He, M. L., Gibb, D., McKinnon, J. J. and McAllister, T. A. 2013. Effect of high dietary levels of canola meal on growth performance, carcass quality and meat fatty acid profiles of feedlot cattle. Can. J. Anim. Sci. 93: 269–280. This study investigated the effect of substituting canola meal (CM) for barley grain on growth performance, carcass quality and meat fatty acid (FA) profiles of feedlot cattle. Cross bred calves (n=140; 285±27 kg) were individually fed diets comprised of a barley grain based concentrate (including 5% supplement) and barley silage at ratios of 45:55 and 92:8 (DM basis) during growing and finishing periods, respectively. Pressed CM from Brassica napus, containing 11.4% residual oil and solvent-extracted CM derived from B. napus or Brassica juncea canola seed were compared. Canola meal was substituted for 0 (control), 15, or 30% barley grain (DM basis) in both growing and finishing diets. Regardless of diet, cattle did not differ (P>0.05) in average daily gain in either the growing or finishing period. For the overall feeding period, inclusion of 30% CM increased (P<0.01) DMI of cattle compared with 15% CM groups, but reduced (P<0.05) gain: feed (G:F) as compared with control and 15% B. juncea and 15% pressed CM. Gain: feed of cattle fed CM was also reduced (P<0.05) during the finishing period as compared with the control diet with this reduction being more notable at the 30% level. Carcass quality and incidence of liver abscesses were not affected (P>0.05) by inclusion of CM. Inclusion of 30% pressed CM resulted in higher (P<0.05)%FAME of total polyunsaturated fatty acid, n-3, alpha-linolenic acid and conjugated linoleic acid (CLA), and a decrease (P<0.05) in n-6/n-3 ratio in the pars costalis diaphragmatis muscle as compared with the control diet. In conclusion, inclusion of CM did not alter the growth performance or G:F of beef cattle during the growing period, but did lower G:F during the finishing period. The inclusion of 15 or 30% solvent-extracted CM did not alter carcass quality, whereas 30% pressed CM increased the levels of desirable fatty acids (i.e., n-3 and CLA) in beef.
The pesticide trichlorfon is readily degraded under experimental conditions to dichlorvos. A method has therefore been developed by which residues of trichlorfon in milk are determined as dichlorvos, using gas chromatography with μ-electron capture detection. The identification of dichlorvos was confirmed by mass spectrometry. Milk was extracted with acetonitrile followed by centrifugation, freezing lipid filtration, and partitioning into dichloromethane. The residue after partitioning of dichloromethane was dissolved in ethyl acetate for gas chromatography. Recovery concentration was determined at 0.5, 1.0, and 2.0 of times the maximum permitted residue limits (MRLs) for trichlorfon in milk. The average recoveries (n = 6) ranged from 92.4 to 103.6%. The repeatability of the measurements was expressed as relative standard deviations (RSDs) ranging from 3.6%, to 6.7%. Limit of detection (LOD) and limit of quantification (LOQ) were 3.7 and 11.1 μg/l, respectively. The accuracy and precision (expressed as RSD) were estimated at concentrations from 25 to 250 μg/l. The intra- and inter-day accuracy (n = 6) ranged from 89.2%to 91% and 91.3% to 96.3%, respectively. The intra- and inter-day precisions were lower than 8%. The developed method was applied to determine trichlorfon in real samples collected from the seven major cities in the Republic of Korea. No residual trichlorfon was detected in any samples.
He, M. L., Xu, L., Yang, W. Z., Gibb, D. and McAllister, T. A. 2014. Effect of low-oil corn dried distillers’ grains with solubles on growth performance, carcass traits and beef fatty acid profile of feedlot cattle. Can. J. Anim. Sci. 94: 343–347. The objective of this study was to investigate the effects of dietary inclusion of low-oil corn dried distillers’ grains with solubles (LO-DDGS) on growth, carcass traits and beef fatty acids profiles of finishing feedlot cattle. One hundred and eighty British crossbred steers (450±28.5 kg; six pens/treatment) were offered barley grain-barley silage as the control diet with LO-DDGS replacing barley grain at 200 and 300 g kg−1 dry matter basis in treatment diets. Compared with control, LO-DDGS at 200 g kg−1 did not affect growth performance or carcass traits, whereas at 300 g kg−1 it decreased (P<0.05) gain:feed, but increased (P<0.05) levels of desirable fatty acids in beef. LO-DDGS can replace 200 g kg−1 barley grain in finishing feedlot diets without undesirable impacts on growth performance or carcass traits.
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