Variance components for susceptibility to Mycobacterium bovis infection in dairy and beef cattle

Table 3 Results and summary statistics for univariate analyses for susceptibility to bovine tuberculosis infection across disease prevalences

	Very low	Low	High	Very high
N	87 609	16 812	3082	3359
Mean	0.07	0.34	0.62	0.93
σ_g (LAM)	0.07^A	0.16^B	0.12^A	0.09^C
Heritability (LAM)	0.07 (0.008)	0.16 (0.024)	0.08 (0.048)	0.25 (0.072)
σ_g (TAM)	0.71	0.89	0.83	1.39
Heritability (TAM)	0.13 (0.012)	0.19 (0.016)	0.17 (0.037)	0.37 (0.081)
Transformed	0.25	0.27	0.31	0.88

Number of records (N); mean prevalence (Mean); estimates of the genetic standard deviation (σ_g¹); estimates of the heritability from the linear animal model (LAM), threshold animal model (TAM) and based on the standard Robertson transformation (Transformed), for environments with very low (<0.25), low (0.25 to 0.5), high (0.5 to 0.75) and very high (>0.75) prevalence of bTB infection; genetic variance estimates with the same superscripted letter were not different (P <0.05) from each other.

ISSN: 1297-9686