Inflammatory response of feedlot cattle to clostridial vaccination: a comparison of 7-way bacterin-toxoid and C&D toxoid

Twenty-four finishing steers (758 lb) were subcutaneously vaccinated and revaccinated 31 days later with 1) sterile saline, 2) a clostridial perfringens C&D toxoid, or 3) a 7-way clostridial bacterin-toxoid to evaluate the effects of vaccine type on inflammatory response in feedlot cattle. Injection site reactions were most severe (P<.05) and persistent for 7-way bacterin-toxoid and were accompanied by elevated (P<.05) blood haptoglobin levels indicative of acute inflammation. Revaccination with 7-way bacterin-toxoid reduced (P<.05) feed consumption for a 4-day period postvaccination. Although some reactions were severe, they appeared transient because blood parameters and volume of injection site reactions returned to baseline levels 25 to 60 days after injection. Performance over the entire feeding period was not significantly altered by treatment. We strongly recommend that clostridial products be used subcutaneously only, to minimize potential damage to carcass tissue from intramuscular injection.


Introduction
Recent observations indicate that multiple clostridial bacterin-toxoids may contribute to localized inflammatory responses, depressed feed consumption postvaccination, and damage to carcass tissue.In addition to heightened inflammation, the impact of depressed feed consumption can be direct, resulting in reduced gain, or indirect, through digestive upsets.Any factor that contributes to an unstable consumption pattern can increase bunk management problems and increase morbidity or mortality from bloat or other digestive disorders.Therefore, the purposes of this research were to: 1) evaluate injection site reactions resulting from clostridial vaccination; 2) examine the inflammatory response associated with clostridial vaccination; and 3) evaluate the impact on appetite associated with clostridial vaccination.

Experimental Procedures
Twenty four crossbred steers were selected for uniformity of size and conformation from a group of 108.All cattle were processed on January 20, 1992 using a 7-way clostridial product in combination with Hemophilus somnus (Ultrabac® 7/Somubac™, SmithKline Beecham Animal Health, Exton, PA).On June 20, the calves received a 7-way clostridial booster.The steers were delivered to the KSU Beef Research Unit on June 30.On July 1 (day 1 of the trial), they were individually weighed (758 lb average), ear tagged, and randomly allotted to immunization treatments to be administered on day 15.Treatments were: 1) 5cc of sterile saline; 2) a clostridial vaccine consisting of the antigens of Clostridium perfringens type C&D in a 2cc dose (C&D; Ultrabac ® CD, SmithKline Beecham Animal Health, Exton, PA); and 3) a clostridial vaccine consisting of the antigens of Clostridium chauvoei, sordellii, septicum, novyi, and perfringens type C&D in a 5cc dose (7-way, Ultrabac® 7).
On the last day of the 14-day feedlot acclimation period, the steers were weighed, blood was drawn, and any reactions from previous injections were noted.On the following day (day 15), the steers were vaccinated according to the random allotment they received on day 1.
All products were delivered subcutaneously using a skin tenting technique.Each animal was injected using a new, sterile, 16-gauge 3/4-inch needle.The hair over the injection site was clipped to identify the exact site of injection.The calves were weighed and bled on days 18, 21, 25, 30, and

Results and Discussion
Inflammatory response.White blood cell counts, segmented neutrophils, lymphocytes, and gammaglobulin levels all showed small increases in response to treatment, but remained within or close to normal limits.Plasma protein and fibrinogen levels also showed slight increases but remained well within normal limits.Blood haptoglobin levels were increased after injection in the C&D and 7-way treatment groups, whereas the sterile saline group showed no change over time (Table 1).The response to C&D and 7-way injection was greatest on day 3 postinjection.An increase in haptoglobin level is indicative of an acute inflammatory response.
Injection site reactions.Injection site reactions were noted in 100% of the clostridialvaccinated calves within 24 hours after administration.The injection reactions were raised above the skin surface and varied in shape among animals.By day 3 when the sites were measured, the average involvement was 219 cc in the 7-way group vs 78 cc in the C&D group (Table 2; P<.05).No calves in the saline group developed injection site reactions.At the time of slaughter, no significant palpable lesions remained in either clostridial group.
Performance.Calf feed consumption was not significantly impacted during the 4day period after the first injection, although intake declined 1%, 2%, and 10% for the saline, C&D and 7-way groups, respectively (Table 3).Following the second injection, consumption of the saline group increased 4%, whereas that of the C&D and 7-way groups declined 8% and 20% (P<.05), respectively.Although steer gains were not significantly influenced by treatment, steers in the 7-way group were 14 lb lighter at slaughter than the saline-injected steers.
These data suggest that injection of feedlot cattle with clostridial vaccines can result in a transient, yet significant, inflammatory response.Subcutaneous injection-site reactions may persist for months.Injection with 5 ml of 7-way bacterin-toxoid resulted in a more severe, longer lasting reaction than injection with 2 ml of C&D toxoid.Whether the reaction severity in the 7-way group was from the antigens themselves, or from higher levels of potentially irritating vaccine adjuvants, is unknown.Using clostridial products subcutaneously is strongly advised to minimize potential damage to carcass tissue.

Table 3 . Average Daily Feed Consumption (lb as-fed) by Steers during the Four-Day Preinjection and Four-Day Postinjection Periods
b Means for a treatment within an injection period differ (P<.05).a,b