Effects of graded levels of vitamin E on inflammatory response and evaluation of methods of supplementing vitamin E on performance and health of beef steers1

Professional Animal Scientist, Apr 2003 by Rivera, J D, Duff, G C, Galyean, M L, Hallford, D M, Ross, T T

Serum samples were analyzed for non-esterified fatty acids (NEFA) and serum urea nitrogen (SUN) on an Elx 808 Ultra Microplate Reader(R) (Bio Tek Instruments, Inc., Winooski, VT). Non-esterified fatty acids were analyzed using a commercially available enzymatic colorimetric test kit (NEFAC(R); Wako Chemicals, Richmond, VA). Because of equipment limitations, samples were read at 570 nm rather than at 550 nm, as described in the procedure. Serum urea nitrogen concentrations were analyzed using an enzymatic colorimetric kit (urea nitrogen, Sigma P-640; Sigma Diagnostics, St. Louis, MO). To ensure repeatability, duplicate coefficients of variation were kept at 5% or less in both assays. Insulin concentrations were analyzed using a solid-phase radioimmunoassay (Diagnostic Products Corp., Los Angeles, CA) as described by Reimers et al. (1982). The interassay CV was 11.3%.

Body weight, ADG, DMI, and rate of rectal temperature increase were analyzed using a fixed effects model and the GLM procedure of SAS (SAS Inst. Inc., Cary, NC); animal was the experimental unit. Rate of temperature increase was calculated as the difference between d 0 rectal temperature and the rectal temperature that was =39.7[degrees]C, divided by the number of days required to reach that temperature. Rectal temperature, NEFA, SUN, and insulin (INS) data were analyzed as a repeated measures through time using PROC MIXED, with a model that included effects of treatment, day, and day x treatment using the AR-1 covariance structure, after model testing determined the AR-1 to be the best fit. Orthogonal polynomials (linear, quadratic, and cubic) were used to evaluate response to treatment.

Experiment 2. One hundred twenty steer and bull calves were shipped 1,648 km from an order buyer facility in West Point, MS to the CLRC. Cattle were in transit approximately 17 h and experienced a 4.2% shrink from a pay weight of 185 kg. Cattle were processed immediately after arrival, which included vaccination with modified live IBR/PB-BVD-BRSV virus plus Pasteurella haemolytica vaccine, seven-way Clostridial vaccination, and deworming with moxidectin. Additionally, bull calves were castrated surgically (77%), horns were tipped as needed (41%), and each calf was fire-branded. Each animal received an individual ear tag, and individual BW was recorded.

Cattle were assigned randomly to one of three treatments at processing: 2,850 IU of vitamin E administered as a 9.5-mL s.c. injection in the neck region (Vital-E Inectable Tocopherol(R); Schering Plough Animal Health, Union, NJ), an oral drench of 2,850 IU of vitamin E (Vital E Injectable Tocopherol(R) mixed with vegetable oil to give a total volume of 30 mL), or 570 IU/d per animal of vitamin E added to the receiving diet for a period of 5 d. All these treatments were designed to deliver an additional 570 IU per animal daily for 5 d. Additionally, all three treatment groups were fed a standard receiving diet that was formulated to supply 60 IU of vitamin E/kg of feed (Table 1). Pen was the experimental unit, with four pens per treatment and 10 animals per pen.