Recipient Organization
OREGON STATE UNIVERSITY
(N/A)
CORVALLIS,OR 97331
Performing Department
Animal and Rangeland Sciences
Non Technical Summary
Bovine respiratory disease (BRD) is the most common and costly disease of feedlot cattle in the US. Preconditioning programs that include vaccination for viral and bacterial agents that cause BRD are one of the most effective management methods that mitigate the incidence of this disease. In typical western US beef operations that adopt preconditioning programs, calves receive vaccination against BRD pathogens at weaning and are revaccinated 30 days later at feedlot entry. However, weaning and feedlot entry are two of the most stressful situations encountered by feeder cattle, and vaccine efficacy can be reduced if administered to highly-stressed animals. In addition, vaccination against BRD pathogens elicits innate immune responses known that impair cattle performance, particularly during feedlot receiving. Therefore, altering the time of vaccination/revaccination against BRD pathogens is a strategy that has been recently, but partially, investigated. Research conducted to date focused on delaying the time of vaccination by 2 weeks following a stressful situation, and indicated that delaying vaccination increased performance and seroconversion to a BRD pathogen in feedlot cattle. However, the majority of BRD cases occur within the first 14 days upon feedlot arrival, and delaying revaccination by 2 weeks may not provide full immunological protection against BRD pathogens to newly-received feeder calves. Based on this rationale, we hypothesized that anticipating vaccination and revaccination against BRD pathogens by 2 weeks is a strategy to further enhance vaccine efficacy, health variables, and performance traits of in feeder cattle. One example is providing the initial vaccination 15 days prior to weaning, and revaccination 15 days prior to shipping to the feedlot within a 30-day preconditioning program. This strategy would allow for vaccine administration during periods of minimal tress, ensure that cattle receive both doses and are better protected against BRD prior to feedlot entry, and eliminate the performance losses caused by vaccination during feedlot receiving. Therefore, the goal of the proposed research is compare the effects of anticipated (15 days prior), delayed (15 days after), or vaccination at the time of weaning and feedlot entry on vaccine efficacy, health, and performance variables of feeder cattle.
Animal Health Component
70%
Research Effort Categories
Basic
30%
Applied
70%
Developmental
0%
Goals / Objectives
Compare the effects of anticipated (15 days prior), delayed (15 days after), or vaccination at the time of weaning and feedlot entry on vaccine efficacy, health, and performance variables of feeder cattle.
Project Methods
One hundred and eight Angus × Hereford calves (54 steers and 54 heifers) born in February 2015 will be assigned to the experiment. All calves were vaccinated against clostridial diseases (Clostrishield 7; Novartis Animal Health; Bucyrus, KS) and bovine virus diarrhea complex (Virashield 6 + Somnus; Novartis Animal Health) at 45 days of age (April 2015). Calves are being reared on semi-arid rangeland pastures (Ganskopp and Bohnert, 2009) with their respective dams until weaning at 7 months of age (day 0 of the experiment; September 2015). Fifteen days before weaning (day -15 of the experiment), calves will be ranked by gender, dam's parity, body weight, and age, and assigned to 1 of 3 treatments:Control:Initial vaccination: At weaning (day 0 of the experiment), calves will be vaccinated against Clostridium (2 mL s.c. injection of One Shot Ultra 7; Zoetis, Florham Park, NJ), parainfluenza virus (TSV-2; Zoetis), infectious bovine rhinotracheitis virus, bovine viral diarrhea Types 1 and 2 viruses, and Mannheimia haemolytica (2 mL s.c. injection of Bovi-Shield Gold One Shot; Zoetis), and administered an anthelmintic (s.c. injection at 1 mL/50 kg of BW of Dectomax; Zoetis).Re-vaccination: At feedlot entry (day 30 of the experiment), calves will be vaccinated against bovine rhinotracheitis virus, bovine viral diarrhea Types 1 and 2 viruses, parainfluenza3 virus and bovine respiratory syncytial virus (2 mL s.c. injection of Bovi-Shield Gold 5; Zoetis), and Clostridium (2 mL s.c. injection of One Shot Ultra 7; Zoetis).Anticipated: Calves will receive the same vaccines as control calves, but the initial vaccination will be administered 15 days before weaning (day -15 of the experiment), and the revaccination will be administered 15 before feedlot entry (day 15 of the experiment).Delayed: Calves will receive the same vaccines as control calves, but the initial vaccination will be administered 15 days after weaning (day 15 of the experiment), and the revaccination will be administered 15 after feedlot entry (day 45 of the experiment).All calves will receive treatments at approximately 7 months of age, when calves are mature enough to properly respond to vaccination against BRD pathogens (Downey et al., 2013), whereas a 30-day interval between initial vaccination and revaccination will be maintained in all treatments (as recommended by the manufacturer; Zoetis). In addition, all calves assigned to the experiment will be processed when treatments are administered, and calves not receiving vaccines during processing will receive a 10 mL s.c. injection of 0.9% of sterile saline to account for any injection placebo effects. During the experimental period, calves will be assigned to the following management scheme:Pre-weaning phase (day -15 to 0): All calves will remain with their respective dams within a single semi-arid rangeland pasture at the EOARC Burns.Preconditioning phase (day 0 to 29): On day 0, all calves will be weaned and transferred to a single meadow foxtail (Alopecurus pratensis L.) pasture at the EOARC Burns for a 30-day preconditioning period, and will receive supplemental alfalfa hay to allow an ADG of 1 lb/day. On day 29, all calves will be loaded into double-deck commercial livestock trailers (Legend 50' cattle liner; Barrett LLC., Purcell, OK), and transported for 24 h to elicit the stress challenges of a long-haul (Arthington et al., 2008). Calf distribution between trailers (n = 2) will be balanced by treatment, calf body weight, gender, and age.Feedlot receiving phase (day 30 to 75): On day 30, all calves will be unloaded into the experimental feedlot of the EOARC Burns for a 45-day feedlot receiving period. Upon unloading, calves will be ranked by gender, body weight, and age within each treatment group, and assigned feedlot pens (7 × 15 m) containing 3 steers and 3 heifers of the same treatment per pen (6 pens/treatment). During feedlot receiving, calves will receive a diet based on mixed alfalfa-grass hay, cracked corn, and soybean meal with a forage:concentrate ratio of 40:60 from day 30 to 40, 60:40 from day 41 to 50, and 75:25 from day 51 to 75.Finishing phase (day 76 to slaughter): On day 76, all calves will be transferred to a commercial finishing yard (Beef Northwest; Boardman, OR) where they will be equally managed as a single group according to the yard's guidelines until slaughter (June 2016) at a commercial packing facility (Tyson Fresh Meats, Inc.; Pasco, WA).Sampling and analysesCalf body weight will be collected for 2 consecutive days at the beginning the experiment (days -16 and -15), upon weaning (days -1 and 0), trailer loading and unloading (day 29 and day 30 adjusted to a 10% shrink; Guarnieri Filho et al., 2014), and at the end of preconditioning (days 74 and 75). These body weight values will be used to calculate ADG during the pre-weaning (d -15 to 0), preconditioning (d 1 to 29), and feedlot receiving (d 30 to 75) phases. The ADG during finishing phase will be calculated based on preconditioning final body weight, and the hot carcass weight adjusted to a 63% dressing percentage (Loza et al., 2010).During feedlot receiving (day 30 to 75), feed intake will be recorded daily by measuring offer and refusals from each pen. Feed efficiency of each pen will be calculated according to intake and BW gain from day 30 to 75. Upon slaughter, the following carcass characteristic will be obtained: USDA Yield Grade, hot carcass weight, 12th-13th rib adjusted fat thickness, longissimus area, KPH%, USDA Quality Grade, and USDA marbling score. Final carcass value will be assessed based on the aforementioned carcass traits and contemporary beef prices.Blood samples will be collected via jugular venipuncture on day -15, 0, 15, 30, 45, 60, and 75 for serum and plasma harvest, in a manner that calves from each treatment group will be sampled at the time of vaccine administration, as well as 15 and 30 later to estimate vaccine efficacy via serum antibody titers or concentrations (Callan, 2001). These serum samples will be analyzed for concentrations of antibodies against M. haemolytica (Confer et al., 2009), as well as titers against bovine respiratory syncytial virus, bovine herpesvirus-1, bovine viral diarrhea virus-1, and parainfluenza3 virus (Oklahoma Animal Disease Diagnostic Laboratory; Stillwater, OK). Blood samples will also be collected 3 days after treatment administration, and analyzed for plasma haptoglobin concentrations (Cooke and Arthington, 2013), to assess the vaccine-induced acute-phase protein response based on these and the plasma samples collected at the time of vaccine administration. Plasma concentrations of cortisol and IGF-I (Immulite 1000; Siemens Medical Solutions Diagnostics, Los Angeles, CA) will be analyzed in all plasma samples to compare metabolic stress (cortisol; Sapolsky et al., 2000) and nutritional status (IGF-I; Hess et al., 2005) among treatments.Throughout the experiment, calves will be observed daily for BRD symptoms, and treated with an antimicrobial when clinical symptoms are observed (Berry et al., 2004). Accordingly, incidence of BRD treatment, morbidity, and mortality will be recorded daily. Upon the completion of the experiment, an economic analysis will be performed to compare treatments on resultant expenses and returns, including medications, feed costs, cattle productivity, and final carcass value.The sample size planned for this experiment is adequate to result in statistical significances for all measurements proposed, according to the G*power 3 software (Faul et al., 2007). Data will be analyzed with the MIXED procedure of SAS using calf as the experimental unit, and treatment comparisons will be made on an equivalent post-vaccination day basis when appropriate (Richeson et al., 2008). For all measurements, the model statement will contain the effects of treatment, in addition to time of collection and the resultant interaction when appropriate.