Breed, transport and lairage effects on animal welfare and quality of Namibian beef

Luhl, Juljane (Stellenbosch : University of Stellenbosch, 2010-03)

Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2010.

Thesis

ENGLISH ABSTRACT: Namibia by nature is very well suited for livestock production and is a net exporter of beef. Beef is currently exported to South Africa, the European Union (EU) and Japan while market access to the United States of America is being explored. Food safety, traceability and lately animal welfare are all aspects which are requested by Namibians trading partners when exporting meat to those countries. The first two aspects have been addressed with the introduction of the Farm Assured Namibian Beef scheme (FAN Meat) which also provides basic guidelines for animal welfare. Beef in Namibia is produced from extensively managed enterprises which are privately owned and managed, or state owned and communally utilized. The events of handling and transport are considered stressful to all animals but especially so to extensively raised animals and their reaction to these events has the potential to severely infringe on their welfare. The aim of this study was to determine the effect of pre-, during, and post-transportation handling on animal welfare status under Namibian transport conditions. The study also investigated the influence of breed on the meat quality of Namibian beef. The level of bruising recorded on slaughter was used to measure animal welfare. Interviews with producers were conducted to describe the pre-transport handling. Questionnaires that included variables considered as important indicators of animal welfare during transport were distributed to truck drivers. Observations of the off-loading event and animal behaviour were completed in lairage at the export abattoir in Windhoek. The variables that were identified as high risk factors and had a significant influence on the level of bruising under Namibian transport conditions include animal factors (i.e. breed type, age, sex, condition and subcutaneous fat cover), pre-transport handling (i.e. re-branding of animals), transport related risks (loading density and animals lying down during transit) as well as lairage factors (i.e. fit of truck floor to off-loading ramp, the way animals moved to holding pens, pen size and minimum environmental temperatures). The influence of breed on meat tenderness and water-holding capacity of the Longissimus dorsi muscle of the four main beef breeds (i.e. Brahman, Bonsmara, Simbrah and Simmental), as well as the effect of different aging periods on meat quality (i.e. 2, 9, 16, 23, 30 & 37 days post mortem) were investigated. The Brahman differed significantly (p < 0.05) from the other three breeds in terms of all aging treatments; with higher Warner-Bratzler shear force values reported for this breed. Interactions between days post mortem and breed were found for the Simbrah, and Simmental breeds, which may be indicative of a delayed response to aging of meat samples obtained from Simbrah animals. This can possibly be ascribed to an increased calpastatin activity in these animals. Meat samples obtained from the Bonsmara steers showed the highest rate of tenderization, with this effect retained until day 30 post mortem. Recommendations as pertaining to the ante mortem handling of cattle are made.

AFRIKAANSE OPSOMMING: Namibië word gekenmerk deur toestande wat uitstekend vir diereproduksie is, met die land wat as ‘n netto uitvoerder van beesvleis beskou word. Vleis word na Suid-Afrika, die Europese Unie (EU) en Japan uitgevoer, met die moontlikheid van die Verenigde State van Amerika wat as ‘n uitvoermark ondersoek word. Voedselveiligheid, naspeurbaarheid en dierewelsyn is drie vereistes wat deur die invoerders van Namibiese vleis daargestel word. Die eerste twee vereistes is reeds deur die implementering van die Farm Assured Namibian beesvleis skema (FAN Meat) aangespreek, met die skema wat basiese riglyne vir dierewelsyn voorskryf. Namibiese beesvleis word geproduseer onder grootskaalse ekstensiewe boerdery omstandighede, wat of privaat besit en bestuur word, of aan die regering behoort en deur plaaslike gemeenskappe benut word. Die invloed van hantering en vervoer is besonder stresvol vir diere en in besonder vir diere wat onder ekstensiewe omstandighede geproduseer word. Omdat diere onder ekstensiewe omstandighede ongewoond aan hantering en vervoer is, kan dié twee aksies ‘n ernstige impak op die welsyn van sulke diere hê. Die doelwit van die studie was om die invloed van hantering voor-, tydens en na-vervoer onder Namibiese vervoertoestande te ondersoek. Die invloed van ras op Namibiese beesvleiskwaliteit is ook ondersoek. Die mate van kneusing waargeneem met slagting was as standaard gebruik om die welsynstatus van diere te bepaal. Onderhoude is met produsente gevoer om inligting oor die pre-vervoer toestande in te win. Vraelyste wat veranderlikes wat as belangrike indikators van dierewelsyn tydens vervoer beskou kan word, ingesluit het, is aan vragmotorbestuurders versprei. Waarnemings van die aflaai en verwante diergedrag was by die houfasiliteite van die uitvoer abattoir in Windhoek, waarnatoe die diere vervoer is, gedoen. Verskeie hoë risiko faktore wat ‘n betekenisvolle invloed op die mate van kneusing wat tydens vervoer opgedoen is, gehad het, is in die studie geïdentifiseer. Hierdie faktore het dierverwante eienskappe (d.i. ras, ouderdom, geslag, liggaamskondisie en onderhuidse vetvoorsiening), voorvervoer hantering (d.i. herbrandmerk van diere), vervoerverwante risiko’s (d.i. aantal diere per trok kompartement en diere wat tydens vervoer gaan lê), asook ontwerp van houfasiliteite (d.i. verbinding tussen trokvloer en laaibrug, die manier wat diere na houkampies beweeg het, grootte van houkampies en lae omgewingstemperature), ingesluit. Die invloed van ras op die sagtheid en waterhouvermoë van die Longissimus dorsi spier van die vier hoof vleisbeesrasse (d.i. Brahman, Bonsmara, Simbrah en Simmentaler), asook verskillende verouderingstydperke op vleiskwaliteit (d.i. 2, 9, 16, 23, 30 en 37 dae post mortem) van die vier rasse is ondersoek. Die Brahman het betekenisvol (p < 0.05) van die ander drie rasse in terme van die effek van veroudering op vleiskwaliteit verskil, met hoë Warner-Bratzler skeursterkte waardes wat vir dié ras aangeteken is. ‘n Interaksie tussen aantal dae post mortem en ras is gevind vir die Simbrah en Simmentaler rasse, wat dui op ‘n vertraagde effek van vleisveroudering vir die Simbrah ras, moontlik as gevolg van ‘n hoër mate van kalpastatien aktiwiteit. Vleismonsters bekom van jong Bonsmara bulle het die grootste mate van versagting getoon, met die voordeel wat waargeneem is tot dag 30 van die post mortem vleisveroudering. Aanbevelings betreffende die voorslag hantering van beeste word gemaak.

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