Higher Warner-Bratzler Shear Force Research Articles

Conventional versus Accelerated Beef Production with Carcass Electrical Stimulation2

Sixty-four 8-too-old steers, produced from 7/8 Simrnental sires mated to crossbred dams, averaged 265 kg initial weight. Forty-eight steers were assigned to an Accelerated (ACC) production system, while 16 steers were assigned to a Conventional (CONV) production system. Steers on the ACC system were fed an 85% concentrate diet; steers on the CONV system were backgrounded for 110 d on a high silage diet and then finished on an 85% concentrate diet. The ACC steers were slaughtered in three groups at average weights of 438, 492 and 554 kg; CONV steers were slaughtered at 591 kg. Days-on-feed were 139 (ACC-I), 174 (ACC-II), 2,0,.2 (ACC-III) and 284 (CONV), respectively. At slaughter, one side of the carcass was pulse-electrically stimulated (ES) with 400 V at 45 min postmortem and the other side served as a nonelectrically stimulated control (C). Semimembranosus (SM) and longissimus (LD) C and ES steaks were removed at 48 and 24 h postmortem, respectively, vacuum packaged, aged 6 d at 2 C, frozen and later thawed for trained sensory panel and Warner-Bratzler shear (WBS) evaluations. Overall average daily gains were not different among slaughter groups, but CONV steers gained faster (P .O5) from CONV steers. Electrical stimulation decreased (P<.05) 2-, 4- and 6-h pH readings. The LD steaks from ACC-II and ACC-III steers were at least equal in all sensory traits, except juiciness, to those from CONV steers. The SM steaks from CONV steers had the highest WBS force and lowest sensory scores. Electrical stimulation decreased (P<.0$) LD myofibrillar and overall tenderness scores, but had no effect on SM palatability.

CARCASS QUALITY CHARACTERISTICS OF THREE-WAY CROSS BEEF CATTLE REARED AT TWO LOCATIONS

Carcass quality characteristics of 3673 steers (M) and heifers (F) born over a 6-yr period (1973–1978) at Brandon, Manitoba (farm conditions) and Manyberries, Alberta (range conditions) were compared. The progeny produced were out of 10 specific F1 crosses of dams mated to bulls of the Charolais (C), Simmental (S), Limousin (L) and Chianina (Chi) breeds. Dam crosses included Hereford × Angus (HA) and crosses sired by C, S and L out of H, A and Shorthorn (N) dams. Calves weaned at Manyberries were fed and evaluated at Lacombe. Sex differences, at both locations, indicated F&gt;M for Warner-Bratzler shear force. At Brandon, M&gt;F for conformation score, F&gt;M for firmness score and F&gt;M for percentage protein. For Lacombe data, M&gt;F for chemical fat percentage, F&gt;M for water holding capacity and F&gt;M for percentage moisture. Terminal sire breed differences in the paired comparisons involving progeny of Chi (the comparisons with maximum degrees of freedom) indicated Chi progeny to have the highest color scores (darker cherry red) and C progeny the lowest (lighter cherry red), Chi progeny the lowest percentage chemical fat and C the highest, and Chi progeny the highest percentage moisture and C the lowest at both locations. At Brandon, the progeny ranking for Warner-Bratzler shear force was S&gt;Chi&gt;L, for pH Chi&gt;S = L, for texture score Chi&gt;C = S = L and Chi progeny had the lowest conformation scores and L progeny the highest. At Lacombe, significant progeny differences were recorded for Warner-Bratzler shear force with Chi&gt;L and for water retention capacity S&gt;Chi. At Brandon, breed of sire of dam effects indicated the progeny from S-cross dams had the highest texture scores. Progeny from L-cross dams had the lowest percentage chemical fat, the lowest skeletal maturity scores, and the highest percentage moisture. Progeny from C-cross dams had the highest conformation scores. At Lacombe, progeny from S-cross dams had the highest Warner-Bratzler shear force. At both locations, progeny from dams of Shorthorn breeding had the highest marbling scores. Direct comparison of progeny from exotic cross dams vs. progeny from HA dams at both locations indicated that the progeny from HA dams had lower color scores (lighter cherry red), a lower percentage moisture, higher marbling scores and a higher percentage chemical fat. At Lacombe, the HA dams had progeny with lower Warner-Bratzler shear force. At Brandon, the progeny from the HA dams had lower texture scores, higher firmness scores, a lower percentage protein and generally had lower conformation scores. The differences found between breeds of terminal sire and breed cross of dam for the traits evaluated are not of any commercial consequence. Key words: Cattle, breeds, carcass, quality

Growth and carcass characteristics of crossbred and straightbred Hereford steers. II. Carcass measurements and composition

The effect of sire breed on the growth and development of carcass characteristics was examined in 104 steer carcasses, over the weight range of c. 300 to 600 kg liveweight. The carcasses were obtained from 28 straightbred Hereford, 27 Brahman x Hereford, 23 Simmental x Hereford and 26 Friesian x Hereford steers, which were grown on pasture and slaughtered in four groups when the Herefords weighed c. 270, 370, 470 and 570 kg liveweight. Changes in carcass characteristics with weight were examined by using the linear form of the allometric equation (log10Y = log10A+blog10X). As liveweight increased, the proportion of carcass in the body increased (b = 1.152). At the same liveweight, Brahman cross steers had heavier carcasses than the Hereford steers, which were heavier than either the Simmental or Friesian cross steers (P &lt; 0.05). Fat thickness at the 12th-13th rib site, and kidney and channel fat weight both increased at a proportionally faster rate than carcass weight (b = 1.511 and 1 567 respectively). At the same carcass weight, Hereford and Brahman cross carcasses had a greater fat thickness than Simmental and Friesian cross carcasses (P i 0.05). Differences between sire breeds in kidney and channel fat weight were not significant (P &gt; 0.05). C:rcass length and eye muscle area increased at a proportionally slower rate than carcass weight (b = 0.268 and 0.466 respectively). At the same carcass weight, Friesian cross carcasses were longer, and Simmental cross carcasses had a larger eye muscle area than the other breed crosses (P &lt; 0.05). As total side weight increased, the proportions of subcutaneous and intermuscular fatAincreased (b = 1.554 and 1.535 respectively), and the proportions of muscle and bone decreased (b = 0.938 and 0.676 respectively). At the same side weight, the Hereford and Brahman cross carcasses had more subcutaneous fat than the Simmental and Friesian cross carcasses (P &lt; 0.05). The Hereford carcasses had more intermuscular fat than the Simmental cross carcasses, which had more muscle than the other breed crosses (P &lt; 0.05). Friesian cross carcasses had more bone than the Simmental crosses, with Brahman cross and Hereford carcasses having the least bone (P &lt; 0.05). Brahman cross carcasses had a higher conformation score than the Simmental cross and Hereford carcasses, the Friesian cross carcasses having the lowest (P &lt; 0.05). Samples of the M. longissimus from Brahman cross carcasses had a higher Warner-Bratzler shear force than samples from the other breed crosses (P &lt; 0.05).

The beef tenderness model

In Phase1 of this study, three breed types (Simmentaler-, Brahman- and Nguni bulls; n = 60 each) were grain-fed and slaughtered at 12 months of age (A-age, fat-class 2). Feed was withdrawn for either three hours or 24 hours pre-slaughter. Within each feed withdrawal group, three electrical stimulation (ES) treatments were applied, viz. ES for 15 seconds, 120 seconds or no stimulation. In Phase 2, the effects of animal age and feeding regime were investigated using of A-age (feedlot and pasture), AB-age (feedlot and pasture) and B-age (pasture) animals. All carcasses were electrically stimulated for 15 seconds. Longer feed withdrawal increased dark-firm-dry (DFD) meat occurrence (pHu &gt;6) in the Nguni and Simmentaler-cross. Brahman-cross longissimus (LL) tended to be more tender with paler colour and higher drip loss when 120 ES was applied. Longer feed withdrawal recorded higher Warner Bratzler shear force (WBSF) than three hour feed withdrawal. However, ES neutralized the effect of stress on tenderness. On average the AB-age feedlot animals produced the most tender LL followed by the B-age pasture and A-age feedlot which was similar to the AB-age pasture. A-age pasture animals produced the least tender LL steaks. The calpain proteolytic system played a pivotal role in determining the ultimate meat tenderness and although connective tissue becomes less soluble in older animals it did not play the determinant role in tenderness in this study. The intramuscular fat (&lt; 3%) played an important role in the tenderness outcome of Nguni LL which marbled well at AB-age.Keywords: Meat tenderness, pH and temperature decline profile, pre- and post-slaughter conditions, production systems