BY BEEF CRC BEEF BULLETIN AUTUMN 2009

BRAHMAN NEWS SEPTEMBER 2009 Issue #164

Calmer cattle grow more quickly than more temperamental ones, and produce larger, better finished carcasses with more tender meat.

That is just one of the main findings from research carried out by the Beef CRC and NSW Department of Primary Industries.

PhD student, Linda Cafe has discovered an animals’ temperament can affect its long term growth rate and reduce carcass and meat quality.

The results of the study have the ability to not only improve productivity but it could improve the safety of cattle and their human handlers as well.

It’s a natural response for all animals, including humans. When you’re in a dangerous situation, you have two options, fight or flight.

When it comes to cattle, a prey animal, appropriate fear responses are what keeps them alive in the wild.

However, in a domestic situation, extreme responses are not that helpful, as animals need to cope with handling by humans.

Extreme or reactive fear responses can be detrimental to not only the safety and welfare of the cattle, the human handlers, and the longevity of farm infrastructure.

“Over time, we know that animals get used to the quality of handling they receive,” Linda Cafe said.

“But do they ever really change their temperament? That’s what I wanted to find out.”

Ms Cafe’s study centered around Brahman heifers and steers sourced from a number of commercial herds in central Queensland.

The cattle were backgrounded for six months at NSW Department of Primary Industries Glen Innes Agricultural Research and Advisory Station from soon after weaning, and finished on grain for 120 days at the Beef CRC’s “Tullimba” feedlot west of Armidale.

“The cattle had been yard-weaned on their home properties and were a very manageable group of weaners at the start of the study. None had ‘wild’ or extreme temperaments,” Ms Cafe said.

In fact, cattle with very reactive temperaments were not selected for the study at all, as it was feared they would not cope well with the intensive handling required to collect the necessary samples.

Ms Café said the cattle were assessed for temperament regularly during the backgrounding phase and when they were in the feedlot.

“We used two measures familiar to industry. That being flight speed and crush score,” she said.

“Flight speed was calculated in metres per second (m/s) from the animals’ flight time”.

Flight time is an electronic measure of the time it takes an animal to cover a short distance (roughly about 2m) after leaving a weighing crush.

Ms Cafe said a higher flight speed represents a faster, more flighty animal.

“A flight speed of around 1 m/s is equivalent to a walk, and 3 m/s to a run.”

The crush score is a subjective assessment of how agitated the animal is while confined in the crush.

A score of one is very calm while five is highly agitated,” according to Ms Cafe.

The cattle were then grouped into three temperament categories based on their backgrounding flight speed: ‘quiet’, ‘average’ and ‘flighty’.

“The herd quickly became used to the intensive handling required for the experiment. While the cattle became calmer over time, the ‘flighty’ cattle still recorded the highest flight speed throughout the experiment.” The flighty cattle grew more slowly throughout the entire experiment.

They had lower lower individual feedlot intakes as slower growth rates.

“Temperament would not usually be expected to have an impact on an animals’ growth rate during backgrounding in extensive pasture situations, as the cattle have little human interaction,” said Ms Cafe. “However, this was not the case with this herd, due to the study requiring more intensive handling for collection of data and samples.”

Ms Cafe said while the flighty animals had lower feed intakes, there was no difference in feed conversion ratio or net feed efficiency between the three groups of animals.

“The poorer growth rates of the ‘flighty’ cattle is more related to a lower motivation to eat, rather than a difference in how the feed was utilised by the cattle,” she said.

After 120 days on grain the ‘flighty’ animals yielded carcasses which were 10 per cent lighter than quiet animals. She added they also had 18 per cent less rib fat and tended to have less tender meat.

“The ‘flighty’ animals were about half a kilogram higher in shear force. Shear force is a measure of how much force it takes to cut through a piece of meat. It can be likened to taking a bite from a piece of steak,” Ms Cafe said.

She said the production of poorer quality meat has to do with the chemicals circulating in the animals’ blood.

“The level of the stress hormone cortisol and the levels of metabolites, which are indicators of fat and muscle mobilisation, circulating in blood increased in the temperamental animals,” she said.

“This indicates that even in this quiet, well-handled herd, the flightier animals were more responsive to the stresses of routine handling than the calmer ones.”

Ms Cafe said during times of high stress such as transport, the stress response can be a bigger drain on an animal’s body reserves.

“If the cattle are being sent to an abattoir, they need the energy reserves to fuel the post-slaughter metabolism necessary to produce good quality meat.”

Hence, if the cattle have a heightened stress-response already, it will be detrimental for meat quality.”

Ms Cafe said even though the cattle became used to the handling, the rankings of the cattle did not change over time.

The cattle that were more temperamental at the beginning of the experiment were still more temperamental at the end.

Ms Cafe said the results confirm that selecting cattle with better temperaments, not just culling those with poor temperaments, can improve productivity as well as improving safety for the cattle and their handlers. “The benefits may be more apparent in more intensive systems such as feedlots, but they will apply to any animal which ends up being trucked to an abattoir,” Ms Cafe said.