Growth performance and pork fat quality as measured by three methods of pigs fed 20% DDGS and slaughtered using a standard industry split marketing strategy.

A total of 40 pens containing 22 crossbred barrows (initial BW = 43.07 ± 1.61 kg; PIC 1050 × PIC 337 genetics) were housed in a commercial wean to finish facility. Pens were randomly allotted to dietary treatments in a 2 × 3 factorial arrangement with 2 levels of dried distillers grains with solubles (DDGS; 0% or 20%) and chosen for 1 of 3 marketing cuts removing 4, 8, and 10 animals from each pen. Fat tissue samples were removed from the anterior tip of the jowl and posterior to the sternum on the belly edge 1d postmortem. Fatty acid composition was determined via the Folch method, and iodine values (IV) were calculated from chemical titrations, fatty acid profile (GC IV), and in-plant Bruker near-infrared (NIR) spectroscopy. Pearson's correlation coefficients for IV determination methods were estimated. Inclusion of 20% DDGS did not change ( > 0.05) growth performance, whereas marketing cut affected performance, with the second cut producing the most efficient pigs ( < 0.01). Total SFA and MUFA concentrations were higher ( < 0.01) in belly and jowl fat from pigs fed 0% DDGS. Total PUFA and the PUFA:SFA in belly and jowl fat was higher ( < 0.01) when 20% DDGS was fed. Dried distillers grains with solubles inclusion increased IV in belly and jowl as determined by all 3 methods. Regardless of dietary treatment or fat depot, Pearson correlation coefficients between titration and GC IV, titration and NIR, and GC IV and NIR were 0.46 ( < 0.01), 0.68 ( < 0.01), and 0.43 ( < 0.01), respectively. These correlations suggest methods may rank samples equally but do not provide the same absolute IV. Belly fat had a lower IV ( < 0.01) than jowl fat using titration or GC IV methods, suggesting pigs have varied degrees of physiological maturity at specific fat depots when weight end points are used during the finishing phase. In conclusion, feeding 20% DDGS negatively affected fat quality but not growth performance, and marketing time changed growth performance.

Combining two proven mechanical tenderness measurements in one steak.

This research was performed to determine the true efficacy of measuring both Warner-Bratzler shear force (WBSF) and slice shear force (SSF) in the same steak. The objectives were to compare cooking methods commonly used in preparing steaks for WBSF and SSF procedures and compare them at different cooling times. United States Department of Agriculture select strip loins (n = 240) were aged for either 7 or 14 d to increase the variation in tenderness. Each strip loin was then frozen and cut into 2.54-cm steaks. Steaks were then cooked to an internal temperature of 71°C using a convection conveyor oven (conveyor), a convection oven, clamshell grill, or an open hearth grill. Steaks were allotted to 4 different cooling times to create the combinations of: WBSF 4 h/SSF 0 h, WBSF 4 h/SSF 4 h, WBSF 24 h/SSF 0 h, WBSF 24 h/SSF 24 h. Five 1.25-cm cores were used for WBSF and one 1- by 5-cm slice for SSF. The WBSF from steaks cooked with conveyor were tougher than convection oven cooked steaks [51.9 Newtons (N) vs. 46.1 N; P < 0.05]. However, SSF were tougher when cooked in oven compared with those cooked in conveyor (267.5 N vs. 237.2 N; P < 0.05). Correlations for WBSF and SSF performed in the same steak ranged from 0.51 to 0.88 (P < 0.0001). The WBSF 24 h/SSF 0 h and WBSF 4 h/SSF 4 h had the strongest relationships (0.88 and 0.82, respectively; P < 0.05) between WBSF and SSF when using clamshell method. Performing WBSF and SSF in the same steak was successful based on moderate to high correlation values but the magnitude of the relationship is dependent on the combination of cooking method and cooling time.