Table 4.

Variance component and heritability estimates for health, performance, and carcass traits obtained from single trait sire model analysis¹

Item2	n	VA	VP	h2
Preweaned calf genetic component
Entire population
BRD3 incidence	1,519	88.9	789.5	0.11 ± 0.06
NoTrt	1,519	119.1	1,478.2	0.08 ± 0.05
Birth BW, kg2	1,516	19.8	29.7	0.67 ± 0.14
Weaning BW, kg2	954	421.3	852.2	0.49 ± 0.16
Angus only
BRD incidence	484	78.4	805.3	0.10 ± 0.11
NoTrt	484	117.9	1,621.2	0.07 ± 0.10
Simmental only
BRD incidence	655	12.9	803.3	0.02 ± 0.06
NoTrt	655	0.0	1,587.5	0.00 ± 0.06
Feedlot cattle genetic component
BRD incidence	3,277	57.7	775.4	0.07 ± 0.04
NoTrt	3,277	55.1	2,594.6	0.02 ± 0.03
Acclimation ADG, (kg/d)2	3,244	0.129	0.232	0.56 ± 0.08
On-test ADG, (kg/d)2	3,189	0.0248	0.0459	0.54 ± 0.09
Overall ADG, (kg/d)2	3,189	0.0220	0.0327	0.67 ± 0.09
Final BW, kg2	3,189	676.2	950.7	0.71 ± 0.10
HCW, kg2	3,213	479.7	672.6	0.71 ± 0.10
LMA, (cm2)2	3,213	21.34	37.01	0.58 ± 0.08
Fat, mm2	3,213	3.15	9.28	0.34 ± 0.07
MarbS2 4	3,213	0.403	0.598	0.67 ± 0.09

¹V_A = additive genetic variance; V_P = phenotypic variance (total variance); h² = heritability.

²Entire population = all animals; BRD incidence = untreated (100) vs. treated (200); NoTrt: 100 = nontreated cattle, 200 = cattle treated once, 300 = cattle treated twice, 400 = cattle treated 3 or more times; birth BW = BW at birth; weaning BW = BW of cattle at weaning time; Angus only = Angus calves; Simmental only = Simmental calves; acclimation ADG = early period of feedlot; on-test ADG = late period of feedlot; overall ADG = total feedlot period; fat = subcutaneous fat cover; and MarbS = marbling score.

³BRD = bovine respiratory disease.

⁴2.00 = practically devoid⁰⁰; 3.00 = traces⁰⁰; 4.00 = slight⁰⁰; 5.00 = small⁰⁰; 6.00 = modest⁰⁰; 7.00 = moderate⁰⁰; 8.00 = slightly abundant⁰⁰; 9.00 = moderately abundant⁰⁰; 10.00 = abundant⁰⁰.