Performance and carcass quality of steers fed whole raw soybeans at increasing inclusion levels

Short Communication: Use of high-lipid by-product pellets as a partial replacement for barley grain and canola meal in finishing diets for beef steers

Górka, P., McKinnon, J. J. and Penner, G. B. 2013. Short Communication: Use of high-lipid by-product pellets as a partial replacement for barley grain and canola meal in finishing diets for beef steers. Can. J. Anim. Sci. 93: 523–528. The objectives were to determine the effect of the inclusion rate (0%, CON; 30%, HLP30; 60%, HLP60) of high-lipid by-product pellets (HLP) as a partial replacement for barley grain and canola meal on feed intake and growth performance of steers (n=264). Dry matter intake and gain:feed ratio were greater (P<0.01) for HLP30 and HLP60 relative to CON. This study indicates that up to 60% of the barley grain and canola meal in finishing diets for steers can be replaced with HLP, although feed efficiency may be compromised.

Meta-analysis of factors affecting carcass characteristics of feedlot steers

A meta-analysis was conducted to assess the effects of biological type (early-moderate or late maturity) and implant status (estrogenic, combination, or nonimplanted; repeats included) on HCW (kg); LM area (cm2); 12th-rib fat thickness (fat thickness, cm); KPH (%), and intramuscular fat (%) at harvest, to provide inputs to an ongoing program for modeling beef cattle growth and carcass quality. Forty-three publications from 1982 to 2004 with consistent intramuscular fat data were evaluated. Two studies were undertaken: 1) with fat thickness as a covariate and 2) with BW as a covariate. The intercept-slope covariance estimate was not statistically different from 0 for LM area (P = 0.11), KPH (P = 0.19), and intramuscular fat (P = 0.74) in study 1, and for LM area (P = 0.44), fat thickness (P = 0.11), KPH (P = 0.19), and intramuscular fat (P = 0.74) in study 2; therefore, a reduced model without a covariance component was fitted for these carcass characteristics. A covariance component was fitted for HCW (P = 0.01, study 1 and P = 0.05, study 2) and for intramuscular fat (P = 0.05, study 2). In study 1, the results for maturity indicated differences between early-moderate and late maturity for HCW (P < 0.01) and LM area (P < 0.01) but no differences for KPH (P = 0.26) and intramuscular fat (P = 0.50); for implant status, an estrogenic or combination implant increased HCW by 2.9% (P = 0.27) or 4.8% (P < 0.01), increased LM area by 3.2% (P = 0.23) or 6.3% (P < 0.01), decreased intramuscular fat by 8.1% (P < 0.01) or 5.4% (P < 0.01), respectively, and decreased KPH by 7.6% (P = 0.34) for estrogenic implants but increased KPH by 1.1% (P = 0.36) for combination implants, compared with nonimplanted steers. In study 2, the results at 600 kg of BW for implant status (implant or nonimplant) indicated no differences for HCW (P = 0.63) and LM area (P = 0.73), but there were differences for fat thickness (P < 0.01), KPH (P < 0.01), and intramuscular fat (P < 0.01); the results for maturity (early-moderate or late maturity) indicated no differences for HCW (P = 0.94), but there were differences for LM area (P < 0.01), fat thickness (P < 0.01), KPH (P < 0.01), and intramuscular fat (P < 0.01). The difference between early-moderate and late maturity (studies 1 and 2) confirmed that frame size accounts for a substantial portion of the variation in carcass composition. Studies 1 and 2 also indicate that implant status had significant effects on carcass quality.

Increasing the amount of n-3 fatty acid in meat from young Holstein bulls through nutrition1

Fifty-four Holstein bulls were blocked by initial BW (301 +/- 7.4 kg) and randomly assigned to 6 treatments following a 3 x 2 factorial arrangement, with 3 concentrate lipid levels (5, 8, and 11% of DM) and 2 lipid sources (whole canola seed and whole linseed), with the objective of evaluating the possibility of increasing the content of n-3 fatty acids in meat. Concentrates (mostly corn meal) were isonitrogenous and isocaloric. Concentrate and straw were both fed ad libitum. Animal BW was recorded every 2 wk, and feed consumption was recorded weekly. Ruminal pH and VFA concentrations were determined monthly. Bulls were transported to the slaughterhouse when they achieved the target slaughter weight of 443 kg (after 105 +/- 4 d of fattening). After slaughter, a sample of LM from the sixth to the eighth ribs was dissected and analyzed for intramuscular fat content and fatty acid profile. Dietary lipid source did not affect overall animal performance, rumen fermentation, or carcass quality. Rumen pH was >6.0 despite consumption by the bulls of large amounts of concentrate. In bulls fed linseed, the percentage of n-3 fatty acids in LM increased linearly with lipid level, whereas in bulls fed canola seed it remained constant. The ratio of n-6:n-3 fatty acids was lower (P < 0.01) in the LM of bulls fed linseed (10.0) than in those fed canola seed (26.0). The content of cis-9, trans-11-CLA in the LM tended (P = 0.06) to be greater in the bulls fed linseed than in those fed canola seed (62.9 vs. 49.2 mg/kg of LM, respectively). Concentration of n-3 fatty acids in meat of bulls fed high-concentrate diets can be enhanced by whole linseed supplementation without affecting animal performance, ruminal fermentation, or carcass quality.

Effect of refined soy oil or whole soybeans on intake, methane output, and performance of young bulls

An experiment was conducted to establish the effects of feeding refined soy oil (RSO) or whole soybeans (WSB) containing soy oil on DMI, animal performance, and enteric methane (CH4) emissions in young bulls. Thirty-six Charolais and Limousin cross-bred, young beef bulls (338 +/- 27 kg of BW, 218 +/- 17 d of age at the beginning of the experiment) were blocked by BW, age, and breed before being assigned in a randomized complete block design to 1 of 3 experimental treatments (n = 12). The experimental period lasted for 103 d, with enteric CH4 output recorded for 2 periods of 5 consecutive days on d 37 to 41 and d 79 to 83. The 3 dietary treatments consisted of a barley/soybean meal-based concentrate with 0 g/d of RSO; oil from WSB as 6% of DMI (WSB treatment); and oil from RSO as 6% of DMI (RSO treatment). Each diet had a 10:90 forage:concentrate ratio, using barley straw as the forage source. Diet affected DMI (P < or = 0.001) and GE intake (P < 0.05 during the CH4 measurement periods), with the WSB treatment producing the lowest values. The addition of WSB decreased ADG (P < 0.05) compared with the RSO treatment. The WSB treatment also decreased (P < 0.05) average daily carcass gain (ADCG). Both the RSO and WSB concentrates decreased (P < 0.05 to P < 0.001) daily enteric CH4 output when expressed in terms of liters per day, liters per kilogram of DMI, percentage of GE intake, liters per kilogram of ADG, and liters per kilogram of ADCG. Diet had no effect (P = 0.557) on ruminal protozoal numbers. The reductions in enteric CH4 were achieved at relatively high oil inclusion levels. Such oil levels have previously been reported to decrease DMI of high-forage diets, although no effect on DMI was noted with the low-forage diets fed in this experiment. This impact on DMI of high-forage diets may limit the range of diets for which this CH4 reduction strategy may be applicable. The inclusion level of WSB in the current experiment (27%) was beyond the palatability threshold of the bulls used and resulted in a marked decline in intake and performance. Therefore, WSB may have a role to play in ruminant diets, but only at a reduced inclusion rate.

Effect of processing flax in beef feedlot diets on performance, carcass characteristics, and trained sensory panel ratings1

To assess the effects of flax addition and flax processing on feedlot performance and carcass characteristics, 128 yearling beef heifers (360 +/- 14 kg of initial BW) were blocked by weight and assigned randomly to feedlot diets that included no flax (control), whole flax (WHL), rolled flax (RLD; 1,300 microm), or ground flax (GRD; 700 microm). Heifers were fed a growth diet (31% corn, 30% corn silage, 18% barley malt pellets, 14% alfalfa, 4% linseed meal, and 3% supplement; DM basis) for 56 d, after which they were adapted to a finishing diet (79% corn, 7% corn silage, 7% alfalfa, 4.75% linseed meal, and 2.25% supplement; DM basis). In WHL, RLD, and GRD, flax replaced all linseed meal and partially replaced corn at 8% of diet DM. All diets provided 0.5 mg of melengestrol acetate, 2,000 IU of vitamin E, and 232 mg of monensin per heifer daily. Cattle were slaughtered by block after 96, 97, and 124 (2 blocks) d on feed. At 24 h postmortem, carcass data were collected, and a portion of the loin was removed, vacuum-packaged, and aged for 14 d. After aging, 2 steaks were removed from each loin for Warner-Bratzler shear force measurement, sensory panel evaluation, and fatty acid analysis (approximately 100 g of muscle was collected). Flax inclusion (WHL, RLD, and GRD vs. control) did not affect DMI (P = 0.79), fat thickness over the 12th rib (P = 0.32), or LM area (P = 0.23). Flax inclusion increased ADG (P = 0.006), G:F (P = 0.006), and USDA yield grade (P = 0.01). Flax processing (RLD and GRD vs. WHL) increased ADG (P = 0.05), G:F (P = 0.08), and apparent dietary NEm and NEg (P = 0.003). Muscle from heifers fed flax had greater phospholipid 18:3n-3 (P < 0.001), 20:5n-3 (P < 0.001), 22:5n-3 (P < 0.001), and 22:6n-3 (P = 0.02) fractions, and greater neutral lipid 18:3n-3 (P < 0.001). Feeding 8% flax to feedlot heifers increased gain and efficiency, and processing flax increased available energy and resulted in increased efficiency of gain. Feeding 8% flax also increased levels of n-3 fatty acids in fresh beef.