Kemp,VP Genetic Programs and R&D, Genesus Inc.
Per capita consumption of pork in the US has not increased over the last few years (USDA – Livestock-Meat Domestic Data) and retail pork quality has been implicated as one of the factors affecting consumer acceptance of pork.
1 Carcass weight basis (pounds)
The National Pork Board conducted pork quality benchmarking studies in 2012 and 2015 to assess the quality and variation of pork at the retail case level. The conclusion from these studies was that wide variation exists in retail case pork quality in both 2012 and 2015 and that no pork quality attributes improved from 2012 to 2015 (Bachmeier, L.A. 2016. 2015 National Pork Benchmarking Study. MS Thesis, North Dakota State University, Fargo, ND).
Many carcasses in the US and Canadian markets are valued based on grid systems focused on lean yield or other carcass composition measurements with little to no focus on pork quality. Producers have responded by marketing groups of pigs that minimize variation in body weight. However other factors contribute to variation in carcass composition and pork quality.
Arkfeld et al. (J. Anim. Sci. 2017.95:697-709; doi:10.2527/jas2016.1097) evaluated the effects of: sex; season in which the pig was raised; and production focus, in addition to marketing group.
All pigs were in one of two production focus alternatives, meat quality or lean growth for which the cooperating packer identified proprietary genetics from proprietary suppliers. Unaccounted variation was included in a group referred to as “pig & other” and reflected, to a large extent, differences between individual pigs not accounted for by the effects listed above. “Pig & other” explained the largest variation in carcass composition traits and compared to production focus explained variation as follows:
- fat depth (51.2 vs 26.7%),
- loin depth (60.5 vs 20.2%) and
- hot carcass weight (93.5 vs 0.3%).
“Pig & other” also explained the most variation in boneless loin, ham and belly primal weights and the largest amount of variation in belly width, length and average depth (>70%) compared to production focus (<23%).
For pork quality traits loin Minolta L*, loin pH and loin slice shear force variation, “pig & other” explained (>62%) compared to production focus (<12%). Two main focus traits for production group differences, %lean and marbling score, also had more variation explained by “pig & other” compared to production focus (39.4 vs 36.4% and 48.9 vs 39.0%, respectively).
These results indicate that significant variation remains even after defining a general production focus and suggest more refined approaches are needed to reduce variation in carcass and pork quality traits.
There has been increased interest in utilizing Duroc-based sire lines to produce commercial pigs in the US in recent years. One main reason is the meat quality production focus used above whereby commercial pigs from Duroc-based sire lines are grouped together. However, differences in selection goals, population sizes, technology adoption, etc. among genetic improvement programs have created differences among Duroc-based sires available to the industry. This, in addition to differences in female lines can produce large variation in the commercial pigs that are from one focused group.
It will be increasingly important for industry to more accurately define their needs and specifications to reduce variability and capture more value in important consumer-focused traits.