Carcass Composition Of Steers Research Articles

Reduced age at slaughter in youthful beef cattle: Effects on carcass merit traits

López-Campos, Ó., Basarab, J. A., Baron, V. S., Aalhus, J. L. and Juárez, M. 2012. Reduced age at slaughter in youthful beef cattle: Effects on carcass merit traits. Can. J. Anim. Sci. 92: 449–463. Two-hundred and twenty-four spring-born British×Continental crossbred steers were used in a 2-yr project to evaluate the effect of production system (calf-fed vs. yearling-fed) and its interaction with breed cross and hormone implant strategies, with and without β-adrenergic agonist on carcass characteristics. Carcasses from yearling-fed steers were 32% heavier (P<0.001), resulting in higher (P<0.05) dressing percentages, grade fat and rib-eye (longissimus thoracis) area (REA) (1.1, 32 and 10%, respectively). However, despite being lighter, the estimated lean yield percentage was 3% greater (P=0.010) in carcasses from calf-fed steers. No difference (P>0.05) was observed for marbling scores between production systems. Use of hormonal implants increased (P<0.001) weights of live animals and carcasses (7 and 9%, respectively). However, non-implanted yearling-fed steers had the lowest proportion of Canada Quality Grade A and the highest proportion of Canada Quality Grade AAA carcasses (P<0.001). Moreover, the observed increase (P=0.016) in marbling scores (up to 37%) from British cross-bred steers disappeared with the use of implants. The only effect observed on carcass traits from the use of β-adrenergic agonists was an increase of 6% in REA (P=0.032). The main production system effect observed for carcass composition was a lower (P=0.008) proportion of bone in carcasses from yearling-fed steers. The use of hormonal implants increased (P<0.001) the proportion of lean and decreased (P=0.019) the proportion of fat (P<0.05). Overall carcass composition of steers with large Continental influence (>50%) had a higher proportion of lean and bone and a lower proportion of fat than carcasses from 50–75% British steers (P<0.001), which was also reflected in the composition of several individual primal cuts (e.g., rib, short-loin, flank, chuck and plate). The interactions amongst production systems and the other production factors studied were minimal. Therefore, despite expected differences in carcass size, reducing age at slaughter did not have a negative impact on Canadian beef carcass traits.

Short Communication: Growth and attainment of puberty in calves from cows supplemented with linseed meal during late gestation and early lactation

Ilse, B. R., Anderson, V. L., Buchanan, D. S., Odde, K. G., Lardy, G. P. and Vonnahme, K. A. 2012. Short Communication: Growth and attainment of puberty in calves from cows supplemented with linseed meal during late gestation and early lactation. Can. J. Anim. Sci. 92: 443–447. To test the objective that a linseed meal (LSM) supplement in beef cows during late gestation and early lactation would impact offspring growth performance, steer carcass composition, and attainment of puberty in heifer calves, multiparous beef cows received either LSM or a control supplement for the last 60 d of gestation (exp. 1; n=72) or during the first 60 d of lactation (exp. 2; n=91). In both experiments, birth weight, weaning weight, and ADG of calves were not affected (P>0.31) by LSM supplementation. There was no effect (P>0.09) of supplementation on carcass characteristics of steer progeny fed to market weight. In exps. 1 and 2, attainment of puberty in heifer calves was not influenced (P>0.58) by supplement type. Linseed meal supplementation during late gestation or early lactation does not appear to affect calf growth, onset of puberty in heifer calves, or steer carcass quality.

Effects of energy intake, implantation, and subcutaneous fat end point on feedlot steer performance and carcass composition.

The purpose of this experiment was to evaluate the effects of energy intake, implantation, and fat end point on feedlot performance and carcass composition of steers. Three hundred eighty-four yearling crossbred steers (368 +/- 23.1 kg) were allotted in a completely randomized design. Treatments were arranged in a 2 x 3 x 2 factorial experiment. Main effect factors were two levels of intake, three implant strategies, and two compositional fat end points at slaughter. The levels of intake were ad libitum (AL) and restricted (RS) intake (90% ad libitum). The three implant strategies were Revalor-S (REV) (120 mg trenbolone acetate, 24 mg estradiol), Synovex-Plus (SYN) (200 mg trenbolone acetate, 28 mg estradiol benzoate), and no implant (control). The compositional target end points were 1.0 and 1.4 cm s.c. fat cover over the 12th and 13th rib. Restricted-intake steers consumed 9.2% less (P < .01) DM than AL steers. Ad libitum-intake steers gained weight 15.5% more rapidly (P < .01) than RS-intake steers. Steers implanted with REV tended (P < .07) to gain faster than SYN steers, who in turn gained 15.2% more (P < .01) than control steers. Ad libitum-intake steers were 4.8% more (P < .01) efficient than RS steers. Steers fed to a targeted 1.4 cm s.c. backfat cover were 2.9% less (P < .05) efficient than steers fed to 1.0 cm, and steers implanted with either REV or SYN had similar (P = .47) feed efficiencies, whereas control steers had lower (P < .01) feed efficiencies. Steers fed to a targeted compositional fat end point of 1.4 cm had 1.3% higher (P < .01) dressing percentage (DP) than steers fed to 1.0 cm. Control and SYN steers had similar (P = .13) DP; however, REV steers had 6.1% greater (P < .01) DP than SYN steers. Steers fed to 1.4 cm s.c. fat end point had higher (P < .01) numerical yield grades than steers fed to 1.0 cm (3.34 vs 2.71). There was an interaction (P < .01) for intake level and implant for marbling score. Marbling scores were lower (P < .05) for RS x SYN and AL x REV than in other treatments. Steers on the RS x REV treatment were intermediate in marbling to all treatments except AL control, which was higher (P < .01) than RS x SYN, AL x REV, and RS x REV. No interaction for dry matter intake level and anabolic implants was observed for growth performance. The depression in carcass quality resulting from implanting is reduced as backfat increases from 1.0 to 1.4 cm at slaughter.

Effects of forage:Concentrate ratio in the diet and restricted dry matter intake on the performance and carcass composition of steers

The efficient production of lean beef suitable for current consumer demand necessitates effective rationing of beef cattle. Feeding standards for beef cattle given by ARC (1980) predict that a reduction in energy intake produces a large reduction in performance with little effect on the energy or fat contents of the gain. However previous studies have shown that diets containing a high proportion of grass silage may sustain lower levels of performance and result in a greater proportion of fat in the gain in both calves and finishing cattle, than when similar quantities of energy and protein are given in the form of high-concentrate diets. The effects of a change in energy intake on performance and carcass composition of beef cattle are therefore likely to depend on whether this change is achieved by restricting the quantity of food given or changing the forage: concentrate ratio of a diet given ad libitum.The present experiment was carried out to examine the effects of forage:concentrate ratio in the diet and ad libitum versus restricted dry matter intake on the performance, carcass composition and efficiency of lean meat production by steers.

The effect of plane of nutrition and forage:concentrate ratio on the performance and carcass composition of steers

Consumer demand for leaner beef necessitates a reduction in the fat content of a major proportion of the beef carcasses currently produced. It is generally accepted that reducing the plane of nutrition of beef cattle reduces fat content. However the effects on growth rate and overall efficiency of production are also important. The effects of reducing energy intake on performance and carcass composition may be influenced by the nature of the change in energy intake. An experiment has been carried out to examine the effects of reducing energy intake, either by increasing forage: concentrate ratio (F:C) in the diet or reducing dry matter intake at constant F:C.Thirty-six Friesian (F), Limousin x F and Belgian Blue x F 12-month old steers which were initially 368 kg, and which had been reared under uniform management and nutrition were used. They were purchased from dairy farms during October and November at approximately 10 days old, were aritifically reared and were at pasture from April until October. After a three week acclimatization period they were divided into blocks according to breed and live weight and allocated to the three treatments at random with each block. The three treatments were a complete diet consisting of 0.67 grass silage (719 g digestible organic matter and 144 g crude protein/kg DM; 82 g ammonia N/kg total N) and 0.33 concentrates (0.9 rolled barley and 0.1 soyabean meal) offered (1) ad libitum or (2) at 0.8 of ad libitum intake.

Failure of photoperiod to alter body growth and carcass composition in beef steers.

In each of two experiments, 70 crossbred steers were blocked by BW and assigned to initial slaughter groups or to treatments in a 2 x 2 design. In Exp. 1, treatments were 168 d of photoperiod (8 h of light [L]:16 h of dark [D] or 16L:8D) and plane of nutrition (high energy [HPN] or low energy [LPN]). On d -22, 67 and 155, blood was sampled every 20 min for 8 h. Relative to LPN, HPN increased (P less than .01) ADG by 28%, carcass weight by 26% and accretion of carcass fat by 109% and carcass protein by 20%. On d 155, compared with LPN, HPN increased (P less than .01) serum insulin (INS; 1.09 vs .64 ng/ml) and lowered (P less than .05) growth hormone (GH; 2.14 vs 3.70 ng/ml), but prolactin was not affected. Photoperiod did not affect BW gains, carcass composition or serum hormones. In Exp. 2, treatments were 113 d of photoperiod (8L:16D or 16L:8D) and Synovex-S implant (presence [IMP] or absence [NONIMP]). On d 93, blood was sampled every 30 min for 10 h. Relative to NONIMP, IMP increased (P less than .01) ADG by 12% and accretion of carcass protein by 16%. Implants did not affect carcass weight or accretion of fat. Compared with NONIMP, IMP increased (P less than .05) GH (3.16 vs 2.39 ng/ml) and INS (.68 vs .46 ng/ml) but did not affect PRL. Photoperiod did not affect BW gain, carcass composition or serum hormones. We conclude that photoperiod fails to influence growth and carcass composition of steers.

The effect of zeranol on live weight gain, feed intake and carcass composition of steers during compensatory growth.

To evaluate the effect of zeranol implants in steers on compensatory ++growth, 80 steer calves (9 mo of age; 200 kg) were fed at two feeding levels (RO = 9.2 MJ ME/kg DM; R1 = 6.9 MJ ME/kg DM) for 119 d (Period 1). During Period 2, steers were full-fed to 400 kg BW with (Z1) or without (ZO) zeranol implants. Ten steers were slaughtered at the end of Period 1 to estimate carcass composition. Differences of 100 kg in BW were achieved by restriction in Period 1. Subsequent to restriction, cumulative ADG remained greater (P less than .05) up to the 24th wk of recuperation and implants increased (P less than .001) BW gain by 31% and 24% for RO and R1, respectively. The average daily energy intake (ME/W(.75) in Period 2 was similar for all treatments. Feed conversion was improved by 21.5% (P less than .05) by implants. At the end of Period 2 the R1ZO had 8.6 kg less muscle (P less than .001), 2.9 kg less bone (P less than .001) and 5.9 kg more fat (P less than .05) than the ROZO. In comparison, the carcasses of the implanted animals did not show significant differences (P greater than .05) due to restriction. Carcass daily gains were increased by previous restriction (P less than .01) and implants (P less than .05). Zeranol increased daily live weight gain and feed conversion in animals in continuous growth as well as in those observed in compensatory growth an tended to eliminate a tendency for higher content of fat in carcasses of nonimplanted animals making compensatory growth.

Sire-breed comparison of carcass composition of steers from Angus dams

SUMMARYBody composition of 324 steers from Angus dams by ten different sire breeds was compared at constant age. Progeny of the large European breeds and the Friesian attained heavier fasted live weights and carcass weights than the local Angus and Hereford breeds. Friesian cross-breds had the lowest dressing percentage. The Blonde d'Aquitaine and Limousin crosses had the lightest bone weights and this was reflected in high meat yields. The European breeds had the leanest carcasses, the traditional beef breeds the heaviest subcutaneous fat weights and the dairy breeds the heaviest internal fat weights. The results are discussed in relation to overseas findings.

An examination of sample joint dissection and specific gravity techniques for assessing the carcass composition of steers slaughtered in commercial abattoirs

SummaryThe relationships between joint and carcass specific gravities and composition are examined and the prediction efficiency of equations relating these parameters tabulated. The problems of assessing carcass composition in large abattoirs are indicated. The use of the tenth rib sample joint in conjunction with a specific gravity estimation technique is recommended.