Optimum Lower carcass contamination and optimum pork quality are achieved with 14 to 18 hours of fasting
Not withdrawing feed for a period prior to shipping market hogs can cost up to $5 per head, according to Dr. Eduardo Beltranena of Alberta Agriculture and Rural Development. Not only that, he says, it can also increase transportation losses and compromise pork safety.
However, while packer contracts stipulate that feed withdrawal should be carried out, many finisher barns were not designed to implement this practice, so producers tend to avoid it.
Producers not practising hog feed withdrawal take two main hits to their pocket, says Beltranena.
“Any feed left in the gut at the time of slaughter goes entirely to waste, and if 10 kg of finishing feed is left in the gut, this results in a loss of $3 per hog at current high feed prices,” he says. “Second, there is a drop in dressing percentage. Feed in the gut increases live hog weight, but after evisceration results in a lower carcass weight.”
Beltranena points out that a one per cent point drop in dressing percentage equates to $2 loss per hog.
More feed in the gut increases defecation during transport and leads to skin contamination. Also, pigs that gorge on feed before leaving the farm are more prone to vomiting.
“Truckers tell us that hogs with full guts are much harder to move, increasing loading time and prod use,” says Beltranena. “These hogs are more susceptible to die in transit or in the lairage due to their reduced ability to cope with the stress of transportation and mixing.”
Feces on the skin of the pigs increases contamination in the plant lairage pens and in the scalding tank, thus increasing the pathogen load at the packer, he adds.
Problems in the packing plant
During slaughter and processing, feed in the gut leads to a number of problems in the plant.
“Feed in the gut at the time of slaughter increases the chances of someone nicking or cutting it during evisceration,” says Beltranena. “The weight of the hanging full guts can create tears in the intestines. According to the extent of contamination with digestive material, a part of or the whole carcass could be condemned, reducing the payment to the producer.”
Even slight carcass contamination reduces line speed because someone has to trim it off, and this increases labour cost and compromises line efficiency, Beltranena says.
Despite the most rigid hygiene procedures employed at packing plants, a single contaminated carcass can contaminate others during the cutting and packaging process. In addition, contaminated pork may then spoil in transit to an export customer.
“Fresh pork boxed for export may take up to 30 days to reach Asian consumers,” says Beltranena. “A pork contamination scandal could cost Canada access to treasured export markets, which are difficult to secure and retain.”
Lack of a fasting period prior to slaughter impacts meat quality. “Hogs that gorge on feed prior to slaughter have a higher incidence of pale, soft and exudative (PSE) pork,” Beltranena says. “Consumers then see whitish, mushy pork sitting in a pool of juice at the retail counter and avoid it.”
Solutions for the producer
Lower carcass contamination and optimum pork quality are achieved with 14 to 18 hours of fasting. Therefore, producers should work out the time of day that hogs should have feed withdrawn, based on the estimated time of slaughter.
“First, communicate with your packer or marketing agency and find out at what time hogs must be at the plant by to be slaughtered the same day,” Beltranena says. “Also, ask what is the minimum lairage time at the plant. Packers typically require hogs to rest for a minimum of three hours and drink to rehydrate after transport to ensure animal well-being and minimize pork quality problems.”
Next, the time taken to load and transport hogs to the plant should be taken into account. Adding this to the lairage time, and subtracting the total from the 14- to 18-hour optimum fasting period, determines the time of feed withdrawal. For example, if hogs need to be loaded by 7 a.m. for a same-day kill, feed access should be denied as of late afternoon the day before.
Ideally, pigs should be fasted in dedicated loadout pens where they only have water access, Beltranena says. However, it is still possible to ensure fasting without this facility.
“If you must fast pigs in finishing pens, weigh and tattoo the hogs to be shipped in advance,” he suggests. “Deny feeder access by 7-8 p.m. and turn the lights off. The next morning, remove hogs promptly for shipping after turning the lights on. Restore feed access for the remaining pigs to limit their time without feed to the time they were sleeping. This achieves the necessary fasting period for hogs destined for slaughter.”
For the producer, the high cost of not withdrawing feed justifies investment in a specialized loadout area, Beltranena says. “A farm that ships two truckloads of hogs per week would save $1,000 per week, which could quickly pay back a $50,000 investment in a loadout area with holding pens to fast hogs overnight.” For the packer, the outcome is increased plant efficiency and a reduced risk of food safety issues, both in domestic and export markets.