Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: A total of 32 cattle were divided into four groups of eight each (A1-8, A9-16, A17-24, B1-B8) to be
slaughtered on different days over a period of 45 days. All the cattle in Groups A were of Bonsmara type
and those in Group B were of Charolais type. Three treatments, Tenderstretch (TS), Tendercut (TC) and
Hock suspension (HS) were randomly allocated to each of the 48 sides from group A. Only two
treatments (TC and HS) were implemented on the carcass sides in Group B alternating between the right
and left sides. Two muscles from each side namely Gluteus medius and Longissimus dorsi were
evaluated for purge, cooking loss, shear force and sarcomere length after 2, 4, 6, 10 and 14 days of
aging. Paired t-Tests were performed for each pair of treatments and each day separately, on all
variables accessed (Snedecor, 1980). The differences in purge and cooking loss between treatments
were all found to be inconclusive for each day of aging. Although purge had significant differences
between the treatments TC and TS for the GM and LD muscle after 14 days of aging (P = 0.0341 and P =
0.0348 respectively) these were found to be open to doubt as the treatment that delivers the most purge
differs between muscles and that the two treatments delivered no differences compared to its HS values.
Aging had a significant effect on purge as it doubles after 14 days of aging. Cooking loss values only
differed significantly on day 2 for the LD muscle between treatments TC and HS. The differences in
shear force were all smaller than 0.3205 kg/ 1.27cm and not consistent over all carcasses. A mean
positive improvement in tenderness was calculated from high difference in mean values from some
carcasses although some carcasses showed a decrease in tenderness when using TS and TC, which
suggests that the treatments are of no relevance towards the industry. Although the differences in shear
force become smaller as aging commences, it is not constant, a phenomenon most probably due to the
variance between animals. Aging again had the most significant effect (P<.0001) on shear force.
Correlations between sarcomere lengths and shear force were low for all the treatments on the GM
muscle (HS = -0.453; TC = -0.401 and TS = -0.2) but in the LD muscle the TS method showed a higher correlation (TS = -0.665) than the other treatments (HS = 0.059 and TC = 0.059). / AFRIKAANSE OPSOMMING: `n Totaal van 32 beeste was opgedeel in vier groepe van agt elk (A1-8, A9-16, A17-24, B1-B8)
wat geslag is op verskillende dae oor n periode van 45 dae. Beeste van die A groep was almal Bonsmara
tipe en die van die B groep charolais tipe. Drie behandelings naamlik Tenderstretch (TS), Tendercut (TC)
en Hak suspensie (HS) was ewekansig tot die 48 sye van die karkasse van groep A toegedeel. Groep B
se 16 sye is net met TC en HS ewekansig tot die linker en regter sy toegedeel. Twee spiere naamlik
Gluteus medius en Longissimus dorsi was geevalueer vir drup verlies, kook verlies, sarkomeer lengte en
taaihied na 2, 4, 6, 10 en 14 dae se veroudering. Gepaarde t – toetse is gedoen vir elke paar
behandelings vir elke dag van veroudering op al die veranderlikes genoem. Die verskil in drup verlies en
kook verlies tussen behandelings was as nie betekeinisvol bestempel. Behalwe vir die feit dat drup verlies
betekenisvolle verskille getoon het tussen die behandelings TC en TS vir die GM (P = 0.0341) en die LD
(P = 0.0348) spiere na 14 dae se veroudering was dit bevind as nie betekenisvol juis oor dat die twee
behandelings teenoor hul HS waardes geen verskille getoon het nie. Veroudering van die vleis het wel
die grootste betekenisvolle verskil in drupverlies gemaak waar dit amper verdubbel soos die vleis
verouder vir 14 dae. Kookverlies het net op dag twee n betekenisvolle verskil getoon in die LD spier vir
die HS – TC kombinasie. Die verskil in taaiheid was almal kleiner as 0.3205 kg/ 1.27cm en nie kostant vir
alle karkasse nie. n’ Positiewe gemiddelde verbetering in sagtheid is verkry deur die kalkulasie van hoë
positiewe waardes en lae negatiewe waardes vir sommmige karkasse wat n laer sagtheid getoon het
wanneer TS en TC gebruik is. Hierdie onkonsekwente verbeterings in sagtheid maak dat hierdie
behandelings van min praktiese nut vir die bedryf is. Alhoewel hierdie verskille tussen behandelings
kleiner raak tydens veroudering, is dit nie konstant nie, wat as gevolg van die variasies tussen diere kan
wees. Veroudering het weereens die mees betekenisvolle effek op die vleis getoon (P< 0.001). Die
korrelasie tussen sarkomeer lengte en WBSF taaiheid was laag vir alle behandelings in die GM spier (HS
= -0.453; TC = -0.401 en TS = -0.2) behalwe vir die LD spier waar die TS behandeling n hoer korrelasie
van TS = -0.665 as die ander twee behandelings (HS = 0.059 en TC = 0.059) opgelewer het.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/4359 |
| Date | 03 1900 |
| Creators | Du Toit, Francois Matthys |
| Contributors | Hoffman, L. C., McMillan, K. W., University of Stellenbosch. Faculty of Agrisciences. Dept. of Animal Sciences. |
| Publisher | Stellenbosch : University of Stellenbosch |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 118 p. : ill. |
| Rights | University of Stellenbosch |
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