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This Article Full Text (PDF) All Versions of this Article: jas.2008-0875v1 86/11/3125    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Mir, P. S. Articles by Yip, B. Search for Related Content PubMed PubMed Citation Articles by Mir, P. S. Articles by Yip, B.

Effects of dietary sunflower seeds and tylosin phosphate on production parameters, carcass characteristics, fatty acid composition, and liver abscess incidence in crossbred steers

P. S. Mir^*, M. E. R. Dugan, M. L. He^*, T. Entz^* and B. Yip^*

^* Agriculture and Agri-Food Canada, 5304, 1^st Ave. S., P.O. Box 3000, Lethbridge, AB, Canada. T1J 4B1 Agriculture and Agri-Food Canada, 6000 C&E Trail, Lacombe, AB, Canada. T4L 1W1

mirp{at}agr.gc.ca

Abstract

A 2 x 2 factorial experiment with 48 crossbred steers (with Hereford, Angus, Charolais genetics, and initial BW of 373 ± 8.4 kg) was conducted to evaluate effects of dietary sunflower seeds (SS) and tylosin phosphate (TP) on production factors, carcass characteristics, liver abscess incidence, and fatty acid composition of muscle (pars costalis diaphgramatis; PCD) and subcutaneous fat (SF). Individually penned steers were fed either a control diet of 84.5% rolled barley, 14% barley silage, and 1.5% mineral, and vitamin mix on DM basis, or a SS diet, where SS replaced 15% of the diet. Half the animals fed each diet received TP at 11mg/kg DM as a top-dress. Interactions were significant for all production factors. A reduction (P = 0.008) in DMI was observed in steers from 10.1 ± 0.4 kg/d fed the control diet to 8.9 ± 0.3 and 8.6 ± 0.3 kg/d fed SS and SS+TP diets, respectively. Greater (P = 0.014) ADG was observed for steers fed the control diet than those fed SS or SS+TP diets (1.4 vs 1.1 and 1.2 SE = 0.1 kg/d; respectively); however, G:F ratios were greater (P = 0.011) in steers fed the control diets than in those fed the SS diets. Steers fed the control and SS diets had the heaviest and lightest HCW (347 ± 6.9 vs 325 ± 8.4 kg; P = 0.025) respectively. Lean meat yield (%) of steers fed SS was greater (P = 0.117) than those fed control diets, while total lean yield [(HCW x lean meat yield)/100] was similar (P = 0.755). Provision of SS or SS+TP diets eliminated (P = 0.08 for interaction) liver abscesses relative to the 36 and 9% incidence in steers fed control and control+TP diets, respectively. Fatty acid weight percentages (wt%) followed similar patterns in PCD and SF. Feeding SS diets led to greater (P = 0.001) wt% of 18:0 and 18:2n-6, but reduced that of 16:0, 9cis (c)-18:1 and 18:3n-3 in PCD relative to that in steers fed control diets, but wt% of 9 c, 11 trans (t) and 10t,12c conjugated linoleic acid (CLA) were increased (P = 0.001) by 36 and 400% in PCD. Dietary SS increased (P < 0.001) wt% of trans-18:1 isomers, 10t-18:1 and 11t-18:1 were the greatest, but dietary TP elevated (P = 0.004) only 10t-18:1, yet total trans-18:1 (excluding 11t-18:1) was 0.47 ± 0.06g/100g of PCD. Dietary SS for finishing steers reduced liver abscesses incidence, without affecting total lean yield of the carcass with modest increases in trans fatty acids and potentially beneficial fatty acids (11t-18:1 and CLA).

Key Words: carcass characteristics • conjugated linoleic acid • liver abscesses • sunflower seeds • trans fatty acids • tylosin phosphate