Heavy Weight Market Pigs: Status of Knowledge and Future Needs Assessment.

Marketing weight is an important economic variable that impacts the productivity and profitability of finishing pig production. Marketing weight has been increasing worldwide over the past decades driven by the dilution of fixed production cost and the improvement of genetic selection of lean-type pigs. A literature review was conducted based on studies reporting production of finishing pigs with marketing weight greater than 130 kg. Sensitivities of growth, carcass, and pork quality traits in response to increasing marketing weight by 10 kg increments were generated using simple linear regression. Average responses were calculated as the mean among studies. Increasing marketing weight affected overall pig growth; in particular, cumulative ADG over the finishing period decreased by 4.0 g/d, ADFI increased by 78.1 g/d, and G:F decreased by 0.011 for every 10 kg increase of marketing weight. Increasing marketing weight by 10 kg increased carcass yield by 0.41 percentage units, backfat by 1.8 mm, LM area by 1.8 cm², carcass length by 2.2 cm, and belly yield by 0.32 percentage units, but decreased percentage of fat-free-lean by 0.78 percentage units loin, shoulder, and ham yields by 0.13, 0.16, and 0.17 percentage units, respectively. Studies evaluating the effects of marketing weight on pork quality observed decreased pH by 0.02 and 0.01 at 45 min and 24 h postmortem, respectively, and an increased a* value by 0.28 per 10 kg marketing weight increase. Heavier pigs had increased concentrations of SFA and intramuscular fat. Conflicting results for L* and b* values, drip loss, Warner-Bratzler shear force, and sensory properties were reported. Also, there has been limited evaluation of nutrient requirement for pigs greater than 140 kg BW. Increased weight and size of heavy pigs require adjustments on barn and facility design; specifically, greater floor space (0.2 m²), feeder space (0.45 cm), drinker height (1 cm), truck space (1.4 m²), and ventilation requirement are needed for every 5 kg increase in BW from 125 to 150 kg. Increasing marketing weight also creates challenges for processing facilities and equipment but no published data is available to address the chilling rate requirement, pork safety, and consumer preference associated with heavier carcasses. In conclusion, increasing marketing weight creates both opportunities and challenges to current finishing pig production, and future research is needed to provide nutritional and management guidelines as well as understand how meat quality may be influenced.