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To assess plasma trace mineral (TM) concentrations, the acute phase protein response, and behavior in response to a lipopolysaccharide (LPS) challenge, 96 Angus cross steers (average initial body weight [BW]: 285 ± 14.4 kg) were sorted into two groups by BW (heavy and light; n = 48/group), fitted with an ear-tag–based accelerometer (CowManager SensOor; Agis, Harmelen, Netherlands), and stagger started 14 d apart. Consecutive day BW was recorded to start the 24-d trial (days −1 and 0). Dietary treatments began on day 0: common diet with either 30 (Zn30) or 100 (Zn100) mg supplemental Zn/kg DM (ZnSO4 ). On day 17, steers received one of the following injection treatments intravenously to complete the 2 × 3 factorial: 1) SALINE (~2–3 mL of physiological saline), 2) LOWLPS: 0.25 µg LPS/kg BW, or 3) HIGHLPS: 0.375 µg LPS/kg BW. Blood, rectal temperature (RT), and BW were recorded on day 16 (−24 h relative to injection), and BW was used to assign injection treatment. Approximately 6, 24 (day 18), and 48 (day 19) h after treatment, BW, RT, and blood were collected, and final BW recorded on day 24. Data were analyzed in Proc Mixed of SAS with fixed effects of diet, injection, diet × injection; for BW, RT, dry matter intake (DMI), plasma TM, and haptoglobin-repeated measures analysis were used to evaluate effects over time. Area under the curve analysis determined by GraphPad Prism was used for analysis of accelerometer data. Body weight was unaffected by diet or injection (P ≥ 0.16), but there was an injection × time effect for DMI and RT (P < 0.05), where DMI decreased in both LPS treatments on day 16, but recovered by day 17, and RT was increased in LPS treatments 6 h post-injection. Steers receiving LPS spent less time highly active and eating than SALINE (P < 0.01). Steers in HIGHLPS spent lesser time ruminating, followed by LOWLPS and then SALINE (P < 0.001). An injection × time effect (P < 0.001) for plasma Zn showed decreased concentrations within 6 h of injection and remained decreased through 24 h before recovering by 48 h. A tendency for a diet × time effect (P = 0.06) on plasma Zn suggests plasma Zn repletion occurred at a greater rate in Zn100 compared to Zn30. These results suggest that increased supplemental Zn may alter the rate of recovery of Zn status from an acute inflammatory event. Additionally, ear-tag–based accelerometers used in this study were effective at detecting sickness behavior in feedlot steers, and rumination may be more sensitive than other variables. [ABSTRACT FROM AUTHOR]

To assess relative bioavailability (RBV) of hydroxy and organic Cu sources compared with CuSO4 in steers fed a high Cu antagonist diet, 84 steers were stratified by BW to pens randomly assigned to dietary treatments for 90 d. Steers received a common corn silage-based diet supplemented with Cu antagonists (diet analyzed 0.25% S; 6.8 mg Mo/kg DM). Supplemental (SUPP) Cu treatments included: control (CON ; no SUPP Cu), low or high inorganic (ING5 or ING10 ; 5 or 10 mg Cu/kg DM from CuSO4; Old Bridge Chemical Inc. Old Bridge, NJ, USA), low or high organic (ORG5 or ORG10 ; 5 or 10 mg Cu/kg DM from Cu lysine; CuPlex 100, ZinPro Corp. Eden Prairie, MN), and low or high hydroxy (HYD5 or HYD10 ; 5 or 10 mg Cu/kg DM; IntelliBond CII, Micronutrients USA LLC, Indianapolis, IN). Body weights were recorded on days −7, −6, 28, 56, 84, and 85, and plasma samples collected on days −7, 28, 56, and 85. Liver samples were collected to start and end the trial. Data were analyzed using the mixed procedure of SAS and the model included treatment with initial liver Cu values used as a covariate in analysis of final liver Cu. Contrast statements were used to separate treatment means: 0 vs. 5 mg SUPP Cu/kg DM, 0 vs. 10 mg SUPP Cu/kg DM, 5 vs. 10 mg SUPP Cu/kg DM, HYD vs. ORG, HYD vs. ING, and ORG vs. ING. Initial liver Cu concentrations were similar across all treatment comparisons (P ≥ 0.22). Final liver Cu concentrations were lesser in CON compared with either 5 or 10 mg Cu/kg DM (P ≤ 0.001). Final liver concentrations were lesser in ORG compared with HYD and ING (P ≤ 0.009), but HYD was similar to ING (P = 0.14). There was a treatment × time interaction (P ≤ 0.001) for plasma Cu concentrations where CON exhibited a rapid decline in plasma Cu, steers receiving 5 mg SUPP Cu/kg DM were decreased to a greater extent in ORG, and steers supplemented with 10 mg Cu/kg DM did not differ at the end of the trial. Assessment of RBV was conducted for liver and plasma Cu concentrations using a slope-ratio assay in the GLM procedure. The RBV of Cu tended (P = 0.07) to be increased in HYD (112%) compared with ING (100%) for liver Cu values, but RBV was similar for all other source comparisons based on liver and plasma Cu values (P ≥ 0.22). These data suggest in steers fed high antagonist diets hydroxy Cu may be more available. Based on plasma and liver Cu concentrations, supplementation of 10 mg Cu/kg DM is needed to maintain Cu status in cattle fed diets high in S and Mo. [ABSTRACT FROM AUTHOR]