Effects of wheat processing and dietary fat sources on performance, ruminal and blood parameters, and steak fatty acids profile of Holstein steers

The objective of this study was to examine the effects of total mixed rations (TMR) containing wheat grain processed by different methods and different fat sources on growth performance, ruminal fermentation and meat fatty acid composition of growing steers. The experiment, which lasted 14 weeks, involved 28 growing Holstein steers (296±56 kg BW). A 2×2 factorial design was used, with steers receiving two types of wheat processed and two fat sources. Treatments included: (1) steam-flaked wheat (SFW) diet with palm oil (RumiFat); (2) SFW diet with roasted soybean (RSB); (3) formaldehyde-treated wheat (WHCHO) diet with RumiFat; and (4) WHCHO diet with RSB. During the feeding trial, ruminal fluid and blood samples were collected, and after 85 days steer were slaughtered and carcass data were recorded. Results from growth trial of steers showed that final BW and gain as well as feed efficiency and dry matter intake (DMI) were not influenced by dietary treatments. None of the carcass traits studied was significantly by diet, and wheat processing and fat source had no effect on total tract nutrient digestibility. Ruminal parameters were unaffected by diets, except for propionate concentration that was greater (P<0.01) for steers fed SFW. The variables related to metabolic blood profile had a high (P<0.01) range of variation among diets. The polyunsaturated fatty acid (PUFA) and conjugated linoleic acid (CLA) concentrations in steaks were greater significantly from steers fed RSB, whereas the saturated fatty acids (SFA) were higher in steaks from both groups fed RumiFat. Although wheat processing method and fat sources did not affect steer performance, but the use of RSB in steer diets produced steak with a lipid profile that can prevent human diseases.