|Arthington, J - UNIVERSITY OF FLORIDA|
|Qiu, X - UNIVERSITY OF FLORIDA|
|Cooke, R - UNIVERSITY OF FLORIDA|
|Vendramini, J - UNIVERSITY OF FLORIDA|
|Araujo, D - UNIVERSITY OF FLORIDA|
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 7, 2008
Publication Date: October 1, 2008
Repository URL: http://jas.fass.org/cgi/reprint/86/8/2016.pdf
Citation: Arthington, J.D., Qiu, X., Cooke, R.F., Vendramini, J.M., Araujo, D.B., Chase, C.C., Coleman, S.W. 2008. Effects of pre-shipping management on measures of stress and performance of beef steers during a feedlot receiving period. Journal of Animal Science. 86:2016-2023. Interpretive Summary: Three of the most stressful events encountered by a feeder calf are weaning, transportation, and entry into the feedlot. Stressors associated with weaning and shipping are key factors affecting subsequent calf health and performance. Previous research efforts on early weaning calves have reported improved feedlot performance. This response appears to be related, at least in part, to reduced plasma concentrations of acute phase proteins. This study was conducted to evaluate the effects of four pre-weaning management systems on subsequent performance during the first 30 days in the feedlot. Steers were allocated to one of four treatments: 1) control – weaned on the day of shipping; 2) creep fed – allowed free choice access to concentrate prior to weaning and shipping; 3) pre-weaned – weaned and provided supplemental concentrate on pasture prior to shipping; and 4) early weaned – weaned at 70 to 90 days of age and kept on pasture. On the day of shipping, steers were loaded onto a commercial livestock trailer and transported 1,600 km over 24 hours. During the first 30 days at the feedlot, average daily gain and feed intake and efficiency were greater for early weaned compared to control steers. Average feed intake was greater for pre-weaned compared to creep fed, but feed efficiency was similar. Acute phase protein profiles after shipment indicated that haptoglobin concentrations were higher in creep fed than pre-weaned steers. Ceruloplasmin concentrations after shipment were higher in control than early-weaned steers, and at times were higher in creep fed steers than pre-weaned steers. Results suggest that early weaned steers have a productivity advantage over those weaned and shipped on the same day (control). The acute phase protein response is affected by pre-weaning management system.
Technical Abstract: Over two 2 yr, a total of 96 steers (approx. 7 mo of age) were allocated 1 to 4 weaning management strategies: 1) control: weaned on the day of shipping; 2) creep-fed: allowed free-choice access to concentrate prior to weaning and shipping; 3) pre-weaned: weaned and provided supplemental concentrate on pasture prior to shipping; and 4) early-weaned: weaned at 70 to 90 d of age and kept on pasture. On the day of shipping steers were loaded together onto a commercial livestock trailer and transported 1,600 km over 24 h before being received into the feedlot. At the feedlot, steers were penned by treatment (4 pens/treatment) and provided access to free-choice hay and concentrate in separate feeding spaces. Samples of blood were collected on d 0, 1, 4, 8, 15, 22, and 29 relative to shipping. Steer performance was assessed over the receiving period, including percent transport shrink, DMI of hay and concentrate, ADG, and G:F. Pre-determined contrasts included: control vs. early-weaned, creep-fed vs. pre-weaned, and control vs. creep-fed and pre-weaned. Overall ADG was greater (P<0.01) for early weaned vs. control steers. In wk 1, early-weaned steers consumed more concentrate and less hay compared to control steers (P < 0.01) and pre-weaned steers consumed more concentrate (P < 0.01), but a similar amount of hay (P = 0.59) compared to creep-fed steers. Average DMI intake was greatest for early-weaned compared to control (P = 0.01), and pre-weaned compared to creep-fed steers (P < 0.01). Feed efficiency of early-weaned steers was greater than control (P < 0.01), but similar for pre-weaned compared to creep-fed steers (P = 0.68). Haptoglobin concentrations were less in creep-fed vs. pre-weaned steers on d 0 (P < 0.05), but increased sharply after shipping and were greater than pre-weaned steers on d 1 and 4 (P < 0.05). In Yr. 1, control steers experienced a sharp increase in ceruloplasmin concentrations, resulting in concentrations greater (P < 0.05) than early-weaned steers on d 15, 22, and 29. Creep-fed steers also experienced greater (P < 0.05) ceruloplasmin concentrations than pre-weaned steers on d 29 (Yr. 1) and d 4 (Yr. 2). These data suggest that early-weaned steers have improved performance in the receiving yard compared to steers weaned directly prior to transport and feedlot entry. Differences in pre-shipping management appear to significantly impact measures of the acute phase protein response in steers.