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There was no difference between the 60 and 600 km groups, nor within the groups over time in the plasma levels of total protein, globulin and albumin. This is an indication that dehydration and the immobilisation of body reserves through protein catabolism did not occur when the ostriches were transported to the abattoir and deprived of feed and water for a certain period. The WBC count increased over time within each group, whilst the groups at each time point did not differ from each other. The increases seen in the WBC count during the ante-mortem period is an indication that there was a degree of cell damage that led to an inflammatory response.

Transport of 600 km caused a significant increase in the H:L ratio from pre-transport to post-transport, whilst no differences in the H:L ratio were seen at any stage in the birds that travelled 60 km. At all stages during the trial, except after transport, there was no difference between the two groups’ H:L ratio. The H:L ratio is known to be an accurate assessor of stress and is possibly an indication that the birds that travelled 600 km encountered more stress during transport. An increase in the H:L ratio during periods of stress may possibly affect the immune status of the bird, rendering them more susceptible to diseases.

The birds that travelled 60 km had significantly greater levels of plasma corticosterone at every stage of the trial except at baseline. The highest corticosterone concentration was, however, seen prior to transport when the birds (60 km group) had not even been exposed to transport. On the other hand, the birds of the 600 km group had similar plasma corticosterone levels at each phase during the protocol without any increases in plasma corticosterone levels from baseline values. Elevated plasma corticosterone levels are also an indication that ostriches suffer from acute stress and would suggest that, prior to transport, the birds of the 60 km group probably suffered from an acute stress exposure that was not related to transport. Unfortunately, at this time, a definite conclusion regarding the effect of transport on ostrich plasma corticosterone cannot be drawn.

There were differences in effects that no travel, short travel and lengthy travelling distances had on the extent of post-mortem pH decline or meat quality in ostriches. Increased travelling distances led to ostrich meat with increased pHu and decreased water-holding capacity. Distance travelled also affected the amount of live weight lost by ostriches, with the birds having travelled the furthest to the abattoir exhibiting the greatest live weight loss. This finding confirms the belief of farmers that birds that travel greater distances lose more weight than those that did not travel, regardless of the time they spent off feed.

There were differences in pHu of ostriches that were raised in different systems and then transported before being slaughtered. As expected, feedlot ostriches had the lowest pHu post-mortem, probably due to the fact

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that they were more accustomed to people and stressed less during transport, whilst the semi-intensive ostriches had the greatest pHu. However, the feedlot ostriches had the lowest water-holding capacity, which could have been attributed to the increased incidence of bruising on the carcasses of the feedlot ostriches compared to the extensive and semi-intensive ostriches. It seems as if the amount of bruising cut off from carcasses during meat inspection is not dependant on the farming system the birds were raised in, but rather due to factors such as stocking density on the truck, road conditions and truck flooring. In the case of the feedlot birds, their stocking density was not appropriate, added to which the road they travelled on consisted out of sharp turns and bends that may have resulted in postural instability and consequently led to bruising.

SUMMARY OF CONTRIBUTIONS

The manner in which we calculate stress in various species is not standard. By using blood haematology to determine stress levels, there must be definite indicators of both physical stress and psychological stress in ostriches. Some haematological metabolites may prove better indicators of physical stress and others better indicators of psychological stress. When the two groups of ostriches were transported for 60 and 600 km respectively, there were different trends in the concentration of the blood metabolites corticosterone and H:L ratio, both of which are indicators of stress in avians. The birds that travelled 600 km had an increased H:L ratio (stress) during the ante-mortem period, whilst the ostriches that travelled 60 km hadn’t. With regards to corticosterone, the ostriches that travelled 60 km were the only group that exhibited an increased plasma corticosterone concentration (stress). However, the increased corticosterone levels occurred prior to transport and can thus not be related to transport. Another factor could possibly have led to the increased corticosterone levels. Further studies are needed to make definite claims on the type of stress (physical or psychological) leading to increased corticosterone and an increased H:L ratio.

When considering the H:L as an indicator of stress, lengthy transportation of slaughter ostriches caused more ante-mortem stress than shorter travelling distances. This was also evident in the meat quality of these ostriches, with the ostriches that travelled further having greater post-mortem pHu.

Transportation as a whole caused increases in WBC counts and the enzymes s-AST and s-CK. This is an indication that the transported ostriches suffered muscle damage during transit that could influence the meat quality of the ostriches

Regardless of feed deprivation period, transport distance affects live weight loss, with the longer periods of road travel resulting in greater live weight losses that ultimately lead to a reduced income to the producer. Road conditions truck specifications had a definite effect on ostrich meat quality and on the amount of bruising caused during transit.

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A sedative may help to decrease the negative effect that acute stressors have on the welfare of ostriches whilst they are being transported to an abattoir or to another farm, and warrants further research.

Transport of ostriches at times when traffic is at a minimum will help to alleviate stress, although it will have no effect on metabolic stress. In other studies, transport of ostriches at night has shown that birds tend to sit down and are more relaxed when they travel in darkness. This requires further research.

Further research is needed to determine where live weight losses take place in ostriches during transport, specifically whether the losses are due to faecal output or due to losses in the muscle. Research is also required to decrease live weight losses by using supplements such as electrolyte solutions that have been tested in cattle.

Greater research is needed on the changes that occur in the haematology of ostriches under stress to determine which metabolite is related to physical stress and which metabolite is related to psychological stress.

More research is needed on the optimal truck conditions ostriches must be transported under to reduce stress susceptibility, bruising and mortalities and improve meat quality post-mortem. These factors should include truck floor type, road conditions, driver capabilities and bird density on the truck.

Research is also needed to prove whether farming system affects stress susceptibility and meat quality of birds.