Vet Microbiol. 2015 Nov 18;180(3-4):180-5.

Serological detection of infection dynamics for respiratory viruses among dairy calves.
 

Tuncer P1, Yeşilbağ K2.

  • 1Department of Virology, Uludag University Faculty of Veterinary Medicine, Görükle Campus, 16059 Bursa, Turkey.
  • 2Department of Virology, Uludag University Faculty of Veterinary Medicine, Görükle Campus, 16059 Bursa, Turkey. Electronic address: kyesilbag@uludag.edu.tr.

 

Abstract

The aim of this study is to reveal infection dynamics of bovine respiratory syncytial virus (BRSV), bovine parainfluenza virus type 3 (PI-3), bovine herpesvirus 1 (BHV-1), bovine viral diarrhea virus (BVDV), bovine adenovirus type 3 (BAV-3) and bovine coronavirus (BCoV), which are important viral pathogens of respiratory disease complex in ruminants. Through such an analysis, the regression period of maternally derived antibodies and optimum vaccination time in calves can be recommended. A total of 10 farms were grouped as large (4)-, medium (2)- and small (4)- sized enterprises according to their animal population. Newborn calves (n: 94) delivered during a calendar month on the farms were studied. Blood samples were collected from these calves during their 1st, 2nd, 3rd, 4th, 6th, 8th, 10th and 12th months of age. Blood samples were also taken from their dams during the first sampling. Neutralizing antibody titers were detected using the serum neutralization test (SN50). New PI-3 and BVDV infections at the early stages of life were determined in the calves. Maternal antibodies began to decrease in the 2nd month for BRSV, BHV-1 and BAV-3 (97.8%, 25.5% and 91.4%) and in the 3rd month for PI-3, BVDV and BCoV (85.1%, 67% and 93.6%). It was concluded that maternal antibodies begin to decrease after the 1st month and that the possible first exposure of calves to respiratory viruses is after the 2nd month. Therefore, it is recommended that the first vaccination program including prime and booster doses can be applied between 2 and 4 months of age. Furthermore, re-vaccination of animals at 6 months after the booster dose is also suggested.

KEYWORDS: BHV-1; BRSV; BVDV; Calves; PI-3; Respiratory viruses

PMID: 26380946

 

Supplement:

We couldn’t include the diversified inferences about the possible incidence of the studied infections between sexes and vaccinated 18 female calves into the article because of subject integrity. The female calves vaccinated with a commercial vaccine against BVDV type-1 and type-2, BHV-1, PI-3 and BRSV at the 4th month of age based on one of the enterprise (3rd) rearing procedures. These additional data may not have direct effect on the possible vaccination time about respiratory viruses but we need to share our findings with other researchers. As shown in the article none of the other calves (n: 94) were vaccinated against the examined viruses during the study. Accordingly, the studied population was subgrouped into vaccinated and unvaccinated calves.

Fischer’s exact test was employed for the statistical analysis on the effect of gender and vaccination status of the calves (p<0.05).

When the seropositive calf number was examined according to gender, only BHV-1 showed a significant difference (p=0.005), with a high rate of seropositivity in female calves (Table 1). Between the vaccinated and unvaccinated groups, there was no significant difference detected in the number of seropositive calves (p>0.05) (Table 1).

 

Table 1. Seroprevalence for studied virus according to gender and vaccination status at the end of the sampling period (12th m.)

tab1

*Unvaccinated calves

** Data from calves in the 3rd enterprise

 

In the unvaccinated calf population (n:94), 38 male and 56 female calves were analyzed. Although PI-3 infection was reported to be higher in females (Durham and Hassard, 1990), no significant difference in the incidence was detected between sexes up to the end of the first year of life in the present study. As opposed to previous study (Durham and Hassard, 1990), no significant difference was detected between the sexes for BRSV, whereas BHV-1 infection was more frequent in females (p = 0.0051), as also reported previously (Durham and Hassard, 1990). Although no difference for BVDV infection between the sexes was reported (Mockeliüniene et al., 2004), Durham and Hassard (1990) found a high seroprevalence in 4-10-month-old female calves. In the present study, no significant difference was observed for BVDV infection between sexes. Interestingly, maternal antibodies against BAV-3 decreased faster in the male calves than in the females, and the virus caused frequent infections at the 6th month in males and after the 8th month in females (data not shown). In addition, the propagation velocity of infection was faster among the female calves. Females are commonly infected with BCoV at 8th months of age, whereas males are more heavily infected after 10 months. The respiratory viruses other than BHV-1 showed no significant difference between sexes. Analyzing more animals may provide more credible results.

A group of 18 female calves was vaccinated with a commercial vaccine including BVDV type 1 and type 2, BRSV, PI-3 and BHV-1 agents during their 4th month of age. As a result of the statistical analysis of infection dynamics, no significant difference was found between the vaccinated and unvaccinated calves. Acceleration was observed in the reduction of the number of seropositive animals against BHV-1 and BVDV after the post-vaccination stage (data not shown). When the geometric mean of antibody titers was analyzed (Fig. 1), a decrease in the mean antibody titers was found after vaccination. This unexpected situation may be explained by the existence of maternal antibodies during the vaccination time, which can lead to the suppression of active immunity generated by the vaccination (Brar et al., 1978; Ellis et al., 2001; Fulton et al., 2004).

This study is important because we set our sights on searching for a solution for breeders to protect their cattle from bovine respiratory disease (BRD) which has a huge economic impact by causing decrease in yield.

 

 

fig1

Fig 1. Mean antibody titers of vaccinated calves.

 

 

References

  1. Brar, J.S., Johnson, D.W., Muscoplat, C.C., Shope, R.E. Jr., Meiske, J.C., 1978. Maternal immunity to infectious bovine rhinotracheitis and bovine viral diarrhea viruses: duration and effect on vaccination in young calves. Am. J. Vet. Res. 39, 241-244.
  2. Durham, P.J.K., Hassard, L.E., 1990. Prevalence of antibodies to infectious bovine rhinotracheitis, parainfluenza 3, bovine respiratory syncytial and bovine viral diarrhea viruses in cattle in Saskatchewan and Alberta. Can. Vet. J. 31, 815-820.
  3. Ellis, J.A., West, K., Cortese, V., Konoby, C., Weigel, D., 2001. Effect of maternal antibodies on induction and persistence of vaccine-induced immune responses against bovine viral diarrhea virus type II in young calves. J. Am. Vet. Med. Assoc. 219, 351-356.
  4. Fulton, R.W., Briggs, R.E., Payton, M.E., Confer, A.W., Saliki, J.T., Ridpath, J.F., Burge, LJ, Duff, GC., 2004. Maternally derived humoral immunity to bovine viral diarrhea virus (BVDV) 1a, BVDV 1b, BVDV2, bovine herpesvirus-1, parainfluenza-3 virus, bovine respiratory syncytial virus, Mannheimia haemolytica and Pasteurella multocida in beef calves, antibody decline by half-life studies and effect on response to vaccination. Vaccine. 22, 643-649.
  5. Mockeliüniene, V., Salomskas, A., Mockeliünas, R., Petkevicius, S., 2004.Prevalence and epidemiological features of bovine viral diarrhoea virus infection in Lithuania. Vet. Microbiol. 99, 51-57.

 

 

Contact:

Prof. Dr. Kadir YEŞİLBAĞ

Uludag University Faculty of Veterinary Medicine Department of Virology, Görükle, Bursa, 16059, Turkey

kyesilbag@uludag.edu.tr

 

 

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