Last supper - the effect of feed intake before slaughter on pork quality traits

As part of the central performance test in the Swiss pig breeding program various meat quality traits are measured, including early postmortem and ultimate pH, drip and cook loss. These traits can be affected by the course of the post-mortal muscle metabolism, which in turn might be affected by various environmental factors. It was speculated that energy supply and thus feed intake during the period before slaughter might be such a factor, which could possibly be controlled by applying a standardized fasting period.
In the Swiss performance testing station, pigs are kept in groups up to 12 animals and feed is provided ad libitum. The individual feed intake is recorded by two types of transponder-controlled feeders (FIRE pig feeder, Osborne Industries; Compident MLP II Station, Schauer Agrotonic AG). Feed intake during the last 6, 12, 18 or 24 hours before stunning (at 6:00 a.m.) and meat quality data of 11’157 pigs slaughtered between Jan. 2017 and Jan. 2021 was used. Early postmortem and ultimate pH were measured 90 min and 24 h after stunning in m. long. dorsi (LD) and m. semimembranosus (SM) of all pigs, including Swiss Landrace (SL) and Large White (LW). Drip and cook loss were only measured in LD samples of sire lines (LW sire line, Duroc, Piétrain) and their 3-way-crosses with F1 sows (SLxLW). The generalized linear model included sex, breed, and type of feeder as fixed effects, slaughter date as random factor, and the feed intake during the specified periods as covariate.
The analysis of variance indicated significant effects (p<0.05) of the feed intake on ultimate pH in the SM and on cook loss. However, the proportion of variance explained by feed intake never reached 0.5 % while the coefficient of determination of the models ranged between 22 % - 42 % with slaughter date and breed as strongest factors.
It is concluded that the feed intake pattern hardly affected the examined meat quality traits, indicating no need to consider feed intake shortly before slaughter in the breeding value estimations or to introduce a defined fasting period preceding slaughter. It might be worth mentioning that under ad libitum feeding conditions, the individual feed intake varies vastly over time, making a standardized fasting impossible. A short feed deprivation could nevertheless be recommended to reduce feed waste and enhance the valorization of organs.