Pork Cut Study Brings Bellyful of Benefits

“On a per-pound basis, bellies and ribs are the most valuable pork cuts,” says Dr. Manuel Juarez, research scientist with Agriculture and Agri-Food Canada (AAFC).  

In the past, studies to enhance quality focused mainly on the loin. Little was known about improving belly attributes such as width and thickness, lean-to-fat ratio and firmness. 

Through their previous work, Dr. Juarez and his team developed new methods to measure belly firmness and collected quality data to assess the results. One of the findings was that belly quality traits show medium to high heritability, prompting scientists to explore genetic options that could influence quality as part of the current study. 

“Our objective is to select for animals based on pork belly attributes, while still being mindful of carcass price. To reach that goal, partnerships with industry leaders like Genesus are a huge piece of the puzzle. We don’t want to produce a great belly but impair the efficiency of the live animal.”  

At the study’s outset, the team reviewed data from previous trials to confirm that belly traits like firmness, thickness and width are heritable. They also gauged the genetic correlation of those traits with other primals. If that connection is significant, it means that whatever scientists do to impact the belly will also affect hams, loins and other cuts. 

“Thus far, we have seen a strong correlation, but there is still room for improvement.”  

Scientists also dug deeper, pinpointing two areas of the belly - near the head and at the center – that are especially linked to quality, so they are giving those spots special attention. 

“We developed an ultrasound method for scanning live animals, based on the traits with the highest potential identified in the preliminary genetic analysis. Last year, we used it to scrutinize the loin and belly. Prior to this method, you knew nothing about the belly until the pig was slaughtered. Now, you can measure things like belly thickness on live pigs and determine quality prior to slaughter.” 

To this point, the researchers have collected quality data on about 600 pigs, and are currently analyzing the results. They recently began gathering data for an additional 1000 pigs from specific lines of the genetics company that serves as their industry partner.  

“When it comes to predicting belly firmness, the standard approach is using iodine value [a measure of the fatty acid saturation in the fat]. While that is effective, we’re finding that the total level of polyunsaturated fats [essential fats required for normal body functions], especially omega-6 fatty acids, are a better predictor than iodine.” 

Though progress in the lab pays off, it’s on-farm success that helps producers pay the bills. To bridge the gap between theory and practical application, researchers are testing their results at a commercial abattoir. 

“Upon completion of our study, we want to have identified genetic markers to select for belly firmness, thickness and other traits related to quality with commercial animals.” 

In research, the larger your data set, the more reliable your results. With that in mind, Dr. Juarez and his colleagues hope to analyze a minimum of 1500 pork bellies, and are shooting for 2000. 

“A key part of this process is genotyping the animals [detecting small genetic differences that can influence physical traits of interest]. For this task, we will use a different method from the one commonly employed.” 

The method is called low-pass skim sequencing with imputation, which reduces bias in genetic evaluations. Scientists currently have about 800 animals that are fully genotyped, so the team is well on its way.  

“By the project’s end, we should have a database of 4000 – 5000 animals, including their genotypes and phenotypes [observable characteristics]. That number should be sufficient to aid any farm in improving belly quality.” 

Of note, this study dealt with crossbred animals rather than purebreds, making the results more applicable for industry. Armed with that data, pig genetic companies could develop specific lines that support the quest for quality by producers and packers. 

“I’m very grateful to SIP and our industry partners, including commercial producers, abattoirs and genetic companies. This was a large, complex study, and we aim to reward their support with concrete results that can be applied in the near future.”