Chromium supplementation alters the performance and health of feedlot cattle during the receiving period and enhances their metabolic response to a lipopolysaccharide challenge.

Crossbred steers (n = 180; 230 ± 6 kg) were fed during a 56-d receiving period to determine if supplementing chromium (Cr; KemTRACE Chromium Propionate 0.04%, Kemin Industries) would improve feedlot performance and health of newly-received cattle. A completely randomized block design (36 pens; 9 pens/treatment; 5 steers/pen) was used. Chromium premixes were supplemented to add 0 (Con), 0.1, 0.2, or 0.3 mg/kg of Cr to the total diet on a DM basis. No differences were detected on d 0 or after the first 14 d on feed. From d 0 to d 28, DMI (P = 0.07) and ADG increased linearly (P = 0.04) as Cr concentrations increased. From d 0 to d 56, BW (P = 0.08) displayed a tendency to increase linearly, and consequently ADG and G:F increased linearly (P ≤ 0.05) as Cr concentrations increased. The number of steers treated at least once for respiratory symptoms tended (P = 0.07) to linearly decrease as Cr concentrations increased. Twenty additional steers (235 ± 4 kg) were fed 56 d to determine if supplementing Cr (Con or 0.2 mg/kg Cr) would alter the metabolic response of newly-received cattle to a lipopolysaccharide (LPS) challenge. Cattle were fitted with jugular catheters on d 52. On d 55, blood samples were collected at 0.5-h intervals from -2 to 8 h, and again at 24 h relative to a LPS challenge (0.5 µg/kg BW) at 0 h. Serum glucose, insulin, and NEFA concentrations were determined from blood samples. Steer BW was also measured at cannulation, and 24 h and 8 d post-LPS. Steer BW did not differ at cannulation (P = 0.37), but 24 h post-LPS, Cr-supplemented steers had lost less BW (P = 0.03). Pre-LPS glucose concentration did not differ (P = 0.97). Post-LPS, there was a time × treatment interaction (P < 0.01) such that glucose concentration peaked earlier (0.5 h) and at a greater concentrations in Cr-supplemented steers (P < 0.01). Insulin concentration did not differ between treatments pre- or post-LPS (P > 0.13). Concentration of NEFA did not differ pre-LPS (P = 0.54); but 0.5 h post-LPS Cr-treated steers produced a greater peak NEFA concentration (P < 0.04). Results of this study indicate that supplementation of Cr to the basal diet can have beneficial effects on the performance and health of newly-received steers. These data also suggest that supplementation of Cr attenuated BW loss and allowed for a quicker recovery after a LPS challenge.

Chromium supplementation alters both glucose and lipid metabolism in feedlot cattle during the receiving period.

Crossbred steers (n = 20; 235 ± 4 kg) were fed for 53 d during a receiving period to determine if supplementing chromium (Cr; KemTRACE Chromium Propionate 0.04%, Kemin Industries, Des Moines, IA) would alter glucose or lipid metabolism of newly received cattle. Chromium premixes were supplemented to add 0 (Con) or 0.2 mg/kg of Cr to the total diet on a DM basis. Cattle were fitted with jugular catheters on d 52. A glucose tolerance test (GTT) and an insulin sensitivity test (IST) were conducted on d 53. Blood samples were collected from -60 to 150 min relative to each infusion. Serum was isolated to determine glucose, insulin, and NEFA concentrations. Throughout GTT, no differences were detected in glucose concentrations, glucose clearance rates (k), or preinfusion insulin concentrations (P > 0.50), but insulin concentrations postinfusion tended (P = 0.06) to be greater for the Cr-supplemented steers. This caused an increase in the insulin to glucose ratio (I:G) from 0 to 150 min postinfusion for the Cr-supplemented steers (P = 0.03). In addition, NEFA concentrations during GTT were lower (P ≤ 0.01) for Cr-supplemented steers both preinfusion and postinfusion. During IST, there was no treatment effect on glucose concentrations preinfusion (P = 0.38), but postinfusion glucose concentrations were greater (P< 0.01) in the Cr-supplemented steers. The k of Cr-supplemented steers tended (P = 0.06) to be faster than Con steers from 30 to 45 min postinfusion. During the same test, there was no treatment effect detected for insulin concentrations (P > 0.33). The I:G were not affected by treatment (P > 0.40).Concentrations of NEFA were reduced (P < 0.01) both preinfusion and postinfusion during IST for Cr-supplemented steers. Results of this study indicate that supplementation of Cr can significantly alter lipid metabolism. This suggests that these steers had less dependence on lipid metabolism for energy or sensitivity of adipose tissue to antilipolytic signals was reduced. Results of glucose and insulin metabolism were inconsistently modified after a GTT and an IST.