McGregor, E M., Campbell, C. P., Miller, S. P., Purslow, P. P. and Mandell, I. B. 2012. Effect of nutritional regimen including limit feeding and breed on growth performance, carcass characteristics and meat quality in beef cattle. Can. J. Anim. Sci. 92: 327–341. The effects of nutritional management regimen and breed on growth performance, carcass attributes, and meat quality were evaluated in 68 British (BRIT) and Continental (CONT) crossbred steers, managed on one of three nutritional regimens: (1) ad libitum access to a 77% corn diet (ALGRAIN), (2) limit feeding initially of the 77% corn diet, followed by ad libitum access to the 77% corn diet (LFGRAIN), and (3) limit feeding initially of a 90% haylage diet, followed by ad libitum access to the 77% corn diet (LFHAYL). Nutritional regimen by breed interactions (P<0.02) were present for average daily gain, dry matter intake (DMI), gain to feed, and shear force. LFHAYL regimen decreased gains to a greater extent for BRIT steers than CONT steers managed on ALGRAIN or LFGRAIN. Feed intakes were similar across nutritional regimens for CONT steers, while DMI was depressed in BRIT on LFHAYL as compared with steers started on ALGRAIN or LFGRAIN. Gain to feed was greater in BRIT cattle on LFGRAIN vs. ALGRAIN, while gain to feed was similar in CONT started on grain (ALGRAIN, LFGRAIN). Shear force was lower for beef from LFHAYL BRIT vs. beef from BRIT on ALGRAIN or LFGRAIN, while the converse was true for CONT. Limit feeding of a high-energy diet may be appropriate for cattle of British background to reduce feed input costs, while ensuring tenderness.

Berthiaume, R., Lafrenie`re, C., Girard, C., Campbell, C. P., Pivotto, L. M. and Mandell, I. B. 2015. Effects of forage silage species on yearling growth performance, carcass and meat quality, and nutrient composition in a forage based beef production system. Can. J. Anim. Sci. 95: 173Á187. Forty weaned, crossbred beef calves (predominantly Angus and Simmental) were forage-finished using all-silage diets (red cloverÁtimothy versus tall fescue) to examine forage species' effects on growth performance, carcass traits, meat quality, and nutrient composition. Weaned calves (257 d of age) were forage-finished using red cloverÁtimothy or tall fescue silage and harvested at approximately 1 yr of age. During carcass processing, one side from each carcass was covered with a polyliner to examine if reducing rates of chilling could compensate for limited fat cover expected from low dietary energy contents fed, and limited time on feed. Longissimus thoracis, semimembranosus, and semitendinosus steaks were aged 10, 14, and 21 d to examine effects on WarnerÁBratzler shear force values while fatty acid and vitamin B 12 composition were determined on 10-d-aged steaks. Average daily gain, feed efficiency, hot carcass weights, and longissimus muscle area were greater (P B0.03) when cattle were fed red cloverÁtimothy versus tall fescue silage, most likely due to the higher protein content of red cloverÁtimothy silage. Shear force was greater (PB0.002) in steaks from all muscles evaluated from cattle fed tall fescue versus red cloverÁtimothy silage. In comparison to 10-d-aged steaks, 14 d of ageing were needed to reduce (P B0.001) shear force for longissimus steaks, while 21 d of ageing were needed to reduce (PB0.001) shear force for semitendinosus steaks. Use of a polyliner decreased (P 00.0001) the rate of temperature decline at selected carcass sites, but did not reduce shear force values. The percent of n-3 fatty acids and polyunsaturated fatty acid/saturated fatty acid ratio were greater (PB0.04) in longissimus from cattle fed red cloverÁ timothy versus feeding tall fescue silage. Feeding red cloverÁtimothy silage improved growth performance, carcass, shear force, and fatty acid composition traits versus feeding tall fescue silage.

Glanc, D. L., Campbell, C. P., Cranfield, J., Swanson, K. C. and Mandell, I. B. 2015. Effects of production system and slaughter weight endpoint on growth performance, carcass traits, and beef quality from conventionally and naturally produced beef cattle. Can. J. Anim. Sci. 95: 37–47. Effects of production system and slaughter endpoint on performance, carcass traits, and beef quality were investigated in 64 Simmental cross steers (minimum 75% Continental breeding). Cattle were allocated to: (1) conventional production system based on use of implants and dietary ionophores or (2) natural production system in which no implants or ionophores were used. Within each production system, cattle were allocated for slaughter at 545 or 636 kg liveweight. Steers were fed an 85.5% concentrate diet based on high-moisture corn, soybean meal, and alfalfa silage. Average daily gain tended to be greater (P<0.06) in conventional production system cattle, while there was a trend (P<0.08) for production system by endpoint interactions for dry matter intake and gain to feed. Natural production system cattle tended to have greater (P<0.08) marbling and percent intramuscular fat (%IMF) with lower (P<0.09) longissimus shear force, while production system by endpoint interactions were present (P ≤ 0.03) for%IMF and carcass lean composition via rib dissection. At-home consumer evaluation of longissimus muscle steaks found tenderness, juiciness, flavour, and overall acceptability rankings were greater (P<0.01) for steaks slaughtered from heavier cattle (636 vs. 545 kg liveweight). Marketing cattle at lighter slaughter weights may have benefits for performance at the expense of eating quality.

Campbell, C. P., Haley, J., Swanson, K. C. and Mandell, I. B. 2013. Packing plant differences in meat quality for grain-fed veal. Can. J. Anim. Sci. 93: 205–215. Packing plant differences in meat quality were investigated in grain-fed veal from three commercial packing plants and a university research facility. Postmortem chilling rates were investigated in three plants including facilities which encased carcass sides in a polyliner bag intended to reduce shrinkage during chilling. Packing plant differences (P ≤ 0.01) in chilling rates were not always accompanied by plant differences in sarcomere length for longissimus or semitendinosus muscles. Drip and cooking losses and shear force for longissimus varied (P≤0.04) across packing plant with lower (P≤0.02) values found in veal slaughtered at the university research facility vs. veal from commercial packing plants. A packing plant by postmortem ageing interaction (P<0.05) for shear force was due to differences in extent of postmortem tenderization with ageing across packing plants. While use of a polyliner to encase the carcass during chilling decreased (P<0.001) rate of chilling and carcass shrinkage, there was no effect (P>0.20) on drip loss, shear force, or cooking losses vs. carcasses chilled uncovered.