Transporting cattle from southern Alberta into the United States (US) plays a substantial economic role in the western Canadian beef industry. Thermal environments within cattle transport trailers are dependent on ambient conditions, and if inadequately managed, can be a welfare concern. To effectively manage cattle transport, the environmental conditions throughout the livestock trailer must be understood. The objective of the present study was to investigate the trailer micro-climate and welfare during 5-paired commercial long-haul transports of slaughter cattle from Alberta, Canada to Washington State, US during summer months. In addition, the effect of compartment location and trailer porosity (8.7% vs 9.6%) on trailer micro-climate, shrink and core body temperature were also investigated during the warmest in-transit hour and stationary events. The compartment location had an effect on micro-climate variables where the upper compartment had greater (P < 0.05) temperature than the bottom deck compartments and relative humidity variables had the opposite effect for both the warmest in-transit hour and stationary events. There was also an effect of trailer porosity on micro-climate variables where it was generally warmer in the trailer with the higher porosity in the stationary event. Differences between trailers included 2 additional roof hatches on the trailer with lower side-wall porosity and lower internal temperatures, which could suggest the location of the trailer porosity, could be important for heat and moisture exchange during transit. The nose of the trailer with higher porosity had generally warmer internal conditions (larger T(trailer)°C and THI(trailer)) than the trailer with lower porosity. This study also found that the temperatures inside the trailer can be 10.5°C greater than ambient temperatures during stationary events and 9°C greater than ambient levels during the warmest in-transit hour. The average amount of per-animal weight loss was 4.3 0.3 % and was affected by trailer porosity and compartment, which followed the trends in thermal environment variables. The transit status (stationary or in-transit) and trailer porosity affected the vaginal core body temperature of the heifers in transit. The core body temperature was greater during stationary events for animals transported in the trailer with lower porosity. It is suggested that the lower side-wall porosity and/or the shape of perforation pattern could impair the movement of fresh air to the respiratory tract of heifers, thus impacting the main mechanism for dissipating heat. The difference in temperature from the trailer ceiling to the animal level was 3.38°C in the trailer with lower porosity (cooler at the ceiling) and 2.23°C in the trailer with the higher porosity. This relationship also had a compartment location effect that followed the micro-climate compartmental differences. This could suggest that excess heat in the trailer with the lower porosity, that also had lower overall temperatures, exited through roof hatches, while in the trailer with the higher porosity, the heat escaped through the side-wall perforations. This theory also supports the idea that the location of where the porosity is located on the trailer may be important to alleviating heat stress in summer months during transport. The results of this study also indicated that there was no difference in the location of the data logger plane (driver, middle passenger) and within the compartments (front, middle, back), suggesting that compartment location effect is substantial when considering micro-climate but temperatures within a compartment are mostly homogenous. The trip that had average ambient temperatures of 25.9 ± 6.06°C for the entire journey, had a temperature Humidity Index that was considered in the danger or emergency category according to the Livestock Weather Heat Index during 95% of the warmest in-transit hour. This suggests that during ambient temperatures of 25.9°C, both trailers used in this study did not have sufficient heat exchange to mitigate the risk of heat stress for cattle.

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