Figure 1.
Percentage of positive animals in vaccinated (VH) and Testing and Culling (TC) herds to bovine single (BSIT) and comparative (CIT) intradermal tests throughout the study.
No significant difference (p = 1.0000) between strategies was observed in the BSIT at the initial testing (M0), nor at the last two testings (p = 0.1444 and p = 0.1324); but the frequencies were significantly different at each of the three immediate post-vaccination testings (p<0.0001). Regarding evolution along time, only frequencies in the M12, M24 and M36 yearly testings were significantly different (p<0,0009) from M0 in VH. No statistically significant differences were observed between strategies, or between testings within each strategy in the CIT. Table on the x-axis shows frequencies and table below axis legend shows statistical probabilities for the differences. These p values were obtained with a Student t-test with the Tukey-Kramer adjustment for multiple comparisons on the least square frequency means calculated in the analysis of variance.
Figure 2.
Skin–fold thickness increases at 72 h after PPD-Av and PPD-Bov intradermal inoculation in vaccinated (VH) an Testing and culling (TC) herds at all the yearly testings.
A positive bovine reaction, which was 4(0.05%) corresponded to TC herds and three (0.14%) occurred in VH herds.
Figure 3.
Percentage of positive animals to bovine single (BSIT) and comparative intradermal (CIT) tests in vaccinated (VH) and Testing and culling (TC) herds according to the time elapsed since their individual inclusion in the program.
Regarding the BSIT, no significant differences in the proportion of positive reactions was observed at the initial testing between both strategies (p = 1.0000), nor at three (p = 0.2953), four (p = 0.9714) and five (1.0000) years post-vaccination. However, significant differences were observed at one (p<0.0001) and two (p<0.0001) years post-vaccination. These frequencies in the BSIT one and two years after vaccination were significantly higher (p<0.0001) than in any other control in the VH, but from 3 years onwards, differences were not different from the pre-vaccination testing or the other testings (p = 0.5580, p = 0.9931 and p = 1.0000). Frequencies in the TC group were not significantly different from the pre-vaccination frequency at one (p = 0.9941), two (0.9959), three (1.0000), four (p = 1.0000)1 and five (1.0000) years post-vaccination. No statistically significant differences were observed between strategies, or between testings within each strategy in the CIT. Table on the x-axis shows frequencies and table below axis legend shows statistical probabilities for the differences. These p values were obtained with a Student t-test with the Tukey-Kramer adjustment for multiple comparisons on the least square frequency means calculated in the analysis of variance.
Table 1.
Overall comparison of BSIT and CIT between VH and TC herds in annual testings (least square means and adjusted standard errors).