Association of pro-melanin concentrating hormone genotype with beef carcass quality and yield.
Beef cattle from 3 independent studies conducted in the Texas Panhandle (Exp. 1: n = 3,906 and Exp. 2: n = 4,000) and southern Idaho (Exp. 3; n = 542) were used to investigate the association of pro-melanin concentrating hormone (PMCH) genotype with beef carcass quality and yield attributes. Tissue samples were collected from each animal to determine which PMCH allele they expressed (Trial 1: AA, 62.60%; AT, 32.05%; and TT, 5.35%; Trial 2: AA, 64.33%; AT, 31.07%; and TT, 4.60%; Trial 3: AA, 65.87%; AT, 29.34%; and TT, 4.80%). Twenty-four hours after harvest, carcass attributes were evaluated for all carcasses and longissimus dorsi steak samples were allocated from a subset of carcasses in Exp. 2 (n = 352; AA, 49.43%; AT, 28.98%; and TT, 21.59%) and each carcass in Exp. 3. Warner-Bratzler shear force measurements were determined for each steak after aging for 7, 14, or 21 d postmortem. Carcasses from Exp. 1 and 2 expressing the AA genotype had greater (P < 0.01) 12th rib subcutaneous (s.c.) fat depth and marbling scores, concurrent with smaller (P < 0.01) LM area than carcasses of AT and TT genotypes. Subsequently, carcasses expressing the AA genotype were represented by a greater (P < 0.02) proportion achieving Prime and Premium Choice quality grades, and a lesser (P < 0.01) proportion grading Select or Standard. In all trials, carcasses of the AA genotype had greater (P < 0.04) calculated yield grades than carcasses of the TT genotype. Carcass composition was associated with PMCH genotype evident by calculated empty body fat differences (P < 0.04) between AA and TT cattle in Exp. 1 and 3, and differences (P < 0.01) among all 3 genotypes in Trial 2. Shear force data on 7-d postmortem aging tended (P = 0.06) to favor cattle of the AA genotype in Exp. 2. However, additional aging to 14 or 21 d minimized any tenderness differences. These data illustrate the potential relationship that may exist among PMCH genotypes and indicators of carcass composition.
Beef Carcass Research Center, Department of Agricultural Sciences, West Texas A&M University, Canyon 79016.
L J
LJ
Walter
C A
CA
Gasch
T J
TJ
McEvers
J P
JP
Hutcheson
P
P
Defoor
F L S
FL
Marquess
T E
TE
Lawrence
D000818:Animals; D001823:Body Composition; D002417:Cattle / Q000235:genetics / Q000502:physiology*; D005838:Genotype; D007028:Hypothalamic Hormones / Q000235:genetics* / Q000378:metabolism; D007061:Idaho; D008297:Male; D008460:Meat / Q000032:analysis*; D018482:Muscle, Skeletal / Q000502:physiology*; D011498:Protein Precursors / Q000235:genetics* / Q000378:metabolism; D011897:Random Allocation; D013781:Texas
D007028:Hypothalamic Hormones; D011498:Protein Precursors; C059991:melanin-concentrating hormone precursors