Ó. López-Campos

Effects of feeding flaxseed or sunflower-seed in high-forage diets on beef production, quality and fatty acid composition.

Yearling steers were fed 70:30 forage:concentrate diets for 205 d, with either grass hay (GH) or red clover silage (RC) as the forage source, and concentrates containing either sunflower-seed (SS) or flaxseed (FS), each providing 5.4% oil to diets. Feeding diets containing SS versus FS significantly improved growth and carcass attributes (P<0.05), significantly reduced meat off-flavor intensity (P<0.05), and significantly increased intramuscular proportions of vaccenic (t11-18:1), rumenic (c9,t11-CLA) and n-6 fatty acids (FA, P<0.05). Feeding diets containing FS versus SS produced significantly darker and redder meat with greater proportions of atypical dienes (P<0.05). A significant forage × oilseed type interaction (P<0.05) was found for n-3 FA, α-linolenic acid, and conjugated linolenic acid, with their greatest intramuscular proportions found when feeding the RC-FS diet. Feeding GH versus RC also significantly improved growth and carcass attributes, sensory tenderness (P<0.05) and significantly influenced intramuscular FA composition (P<0.05), but overall, forage effects on FA profiles were limited compared to effects of oilseed.

Greenhouse Gas Emissions from Calf- and Yearling-Fed Beef Production Systems, With and Without the Use of Growth Promotants

Simple Summary A spring calving herd (~350 beef cows) over two production cycles was used to compare the whole-farm greenhouse gas (GHG) emissions among calf-fed vs. yearling-fed production systems, with and without growth implants. Farm GHG emissions initially included enteric CH4, manure CH4 and N2O, cropping N2O, and energy use CO2. The carbon footprint ranged from 19.9–22.5 kg CO2e per kg carcass weight. Including soil organic carbon loss from annual cropping and carbon sequestration from perennial pastures and haylands further reduced the carbon footprint by 11–16%. The carbon footprint of beef was reduced by growth promotants (4.9–5.1%) and by calf-fed beef production (6.3–7.5%). Abstract A spring calving herd consisting of about 350 beef cows, 14–16 breeding bulls, 60 replacement heifers and 112 steers were used to compare the whole-farm GHG emissions among calf-fed vs. yearling-fed production systems with and without growth implants. Carbon footprint ranged from 11.63 to 13.22 kg CO2e per kg live weight (19.87–22.52 kg CO2e per kg carcass weight). Enteric CH4 was the largest source of GHG emissions (53–54%), followed by manure N2O (20–22%), cropping N2O (11%), energy use CO2 (9–9.5%), and manure CH4 (4–6%). Beef cow accounted for 77% and 58% of the GHG emissions in the calf-fed and yearling-fed. Feeders accounted for the second highest GHG emissions (15% calf-fed; 35–36% yearling-fed). Implants reduced the carbon footprint by 4.9–5.1% compared with hormone-free. Calf-fed reduced the carbon footprint by 6.3–7.5% compared with yearling-fed. When expressed as kg CO2e per kg carcass weight per year the carbon footprint of calf-fed production was 73.9–76.1% lower than yearling-fed production, and calf-fed implanted was 85% lower than hormone-free yearling-fed. Reducing GHG emissions from beef production may be accomplished by improving the feed efficiency of the cow herd, decreasing the days on low quality feeds, and reducing the age at harvest of youthful cattle.

Near infrared reflectance spectroscopy predicts the content of polyunsaturated fatty acids and biohydrogenation products in the subcutaneous fat of beef cows fed flaxseed

This study examined the ability of near infrared reflectance spectroscopy (NIRS) to estimate the concentration of polyunsaturated fatty acids and their biohydrogenation products in the subcutaneous fat of beef cows fed flaxseed. Subcutaneous fat samples at the 12th rib of 62 cows were stored at -80°C, thawed, scanned over a NIR spectral range from 400 to 2498 nm at 31°C and 2°C, and subsequently analysed for fatty acid composition. Best NIRS calibrations were with samples at 31°C, showing high predictability for most of the n-3 (R(2): 0.81-0.86; RMSECV: 0.11-1.56 mg g(-1) fat) and linolenic acid biohydrogenation products such as conjugated linolenic acids, conjugated linoleic acids (CLA), non-CLA dienes and trans-monounsaturated fatty acids with R(2) (RMSECV, mgg(-1) fat) of 0.85-0.85 (0.16-0.37), 0.84-0.90 (0.21-2.58), 0.90 (5.49) and 0.84-0.90 (4.24-8.83), respectively. NIRS could discriminate 100% of subcutaneous fat samples from beef cows fed diets with and without flaxseed.

The impact of ultimate pH on muscle characteristics and sensory attributes of the longissimus thoracis within the dark cutting (Canada B4) beef carcass grade

Canada B4 beef carcasses are penalized because the longissimus thoracis (LT) at the grade site (12-13th ribs) is darker than the color threshold for normal bright cherry-red beef. Previous studies have shown that not all B4 carcasses have pH>6.0; therefore, the relationship between LT pH and meat quality was investigated by collecting thirty half-carcasses comprised of the following: ten Canada AA (AA, control), ten B4 with LT pH>6.0 (CL, classic), and ten B4 with LT pH<6.0 (AT, atypical). LT from CL carcasses had the lowest mean lactate level, lowest glucidic potential and highest mean pH value. LT muscle from CL and AT carcasses was dark and had decreased purge, drip loss and cooking loss. Warner-Bratzler shear force values and sensory panel results showed that AT beef was toughest (P<0.0001), substantiating economic penalty. Causal mechanisms for AT carcasses may be inconsistent with traditional DFD theory because of close to normal final muscle pH.

At line prediction of PUFA and biohydrogenation intermediates in perirenal and subcutaneous fat from cattle fed sunflower or flaxseed by near infrared spectroscopy

NIRS potential to estimate the proportion of PUFA and their biohydrogenation products in adipose tissues from cattle fed sunflower or flaxseed was tested. Immediately after skinning, perirenal and subcutaneous fat samples from 63 steers were collected, scanned intact at 37°C and 33°C, respectively, over a NIR spectral range from 400 to 2498nm using benchtop equipment and then analyzed for fatty acid composition. NIRS calibrations in perirenal fat showed high predictability for total and major omega-6 and omega-3, conjugated linolenic acids, t,t-conjugated linoleic acids (CLA), non-CLA dienes and trans-monounsaturated fatty acids, with R(2) (RMSECV, %) of 0.88-0.89 (0.16-0.20), 0.89-0.91 (0.07-0.08), 0.86-0.89 (0.01-0.09), 0.82 (0.07), 0.89 (0.46) and 0.86-0.88 (0.87-1.29), respectively. NIRS predictions in subcutaneous fat were less reliable, probably due to lower fatty acid variability. The results show NIRS to be a useful technique for the early, fast and relatively inexpensive estimation of proportions of fatty acids with potential human health effects in cattle perirenal fat.

Use of near infrared spectroscopy for estimating meat chemical composition, quality traits and fatty acid content from cattle fed sunflower or flaxseed.

This study tested the ability of near infrared reflectance spectroscopy (NIRS) to predict meat chemical composition, quality traits and fatty acid (FA) composition from 63 steers fed sunflower or flaxseed in combination with high forage diets. NIRS calibrations, tested by cross-validation, were successful for predicting crude protein, moisture and fat content with coefficients of determination (R(2)) (RMSECV, g·100g(-1) wet matter) of 0.85 (0.48), 0.90 (0.60) and 0.86 (1.08), respectively, but were not reliable for meat quality attributes. This technology accurately predicted saturated, monounsaturated and branched FA and conjugated linoleic acid content (R(2): 0.83-0.97; RMSECV: 0.04-1.15mg·g(-1) tissue) and might be suitable for screening purposes in meat based on the content of FAs beneficial to human health such as rumenic and vaccenic acids. Further research applying NIRS to estimate meat quality attributes will require the use on-line of a fibre-optic probe on intact samples.

Effects of calf- and yearling-fed beef production systems and growth promotants on production and profitability

López-Campos, Ó., Aalhus, J. L., Okine, E. K., Baron, V. S. and Basarab, J. A. 2013. Effects of calf- and yearling-fed beef production systems and growth promotants on production and profitability. Can. J. Anim. Sci. 93: 171–184. In each of 2 yr, 112 spring-born steers were used to evaluate the effect of calf-fed vs. yearling-fed with and without growth implant and ß-adrenergic agonist on production parameters and economic potential. Steers were grouped into: (1) non-implanted feeders harvested at 11-14 mo of age, (2) growth implanted feeders harvested at 11-14 mo of age, (3) non-implanted feeders harvested at 19-23 mo of age, and (4) growth implanted feeders harvested at 19-23 mo of age. Production data were collected and economic evaluation was performed. Calf-fed steers grew slower (1.21 vs. 1.99±0.07 kg d-1) and had a poorer feed conversion ratio [5.32 vs. 4.99±0.34 kg dry matter intake (DMI) kg-1 gain] during the feedlot dietary adjustment period than yearling-fed. Calf-fed steers were more efficient than yearling-fed during the first 76-83 d (5.16 vs. 7.33±0.11 kg DMI kg-1 gain) and latter 48-79 d (5.69 vs. 14.28±1.50 kg DMI kg-1 gain) of the finishing period. Implanted steers were more efficient than non-implanted during the dietary feedlot adjustment period (4.80 vs. 5.52±0.15 kg DMI kg-1 gain), and during the first 76-83 d (6.05 vs. 6.44±0.11 kg DMI kg-1 gain) and latter 48-79 d of the finishing period (9.29 vs. 10.69±1.50 kg DMI kg-1 gain). Implanted steers grew 11.4-19.6% faster than non-implanted throughout the finishing period, while yearling-fed grew 11.1-12.9% faster during the first 76-83 d, but 49.1-64.4% slower during the last 48-79 d of the finishing period compared with calf-fed. Quality grade was improved for non-implanted steers, with 43.6% of yearling-fed and 35.7% calf-fed steers grading AAA. Adjusted net return was best for calf-fed implanted (

Rapid discrimination of enhanced quality pork by visible and near infrared spectroscopy

17.52 head-1), followed by calf-fed non-implanted (

Review: Canadian beef grading - Opportunities to identify carcass and meat quality traits valued by consumers

-41.92 head-1), yearling-fed implanted (

Effects of feeding steers extruded flaxseed on its own before hay or mixed with hay on animal performance, carcass quality, and meat and hamburger fatty acid composition

-73.77 head-1), and yearling-fed non-implanted (