Genotype by environment interaction for tick resistance of Hereford and Braford beef cattle using reaction norm models

Table 4 Spearman rank correlations among posterior means of genetic values for tick counts of Hereford and Braford cattle at different tick infestation levels obtained by different models

Model	M1	M4	M4	M4	M10	M10	M10	M12	M12	M12	M9
Environmental level	(Ov.)	(LTI)	(MTI)	(HTI)	(LTI)	(MTI)	(HTI)	(LTI)	(MTI)	(HTI)	(Ov.l)
M₁ (Ov.)		0.97	0.98	0.96	0.98	0.99	0.98	0.94	0.97	0.94	0.98
M₄ (LTI)	0.96		0.97	0.91	0.96	0.97	0.97	0.98	0.96	0.89	0.94
M₄ (MTI)	0.99	0.97		0.98	1.00	1.00	1.00	0.94	0.99	0.96	0.99
M₄ (HTI)	0.96	0.91	0.98		0.99	0.98	0.98	0.88	0.97	0.99	0.98
M₁₀ (LTI)	0.98	0.96	1.00	0.99		1.00	1.00	0.94	0.99	0.97	0.99
M₁₀ (MTI)	0.99	0.97	1.00	0.98	1.00		1.00	0.95	0.99	0.96	0.98
M₁₀ (HTI)	0.99	0.97	1.00	0.98	1.00	1.00		0.94	0.99	0.96	0.99
M₁₂ (LTI)	0.92	0.98	0.93	0.85	0.92	0.93	0.92		0.95	0.88	0.93
M₁₂ (MTI)	0.98	0.97	0.99	0.97	0.99	1.00	0.99	0.94		0.98	0.99
M₁₂ (HTI)	0.96	0.91	0.98	1.00	0.98	0.98	0.98	0.86	0.97		0.98
M₉ (Ov.)	0.99	0.96	0.99	0.98	1.00	0.99	0.99	0.92	0.99	0.98

Correlations between all animal above the diagonal and between the most used sires (60) below the diagonal
LTI = 10th (−0.424); MTI = 50th (0.032); HTI = 90th (0.316) percentiles of the contemporary group effects (environmental gradient)
M ₁ linear animal model based on homoscedastic residual variance; M ₄ one-step linear reaction norm model with homoscedastic residual variance; M ₉ linear animal model with classification function grouped in discrete subclasses on heteroscedastic residual variance; M ₁₀ two-step linear reaction norm model with classification function grouped in discrete subclasses on heteroscedastic residual variance; M ₁₂ one-step linear reaction norm model with classification function grouped in discrete subclasses on heteroscedastic residual variance. LTI low tick infestation; MTI medium tick infestation; HTI high tick infestation; Ov. overall

ISSN: 1297-9686