Location: Livestock Issues ResearchTitle: Yeast probiotic supplementation mitigates some of the negative effects of heat stress in feedlot heifers Author
|Carroll, Jeffery - Jeff Carroll|
|Roberts, Shelby - West Texas A & M University|
|Sharon, Kate - Texas Tech University|
|Richeson, John - West Texas A & M University|
|Corley, Jimmie - Phileo Lesaffre Animal Care|
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 1/8/2016
Publication Date: 3/4/2016
Citation: Broadway, P.R., Carroll, J.A., Sanchez, N.C., Roberts, S.L., Sharon, K.P., Richeson, J.T., Corley, J.R. 2016. Yeast probiotic supplementation mitigates some of the negative effects of heat stress in feedlot heifers. Journal of Animal Science Supplement. 94 (Supplement1):34. Abstract#69.
Technical Abstract: Heat stress (HS) in feedlot cattle can be detrimental to performance, health and profitability; however, utilization of feed additives has the potential to mitigate some of these negative effects. Therefore, this study was designed to determine if supplementation of a combination live yeast and yeast cell wall product in feed could mitigate the negative impacts associated with HS. Crossbred, phenotypically similar beef heifers (n=32; body weight=385 +/-43 kg) were divided into 2 pens in which one pen was fed a standard finishing ration (CON), and the other was fed the same ration plus supplemented via top dress with a combination of a live yeast (1.5grams/head/day) and yeast cell wall product (2.5 grams/head/day; YEAST; Phileo Lessaffre Animal Care, Cedar Rapids, IA). After 50 days of supplementation, cattle were transported to an environmentally controlled facility and placed in individual stanchions where indwelling jugular catheters and vaginal temperature (VT) loggers were inserted. Heifers were kept in thermoneutral (TN) conditions for 48 hours (temperature-humidity index ~67; THI) then were subjected to HS for 4 days (THI~80). From days 2 to 6, hourly blood samples were collected for serum isolation from 1400-1800 hours and again from 2200-0200 hours which represented the targeted peak and nadir of THIs over the 5-day period. A whole blood sample was collected twice daily at 1400 and 2200 hours for complete blood counts (CBC). Data collected included body weight, water intake, respiration rate (RR; measured at 1600 and 2400 hours daily) and serum cortisol, glucose and non-esterified fatty acids. There was no change in body weight (P=0.14) or average daily gain (P=0.53) between the treatments during the heat stress. Yeast supplemented heifers exhibited decreased VT during HS (P<0.01). There was no difference in water intake during the TN phase (P=0.25); however, YEAST heifers consumed more water/hour (P<0.01) and had increased drinking bouts (P<0.01) during HS. Respiration rates were similar (P=0.21) during TN, but YEAST heifers tended (P=0.09) to have decreased RR during HS. There were no differences between treatments when evaluating hematology. There was a tendency (P=0.08) for increased cortisol in the CON heifers during HS; however, glucose (P=0.38) or non-esterified fatty acid (P=0.70) concentrations did not differ. In summary, supplementation of live yeast and yeast cell wall products to feedlot heifers may mitigate some of the negative effects associated with HS in feedlot cattle.