Genetic and Environmental Factors Affecting Meat Quality

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
308	3320	3090	30%
308	3320	1010	10%
308	3320	1080	10%
308	3520	1010	20%
501	3320	1060	30%

Progress 09/01/99 to 09/30/04

Outputs
Two studies were conducted to attempt to lower the glycogen stores in pork muscle in order to improve pork muscle quality. Study 1 used 50 barrows and an ultra-high protein/low carbohydrate diet composed primarily of extruded soybeans fed for 0 to 14 d prior to harvest. Blood glucose levels and muscle glycogen levels were not lowered, and so, no differences in muscle pH or meat quality were found (P>0.05). Study 2 used 177 pigs to determine the effects of fasting (0 or 48 h) and length of transport (0.5, 2.5 or 8.0 h) prior to harvest on pork muscle quality. Longer transportation resulted in lower glycolytic potential (P<0.05). Fasting and longer transport times each had positive effects on pork meat quality, but length of transport effects were greater in magnitude. Progeny from Charolais sires were used to determine genetic mechanisms for differences in postmortem muscle metabolism that influence beef tenderness. Sires were identified in an earlier study as producing progeny with pale-colored lean and tender meat or darker-colored lean and tough meat. In blood, the tender sire group had lower cortisol, creatinine phosphokinase, globulin, and total protein levels and higher phosphorus than the tough sire group (P<0.10). Carcasses from the tender sire group had lower muscle pH early postmortem, higher glycolytic potential, longer sarcomeres, brighter colored semimembranosus muscle, more 30 kDa breakdown product, and more tender steaks than carcasses from the tough sire group (P<0.10). Our data suggest that a genetic condition exists in cattle that is characterized by a lessened physiological response to stress resulting in higher muscle glycogen content and faster pH decline, which leads to longer sarcomeres and enhanced proteolysis causing meat to be more tender. Another study was conducted using thirty steers to compare tenderness improvements in beef round and sirloin muscles resulting from five methods of pre-rigor skeletal separations applied at 60 min postmortem. Most treatments reduced shear force in the rectus femoris, but increased shear force in the semitendinosus and psoas major (P<0.05). A study was conducted to quantify intramuscular tenderness variation within four beef round muscles. Location-specific cores were obtained from cooked steaks and shear force was evaluated. Definable intramuscular tenderness variation (SD=0.56 kg) was almost twice as large as between-animal tenderness variation (SD=0.29 kg) and 2.8 times as large as between-muscle variation (SD=0.20 kg). The biceps femoris had the greatest definable intramuscular tenderness variation. These data could be used to develop alternative merchandising methods for beef round muscles. A trial was conducted to determine the effects of deep marination, quality grade, and degree-of-doneness on palatability of gas-grilled beef steaks from seven muscles. Deep marination resulted in lower shear force and higher tenderness, juiciness, and beef flavor scores (P<0.05). Deep-marinated Select steaks had palatability attributes equal to or greater than top Choice steaks, but the effects of deep marination and marbling were greater at higher degrees-of-doneness and varied by muscle.

Impacts
Improving meat quality would benefit both consumers and livestock producers. Because leaner animals produce meat which is more variable in quality, improvements in meat quality will enable consumers to enjoy tenderness and flavor along with enhanced nutrition and health. Livestock producers will benefit because improvements in meat quality will increase the demand for meat products.

Publications

Kukowski, A.C., Maddock, R.J. and Wulf, D.M. 2004. Evaluating consumer acceptability of various muscles from the beef chuck and rib. J. Anim. Sci. 82:521-525.
Kukowski, A.C., Wulf, D.M., Shanks, B.C., Page, J.K. and Maddock, R.J. 2004. Factors associated with surface iridescence in fresh beef. Meat Sci. 66:889-893.
Koger, T.J., Wulf., D.M., Tjardes, K.E., Mateo, K.S., Engle, T.E., Wright, C.L. and Maddock, R.J. 2004. The influence of feeding various levels of wet and dry distiller's grains on carcass quality, carcass composition, and fatty acid profile of finishing steers. Proc. 57th Annu. Rec. Meat Conf., University of Kentucky.
Sweeter, K.K., Wulf, D.M. and Maddock, R.J. 2004. Determining the optimum ribeye size for beef retail customers. Proc. 57th Annu. Rec. Meat Conf., University of Kentucky.
Searls, G.A., Maddock, R.J. and Wulf, D.M. 2004. Mapping intramuscular tenderness variation within four muscles of the beef chuck. Proc. 57th Annu. Rec. Meat Conf., University of Kentucky.

Progress 01/01/03 to 12/31/03

Outputs
A trial was conducted to determine the effects of USDA quality grade, deep marination, and degree-of-doneness on palatability of gas-grilled beef steaks from seven different muscles. A 7 X 3 X 2 factorial design was used involving seven muscles: gluteus medius (GM), infraspinatus (IF), longissimus (LD), psoas major (PM), rectus femoris (RF), serratus ventralis (SV), and triceps brachii (TB); three classes: top choice (TCH), USDA select (SEL), and deep-marinated USDA Select (DMS); and two degrees-of-doneness: 63C and 79C. Certified Angus Beef (used for TCH) and USDA Select subprimals were purchased commercially, aged 14 d from box date at 3C, and then frozen. One-half of the USDA Select subprimals were pumped 1 d prior to freezing to 108% of green weight with a brine consisting of 91.9% water, 5.0% salt, and 3.1% sodium tripolyphosphate for the DMS class. Steaks (2.5-cm-thick) were cut from frozen subprimals and randomly assigned to degree-of-doneness level and shear force or taste panel. Steaks were thawed 24 h at 3C, seasoned with salt and black pepper, and grilled on popular consumer-model liquid-propane grills. Steaks cooked to 63C had lower shear force, were more tender and juicy, and had more intense beef flavor than steaks cooked to 79C (P<0.05). Top choice steaks had lower shear force, were more tender and juicy, and had more intense beef flavor than SEL steaks (P<0.05). Deep marinated USDA Select steaks had lower shear force, were more tender and juicy, and had more intense beef flavor than SEL steaks (P<0.05). Deep-marinated USDA Select steaks were more tender and had more intense beef flavor than TCH steaks (P<0.05). The interaction of degree-of-doneness and class was significant only for shear force, and indicated that both marbling and deep marination had greater effects on shear force when steaks were cooked to 79C versus 63C. Muscles differed more in tenderness ratings than in juiciness or flavor intensity ratings and ranked from most tender to least tender as follows: PM >IF >LD and RF >SV, TB, and GM (P<0.05). Of the seven muscles, the IF had the most and the LD had the least total off-flavors (P<0.05). Psoas major and IF steaks had the highest and second highest incidence of livery off-flavors, respectively. The interaction of muscle and degree-of-doneness was significant for all palatability traits; palatability of SV steaks was only slightly affected by degree-of-doneness, whereas palatability of GM and LD steaks was much lower at 79C versus 63C. The interaction of muscle and class was significant for shear force and panel tenderness; higher marbling (TCH versus SEL) resulted in more tender IF, LD, SV, and TB steaks (P<0.05), but had no effect on tenderness of GM, PM, and RF steaks (P>0.05). While deep marination improved tenderness in most of the muscles tested, the greatest improvement was observed in LD and TB steaks (P<0.05). In conclusion, DMS steaks had palatability attributes equal to or greater than TCH steaks, but the effects of deep marination and marbling were greater at higher degrees-of-doneness and varied by muscle

Impacts
Improving meat quality would benefit both consumers and livestock producers. Because leaner animals produce meat which is more variable in quality, improvements in meat quality will enable consumers to enjoy tenderness and flavor along with enhanced nutrition and health. Livestock producers will benefit because improvements in meat quality will increase the demand for meat products.

Publications

Maddock, R. J., D. M. Wulf, D. R. McKenna. 2003. The effect of ethoxyquin and Vitamin E supplementation on the display life of beef steaks. J. Food Sci. 68:1072-1074.
Koger, T.J. and D.M. Wulf. 2003. Muscle color, pH, and shear force relationships among eight beef muscles. Proc. 56th Annu. Rec. Meat Conf., University of Missouri. p. 118.
Kukowski, A. C., R. J. Maddock, S. W. Fausti, G. L. Taylor, and D. M. Wulf. 2003. Evaluating consumer acceptability and willingness to pay for various beef chuck muscles. Proc. 56th Annu. Rec. Meat Conf., University of Missouri. p. 119.
Searls, G. A., R. J. Maddock, D. M. Wulf, C. P. Allison, M. E. Doumit, T. W. Hothaus, and R. C. Johnson. 2003. Quality attributes of enhanced case-ready pork loin chops. Proc. 56th Annu. Rec. Meat Conf., University of Missouri. p. 123.
Sweeter, K. K., D. M. Wulf, R. Morrison, L. J. Johnston, and R. J. Maddock. 2003. Effects of finishing pigs using a deep litter, group housing system or a conventional confinement housing system on pork muscle quality. Proc. 56th Annu. Rec. Meat Conf., University of Missouri. p. 124.
Streff, B. A., D. M. Wulf, and R. J. Maddock. 2003. The effect of USDA quality grade, deep marination, and degree-of-doneness on palatability of gas-grilled beef steaks from seven different muscles. Proc. 56th Annu. Rec. Meat Conf., University of Missouri. p. 125.
Walsh, T.A., R. H. Pritchard, D. M. Wulf, and K. W. Bruns. 2003. The influence of calcium metabolism on beef tenderness. J. Anim Sci. 81(Suppl. 1):73.

Progress 01/01/02 to 12/31/02

Outputs
Progeny from Charolais sires and Angus-crossbred cows were used to determine genetic mechanisms for differences in postmortem muscle metabolism that influence beef tenderness. Sires were identified in an earlier study as producing progeny with pale-colored lean and tender meat (Tender sire group; n = one sire; n = eight progeny) or darker-colored lean and tough meat (Tough sire group; n = two sires; n = 10 progeny). Live animal measurements included chute scores, hormone levels, serum chemistry profiles, and live weight; at harvest, hormone levels and serum chemistry profiles were determined. Temperature, pH, and colorimeter values were determined for longissimus (LD), psoas major (PM), semimembranosus (SM), semitendinosus (ST), and triceps brachii (TB) muscles. Fiber typing and SDSPAGE were conducted on LD muscles and selected muscles were sampled for glycolytic potential, purge loss, and sarcomere length determination. Sensory evaluation was performed on LD and SM at 7 and 14 d postmortem and shear force and cooking loss were measured on all muscles examined at various postmortem times. The tender sire group had lower (P < 0.10) cortisol, creatinine phosphokinase, globulin, and total protein levels and higher (P < 0.10) phosphorus than the tough sire group. Carcasses from the tender sire group had lower (P < 0.10) pH at six h postmortem in the LD and ST and lower (P < 0.10) pH at three h postmortem in the SM. Tender sire group carcasses had higher glycolytic potential, longer sarcomeres, and redder and more yellow SM and TB muscles and lighter SM muscles than the tough sire group (P < 0.10). A greater (P < 0.10) amount of 30 kDa region breakdown product was present for the tender sire group at all times postmortem. Steaks from the tender sire group received more desirable (P < 0.10) tenderness scores and lower (P < 0.10) shear force values for LD at 2, 3, 4, 5, 6, 7, 14, 21, and 35 d postmortem, for SM at 4 d postmortem, and for ST at 2, 7, and 14 d postmortem than steaks from the tough sire group. All other measures were similar (P > 0.10) between tough and tender sire groups. Our data suggest that a genetic condition exists in cattle that is characterized by a lessened physiological response to stress resulting in higher postmortem muscle glycogen content and faster pH decline, which leads to longer sarcomeres and enhanced proteolysis causing meat to be more tender. These results could lead to genetic selection for improved tenderness.

Impacts
Improving meat quality would benefit both consumers and livestock producers. Because leaner animals produce meat which is more variable in quality, improvements in meat quality will enable consumers to enjoy tenderness and flavor along with enhanced nutrition and health. Livestock producers will benefit because improvements in meat quality will increase the demand for meat products.

Publications

Reuter, B. J., D. M. Wulf, and R. J. Maddock. 2002. Mapping intramuscular tenderness variation in four major muscles of the beef round. J. Anim. Sci. 80:2594-2599.
Shanks, B. C., D. M. Wulf, and R. J. Maddock. 2002. Technical note: The effect of freezing on Warner-Bratzler shear force values of beef longissimus steaks across several postmortem aging periods. J. Anim. Sci. 80:2122-2125.
Wulf, D. M., R. S. Emnett, J. M. Leheska and S. J. Moeller. 2002. Relationships among glycolytic potential, dark cutting (dark, firm and dry) beef and cooked beef palatability. J. Anim. Sci. 80:1895-1903.
Leheska, J. M., D. M. Wulf, J. A. Clapper, R. C. Thaler and R. J. Maddock. 2002. Effects of high protein/low carbohydrate swine diets during the final finishing phase on pork muscle quality. J Anim. Sci. 80:137-142.
Wheeler, T. L., D. Vote, J. M. Leheska, S. D. Shackelford, K. E. Belk, D. M. Wulf, B. L. Gwartney, and M. Koohmaraie. 2002. The efficacy of three objective systems for identifying beef cuts that can be guaranteed tender. J. Anim. Sci. 80:3315-3327.
Leheska, J. M., D. M. Wulf, and R. J. Maddock. 2002. Effects of fasting and transportation on pork quality development and extent of postmortem metabolism. J. Anim. Sci. 80:3194-3202.
Shanks, B. C., D. M. Wulf, B. J. Reuter and R. J. Maddock. 2002. Increasing tenderness of beef round and sirloin muscles through pre-rigor skeletal separations. J. Anim. Sci. 80:123-128.
Reuter, B. J., D. M. Wulf, B. C. Shanks and R. J. Maddock. 2002. Evaluating the point of separation (break point) between the beef wholesale rib and the beef wholesale chuck. J. Anim. Sci. 80:101-107.
Kukowski, A. C., D. M. Wulf, J. K. Page, and R. J. Maddock. 2002. Factors associated with surface iridescence in fresh beef. Proc. 55th Annu. Rec. Meat Conf., Lansing, MI. p. 140.
Streff, B. A., B. C. Shanks, D. M. Wulf, M. H. Whitney, G. C. Shurson, and L. J. Johnston. 2002. The effect of dried distillers grain with solubles (DDGS) in swine diets on pork muscle and fat quality. Proc. 55th Annu. Rec. Meat Conf., Lansing, MI. p. 138.
Leheska, J. M., D. M. Wulf, and R. J. Maddock. 2002. Effects of fasting and length of transport on pork muscle glycolytic potential and pork quality. Proc. 55th Annu. Rec. Meat Conf., Lansing, MI. p. 136.
Shanks, B. C., D. M. Wulf, and R. J. Maddock. 2002. Relationships among various glucose metabolism traits, fresh beef quality attributes, and cooked beef tenderness. Proc. 55th Annu. Rec. Meat Conf., Lansing, MI. p. 121.

Progress 01/01/01 to 12/31/01

Outputs
One hundred seventy-seven pigs were used to determine the interaction effects of fasting and length of transport prior to harvest on pork muscle quality. The study design was 2 ' 2 ' 3 factorial, which involved two genetic sources, fasting (F) or no fasting (N) of pigs 48-h prior to harvest, and three transport times (0.5, 2.5 or 8.0 h) on a semi-trailer to the packing plant. Fasted pigs had higher longissimus dorsi (LD) ultimate pH (pHu), darker lean color, higher marbling score and lower 7-d purge loss, 24-h drip loss, and cooking loss (P < 0.05) than non-fasted pigs. Meat from pigs that were transported 8.0 h had lower glycolytic potential (GP), higher LD and semimembranosus (SM) pH, darker lean color, and lower L*, 7-d purge loss, 24-h drip loss, cooking loss, and shear force values than meat from pigs transported 0.5 h (P < 0.05). Meat from pigs transported 2.5 h had higher LD and SM pH and lower L*, 7-d purge loss, 24-h drip loss, and cooking loss than meat from pigs transported 0.5 h (P < 0.05). Fasting and length of transport each had positive effects on pork quality, but length of transport effects was greater in magnitude. When pigs were transported for 0.5 h, fasting for 48 h prior to harvest improved pork quality, but when pigs were transported 2.5 or 8.0 h fasting had little effect on pork quality. A study was conducted to quantify intramuscular tenderness variation within four muscles from the beef round: biceps femorus (BF), semitendonosus (ST), semimembranosus (SM), and adductor (AD). At 48 h postmortem, the BF, ST, SM, and AD were dissected from either the left or right side of ten carcasses, vacuum packaged, and aged for an additional 8 d. Each muscle was then frozen and cut into 2.5-cm-thick steaks perpendicular to the long axis of the muscle. Steaks were broiled on electric broilers. Location-specific cores were obtained from each cooked steak and Warner-Bratzler shear force was evaluated. Definable intramuscular tenderness variation (SD = 0.56 kg) was almost twice as large as between-animal tenderness variation (SD = 0.29 kg) and 2.8 times as large as between-muscle variation (SD = 0.20 kg). The ranking of muscles from greatest to least definable intramuscular tenderness variation was BF, SM, ST, and AD (SD = 1.09, 0.72, 0.29, and 0.15 kg respectively). The BF had its lowest shear force values at the origin (sirloin end), intermediate shear force values at the insertion, and its highest shear force values in a middle region 7 to 10 cm posterior the sirloin-round break point (P < 0.05). The BF had lower shear force values towards the ST side than towards the vastus lateralis side (P < 0.05). The ST had its lowest shear force values in a 10 cm region in the middle, and its highest shear force values towards each end (P < 0.05). The SM had its lowest shear force values in the first 10 cm from the ischial end (origin), and its highest shear force values in a 13 cm region at the insertion end (P < 0.05). These data indicate that definable intramuscular tenderness variation is substantial and could be used to develop alternative fabrication and (or) merchandising methods for beef round muscles.

Impacts
Improving meat quality would benefit both consumers and livestock producers. Because leaner animals produce meat which is more variable in quality, improvements in meat quality will enable consumers to enjoy tenderness and flavor along with enhanced nutrition and health. Livestock producers will benefit because improvements in meat quality will increase the demand for meat products.

Publications

Page, J. K., D. M. Wulf and T. R. Schwotzer. 2001. A survey of beef muscle color and pH. J. Anim. Sci. 79:678-687.
Eibs, M. S., B. J. Johnson, D. M. Wulf, B. C. Shanks and T. A. Wittig. 2001. Effect of high oil corn and vitamin E supplementation on ground beef case-life properties. J. Anim Sci. 79(Suppl. 1):440.
Reuter, B. J., D. M. Wulf, B. C. Shanks, J. M. Bok and R. J. Maddock. 2001. Mapping intramuscular tenderness variation in four major muscles of the beef round. Proc. 54th Annu. Rec. Meat Conf. (vol. II), Indianapolis, IN. p. 376.
Bok, J. B., D. M. Wulf, B. C. Shanks, B. A. Reuter and R. J. Maddock. 2001. Effects of high protein/low carbohydrate swine diets during the final finishing phase on pork muscle quality. Proc. 54th Annu. Rec. Meat Conf. (vol. II), Indianapolis, IN. pp. 373-374.
Shanks, B. C., D. M. Wulf, B. J. Reuter, J. M. Bok and R. J. Maddock. 2001. Improving tenderness of beef round and sirloin muscles through pre-rigor skeletal separations. Proc. 54th Annu. Rec. Meat Conf. (vol. II), Indianapolis, IN. p. 372.
Eibs, M. S., B. J. Johnson, D. M. Wulf, B. C. Shanks and T. A. Wittig. 2001. Effect of high oil corn and vitamin E supplementation on beef steak case-life properties. Proc. 54th Annu. Rec. Meat Conf. (vol. II), Indianapolis, IN. p. 366.
Whitney, M. H., G. C. Shurson, L. J. Johnston, D. Wulf and B Shanks. 2001. Growth performance and carcass characteristics of grow-finish pigs fed increasing levels of distiller's dried grains with solubles. J. Anim Sci. 79(Suppl. 1):108.

Progress 01/01/00 to 12/31/00

Outputs
A study was conducted to attempt to lower the glycogen stores in pork muscle in order to improve pork muscle quality by feeding an ultra-high protein/ low carbohydrate (HIPRO) diet composed primarily of extruded soybeans. Fifty barrows at 92 kg were randomly housed in one of ten pens. All barrows consumed a control diet (13.1% crude protein) until their assigned treatment began. A treatment was defined by the number of days that the barrows consumed the HIPRO diet prior to harvest (0 d, 2 d, 4 d, 7 d, and 14 d prior to harvest; two pens per treatment). The HIPRO diet was made of 97% extruded soybeans (35.9% crude protein). Feeding the HIPRO diet had negative effects on feed intake, rate of gain, and feed efficiency (P< .05). Weight gain per day decreased the longer the pigs consumed the HIPRO diet (P< .05). Daily feed intake decreased during the first week on the HIPRO diet, but returned to near control diet levels during the second week, which when coupled with the continued decreases in daily gain, resulted in substantial decreases in feed efficiency during the second week of the HIPRO diet (P< .05). Blood glucose levels and muscle glycogen levels were not lowered through feeding the HIPRO diet (P> .05); and therefore, no differences in rate of pH decline or ultimate pH among dietary treatments were found (P > .05). Likewise, temperature, Py, color, firmness, marbling, water holding capacity, and Warner Bratzler shear force values did not differ among dietary treatment (P> .05). Another study was conducted using thirty crossbred steers to explore and compare tenderness improvements in beef round and sirloin muscles resulting from various methods of pre-rigor skeletal separations. Animals were slaughtered according to industry procedures and at 60 min postmortem one of six treatments was randomly applied to each side: A) control, B) saw pelvis at the sirloin-round junction, C) separate the pelvic-femur joint, D) saw femur at mid-point, E) combination of B and C, and F) combination of B and D. After 48-h, the following muscles were excised from each side and aged for 10 d: semimembranosus (SM), biceps femoris (BF-R), semitendinosus (ST), and adductor (AD) from the round; vastus lateralis (VL) and rectus femoris (RF) from the knuckle; and gluteus medius (GM), biceps femoris (BF-S) and psoas major (PM) from the sirloin. Most skeletal separation treatments resulted in longer sarcomeres than controls for SM, AD, ST, and GM muscles. All skeletal separation treatments yielded shorter sarcomeres for the PM as compared to controls. Warner-Bratzler shear force differed among treatments for RF, ST and PM. For RF, treatments C, D, E, and F resulted in lower (P< 0.05) shear values than for controls. Treatments B, D, and F increased shear force of the ST relative to controls (P< 0.05) within muscle. Treatment F resulted in higher shear force values for the PM than controls (P< 0.05). Correlations between sarcomere length and shear force were found to be low and quite variable among muscles.

Impacts
Improving meat quality would benefit both consumers and livestock producers. Because leaner animals produce meat which is more variable in quality, improvements in meat quality will enable consumers to enjoy tenderness and flavor along with enhanced nutrition and health. Livestock producers will benefit because improvements in meat quality will increase the demand for meat products.

Publications

Wulf, D. M. and J. K. Page. 2000. Using measurements of muscle color, pH, and electrical impedance to augment the current USDA beef quality grading standards and improve the accuracy and precision of sorting carcasses into palatability groups. J. Anim. Sci. 78:2595-2607.
Wulf, D. M. 2000. "Competitive assessment of carcass composition and quality", "Appendix A: How to properly rib a pork carcass", "Appendix B: Examples of carcass contest educational programs". Book chapters in: Pork Carcass Composition and Quality Assessment Procedures. American Meat Science Association, Champaign, IL and National Pork Producers Council, Des Moines, IA.
Wulf, D. M. 2000. "Specifications and grading". Book chapter in: Meat Evaluation Handbook. American Meat Science Association, Champaign, IL.
Shanks, B. C., D. M. Wulf, B. J. Reuter, J. M. Bok, and D. R. Henning. 2000. Effects of -0.5 vs 3.3 degree C refrigeration temperature on storage properties of retail meat products. Proc. 53rd Reciprocal Meat Conference, The Ohio State University. p. 136.
Davis, M. E., H. Y. Chung, H. C. Hines, and D. M. Wulf. 2000. Effects of the calpastatin system on growth of Angus bulls. J. Anim. Sci. 78(Suppl. 1):76.
Chung, H. Y., M. E. Davis, H. C. Hines, and D. M. Wulf. 2000. Effects of calpain and calpastatin genotypes on calpastatin activity and meat tenderness in Angus bulls. J. Anim. Sci. 78(Suppl. 1):76.
Johnson, B. J., D. M. Wulf, M. S. Eibs, B. J. Reuter, J. M. Bok, B. D. Rops, and F. N. Owens. 2000. Impact of high oil corn on meat quality. J. Anim. Sci. 78(Suppl. 1):155.
Chung, H. Y., M. E. Davis, H. C. Hines, and D. M. Wulf. 2000. Relationship of two PCR-RFLPs in the bovine calpastatin gene with calpastatin activity, meat tenderness, and carcass traits. J. Anim. Sci. 78(Suppl. 2):28.
Davis, M. E., H. Y. Chung, H. C. Hines, and D. M. Wulf. 2000. Effects of the calpain system on the growth of Angus bulls. J. Anim. Sci. 78(Suppl. 2):28.
Schoonmaker, J. P., S. C. Lorch, F. L. Fluharty, D. M. Wulf, T. B. Turner, and S. J. Moeller. 2000. Effect of an accelerated finishing program on performance and carcass characteristics of early-weaned bulls and steers. J. Anim. Sci. 78(Suppl. 2):87.