TORONTO – Every year, millions of animals and poultry are moved by truck all over North America.
Canada’s 30-year-old transportation law allows up to 48 hours without feed and water in transport, which is longer than most countries. This has raised questions among animal welfare advocates on the impact to their well-being and among scientists pondering the effect on meat quality.
Transportation stress triggers chemical changes in the body that may make meat darker and drier. Long times spent crowded into a truck with other animals can also cause bruises, scrapes and sometimes death.
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Scientists examining the impacts on pork, poultry and beef reported some of their conclusions at the recent Canadian Meat Council symposium on animal welfare and transportation held in Toronto.
HOGS
If there is a high percentage of bruised hogs or more dead animals on arrival than normal, there is good reason to suspect something went wrong before the animals showed up at the abattoir.
That is one of the conclusions of Jorges Andres Correa, technical director of the Canadian Meat Council. His doctoral research is comparing the effects of farm handling and transportation on animal welfare and pork quality.
Agriculture Canada researcher Luigi Faucitano, who is also researching welfare in the transport and slaughter of pigs, found lairage time can affect pork quality. Lairage includes ramps, alleys and the holding area before pigs are killed.
“If we don’t respect the correct procedures, we have less chance to pass the (animal welfare) audits and sell into different markets,” he said.
Correa has analyzed physiological conditions like body temperature, blood, urine, saliva and feces for signs of heightened stress that can cause pale, soft exudative pork that results in darker, drier meat.
Feed withdrawal is also under scrutiny.
Correa has found if animals are fed just before loading, they are harder to move and have a higher risk of fatigue, dizziness and even death while in transport. Death losses in transit are low in Canada at less than half a percent.
He and Faucitano have examined the design of trucks, barns and lairage areas.
When loading full-sized animals, alleys need to be wide enough so they can pass through easily to avoid scratches and bruises. Ramps should be wide enough where two can pass through at once.
Handlers have to be patient because fear and stress caused by people can show up in the carcasses. Using a paddle to get pigs into a truck is better than an electric prod because the prod increases heart rate. If the same animals continue to be prodded, they panic and do not settle down. They rub against the walls more, run faster and are more prone to injury.
“That animal was more reactive again and has a higher heart rate. With just the action of loading, those animals stay very nervous,” Correa said.
Pig location in a double decker truck can also be stressful. Pigs that have to climb into the higher compartment or go down to the belly of the trailer fare differently. Those in the belly of the truck have the highest concentration of lactic acid in the muscle, which affects meat quality.
Weather conditions also affect pigs. When they were equipped with heart rate monitors, pigs were more stressed and stayed excited in the summer so there was a higher rate of PSE pork as opposed to winter transport when they seemed calmer.
They became more stressed in the winter when the wind started to blow inside the truck.
In winter, animals use more energy to stay warm and may produce more dark meat due to high pH levels in the muscle.
In looking at pigs before slaughter, Faucitano found the longer the lairage time, the higher the hostility of pigs. That can lead to fighting and injuries.
If pigs are mixed with unfamiliar pen mates, fighting increases along with increased body temperatures that can remain high for eight hours after mixing. This also affects meat quality.
Pigs kept in large groups fight more but stocking density has more influence. If they are crowded together, there is less fighting. If they have to wait for a long time, they should have more space so they can lie down.
Pigs do not cope well with heat or high humidity of 70 percent or more so better ventilation is needed to cool the area and remove ammonia. If the pigs are misted, it cleans them up and makes electrical stunning more effective.
Noise can be stressful and can result in PSE pork.
The design of the entrance into the stunning area is important and animals need to be restrained properly so they can be rendered unconscious.
Hogs are often stunned with electrical tongs applied at a specific position on the head. Large plants use a tong that is applied at the head and connected to the chest.
Carbon dioxide stunning is popular in Germany and Spain. There is less PSE pork but loss of consciousness is not immediate and pigs may react adversely to the gas.
BEEF CATTLE
A four-year study of the impact of beef cattle transport on welfare and meat quality shows long journeys cause weight loss and other stress related problems for feeder and fed animals.
Led by Agr iculture Canada researcher Karen Schwartzkopf- Genswein, the study looked at transport times, driver experience and the impact on the cattle being hauled. There were more than 6,500 truckers and 277,000 animals involved.
The study found the average load takes 16 hours from the time the cattle get on the truck until they are released. The average long haul distance was 1,080 kilometres and the average outside temperature was 16 C. Average delays for border crossings, driver breaks or mechanical problems were 3.3 hours.
Many were shipped from southern Alberta to the United States where the average wait at the border was 1.3 hours. The longest delay was 15 hours at the border while another reported waiting 12 hours to unload at a packing plant.
“For every hour the cattle spent in the truck, the shrink occurred at .15 kilos,” she said.
Shrink starts to slow down because after 30 hours in transport, cattle cannot lose any more water.
“We have had some people say we can continue to transport them because they can’t lose anymore,” she said. Schwartzkopf-Genswein does not agree and said more research is needed.
The survey also analyzed animal condition and counted the number of down, lame or dead.
“Feeders and culls are more affected by transport and have a greater likelihood of dying and increased shrink. Fat cattle have the fewest problems,” she said.
Shrinkage occurs depending on the placement in the truck, ventilation, time on the truck, weather conditions and outside and inside temperatures.
In studying ventilation, researchers found the higher the porosity, the higher the temperature inside.
“More porosity and more ventilation do not necessarily mean it is going to be a cooler trailer. It is really about the air flow in the trailer,” she said. Airflow is from back to front and if there are solid walls, there is no movement.
For every increase in temperature and humidity, the shrink increases 1.1 percent. Simple calculations suggest a moderate level of shrink costs $38 per animal.
“Producers think they know the losses they are getting on their loads but if we break it down, they are not knowing the potential to lose,” she said.
The study found some correlations between quality grades and long distances.
Long hauls had more AA grades while short loads had more AAA carcasses. There were almost no dark cutters, which can also be related to stress.
The next phase of study is to assess different effects on high and low densities when transporting feeder cattle.
POULTRY
The cold winters of Saskatchewan and Manitoba can have a large impact when shipping broiler chickens to slaughter, said a University of Saskatchewan researcher.
Stress to the birds may affect meat quality and result in dried out, dark meat, said Samira Dadgar.
Her research looked at western Canadian conditions where the average transit time for chickens was two hours.
Temperature variation in the trailer is considerable and the driver decides whether to cover it with a tarp or have open vents for ventilation.
Further work is needed on loading densities based on the temperatures birds experience in transport.
Exposure to extreme cold prior to slaughter resulted in lower core body temperatures and blood glucose levels. There was more shrinkage and the meat was darker.
“The extreme cold transportation should cause a lower core body temperature and lower blood glucose. These are welfare issues,” she said.
Larger birds coped better than small birds with cold temperature and males seemed to suffer from the cold more than females.
