The development of economic selection indices for the Simmentaler breeds in South Africa
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Date
2004-11
Authors
Kluyts, Johan Francois
Journal Title
Journal ISSN
Volume Title
Publisher
University of the Free State
Abstract
English: The purpose of the first chapter was to give a short introduction to the study. Although there were exponential increases in knowledge, there are still fields of study where there is little understanding and enormous gaps relating to information. A short history of the development of cattle was presented, with special reference to the Simmentaler breed. The objectives of this study were then stated. These objectives were: the definition of breeding objectives, derivation of economic values and development of economic selection indices for the Simmentaler breed in South Africa. 2. In Chapter 2 the development of breeding objectives and the derivation of economic values were reviewed. There seems to be general consensus that definition of breeding objectives should be the primary step in the design of structured breeding programs. Development of the breeding objective can be described in terms of the following phases: specific ation of the breeding, production and marketing system, identification of sources of income and expense in commercial herds, determination of biological traits that influence income and expense, derivation of economic values, choice of selection criteria, and estimation of phenotypic and genetic parameters. The modeling methods to derive economic values can be divided into simulation, dynamic programming and profit functions. 3. In Chapter 3 the important traits, which should be considered for the development of breeding objectives, as well as the criteria to be included in the selection index were reviewed. Traits were classified as fitness-, production-, product-, input-, type- and behavioural traits. The decision whether or not to include a trait in the breeding objective depends on the relative economic value of the trait, the potential for genetic improvement and the possibility of accurate and cheap measurement. Several traits determine economic efficiency, and the required balance of these traits is likely to differ between different production systems. 4. The purpose of Chapter 4 was the development of a general breeding objective for the Simmentaler breed in Southern Africa as well as the derivation of economic values for beef production traits. Income was partitioned between weaners (steers), surplus heifers and cull cows. Expenses were calculated for all classes and included feed cost, husbandry cost and marketing cost. Economic values for weaning weight (direct), weaning weight (maternal), yearling weight (400 days), final weight (600 days) and mature cow weight were derived as partial derivatives of the profit equation. These values, expressed per genetic standard deviation, in South African Rand per cow, corrected with the discounted gene flow and diffusion coefficient methods (in brackets) are, 25.57 (75.01), 15.21 (47.97), 28.49(83.63), -13.95 (-40.79) and -69.29 (-63.39) respectively. 5. The objectives of Chapter 5 were to expand the Simmentaler breeding objective by inclusion of functional traits and to derive economic values for the functional traits calving rate, days -to-calving, calving-ease (direct) and calving-ease (maternal). It was assumed, for these categorical traits, that there is an unobserved underlying normal distribution of the sum of genetic and environmental values, and that the phenotypic category is defined by threshold values on this distribution. The consequences of a change in fitness included changes in costs, changes in culling rate, number of barren cows and the number of surplus offspring available for sale. Results emphasised the relative importance of fertility. Economic values, expressed per genetic standard deviation in South African Rand per cow, corrected with the discounted gene flow and diffusion coeffic ient methods (in brackets) are, 18.98 (15.27), - 93.82 (- 75.51), 1.08 (1.31) and 1.15 (1.08) for calving rate, days-to-calving, calving-ease (direct) and calving-ease (maternal), respectively. 6. The objectives of Chapter 6 were to expand the Simmentaler breeding objective by the inclusion of product quality traits and to derive economic values for dressing percentage, backfat thickness, tenderness and marbling. A method to derive economic values for these optimum traits was described. It was as sumed, for the categorical traits, that there is an unobserved underlying normal distribution of the sum of genetic and environmental values, and that the phenotypic category is defined by threshold values on this distribution. The consequences of a change in the mean performance of a trait include changes in the number of animals in different quality classes and as a result thereof, changes in the expected value of a carcass. Economic values, expressed per genetic standard deviation in South African Rand per cow, corrected with the discounted gene flow and diffusion coefficient methods (in brackets) are, 20.96 (61.50), 0.39 (1.14), -3.52 (-10.33) and 0.18 ( 0.52) for dressing percentage, backfat thickness, tenderness and marbling respectively. 7. The development of economic selection indices for an integrated Simmentaler production system was described in Chapter 7. The breeding objective was defined in terms of production-, functional- and product quality traits. Criteria included in the total index are birth- and weaning weight (direct and maternal), yearling weight, final weight, mature cow weight, days -to-calving, backfat thickness, tenderness and marbling. The total merit index (IT) for an integrated Simmentaler production system is IT = – 1.65 BWD – 1.99 BWM + 2.28 WWD + 1.76 WWM + 1.48YW – 0.50 FW – 2.02 MCW – 13.21 CD + 4.92 BF – 2.34 T + 12.77 M. The correlation between this index and the breeding objective is 0.987. The economic superiority, over the average progeny, of the progeny from the top 40% of animals selected on their ranking in the total index, is expected to be R116.49.
Afrikaans: Die doel van hierdie studie was om, vir die Simmentaler beesras in Suid Afrika, teeltdoelwitte te definieer, ekonomiese waardes vir produksie- funksionele- en vleiskwaliteitseienskappe te beraam, en om ekonomiese seleksie indekse op te stel. Die definisie van ‘n teeltdoelwit is die primêre stap in die opstel van gestruktureerde seleksie en teeltplanne. Ontwikkeling van ‘n teeltdoelwit kan in terme van die volgende stappe beskryf word: beskrywing van die teelt-, produksie - en bemarkingstelsel; identifiseer die bronne van inkomstes en uitgawes in kommersiële kuddes; bepaal die eienskappe wat inkomstes en uitgawes beinvloed; beraming van ekonomiese waardes; keuse van seleksie kriteria; beraming van fenotipiese en genetiese parameters. Die metodes om ekonomiese waardes te beraam kan opgedeel word in simulasie, dinamiese programmering en winsvergelykings. Die relatiewe ekonomiese waarde van die eienskap, die potensiaal om die eienskap geneties te verbeter asook die moontlikheid om die eienskap akkuraat en goedkoop te meet, sal bepaal of ‘n spesifieke eienskap in die teeltdoelw it ingesluit moet word of nie. Ekonomiese doeltreffendheid word deur verskeie eienskappe beinvloed en die relatiewe belangrikheid van hierdie eienskappe verskil tussen verskillende produksie stelsels. Vir hierdie studie is aanvaar dat inkomste verkry is uit die verkoop van speenkalwers, surplus verse en uitskot koeie. Voer-, bestuurs- en bemarkingskostes is vir alle klasse beraam. Ekonomiese waardes is as eerste-orde funksies (parsiele differensiaal) van die winsvergelyking afgelei. Ekonomiese waardes, uitgedruk per genetiese standaard afwyking in Suid Afrikaanse Rand per koei, gekorrigeer met die genevloei- en geendiffusie metodes (tussen hakkies) is 25.57 (75.01), 15.21 (47.97), 28.49 (83.63), -13.95 (-40.79) en -69.29 (-63.39) vir speengewig (direk), speengewig (maternaal), jaargewig (400-dae), 600-dae gewig en volwasse-koei-gewig, respektiewelik. Ekonomiese waardes is ook vir funksionele eienskappe beraam. Vir hierdie kategoriese eienskappe word aanvaar dat daar onderliggend ‘n normal-verspreiding, wat die resultaat van genetiese en omgewings waardes is, bestaan en dat die fenotipiese kategorie deur drempelwaardes op hierdie verspreiding gedefinieer word. Die gevolg van veranderinge in reproduktiewe fiksheid sluit veranderings in kostes, uitskot tempo, aantal onvrugbare koeie en surplus kalwers, in. Die relatiewe belangrikheid van vrugbaarheid word deur die resultate beklemtoon. Ekonomiese waardes is 18.98 (15.27), -93.82 (-75.51), 1.08 (1.31) en 1.15 (1.08) vir kalftempo, dae-tot-kalwing, kalwingsgemak (direk) en kalwingsgemak (maternaal), respektiewelik. Ekonomiese waardes is ook vir vleiskwaliteits eienskappe beraam. As gevolg van ‘n verandering in die gemiddelde prestasie van die bevolking vir die eienskap, is daar ‘n verandering in die relatiewe getal diere/karkasse in die verskillende kwaliteitsklasse. Dit het tot gevolg dat die verwagte waarde van ‘n karkas of die gemiddelde waarde van karkasse uit die bevolking verander. Ekonomiese waardes is 20.96 (61.50), 0.39 (1.14), -3.52 (-10.33) en 0.18 (0.52) vir uitslagpersentasie, rugvetdikte, vleissagtheid en marmering, respektiewelik. Geboorte- en speengewig (direk en maternaal), 400-dae-gewig, 600-dae-gewig, volwasse-koei-gewig, dae-tot-kalwing, rugvetdikte, vleissagtheid en marmering is as kriteria in die indeks ingesluit. Die ekonomiese seleksie indeks vir ‘n geïntigreerde Simmentaler produksie stelsel is beraam as IT = – 1.65 BWD – 1.99 BW M + 2.28 WWD + 1.76 WWM + 1.48YW – 0.50 FW – 2.02 MCW – 13.21 CD + 4.92 BF – 2.34 T + 12.77 M. Hierdie indeks het ‘n korrelasie van 0.987 met die teeltdoelwit. Die verwagte ekonomiese meerderwaardigheid van die nageslag van die top 40% diere, geselekteer op grond van hierdie indeks, is R116.49.
Afrikaans: Die doel van hierdie studie was om, vir die Simmentaler beesras in Suid Afrika, teeltdoelwitte te definieer, ekonomiese waardes vir produksie- funksionele- en vleiskwaliteitseienskappe te beraam, en om ekonomiese seleksie indekse op te stel. Die definisie van ‘n teeltdoelwit is die primêre stap in die opstel van gestruktureerde seleksie en teeltplanne. Ontwikkeling van ‘n teeltdoelwit kan in terme van die volgende stappe beskryf word: beskrywing van die teelt-, produksie - en bemarkingstelsel; identifiseer die bronne van inkomstes en uitgawes in kommersiële kuddes; bepaal die eienskappe wat inkomstes en uitgawes beinvloed; beraming van ekonomiese waardes; keuse van seleksie kriteria; beraming van fenotipiese en genetiese parameters. Die metodes om ekonomiese waardes te beraam kan opgedeel word in simulasie, dinamiese programmering en winsvergelykings. Die relatiewe ekonomiese waarde van die eienskap, die potensiaal om die eienskap geneties te verbeter asook die moontlikheid om die eienskap akkuraat en goedkoop te meet, sal bepaal of ‘n spesifieke eienskap in die teeltdoelw it ingesluit moet word of nie. Ekonomiese doeltreffendheid word deur verskeie eienskappe beinvloed en die relatiewe belangrikheid van hierdie eienskappe verskil tussen verskillende produksie stelsels. Vir hierdie studie is aanvaar dat inkomste verkry is uit die verkoop van speenkalwers, surplus verse en uitskot koeie. Voer-, bestuurs- en bemarkingskostes is vir alle klasse beraam. Ekonomiese waardes is as eerste-orde funksies (parsiele differensiaal) van die winsvergelyking afgelei. Ekonomiese waardes, uitgedruk per genetiese standaard afwyking in Suid Afrikaanse Rand per koei, gekorrigeer met die genevloei- en geendiffusie metodes (tussen hakkies) is 25.57 (75.01), 15.21 (47.97), 28.49 (83.63), -13.95 (-40.79) en -69.29 (-63.39) vir speengewig (direk), speengewig (maternaal), jaargewig (400-dae), 600-dae gewig en volwasse-koei-gewig, respektiewelik. Ekonomiese waardes is ook vir funksionele eienskappe beraam. Vir hierdie kategoriese eienskappe word aanvaar dat daar onderliggend ‘n normal-verspreiding, wat die resultaat van genetiese en omgewings waardes is, bestaan en dat die fenotipiese kategorie deur drempelwaardes op hierdie verspreiding gedefinieer word. Die gevolg van veranderinge in reproduktiewe fiksheid sluit veranderings in kostes, uitskot tempo, aantal onvrugbare koeie en surplus kalwers, in. Die relatiewe belangrikheid van vrugbaarheid word deur die resultate beklemtoon. Ekonomiese waardes is 18.98 (15.27), -93.82 (-75.51), 1.08 (1.31) en 1.15 (1.08) vir kalftempo, dae-tot-kalwing, kalwingsgemak (direk) en kalwingsgemak (maternaal), respektiewelik. Ekonomiese waardes is ook vir vleiskwaliteits eienskappe beraam. As gevolg van ‘n verandering in die gemiddelde prestasie van die bevolking vir die eienskap, is daar ‘n verandering in die relatiewe getal diere/karkasse in die verskillende kwaliteitsklasse. Dit het tot gevolg dat die verwagte waarde van ‘n karkas of die gemiddelde waarde van karkasse uit die bevolking verander. Ekonomiese waardes is 20.96 (61.50), 0.39 (1.14), -3.52 (-10.33) en 0.18 (0.52) vir uitslagpersentasie, rugvetdikte, vleissagtheid en marmering, respektiewelik. Geboorte- en speengewig (direk en maternaal), 400-dae-gewig, 600-dae-gewig, volwasse-koei-gewig, dae-tot-kalwing, rugvetdikte, vleissagtheid en marmering is as kriteria in die indeks ingesluit. Die ekonomiese seleksie indeks vir ‘n geïntigreerde Simmentaler produksie stelsel is beraam as IT = – 1.65 BWD – 1.99 BW M + 2.28 WWD + 1.76 WWM + 1.48YW – 0.50 FW – 2.02 MCW – 13.21 CD + 4.92 BF – 2.34 T + 12.77 M. Hierdie indeks het ‘n korrelasie van 0.987 met die teeltdoelwit. Die verwagte ekonomiese meerderwaardigheid van die nageslag van die top 40% diere, geselekteer op grond van hierdie indeks, is R116.49.
Description
Keywords
Thesis (Ph.D. (Animal, Wildlife and Grassland Sciences))--University of the Free State, 2004, Selection indexes (Animal breeding), Simmental cattle -- Breeding -- South Africa, Simmental cattle -- Breeding -- Selection indexes, Beef cattle, Breeding objective, Economic value