generalized Linear Modelling (GLM) to separate the effects of sheep and rabbits on plant regeneration and their regeneration in response to grazing. These data were also compared to similar data collected by Tiver and Andrew in 1992 (1997) to ascertain if the reduction in rabbit numbers through introduction of RCV had allowed increased regeneration. Regeneration of many species inside paddocks were negatively affected and species in roadside reserves neither did not significantly increase from 1992 to 2004. However, some species showed increase of populations in spite of sheep grazing, with some species being less susceptible than others. This research also indicates kangaroo grazing impact on some plant species. Reduction in rabbit numbers following the 1995 release of calicivirus has not been effective in restoring regeneration. Another experiment was conducted at Middleback Field Station near Whyalla to identify herbivore grazing pressure on the arid zone plant species Acacia aneura using unfenced, sheep fenced and rabbit fenced grazing exclosures. This experiment was set up with seedlings in exclosures, ten replicates of each treatment, at plots four different distances from the watering point to identify the survivorship of seedlings. Data were collected by recording canopy volumes of seedling over an 18 month period and analyzed by Residual Maximal Likelihood (REML). Seedlings both near and far from the watering point were severely effected by large herbivores, either sheep, kangaroos or both, and in a separate experiment kangaroo grazing effects on the seedling were also identified. Seedlings browsed by the rabbits were recovered better than the seedlings grazed by the large herbivores. Decreasing kangaroo activities has been noticed when the rabbit movements increased. Computer modelling was conducted to predict the future plant population structure over 500 years using a matrix population model developed by Tiver et al. (2006) and using data collected in the survey as a starting point. Extinction probabilities of populations of Acacia aneura near watering points, far from watering points and under pulse grazing scenarios were compared. Sheep grazing was found to cause eventual extinction of populations in all parts of sheep paddocks. Together, the results indicate that sheep are the major herbivore suppressing regeneration of perennial plant species. Kangaroo and rabbits have an identifiable but lesser effect. The results have implications for conservation and pastoral management. To achieve ecological sustainability of arid lands a land-use system including a network of reserves ungrazed by sheep and with control of both rabbit and kangaroo numbers will be required.

Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library.
Transient salinity in soils is characterised by high concentrations of salts in the subsoil. Durum wheat (Triticum turgidum L. Var. durum) is less tolerant of transient salinity than locally developed bread wheat (Triticum aestivum) varieties, and this results in reliable durum production being restricted to relatively unaffected soils. Field trials were conducted to assess the relative impact of transient salinity, boron toxicity and bicarbonate on crop production and highlighted the importance of combining tolerance to all three subsoil constraints into varieties intended for widespread adoption; and if the area of durum production is to be expanded. The Na exclusion locus from the landrace Na49 was found to improve the adaptation of durum to sites affected by transient salinity and is now being intogressed into a wide range of breeding material.
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Thesis (Ph.D.) -- University of Adelaide, School of Agriculture and Wine, 2005

Includes bibliographical references (leaves 188-217) Insulin-like growth factor-I circulates at high concentrations in blood, mainly complexed with IGF-binding proteins. The main objective of the thesis is to determine the general role played by plasma IGF-binding proteins in the regulation of IGF transfer from blood to tissues.

Research Doctorate - Doctor of Philosophy (PhD)
The Earth is experiencing a period of mass extinction due to human development and expansion (Wake & Vredenburg 2008). It has been estimated that 866 animal, plant, fungi and protist species have become extinct in recent history, and 25,821 species were declared either Critically Endangered, Endangered or Vulnerable in 2017 (IUCN 2017). Causal agents of population declines and biodiversity loss include climate change, land clearing, habitat modification and the introduction of exotic competitor or predator species (Vitousek et al. 1997) and disease (Skerratt et al. 2007) which affect species from global to local scales. The magnitude of species loss and threat of further extinctions has caused worldwide attention, instigating efforts to identify and conserve species at risk (Redford & Richter 1999). Species management programs typically aim to identify causal agents of decline, assess species requirements for survival and reproduction and understand population proce sses so that informed decisions can be made to reverse population declines. An important step in this process is gaining an understanding of the factors which affect species distribution (Guisan et al. 2013; Noss et al. 1997). Conservation programs often aim to understand an animal’s distribution by identifying what constitutes habitat. Factors commonly examined include abiotic and biotic attributes of the landscape including available shelter and food, as well as an animal’s interaction with heterospecifics (Campomizzi et al. 2008). In the instance that these factors or interactions correlate with species presence or abundance either positively or negatively, it is assumed that these factors are actively selected for or avoided (Batt 1992). However, additional behavioural factors can affect distribution, such as attraction to (Ahlering et al. 2010) or avoidance of conspecifics (same species) (Keren-Rotem et al. 2006; Stamps 1983), causing strong aggregations or segregation of animal distribution over a landscape, respectively. Despite the influence of these factors on distribution, conspecific attraction and avoidance are not commonly considered by conservation programs when attempting to understand, predict and alter species distributions (Campomizzi et al. 2008). As animals experiencing conspecific attraction or avoidance may deviate from the correlation model assumed by habitat selection, research programs aimed at assisting endangered species cannot afford to ignore conspecific interactions (Manly et al. 2009). A last resort for conservation initiatives is breeding animals in captivity, creating or restoring habitat and translocating animals back into populations that are experiencing population decline or have become locally extinct. Current research in conservation biology has focused on identifying and assessing animal behaviour which can limit the success of conservation initiatives such as; multi-spatial-level habitat selection (McGarigal et al. 2016), conspecific attraction (Campomizzi et al. 2008) and mate selection within captive breeding (Chargé et al. 2014a; Chargé et al. 2014b). As these factors influence species distribution and survival, they therefore affect the success of habitat construction programmes and the persistence of naturally occurring or translocated populations. Amphibians are a globally threatened taxon with 33 extinct species and 2,100 species declared either critically endangered, endangered or vulnerable (IUCN 2017). Factors causing amphibian decline include the human facilitated spread of chytrid fungus (Batrachochytrium dendrobatidis) (Skerratt et al. 2007), global climate change, introduced species as well as habitat loss and modification (Brown et al. 2012; Stuart et al. 2004). Considerable research has been undertaken on causal agents of decline, along with understanding population processes and habitat requirements that affect the persistence of populations (Wake & Vredenburg 2008). Despite the fact that many amphibian species show signs of conspecific attraction and/or avoidance, the influence of conspecific interactions on spatial distribution and subsequent declines of amphibians is under-investigated. This current research project explores the potential for particular behaviours which may influence species distribution and the success of habitat creation and translocation programmes for the green and golden bell frog (Litoria aurea). For the first research paper, I assessed conspecific call attraction in L. aurea. Over a landscape, animal distributions can be skewed as a result of conspecific attraction and aggregation. This can hinder habitat restoration and creation programmes as species may fail to colonise available habitat, despite its suitability. It has been noted from past research that L. aurea uses particular habitat and has distributional traits which suggest the presence of conspecific attraction, and using speakers playing calls can successfully attracted L. aurea at short distances, forming new aggregations (James et al. 2015: Attachment 1). In the first research chapter, I aimed to use speaker systems playing calls to manipulate the landscape distribution of L. aurea. I placed a stand with a speaker playing call broadcast in a treatment waterbody (T), a stand with no calls broadcasted as a manipulative control (MC) and no stand or speakers as a control (C). This design was replicated in five areas on Kooragang Island, Australia, and waterbodies were surveyed to measure changes in abundance and calling over two and a half breeding seasons. We found that speaker introduction did not increase abundance or calling at T relative to MC and C. We did, however, find that the length of time males called was longer at T, compared to MC and C. As the length of calling time may be extended using conspecific call broadcast , provision of conspecific stimulation at translocation sites may improve breeding activity and retention of the population post-release by reducing dispersal. For the second research chapter, I assessed habitat selection of L. aurea. The site selection of breeding individuals is a crucial component of a species habitat selection and can help to direct conservation programmes. However, very little is known about the microhabitat selection of calling male L. aurea. This study aimed to distinguish if male aggregations are associated with specific habitat features within a waterbody and describe their use of available habitat structures. Within waterbodies we compared calling locations relative to non-calling locations for water variables (temperature, salinity, dissolved oxygen), microclimate (temperature, humidity, average and maximum wind speed) and habitat (percentage coverage of water, ground, emergent vegetation and floating vegetation). Overall, males were associated with lower salinity and higher dissolved oxygen, higher percentage coverage of emergent vegetation and bare ground, and low percentage coverage of open water. Males were most commonly found in the water floating between or beside emergent vegetation or perched on emergent vegetation above water level. This suggests that males may select habitat to protect themselves from predators, or for breeding; providing appropriate vegetation, dissolved oxygen and salinity for embryo and tadpole development. This provides supportive information for previous studies on habitat selection, indicating what habitat is preferred by breeding males to improve monitoring, habitat creation and rehabilitation. For the third research chapter, I assess a habitat construction programme. Habitat creation programmes are often used to compensate for the loss of habitat for endangered species, with varying results. I describe an early stage wetland construction programme implemented for L. aurea on Ash Island, NSW Australia. Seven ephemeral (flooding) and two permanent waterbodies were constructed near an existing population. The wetland was designed to increase landscape aquatic habitat, based on adaptive management learnings from past research. In this study, I assess the initial use of this habitat by L. aurea, and initial findings on the design suitability. Surveys in constructed wetlands and in the broader Kooragang area showed that L. aurea rapidly colonised and called at constructed ephemeral wetlands but not permanent wetlands. The chorus size in constructed wetlands was large in comparison to other populations in coastal NSW, and a range of other frog species also bred onsite. Female L. aurea used a nearby remnant wetland (adjacent to the constructed wetlands), and used different habitat to males. Similar habitat use variation between sexes was reflected in the broader population. Most male and female L. aurea captured on Ash Island were under 12 months of age, and body condition in the constructed wetlands was higher than in the broader population. Waterbody design successfully protected waterbodies from overland flooding, and ephemeral waterbodies dried, which suggests the drying regime may protect the constructed habitat long-term from infestation of predatory fish. Elevated salinity from ground water in permanent waterbodies (intended to ameliorate chytrid disease in the landscape) was higher than anticipated and requires further monitoring. It is hoped that this programme may help guide other conservation projects creating habitat for amphibians under threat. For the fourth research paper, I assess sexual selection in L. aurea. As a conservation strategy for L. aurea, captive breeding programmes supplement at-risk populations and translocate individuals to their former ranges. However, breeding programmes are undertaken with very little information on sexual selection and its exclusion can reduce the fitness of released animals. The aim of the fourth study was to assess whether forms of sexual selection occur for L. aurea to inform captive breeding programmes. In the wild I studied mate selection. Firstly, we aimed to assess if the size and body condition of amplexing individuals (grasping to breed), differed from other individuals in the population as an indication of female sexual selection or male-male competition. Secondly, we investigated if male and female amplexing pairs were size correlated as an indicator of size assortative mating, and thirdly we made observations on behavioural interactions in the breeding waterbody to complement the analysis. In Whangarei, New Zealand, we captured L. aurea over 4 survey nights, undertaking capture-mark-recapture and measuring morphometrics of snout vent length (SVL), right tibia length (RTL) and weight, calculated body condition. We compared the SVL, RTL and weight of breeding individuals to non-breeding individuals and found that amplexing males were larger with better body condition, however, female size did not differ. Male-female pairs were not size assortative and aggressive interactions were recorded between males. Larger male size may be an indicator of either female selectivity or larger-male mating advantage through aggressive interactions. As removal of sexual selection in captive breeding programmes can reduce fitness and place conservation initiatives at risk, I recommend incorporating sexual selection by placing multiple males of varying sizes in breeding tanks with females to facilitate female selectivity or larger-male mating advantage. Based on the results of the current studies, I have identified possible constraints on the use of conspecific attraction for this species, and also recognised its potential use in translocations programmes to improve project outcomes. As a result of microhabitat assessment, habitat creation and management programmes can use specific parameters to design, maintain and monitor habitat for calling males. Assessment of a habitat construction project designed from previous research recommendations shows initial project success and provides information to refine future habitat construction programmes. Finally, assessment of sexual selection in L. aurea provides vital information to conservation programmes breeding animals for translocation to work toward improving the fitness of released individuals. Overall, the current study provides key aspects of L. aurea’s biology and ecology that have not been clearly addressed in the literature and aims to improve conservation efforts. In light of recent extinctions and increasing pressures on wildlife, continued research on key threatening processes and behavioural ecology is crucial to help guide conservation.