Quantification of springbok (Antidorcas marsupialis) meat yield and meat quality

Malan, Carmen (2020-03)

Thesis (MScAgric)--Stellenbosch University, 2020.

Thesis

ENGLISH ABSTRACT: This study aimed to determine the effect of subspecies, sex and intensity of culling on the meat yield and meat quality of springbok (Antidorcas marsupialis). This was done by analysing data on the carcass yield, carcass composition and the physical and chemical meat quality of selected muscles. A number of game ranchers have started to use Damara (Antidorcas marsupialis angolensis) rams with their Karoo (Antidorcas marsupialis marsupialis) ewes in their breeding programs, in the hope that the progeny of this hybridisation would be larger than the Karoo subspecies parent. This started after speculation arose that the entire Damara subspecies is larger than the Karoo subspecies and would be an ideal choice to breed with the Karoo springbok where the thought that the intensive culling for size amongst the latter, has led to smaller animals. Therefore, baseline data is necessary to evaluate the influence of subspecies (Damara vs Karoo) and intensity of culling on the meat yield and meat quality of springbok. Trial 1 consisted of twenty Damara springbok from the north of Namibia and twenty Karoo springbok from Wellington in the western cape of South Africa. The Damara subspecies (43.37±0.869 kg males, 36.59±0.923 female) had significantly heavier dead weights in comparison to the Karoo springbok (32.04±0.868 males, 26.81±0.660 females). Deadweight and carcass weight also differed between sexes, where male springbok had heavier dead weights and carcass weights. Damara (57.91±0.643 % males, 54.24±0.680 % females) and Karoo (57.66±0.988 % males, 54.28±0.740 % females) springbok exhibited sexual dimorphism for dressing percentage. Trial 2 consisted of the same twenty Karoo springbok from Wellington (low intensity) and an additional twenty springbok from Witsand, where male springbok has been intensively culled for the last decade. Wellington male springbok had heavier dead weights and cold carcass weights than Witsand male springbok, whereas females from the two farms had similar dead weights and carcass. The differences in body weight observed between Damara and Karoo subspecies have economic implications when animals are paid per carcass weight whilst the intensity of over-culling affects linear body measurements and yields of particularly male springbok compared to female springbok, as has been typically reported for the selectively culled sex. The proportional composition of a carcass is economically important and can be utilised for increased meat production and the utilising of certain breed’s naturally superior composition. The Damara springbok had a proportionally smaller shoulder than the Karoo springbok, but subspecies had no effect on the rest of the carcass proportion, nor did subspecies influence the meat, bone or fat percentage. Sex, however, did influence the proportional composition, where females had a higher percentage of hindquarter and males a proportionally larger forequarter. Female springbok also had a higher fat percentage than males and subsequently a lower lean meat yield (Trial 1). The intensity of culling yielded Wellington (low intensity) springbok that had a higher percentage contribution for the forelimb and ventral trunk in comparison to Witsand springbok (high intensity). The Wellington springbok also had higher meat and lower bone composition for the forelimb and ventral trunk than the Witsand springbok (Trial 2), as has been typically reported for younger animals. Damara and male springbok also had a higher Warner-Braztler shear force (WBSF) and cooking loss in comparison to the Karoo and female springbok. Consequently, the Damara springbok had less tender meat, although both subspecies had a WBSF mean that was <33N, and as such could be classified as very tender. The Karoo subspecies had higher L*, a*, b*, and chroma meat colour ordinates in comparison to the Damara subspecies making the Karoo meat lighter, redder, and more vivid (saturated). Physical meat quality differences between subspecies were not necessarily large enough for one subspecies to be beneficial over the other. The intensity of culling trial yielded few differences between Wellington (low intensity) and Witsand (high intensity) springbok for physical meat quality (Trial 2). Thus, the high intensity of culling did not influence the physical meat quality characteristics of springbok when sufficient time has progressed between culls, and the animals have had time to replenish their glycogen reserves. The chemical composition of the Damara and Karoo subspecies meat was also determined where the Damara and Karoo subspecies did not differ for any of the chemical components. Female springbok had a higher intramuscular fat (IMF) content than male springbok, although sex did not affect any other chemical components. The chemical composition of springbok meat was marginally affected by sex, irrespective of subspecies. Subspecies influences the dead weight, carcass weight and all primal weights. But subspecies did not differ drastically for any proportional parameter. Subspecies also did not influence the physical and chemical meat quality to an extent that would negatively influence the perception of a subspecies’ meat. Thus, game ranchers can utilise either subspecies without negative quality repercussions A high intensity of culling influences the dead weight and carcass weight of the selectively culled sex, this means that a high intensity of culling within a herd will ultimately decrease the size of the males culled over time.

AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om die effek van subspesie (Damara vs Karoo), geslag en intensiteit van uitdunning op die vleisopbrengs en vleis gehalte van springbok (Antidorcas marsupialis) te bepaal. Hierdie was verrig deur die analise van data wat versamel is oor die karkas opbrengs, karkas samestelling, vleis kwaliteit en chemiese samestelling van springbok vleis. Daar is tans `n toename in boere wat Damara (Antidorcas marsupialis angolensis) ramme gebruik om die Karoo (Antidorcas marsupialis marsupialis) ooie in hul teel programme te dek. Hierdie word gedoen in die hoop dat die nageslag van die Damara en Karoo kruis, groter sal wees as hul Karoo ouer. Die praktyk het begin nadat daar vermoed is dat die Damara subspesies heelwat groter as die Karoo subspesie is, ter selfde tyd glo boere ook dat oor tyd het die grootte van die Karoo springbokke afgeneem as gevolg van selektiewe oes van groot diere. Grondslag data word dus benodig om die invloed van subspesie, geslag en intensiteit van oes op die vleisopbrengs en vleis kwaliteit van springbokke te bepaal. Proef 1 het bestaan uit twintig Damara springbokke vanuit die noorde van Namibia en twintig Karoo springbokke wat verkry is in Wellington. Die Damara subspesie (43.37±0.869 kg manlik, 36.59±0.923 vroulik) was merkbaar swaarder as die Karoo (32.04±0.868 manlik, 26.81±0.660 vroulik) subspesie. Die dooie gewig en koue karkas gewigte het merkbaar verskil tussen die geslagte, waar die manlike diere swaarder was. Die manlike diere het ook `n hoër uitslag persentasie gehad in vergelyking met die vroulike springbokke. Proef 2 het bestaan uit dieselfde twintig Karoo springbokke vanuit Wellington en dan nog twintig Karoo springbokke wat verkry is vanuit Witsand. Daar is al vir die laaste dekade intensief selektief groot ramme ge-oes op die Witsand plaas. Die Wellington-manlike springbokke was swaarder as die Witsand-manlike springbokke, terwyl die vroulike springbokke van beide plase nie van mekaar af verskil het nie. Die verskille in dooie gewig en koue karkas gewig tussen die subspesies het ekonomiese gevolge wanneer diere per karkasgewig betaal word, terwyl die intensiteit van oes lineêre liggaamsmetings en dus liggaamsgewig van veral manlike diere beïnvloed. Die proporsionele samestelling van `n karkas is van ekonomiese belang aangesien dit benut kan word om potensiële verhoogde vleis opbrengs te bepaal, deur die benutting van `n spesie se genetiese potensiaal. Die Damara springbokke het `n kleiner persentasie skouer gehad, maar verder het subspesie geen invloed gehad op die karkas samestelling nie. Geslag het wel die karkas samestelling beïnvloed, waar vroulike springbokke `n hoër agterkwart persentasie gehad het, terwyl manlike diere `n hoër persentasie voorkwart gehad het (Proef 1). Vroulike sprinbokke het ook ‘n hoër persentasie vet as die manlike springbokke en gevolglik ‘n laer maer vleis opbrengs gehad. Die intensiteit van die uitskot het Wellington (lae intensiteit) springbokke opgelewer wat 'n hoër persentasie bydrae vir die voor- en ventrale snit gehad het in vergelyking met die Witsand-springbokke (hoë intensiteit). Die Wellington-springbokke het ook 'n hoër samestelling van vleis en laer bene vir die voor- en ventrale snit gehad as die Witsand-springbokke (Proef 2), soos gewoonlik by jonger diere gemeld is. Damara en manlike springbokke het ook 'n hoër skuifkrag van Warner-Braztler (WBSF) en kookverlies gehad in vergelyking met die Karoo en vroulike springbokke. Gevolglik het die Damara-springbok minder teer vleis gehad, hoewel beide subspesies 'n WBSF-gemiddelde van <33N gehad het, en sodanig as baie sag geklassifiseer kon word. Die Karoo-subspesies het hoër L *, a *, b * en chroma vleiskleur ordinate gehad in vergelyking met die Damarasubspesies wat die Karoo-vleis ligter, meer rooi en meer helder (versadig) maak. Fisiese vleiskwaliteitverskille tussen subspesies was nie noodwendig groot genoeg dat die een subspesie meer voordelig sou wees as die ander nie. Die intensiteit van die uitdun proef het min verskille opgelewer tussen die Wellington (lae intensiteit) en Witsand (hoë intensiteit) springbok vir fisieke vleiskwaliteit (Proef 2). Die hoë intensiteit van uitdunning het dus nie die fisieke vleiskwaliteitseienskappe van springbokke beïnvloed as daar voldoende tyd tussen die uitdunne gevorder het nie, en die diere tyd gehad het om hul glikogeen reserves aan te vul. Die chemiese samestelling van die Damara- en Karoo-subspesievleis is ook bepaal waar die Damara- en Karoo-subspesie nie verskil het vir enige van die chemiese komponente nie. Die vroulike springbokke het 'n hoër inhoud van die binnespierse vet (IMF) as die manlike springbokke, hoewel geslag geen ander chemiese bestanddele beïnvloed het nie. Die chemiese samestelling van springbokvleis is effens beïnvloed deur geslag, ongeag die subspesie. Die subspesies beïnvloed die dooie gewig, karkasgewig en alle primêre snit gewigte. Die subspesie het egter nie drasties verskil vir enige proporsionele parameter nie. Die subspesies het ook nie die fisiese en chemiese vleiskwaliteit beïnvloed in 'n mate wat die persepsie van 'n subspesievleis negatief sou beïnvloed nie. Dus kan wildboere van enige subspesie gebruik maak sonder negatiewe gevolge vir die kwaliteit. ‘n Hoë intensiteit van uitskot beïnvloed die dooie gewig en die karkasgewig van die geslag wat selektief uitgedun word. Dit beteken dat 'n hoë intensiteit van uitdunning in 'n kudde die grootte van die mannetjies, wat mettertyd uitgeroei word, sal verminder.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/107988
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