11 December 2012

2 minute read

In a paper published recently in Journal of Animal Science, J.S. Schutz of Colorado State University and co-authors there and at USDA-ARS in Lubbock, Texas and in Beltsville, Maryland and Intervet-Schering Plough Animal Health report on work to examine the effects of gastrointestinal parasites on parasite burden, rectal temperature and antibody titer responses to vaccination and infectious bovine rhinotracheitis virus challenge.

Introduction

Gastrointestinal parasite burden is one of the largest health concerns for ruminants worldwide (Armour, 1980). Performance has been shown to decline in relationship to parasite burden (Lee, 1955; Reinhardt et al., 2006). Gastrointestinal parasitism results in a wide range of effects from sub-clinical disease to death depending on parasite load, animal age and breed, plane of nutrition, and overall health status of the animal (Hawkins, 1993). Calves treated with anthelmintics resulted in an improvement of $0.08 to $0.14/kg of BW gain after 41 d post-treatment (Leland et al., 1980). Grimson et al. (1987) reported that average sale prices were greater for calves given anti-parasitic treatments vs. untreated calves, which reflects the perception of buyers that treated calves will outperform untreated calves.

Vaccinations are arguably the most cost-effective means for preventing disease, especially in feedlot environments. Of the schedules most currently used, the most effective deworming and vaccination program to prepare calves for entry into the feedlot has not been determined. It is critical that good management practices are implemented in conjunction with vaccination programs to ensure vaccine efficacy is not compromised. Most calves are vaccinated for respiratory-type infections and dewormed at weaning just before entering an on-site background facility or being transported to a feedlot (Bagley, 2001). Cytokine release associated with parasitic infestation can interfere with the immune response to foreign antigens, potentially affecting the ability of an animal to immunologically respond to vaccination (Kullberg et al., 1992; Urban et al., 2007). The objective of the present study was to determine whether the timing of anthelmintic administration relative to vaccination influences antibody titer response to vaccine components, rectal temperature, and antibody titer response to an intranasal challenge with infectious bovine rhinotracheitis virus (IBRV).

Abstract

Thirty-three colostrum-deprived Holstein bull calves (initial BW of 131 ± 4 kg) were used to determine the effect of timing of anthelmintic administration relative to vaccination on antibody titer response to vaccine component antigens. When calves were at least 3 mo of age, they were sorted randomly into individual pens and assigned to 1 of 3 treatment groups, treatments consisted of 1) dewormed 2 wk before vaccination (DPV), 2) dewormed at the time of vaccination (DV), or 3) control, vaccinated but not dewormed (CONT). All calves were inoculated with infective larvae of brown stomach worms (Ostertagia ostertagi) and intestinal worms (Cooperia spp.) on d 1, 7, 10, 14, and 18 for a total dose of 235,710 infective larvae per calf. Calves (DPV and DV) were dewormed on d 21 or 35 with a 10% fenbendazole suspension at 5 mg/kg of BW. On d 35, all calves were vaccinated with a modified-live virus respiratory vaccine containing IBRV (infectious bovine rhinotracheitis virus), BVDV-1 (bovine viral diarrhea virus genotype 1), BVDV-2 (BVDV genotype 2), PI-3 (parainfluenza-3), and BRSV (bovine respiratory syncytial virus). During the 103-d experiment, weekly fecal egg counts, blood, and rectal temperatures were collected and health status was recorded daily. Blood samples were obtained weekly to determine serum neutralizing (SN) antibody titers to IBRV, BVDV-1, BVDV-2, and PI-3 and cytokine levels for IL-4, IL-6, TNF-? (tumor necrosis factor-?), and IFN-? (interferon-gamma). There was a tendency (P < 0.09) for CONT calves to have greater IL-4 concentrations. By design, control calves had greater (P < 0.01) fecal egg counts during the experiment. All calves developed antibody titers to IBRV, BVDV-1, BVDV-2, and PI-3 by d 15 postvaccination. On d 88, all calves were challenged with IBRV and blood samples were obtained on d 88, 89, 90, 93, 95, 98, 99, and 103. All calves had increased rectal temperatures during the final 7 d of the IBRV challenge. However, the CONT group had greater (P < 0.01) rectal temperatures on each sampling day except d 90 compared with the DPV and DV treatments. Therefore, deworming before or at vaccination reduced parasite burden and decreased rectal temperature increase after an IBRV challenge. Deworming strategy had no effect on antibody response to vaccination or IBRV challenge.

Reference

Schutz J.S., J.A. Carroll, L.C. Gasbarre, T.A. Shelton, S.T. Nordstrom, J.P. Hutcheson, H. Van Campen and T.E. Engle. 2012. Effects of gastrointestinal parasites on parasite burden, rectal temperature, and antibody titer responses to vaccination and infectious bovine rhinotracheitis virus challenge. J. ANIM. SCI. June 2012 vol.90 no. 6:1948-1954. doi: 10.2527/jas.2011-4059

Further Reading You can view the full report by clicking here.

December 2012