|Young, Tanner - Texas Tech University|
|Carroll, Jeffery - Jeff Carroll|
|Jennings, Michael - Texas Tech University|
|Cribbs, Joshua - Texas Tech University|
|Rathmann, Ryan - Texas Tech University|
|Corley, Jimmie - Lesaffre Yeast|
|Johnson, Bradley - Texas Tech University|
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 3/5/2012
Publication Date: 6/25/2012
Citation: Young, T.R., Sanchez, N.C., Carroll, J.A., Jennings, M.A., Cribbs, J.T., Rathmann, R.J., Corley, J.R., Johnson, B.J. 2012. Yeast cell wall supplementation alters the performance and physiological response of beef heifers following an immune challenge [abstract]. Journal of Animal Science. 90:221(E-Suppl. 3).
Technical Abstract: A study was designed to determine the effect of feeding yeast cell wall (YCW) products on the performance response and vaginal temperature of crossbred heifers following a subcutaneous endotoxin (lipopolysaccharide; LPS) challenge. Heifers (n=83; 225±9.4 kg) were obtained from commercial sale barns and transported to the Texas Tech University Beef Center in New Deal, Texas, sorted by source (n=2), and arranged in a completely randomized block design (21 pens; 7 pens/treatment; 4 heifers/pen). Heifers were separated into treatment groups receiving a Control Diet (CON; n=28), YCW A (2.5 grams/head/day; n=28), or YCW C (2.5 grams/head/day; n=27). On day 56, heifers were fitted with indwelling vaginal temperature (VT) recording devices. Heifers were then challenged subcutaneously with LPS (0.5 micrograms/kg body weight) on day 63. Daily dry matter intake was recorded and individual body weight was collected on days 63 and 77. In Source 1, YCW C exhibited greater average daily gain (P<0.01) and gain to feed (P=0.01) compared to CON. There was an increase in VT in all treatments post-LPS (P<0.01), with YCW C (39.14±0.006 degree C) maintaining greater VT post-LPS than CON (38.89±0.006 degree C) and YCW A (38.92±0.008 degree C; P<0.05). In Source 2, no significant differences in performance were observed. There was an increase in VT in all treatments post-LPS (P<0.01), with YCW C (38.91±0.024 degree C) maintaining greater VT post-LPS than CON (38.83±0.024 degree C) and YCW A (38.83±0.024 degree C; P<0.05). Ambient temperature was extremely high during this study (>45 degree C), indicating a period of high heat stress. Collectively, these data suggest that YCW supplementation can affect the physiological response to a mild endotoxin challenge during high heat stress, and thereby alter feedlot performance of newly received beef heifers.