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Thursday, December 10, 2009

Prevention and Treatment for Bovine Respiratory Disease in High Risk, Newly Received Stocker Calves

This is a paper written for one of my classes this semester covering the advantages of using MLV treatments for BRD in stocker calves. I learned a lot by writing this, hope you will too. Enjoy!

Prevention and Treatment for Bovine Respiratory Disease in High Risk, Newly Received Stocker Calves

Bovine Respiratory Disease (BRD) is one of the leading causes of morbidity and mortality in stocker and feedlot operations. Cattle in these operations are highly susceptible to contracting the disease and are classified as high or low risk based on a number of factors; “commingling with other animals, transportation stress, immune status, nutritional condition, environment conditions, and the skill level of management to diagnose cattle displaying symptoms of BRD” (Richeson, 2008). Cattle entering stocker and/or feedlot operations are normally classified as high risk if originating from livestock auctions for reasons including “unknown origin, commingling with numerous other animals, and being recently weaned from small cow-calf operations that seldom use vaccination or other BRD prevention strategies” (Richeson, 2009). Because the number of cattle classified as high risk is relatively high in the stocker and feedlot industry, it is important to find the most effective methods of prevention and treatment for BRD. Although there have been many research trials conducted showing the impact of BRD on cattle, this focus of this paper will be on the methods of prevention and treatment for BRD including 14-day delayed modified live virus vaccination and the efficacy of treatment with different medications.

BRD does have a major impact on health, efficiency, and performance of stocker and feeder calves. According to research from Snowder et al. (2006), BRD has a large impact on both stocker and feeder calves, with 13% and 17%, respectively, of calves being affected by the disease. Snowder’s research shows results of an average economic loss of $15.57 per sick animal. This figure only includes treatment costs and losses from decreased average daily gain (ADG). Similar research conducted by Brooks et al. (2009) shows that BRD has a major effect of costs associated with production. Cattle in this research trial had a decreased ADG of two and a half pounds per day, increased treatment costs of thirty-five dollars per head, and decreased net returns of one hundred fourteen dollars per head, compared to cattle not affected by BRD. These figures show a decrease in economic gains and performance of cattle diagnosed with BRD.

Stress levels at time of initial vaccination can influence the efficacy of modified live virus (MLV) vaccines and health and performance of newly received stocker calves. Richeson et al. (2008) conducted research to evaluate the health, performance, and serum infectious bovine rhinotracheitis (IBR) titers in newly received calves. In this research, stocker calves were tested in two treatments; on arrival vaccination with a MLV vaccine (AMLV) or 14-day delayed MLV vaccination (DMLV). The cattle on the delayed treatment performed better than AMLV cattle with increased body weight (BW) on days fourteen and forty-two (212.7 vs. 208.6kg, p=0.007; 228.1 vs. 224.4kg, p=0.07 (approaching significance), respectively) and greater ADG in periods day-0 thru day-14 and day-0 thru day-42 (1.16 vs. 0.88kg/day, p=0.007; 0.75 vs. 0.65kg/day, p=0.05, respectively). Measurements for effect of vaccination timing on morbidity, mortality, and treatment cost suggest no advantage between the two treatments (AMLV vs. DMLV). Factors involved in these measurements include rectal temperature on day-0 (39.6 vs. 39.6°C, p=0.83), initial BRD treatment (71.5 vs. 63.5%, p=0.12), retreat BRD treatment (25.1 vs. 30.8%, p=0.17), days to first treatment (7.2 vs. 7.7, p=0.72), death loss (2.3 vs. 0.8%, p<0.16), and BRD treatment cost (9.00 vs. $8.75, p=0.76). Morbidity rates were high for both treatments in the trial and did not differ (71.5 vs. 63.5%, p=0.12). Ninety three percent of the BRD cases occurred during the first fourteen days of the trial, suggesting there is no advantage to AMLV treatment to reduce morbidity rates.

Seroconversion rates for IBR titers were measured in the study from Richeson et al. (2008). These measurements show substantially greater amounts of IBR antibodies in the blood system of the calves in the DMLV treatment on day-28 and day-42 after initial vaccination as well as at the end of the trial (p=0.03, p=0.01, p=0.01, respectively). These data suggest an increased vaccine efficacy, likely due to lower stress levels at time of initial vaccination. Later research from Richeson et al. (2009) shows different results. Initially greater (p<0.01) titer levels were present in calves with on-arrival vaccination, but total white blood cell counts were greater for the delayed treatment group. Collectively, the data from these studies suggest an economic advantage to delaying initial MLV vaccination until fourteen days after receiving to improve body weight, average daily gain, and vaccine efficacy.

Research conducted by Wildman et al. (2008) has shown that the type of vaccination given to cattle has an impact on response and number of cases for BRD. In this study, cattle were given MLV vaccines with one or two types of bovine viral diarrhea (BVD) virus. The vaccine type had an effect on the treatment for BRD (p<0.001), mortality rate (p=0.002), and ADG (p=0.008). The rate of BRD cases correlated with the number of yield grade three carcasses, suggesting an economic loss for cattle affected by BRD through the entire cycle, from weaning to harvest. This study enforced the findings of Richeson et al. (2008, 2009) that there is an economic advantage to a well-managed vaccination program as a means of prevention of BRD.

There are several products on the market for treatment of BRD including tilmicosin phosphate (Micotil, Elanco Animal Health), tulathromycin (Draxxin, Pfizer Animal Health), florfenicol (Nuflor, Schering-Plough Animal Health), and enroflaxacin (Baytril, Bayer Animal Health). Use of these medications is for treatment in cases of BRD sickness and mass treatment in high risk newly received calves. Gaylean et al. (1995) conducted a study on the use of tilmicosin phosphate as an arrival medication for mass treatment. Three trials were included in this study to test the effectiveness of tilmicosin phosphate. Trial one involved calves given Micotil on-arrival as a mass treatment and calves were fed a receiving supplement for the duration of the study. Weight gains were greater (p<0.10) for calves receiving on-arrival mass medication than control calves during the first half of the trial but did not differ (p=0.17) over the 28-day period. Dry matter intake (p<0.22) and feed to gain ratio (p<0.81) did not differ between treatments. 46.4% of the control calves were treated for BRD, but none of the mass treatment calves was treated for BRD. The second trial involved mass treatment calves grazing winter wheat pasture. BW and ADG did not differ (p<0.51, p=0.06) between treatments. There was fewer (12.1%) mass control calves treated for BRD than control calves (32.8%). Trial three in this study included three treatments: control, mass treatment with Micotil, and treatment with Micotil when body temperature was greater than 39.7°C (104°F). Calves in this trial were fed a 65% concentrate diet. Calves in this trial receiving Micotil, both mass treatment and treatment by temperature, gained more than control calves (p<0.01). Dry matter intake and feed to gain ratio were lower for calves in the medicated groups than control (p<0.09, p<0.03). No differences were shown between medicated groups. This study has shown that Micotil is highly effective as a mass treatment to increase gains and dry matter intakes. Treated calves had a lower rate of treatment for BRD symptoms. The third trial in this study showed that treatment with Micotil based on body temperature was as effective as mass treatment and reduced the number of calves treated; lowering arrival medication costs.

Studies have been conducted to evaluate the effectiveness of Draxxin. Nutsch et al. (2005), Skogerboe et al. (2005), and Rooney et al. (2005) have all shown that Draxxin is more effective as a treatment than Nuflor or Micotil. Nutsch’s and Skogerboe’s studies resulted in greater weight and performance, and lower retreatment and chronic rates in treatments using Draxxin over Nuflor or Micotil. Rooney’s study showed that when used as a mass treatment, Draxxin decreases morbidity rates and performance of cattle. Collectively these studies show the advantage of Draxxin over other drugs for the treatment and prevention of BRD in newly received stocker calves.

BRD is a major factor in the performance of newly received beef calves in the stocker industry with 13% and 17% of stocker and feeder calves being affected (Snowder, 2006). Cattle affected by BRD often have lower performance with decreased body weights, average daily gains, feed to gain ratios, and dry matter intakes. Morbidity and mortality rates increase cost of gain and decrease net returns for producers by up to $114 per head (Brooks, 2009), making it important to find the most effective means of treatment and prevention for BRD. Richeson et al. (2008, 2009) and Wildman et al. (2008) have shown that delaying treatment with MLV vaccinations by 14 days will increase performance and gains of cattle, increase days to first treatment, as well as decrease morbidity, mortality, and chronic rates and treatment costs in stocker cattle. Vaccine efficacy and calves’ immune response to MLV vaccines is greater when MLV treatment is delayed by 14 days. Several studies have shown that mass medication by Micotil or Draxxin are effective as a means of mass treatment to prevent BRD and reduce the number of retreats and chronics in stocker calves Richeson, 2008; Nutsch 2005).

In conclusion, every situation is different depending on environment and diseases present in the animal herd, so treatment efficacy may differ between operations. Research has shown that delaying MLV vaccination treatment by 14-days combined with mass treatment or treatment by temperature with tilmicosin phosphate or tulathromycin will increase performance and returns in newly received stocker calves at high risk for bovine respiratory disease. With this information, producers will be able to make more informed decisions when creating vaccination and treatment protocols.

Literature Cited
Brooks, K., K.C. Raper, C.E. Ward, B.P. Holland, and C. Krehbiel. 2009. Economic effects of bovine respiratory disease on feedlot cattle during backgrounding and finishing phases. Southern Agricultural Economics Association Annual Meeting.

Galyean, M.L., S.A. Gunter, and K.J. Malcolm-Callis. 1995. Effects of arrival medication with tilmicosin phosphate on health and performance of newly received beef cattle. Journal of Animal Science. 73:1219-1226.

Nutsch, R.G., T.L. Skogerboe, K.A. Rooney, D.J. Weigel, K. Gajewski, and K.F. Lechtenberg. January 2005. Comparative efficacy of tulathromycin, tilmicosin, and florfenicol in the treatment of bovine respiratory disease in stocker cattle. Veterinary Therapeutics. 6:167-179.

Richeson, J.T., E.B. Kegley, M.S. Gadberry, P.A. Beck, J.G. Powell, and C.A. Jones. July 2009. Effects of on-arrival versus delayed clostridial or modified live respiratory vaccinations on health, performance, bovine viral diarrhea virus type I titers, and stress and immune measures of newly received beef calves. Journal of Animal Science. 87:2409-2418.

Richeson, J.T., P.A. Beck, M.S. Gadberry, S.A. Gunter, T.W. Hess, D.S. Hubbell, III, and C. Jones. 2008. Effects of on-arrival versus delayed modified live virus vaccination on health, performance, and serum infectious bovine rhinotracheitis titers of newly received beef calves. Journal of Animal Science. 86:999-1005.

Rooney, K.A., R.G. Nutsch, T.L. Skogerboe, D.J. Weigel, K. Gajewski, and W.R. Kilgore. January 2005. Efficacy of tulathromycin compared with tilmicosin and florfenicol for the control of repiratory disease in cattle at high risk of developing bovine respiratory disease. Veterinary Therapeutics. 6:154-166.

Skogerboe, T.L., K.A. Rooney, R.G. Nutsch, D.J. Weigel, K. Gajewski, and W.R. Kilgore. January 2005. Comparative efficacy of tulathromycin versus florfenicol and tilmicosin against undifferentiated bovine respiratory disease in feedlot cattle. Veterinary Therapeutics. 6:180-196.

Snowder, G.D., LD. Van Vleck, L.V. Cundiff, and G.L. Bennett. 2006. Bovine respiratory disease in feedlot cattle: Environmental, genetic, and environmental factors. Journal of Animal Science. 84:1999-2008.

Wildman, B.K., T. Perrett, S.M. Abutarbush, P.T. Guichon, T.J. Pittman, C.W. Booker, O.C. Schunicht, R.K. Fenton, and G.K. Jim. 2008. A comparison of two vaccination programs in feedlot calves at ultra-high risk of developing undifferentiated fever/bovine respiratory disease. Canadian Veterinary Journal. 49:463-472.