23 May 2011

2 minute read

There are a number of external causes of bruises that are sustained during the last hours and days before beef animals are slaughtered and animal factors, such as sex and age, may contribute to the development of bruises, at least in some cases. Just some of the findings of a review by Dutch and Chilean scientists, led by Wageningen University’s Ana Strappini.

“Better understanding is still needed of the biological mechanisms accounting for the higher bruise rates in females and older animals,” she said, adding that it was also clear that beef cattle sold through markets can suffer bruising that could have been avoided by transporting animals directly from the farm to the slaughterhouse.

Studies of bruises, as detected on carcases at the slaughterhouse, may provide useful information about the traumatic situations the animals endure during the pre-slaughter period.

Many aspects of cattle transport contribute to bruising. Transport conditions, such as stocking density and duration of the journey, seem to have more effect on bruising than distance travelled. “But finding an optimal stocking density for livestock transport under different conditions is still a contentious issue,” said Dr Strappini.

“Bruised tissues may store historical information about the harmful situations that the animal underwent prior to slaughter. The farmer and the transport companies have economic incentives to prevent and reduce bruising. However, slaughterhouses do not have simple and accurate methods for post-mortem age estimation of bruises to assess accurately when bruises were sustained.

This is a relevant problem, due to the importance of having to decide who is economically accountable for the losses. Although the number of bruises, their anatomical location, severity and even the healing process might offer a rapid tool for identifying and evaluating the circumstances during the pre-slaughter period such as high stocking density, rough handling or inappropriate facility infrastructure, other sensitive techniques should be considered for refined assessments of the time the bruises were incurred.”

“More investigation of the time between bruising and slaughter may help to clarify the risk factors that have contributed to the occurrence of bruises and will also help to identify the risks for animal welfare,” she added.

The modern diagnostic techniques applied when evaluating human bruises may be studied for bovine bruises as well. “Immunohistochemistry and cytochemistry seem to be promising methods to be applied to measure morphological or biochemical changes, which can clearly be distinguished from non-bruised tissues.”

“But age assessment of bruises continues to be a crude process. A wide variety of factors intrinsic to the animal can influence the inflammatory process and subsequent repair.

“Normal biological variation among animals is therefore bound to result in substantial overlap among proposed time frames in the healing process.”