Cattle feedlot diets

Studies examining the effects of caffle diet on E. coli 0157 H7 have primarily focused on fhe gasfroinfesfinal tract and fecal incidence. As a result, the interaction of dief x environment on the levels and persistence of E. coli 0157 H7 in caffle producfion has not been fully appreciafed. In addition to influencing fhe numbers of fhis pathogen that are shed in the feces, cattle diets can impact the extent to which E. coli 0157 H7 can persist in manure or feedlot surface soils. Cattle diets that result in enhanced survival in manure and the production environment can further contribute to the scenarios depicted in Fig. 4.2, by (1) increasing the opportunities for fecal-oral exposures resulting in additional or repeated... 

Feedlot cattle have been fed ionophores for decades to alter rumen microbial flora and to improve feed conversions (Russell and Houlihan, 2003), and an early study observed a tendency for increased . coli 0157 herd prevalence when ionophores were fed (Herriott et al, 1998). Grampositive bacteria are more sensitive to ionophores (Russell and Houlihan, 2003), and commonly fed ionophores, such as monensin or lasalocid, have little effect on the Gram-negative E. coli 0157 H7 in pure culture studies (Bach et al, 2002b Edrington et al, 2003). In feedlot studies with cattle fed grain diets, neither monensin or tylosin altered . coli 0157 H7 fecal prevalence (Jacob et al, 2008b McAllister et ah,... 

Berg, J., McAllister, T., Bach, S., Stilborn, R., Hancock, D., and Lejeune, J. (2004). Escherichia coli 0157 H7 excretion by commercial feedlot cattle fed either barley- or corn-based finishing diets. /. Food Prot. 67, 666-671. 

Fox, J. T., Depenbusch, B. E., Drouillard, J. S., and Nagaraja, T. G. (2007b). Dry-rolled or steam-flaked grain-based diets and fecal shedding of Escherichia coli 0157 in feedlot cattle. /. Anim. Sci. 85,1207-1212. 

Yang WZ, Ametaj BN, Benchaar C, He ML, Beauchemin KA (2010) Ciimamaldehyde in feedlot cattle diets intake, growth performance, carcass characteristics, and blood metabolites. J Arum Feed Sd 88 1082-1092... 

Beauchemin, K. A. and S.M. McGinn, 2005. Methane emissions from feedlot cattle fed barley or com diets. J. Anim. Sci. 83, 653-661. 

Vasconcelos, J.T., R.J. Rathmann, R.R. Reuter, J. Leibovich, J. P. McMeniman, K.E. Hales, T.L. Covey, M.F. Miller, W.T. Nichols and M.L. Galyean, 2008. Effects of duration of zilpaterol hydrochloride feeding and days on the finishing diet on feedlot cattle performance and carcass traits. J. Anim. Sci. 86, 2005-2015. 

In ruminates, replacing soy meal with Camelina meal (2.04 kg of dry matter (DM)) in beef steer diets results in a marked reduction in stress response hormones (Cappellozza et al., 2012). Further, no changes in thyroid function are noted, but this meal reduces acute-phase reactive protein reaction, which is known to increase when cattle are transported or when cattle are introduced to a feedlot setting (Cappellozza et al., 2012). These results are indicative of a positive impact of Camelina meal in reducing stress response in cattle. In dairy cows, Camelina meal (2 kg of DM) results in a marked decrease in milk fat without an impact on total milk production (Hurtaud and Peyraud, 2007). Interestingly, inclusion of Camelina meal results in a marked increase in trans fatty acids, t-10 18 1 and t- 18 1, 11- and 2.6-fold, respectively, and a marked sevenfold increase in c-9, t-11 18 2 (conjugated linoleic acid). This may account for the enhanced spreadabiUty of butter made from milk derived from Camelina meal-fed cows (Hurtaud and Peyraud, 2007). Hence, in a limited number of studies, Camelina meal is observed to have a number of positive effects on the health of cattle, as well as in the parameters associated with milk production and quality. 

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