Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The production and export of ostrich meat from southern Africa, to especially the European Union, are
increasing rapidly due to the healthy nature of ostrich meat. The European Union has very high standards
when importing food products, and it is inevitable that more emphasis is being placed on the production of
high quality ostrich meat. Another aspect also of concern to consumers, is the welfare of animals prior to
slaughter, and this forces producers to look at ways to decrease stress of animals during the ante-mortem
period. Research regarding the effect of stress during the ante-mortem period, and as a result, on meat
quality, haematology and weight loss in ostriches, is lacking and thus the purpose of this study was to
investigate the effect of various transport distances, travel conditions and different birds on these factors.
Ante-mortem stress was measured using serum corticosterone levels (ng/ml), heterophil: lymphocyte (H:L)
ratio, white blood cell (WBC) count, aspartate aminotransferase (AST) and creatine kinase (CK), as well as
the rate and extent of pH decline in the M. gastrocnemius. Special emphasis was also placed on the meat
quality parameters drip loss, cooking loss, colour and Warner-Bratzler shear force (kg/1.27 cm diameter).
Live weight losses, as well as carcass weight and weight of bruises cut off from each bird were also recorded
during various stages of the trials.
The effect of transport distance on the meat quality of ostriches was investigated. Ultimate pHu
measurements were taken at 24 hours post-mortem. The muscles of the ostriches from the control group
(i.e. birds that were not transported prior to slaughter) had a lower mean pHu (5.77 ± 0.053) than birds that
travelled 60 (5.93 ± 0.053) and 600 km (6.11 ± 0.053), respectively. Differences in meat drip loss percentage
were also observed between the three treatments. The birds in the control group (0.40 ± 0.07 %) had the
lowest meat drip loss percentage compared to the birds that travelled 60 km (treatment C) (1.36 ± 0.07 %)
and 600 km (treatment B) (0.97 ± 0.07 %), respectively, to a commcerical ostrich abattoir. Ostriches that
were transported for 600 km (8.13 ± 1.16 %) had a greater percentage live weight loss during the antemortem period than birds that travelled a distance of 60 km (2.4 ± 2.185 %) to the abattoir, although both
groups were deprived of feed for the same period. When the haematology of the groups that travelled
different distances was compared at various time intervals in the ante-mortem period, both groups of birds
experienced significant increases in WBC, s-AST and s-CK. An increased H:L ratio from pre-transport to
post-transport was only evident in the birds that travelled 600 km (treatment B). However, the birds that
travelled 60 km were the only group of birds that had significant elevated serum corticosterone levels during
the ante-mortem period. The increase in the various blood parameters indicates severe physical stress,
which negatively affected meat quality.
Another trial also investigated the effect of various farming systems and transport on meat quality and
bruising of ostrich carcasses. Ostriches were raised in three different farming systems, i.e. feedlot -, semiintensive - and free range conditions. Other factors that could maybe impact on stress susceptibility, such as
road conditions, floorspace and floor type were also investigated. A significant difference in meat pHu was
found between ostriches that were raised in a feedlot (5.95 ± 0.018) and semi-intensive (6.04 ± 0.033) environment. The feedlot birds also had the greatest percentage of carcass weight removed due to bruising.
The free range birds were the birds that had the lowest floor density per birds and also had the least amount
of bruising on their carcasses. Incidently the other two groups (feedlot and semi intensive) were the birds
that travelled on the same type of road (mountain pass) in a truck with rubber flooring whilst the free range
birds travelled on a straight road in trucks with metal grid floors.The results indicate that the type of farming
system didn’t have a significant influence on meat quality of ostriches, but that factors such as road
conditions, flooring and bird density did play a significant role in the incidence of bruises and injuries
obtained during transport. / AFRIKAANSE OPSOMMING: Die produksie en uitvoer van volstruisvleis vanuit suidelike Afrika, na veral die Europese Unie, is gedurig aan
die toeneem as gevolg van die gesonde aard van volstruisvleis. Die Europese Unie het baie hoë standaarde
wanneer dit kom by die invoer van voedselprodukte en dit is onvermydelik dat meer klem op die produksie
van hoë gehalte volstruisvleis gelê word. ʼn Ander aspek wat ook kommer wek by verbruikers is die welstand
van diere voor slagting en hierdie aspek noodsaak produsente om te kyk na maniere om stres te beperk
tydens die periode voor slagting. Navorsing rakende die effek van stres tydens die ante-mortem periode,
asook vleiskwaliteit, hematologie en gewigsverlies in volstruise as gevolg van vervoer, ontbreek. Die doel
van die studie was dus om die invloed van verskillende vervoerafstande, vervoersomstandighede en tipe
produksiesisteme op volstruise se stresrespons te ondersoek. Die omvang van ante-mortem stres is bepaal
deur die serum-kortikosteroon vlakke (ng/ml), heterofiel: limfosiet (H:L) ratio, witbloedsel (WBS) telling,
aspartaat aminotransferase AST en creatien kinase CK, asook die tempo en vlak van pH-daling in die M.
gastrocnemius, te meet. Spesiale klem is gelê op die vleisgehalte parameters kookverlies, drupverlies, kleur
en Warner-Bratzler-skeurwaardes (kg/1.27 cm deursnee). Gewigsverlies is aangeteken op verskillende
stadiums tydens die proewe. Karkasgewigte en die hoeveelheid gewig afgesny van elke volstruiskarkas
a.g.v. kneusings is ook bepaal.
Die eerste studie het die invloed van vervoerafstand op vleiskwaliteit van slagvolstruise ondersoek. Vleis
kwaliteit parameters soos pH, drip verlies, kook verlies, taaiheid en kleur is ondersoek. Die pHu metings is op
24 uur post-mortem geneem. Slagvolstruise in die kontrole groep (d.i. -volstruise wat nie voor slagting
vervoer is nie) het ’n laer vleis pHu (5.77 ± 0.05) gehad as voëls wat onderskeidelik 60 km (5.93 ± 0.05) en
600 km (6.11 ± 0.05) ver vervoer is. Verskille in persentasie dripverlies is gesien tussen die vleis van die
voëls wat nie vervoer is nie (0.40 ± 0.07 %) en die voëls wat 60 km (1.36 ± 0.07 %) en 600 km ver (0.97 ±
0.07 %) onderskeidelik vervoer is. Volstruise wat vir 600 km (8.13 ± 1.16 %) vervoer is, het ‘n groter
persentasie lewende gewig tydens die ante-mortem periode as voëls wat 60 km (2.4 ± 2.19 %) ver vervoer is
na die abattoir, verloor, al was beide groepe weerhou van voer vir dieselfde tydperk. Beide groepe wat
vervoer is (60 en 600 km) het merkbare toenames in witbloedsel (WBS) tellings, s-AST’s en s-CK’s getoon
tydens die ante-mortem periode. Daar is slegs ʼn toename in H:L ratio (ʼn indikator van stres) van voor
vervoer tot na vervoer gesien in die voëls wat 600 km vervoer is. Daarteenoor was die voëls wat slegs 60 km
vervoer is die enigste voëls wat ʼn toename in korticosteroon vlakke getoon het gedurende die ante-mortem
periode. Die toenames is heel moontlik ‘n aanduiding van erge fisiese stres wat ‘n negatiewe effek op
vleiskwaliteit het.
Die tweede studie het die effek van verskillende produksiesisteme en die stress respons van die verskillende
groepe slagvolstuise op vervoer ondersoek. Vleis kwaliteit parameters soos pH, drip verlies, kook verlies en
taaiheid is ondersoek. Die hoeveelheid kneusings per volstruis is ook gemeet. Daar was ‘n beduidende
verskil (P = 0.009) tussen die pHu van die voerkraal (5.95 ± 0.018) en semi- intensiewe (6.04 ± 0.033) volstruise. Die voerkraal volstruise se vleis het die grootste drip- en kookverliese gehad in vergelyking met
die ander twee groepe (semi-intensiewe en ekstensiewe) terwyl die ekstensiewe volstruise die taaiste vleis
gehad het. Die voerkraalvoëls het ook die grootste persentasie karkasgewig verloor a.g.v. kneusings wat
afgesny is. Die ekstensiewe voëls het die laagste vloer digtheid per volstruis gehad asook die minste
kneusings. Die ander twee groepe (voerkraal en semi intensief) was die groepe wat op dieselfde pad vervoer
is (bergpas) in vragmotors wat rubber vloere gehad het terwyl die ekstensiewe voêls op ‘n reguit pad vervoer
is in ‘n vragmotor met ‘n metaal oppervlakte. Die resultate van die studie is ‘n aanduiding dat die tipe
plaassisteem nie ‘n groot impak op die hoeveelheid akute stres ervaar deur die voëls tydens vervoer gehad
het of gevolglik op die vleiskwaliteit van die volstruise nie, maar dat faktore soos pad toestand, tipe vloer en
voëldigtheid wel ‘n wesenlike rol speel in die voorkoms van kneusings en beserings opgedoen tydens
vervoer.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/6762 |
| Date | 03 1900 |
| Creators | Wolmarans, Wilhelm J. |
| Contributors | Hoffman, L. C., Brand, T., Smith, C., 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 | 137 p. : ill. |
| Rights | University of Stellenbosch |
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