|Bernhard, Bryan -|
|Rounds, W -|
|Rathmann, Ryan -|
|Finck, Derek -|
|Jennings, M -|
|Young, Tanner -|
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 22, 2012
Publication Date: November 13, 2012
Citation: Bernhard, B.C., Sanchez, N.C., Rounds, W., Rathmann, R.J., Carroll, J.A., Finck, D.N., Jennings, M.A., Young, T.R. 2012. Chromium supplementation alters the performance and health of feedlot cattle during the receiving period and enhances their metabolic response to a lipopolysaccharide challenge. Journal of Animal Science. 90(11):3879-3888. Interpretive Summary: This research represents a collaborative effort by scientists from Texas Tech University, the Livestock Issues Research Unit, and Kemin Industries to determine the influence of supplementing newly received cattle with chromium on performance variables and their response to a provacative immune challenge. Newly received cattle in a feedlot are exposed to stress due to weaning, marketing, and handling associated with transportation events. While stress is known to inhibit performance and immune responsiveness, commingling of cattle further increases pathogen exposure, and therefore the risk of disease. Developing methods to enhance performance and immune responsiveness in newly received feedlot cattle can reduce losses and enhance profit. Therefore, we utilized newly received beef steers to determine the effect of supplementing chromium as chromium propionate on performance over a 56-day feeding trial and on the metabolic response of cattle to an immune challenge. Data from this study suggest that supplementing chromium to the basal diet can have beneficial effects on the performance and health of newly received steers during the first 56 days on feed. Specifically, body weight, average daily gain, and dry matter intake tended to increase as the level of chromium supplementation increased. Additionally, the number of cattle treated for respiratory symptoms tended to decrease as the level of chromium supplementation increased. In response to an immune challenge, chromium supplemented steers demonstrated an enhanced glucose and non-esterified fatty acid response, suggesting that chromium supplementation enhanced the availability of energy resources, attenuating weight loss, and thus allowing for a quick recovery from the immune challenge. This data will be of interest to scientists in the fields of stress physiology, nutrition, and immunology as well as cattle producers, and can be used to enhance performance and health of newly received feedlot cattle.
Technical Abstract: Crossbred steers (n = 180; 230 +/- 6 kg) were fed during a 56-d receiving period to determine if supplementing chromium (Cr; KemTRACE®brandChromiumPropionate0.04%, Kemin Industries) would improve feedlot performance and health of newly-received cattle. A completely randomized block design (36 pens; 9 pens/treatmentt; 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 dry matter basis. No differences were detected on d 0 or through the first 14 d on feed. From d 0 to d 28, DMI (P = 0.07) and average daily gain (ADG) increased linearly (P = 0.04) as Cr concentrations increased. From d 0 to d 56, body weight (P = 0.08) and dry matter intake (DMI; P = 0.12) displayed a tendency to increase linearly, and consequently ADG and gain:feed (G:F) increased linearly (P = 0.05) as Cr concentrations increased. The number of head 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 LPS challenge. Cattle were fitted with jugular catheters on d 52. On day 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 microgram/kg BW). Serum glucose, insulin, and non-esterified fatty acid (NEFA) concentrations were determined from blood samples. Steer body weight was also measured at cannulation, and 24 h and 8 d post-LPS. Steers did not differ at cannulation (P = 0.37), but 24 h post-LPS, Cr-supplemented steers had lost less weight (P = 0.03). Pre-LPS glucose concentrations did not differ (P = 0.97). Post-LPS there was a time x treatment interaction (P < 0.01) such that glucose concentrations peaked earlier (0.5 h) and at greater concentrations in Cr-supplemented steers (P < 0.01). Insulin concentrations did not differ between treatments pre- or post-LPS. Concentrations of NEFA did not differ pre-LPS; but 0.5 h post-LPS Cr treated steers produced greater peak NEFA levels (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 during the first 56 d on feed. These data also suggest that supplementation of Cr enhanced the availability of energy resources, attenuating weight loss, and allowed for a quicker recovery following a LPS challenge.