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Economic value and genetic prediction of clinical mastitis in South African Holstein cattle

dc.contributor.advisorDzama, K.en_ZA
dc.contributor.advisorBanga, C.en_ZA
dc.contributor.authorMan'ombe, Edsonen_ZA
dc.contributor.otherStellenbosch University. Faculty of AgriSciences. Dept. of Animal Sciences.en_ZA
dc.date.accessioned2014-04-16T17:29:11Z
dc.date.available2014-04-16T17:29:11Z
dc.date.issued2014-04en_ZA
dc.identifier.urihttp://hdl.handle.net/10019.1/86396
dc.descriptionThesis (MScAgric)--Stellenbosch University, 2014.en_ZA
dc.description.abstractENGLISH ABSTRACT: Mastitis is the most prevalent and costly production disease of dairy cattle; hence mastitis incidence is a distinctly important trait in dairy cattle. The primary objective of the study was to determine the economic value, and develop a model for genetic prediction of clinical mastitis in South African Holstein cattle. These procedures are a prerequisite to including this trait in the breeding objective. The cost of clinical mastitis per incident was calculated as the sum of revenue loss due to discarded milk during the infection period and the associated treatment costs. Economic value (ZAR/incident) was calculated as the change in profit (increase in costs) resulting from a simulated marginal increase in mastitis incidence in an average herd. Average economic losses due to clinical mastitis were estimated at ZAR919.96/cow/year and the average incidence was 0.9cases/cow/year. The economic value of clinical mastitis was ‐ZAR1079.51/incident. A model for predicting estimated breeding values (EBVs) for clinical mastitis using somatic cell score (SCS), fore teat length (FTL), udder depth (UD) and rear udder height (RUH) was developed, using genetic (co)variances among these traits. Since EBVs for SCS, FTL, UD and RUH are routinely estimated under the national genetic evaluation programme, EBVs for clinical mastitis can be predicted from the model developed in the current study. Thus, the results of the study provide the basis for including clinical mastitis in the breeding objective for South African Holstein cattle.en_ZA
dc.description.abstractAFRIKAANSE OPSOMMING: Mastitis is die mees algemeenste en duursteproduksie siekte wat voorkom by melkbeeste, daarom is die voorkoms van mastitis 'n belangrike eienskap in melkbeeste. Die primêre doel van die studie was om die ekonomiese waarde te bepaal, asook die ontwikkeling van 'n model vir genetiese voorspelling van kliniese mastitis in Suid‐Afrikaanse Holstein beeste. Hierdie prosedures is 'n voorvereiste vir insluiting van hierdie eienskap as ‘n teeldoelwit in seleksie programme. Die koste van kliniese mastitis per voorval is bereken as die som van die inkomste verlies weens melk weggegooi tydens die infeksie periode en die gepaardgaande koste vir die behandeling. Ekonomiese waarde (ZAR / voorval) is bereken as die verandering in wins (toename in koste) wat voortspruit uit 'n gesimuleerde marginale toename in mastitis voorkoms in 'n gemiddelde kudde. Gemiddelde ekonomiese verliese as gevolg van kliniese mastitis was beraam op ZAR919.96/koei/jaar en die gemiddelde voorkoms was 0.9gevalle/koei/jaar. Die ekonomiese waarde van kliniese mastitis was ‐ ZAR1079.51/geval. 'n Model vir die voorspelling van beraamde teelwaardes (EBV’s) vir kliniese mastitis is ontwikkel deur gebruik te maak van die ko‐variansies tussen die onderskeie eienskappe: somatiese sel telling (SST), voorspeen lengte (VSL), uier diepte (UD) en agter uier hoogte (AUH). Aangesien teelwaardes vir SST, VSL, UD en AUH gereeld beraam word onder die Nasionale genetiese evaluasie program, kan teelwaardes vir kliniese mastitis voorspel word vanuit die model wat ontwikkel is in die huidige studie. Dus verskaf die resultate van hierdie studie ‘n basis vir die insluiting van kliniese mastitis as ‘n teeldoelwit in seleksie programme van die Suid‐Afrikaanse Holstein beeste.af_ZA
dc.format.extentix, 58 p.
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.subjectHolstein cattle -- Clinical mastitis -- Economical aspectsen_ZA
dc.subjectHolstein cattle -- Genetic predictionen_ZA
dc.subjectUCTDen_ZA
dc.subjectTheses -- Agricultureen_ZA
dc.subjectDissertations -- Agricultureen_ZA
dc.titleEconomic value and genetic prediction of clinical mastitis in South African Holstein cattleen_ZA
dc.typeThesisen_ZA
dc.rights.holderStellenbosch Universityen_ZA


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