Dehydrated citrus pulp alters feedlot performance of crossbred heifers during the receiving period and modulates physiological and acute phase responses and metabolite concentrations

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dc.contributor.committeeChairRathmann, Ryan J.
dc.contributor.committeeMemberJohnson, Bradley J.
dc.contributor.committeeMemberCarroll, Jeffery A.
dc.creatorCribbs, Joshua
dc.date.accessioned2016-11-14T23:37:19Z
dc.date.available2013-01-24T21:47:20Z
dc.date.available2016-11-14T23:37:19Z
dc.date.issued2012-12
dc.description.abstractA study was designed to determine the effects of feeding dehydrated citrus pulp (DCP) on feedlot performance of newly-received English × Continental heifers. Heifers (n=180) were sourced in two loads (188.7 ±18.0 kg and 225.2 ± 22.2 kg, respectively) from commercial auction barns and placed on trial at the Texas Tech University Beef Center in New Deal, Texas. A completely randomized block design was utilized with BW nested within arrival load and blocked by BW. Three dietary treatments were fed (36 pens; 5 heifers/pen; 12 blocks; 3 pens/block; 12 pens/treatment). Treatment diets were formulated to contain: 1) 0%; 2) 10%; or 3) 20% DCP on a DM basis. Diets containing DCP were formulated to be exchanged with steam flaked corn on a 1:1 basis. Cattle were fed a 63, 73, and 83% concentrate diet from d 0 to 28, d 28 to 42, and d 42 to 56, respectively. Over the entire 56-d trial period, as the amount of dietary DCP increased DMI decreased (P = 0.02; 6.70, 6.13, and 5.96 kg, for 0, 10, and 20% DCP, respectively), ADG decreased (P < 0.0001; 1.88, 1.27, and 1.00, respectively), and G: F decreased (P = 0.02; 0.225, 0.210, 0.191, respectively). From d 0 to d 28 there was no difference in the observed, minus the expected NEg of the diet (P = 0.73), from d 28 to d 42 there was a linear increase in NEg with an increase in the percentage of DCP (P=0.003), and from d 42 to d 56 there was a linear increase in NEg favoring CON cattle over DCP cattle (P = 0.006). At the conclusion of the trial a subset of heifers (n = 24; 218.3 ± 2.4 kg) were utilized to evaluate the physiological and acute phase responses (APR) to an endotoxin (lipopolysaccharide; LPS) challenge. On d 63, heifers were fitted with jugular catheters and moved into individual stalls. On d 64, heifers were challenged i.v. with LPS (0.5 µg/kg BW), and blood samples were collected every 0.5 h from -2 to 8 and again at 24 h relative to LPS challenge (0h). Sickness behavior scores (SBS) were assigned following collection of each blood sample. Serum was analyzed for cortisol, interleukin-6 (IL-6), interferon-γ (IFN-γ), and tumor necrosis factor-α (TNF-α) concentrations as well as serum glucose, blood urea nitrogen (BUN), and non-esterified fatty acid (NEFA) concentrations. Post-LPS SBS increased (P < 0.01) and were greater in 10% DCP than 20% DCP and CON. Heifer BW was measured at cannulation, and 24 and 72-h ) post-LPS. BUN levels showed a treatment effect pre-LPS favoring CON cattle (P < 0.01). Post-LPS glucose, NEFA, and BUN concentrations were greater in CON cattle (P < 0.01) cortisol concentrations were greatest in 10% DCP heifers than CON and 20% DCP treatments ( P < 0.01). IFN-γ, TNF-α, and IL-6 increased post-LPS (P < 0.01) and were greater in 20% DCP over 10% DCP and CON treatments ( P < 0.01). These data indicate that dietary DCP can modulate both the physiological and APR of newly-received heifers to an endotoxin challenge, and it effects feedlot performance variables.
dc.format.mimetypeapplication/pdf
dc.identifier.urihttp://hdl.handle.net/2346/47508
dc.language.isoeng
dc.rights.availabilityUnrestricted.
dc.subjectDehydrated citrus pulp
dc.subjectPeripheral lipopolysaccharide (LPS) challenge
dc.subjectAcute phase response
dc.titleDehydrated citrus pulp alters feedlot performance of crossbred heifers during the receiving period and modulates physiological and acute phase responses and metabolite concentrations
dc.typeThesis

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