Heritability estimation and genetic correlations for mature weight, visual scores, and growth traits in Nellore cattle

Koetz Junior, Celso; Roso, Vanerlei Mozaquatro; Fávaro, Patricia da Cruz; Pereira, Gabriel Ribas; Borges, Marcelo Henrique Favaro; Barca Junior, Flávio Antônio; Barcellos, Júlio Otávio Jardim; Ribeiro, Edson Luis de Azambuja

doi:10.1590/rbz4820170246

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Breeding and Genetics • R. Bras. Zootec. 48 • 2019 • https://doi.org/10.1590/rbz4820170246 copy

Heritability estimation and genetic correlations for mature weight, visual scores, and growth traits in Nellore cattle

Authorship SCIMAGO INSTITUTIONS RANKINGS

ABSTRACT

This study was intended to estimate the genetic associations between growth traits and visual scores with possible changes in mature weight (MW) in 397,900 Nellore animals. A bi-character analysis was performed to estimate the (co)variances and genetic parameters for MW, which comprises the following traits: conformation, finishing precocity, musculature at weaning (WC, WP, and WM) and yearling (YC, YP, and YM), birth weight (BW), weight from birth to weaning (WG), weight from weaning to yearling (YG), and final index (FIND). The observed mean MW was 417.6±56.2 kg, and the direct genetic effect mean estimated heritability ( $h^{2}_{a 1}$ ) of MW was 0.45. Overall, the BW was 31.0±3.7 kg, and the estimated h² was 0.34. The heritability estimate of the maternal additive genetic component ( $h^{2}_{m 2}$ ) of BW was 0.07. We calculated the mean WG to be 144.1±26.3 and estimated the $h^{2}_{a 2}$ as 0.18 and $h^{2}_{m 2}$ as 0.07. The value for $h^{2}_{a}$ YG (0.17) and YW (0.26) were also estimated. The heritability of the weaning WC (0.17), WP (0.19), and WM (0.17) and yearling YC (0.25), YP (0.27), and YM (0.25) were estimated using visual scores. The $h^{2}_{m}$ values for weaning WC, WP, and WM (0.06) with visual scores were estimated. The genetic correlations between body weight (BoW) at YC and WC (0.62) were considered moderately high and positive. In addition, YP (0.18), YM (0.15), WP (0.13), and WM (0.14) were considered moderately low compared with MW. The genetic correlation between BW and FIND (0.38) was considered positive and moderate. The heritability estimation indicates that growth traits, visual scores, and weight of adult cows could be changed by selection. Cows that presented the highest $h^{2}_{a}$ values for live weight responded rapidly to selection based on growth characteristics, visual scores, and FIND and might result in increased final MW.

Keywords:
beef cattle; growth parameters; productive traits; selection

Characteristic	Percentage weight (%)
Weight gain from birth to weaning	25
Weaning conformation	4
Weaning finishing precocity	8
Weaning musculature	8
Weight gain from weaning to yearling	25
Yearling conformation	4
Yearling finishing precocity	8
Yearling musculature	8
Scrotal circumference at yearling	10

Characteristic	Sample size (n)	Mean±SD
MW (kg)	40,340	417.65±56.26
Age (years)	40,340	5.88±2.88
BW (kg)	241,471	31.00±3.77
WG (kg)	339,963	144.12±26.38
WC (score)	285,632	3.06±1.07
WP (score)	285,640	3.17±1.10
WM (score)	285,638	3.00±1.12
YG (kg)	181,426	108.18±36.11
YC (score)	186,293	3.04±1.03
YP (score)	186,292	3.12±1.08
YM (score)	186,285	2.89±1.09
YW (kg)	137,562	286.69±45.94
FIND¹ 1 The weighting factors of characteristics included in the index calculation were defined for a base equal to 10 (i.e., as if each animal was evaluated by 10 characteristics measured in their progenies). Thus, index 10 indicates that, on average, the animal is superior by one expected progeny difference standard deviation in every characteristic integrating the index.	113,571	7.27±5.07

(Co)variance	BW	WG	YW	MW
$σ_{a 1}^{2}$	699.89±28.48	663.34±27.89	690.21±28.87	683.08±26.84
$σ_{m 1}^{2}$	–	–	–	–
$σ_{p 1}^{2}$	–	–	–	–
$σ_{e 1}^{2}$	773.33±24.82	845.63±24.73	782.11±25.18	803.64±23.62
σ_am1	–	–	–	–
$σ_{a 2}^{2}$	4.04±0.14	60.92±2.38	69.85±4.16	153.21±6.82
$σ_{m 2}^{2}$	0.82±0.06	25.53±1.55	7.66±2.00	11.93±2.30
$σ_{p 2}^{2}$	0.25±0.03	55.44±1.26	8.82±1.49	0.0±2.36
$σ_{e 2}^{2}$	7.03±0.09	178.63±1.65	311.54±2.98	385.41±4.68
σ_am2	-0.40±0.07	12.75±1.22	-6.93±2.15	22.76±2.69
σ_a12	24.14±2.39	133.25±7.84	123.13±10.82	237.32±12.32
σ_a1m2	6.75±1.22	32.15±4.36	-5.21±5.80	41.50±6.28
$h_{a 1}^{2}$	0.47	0.43	0.46	0.45
$h_{m 1}^{2}$	–	–	–	–
$h_{a 2}^{2}$	0.34	0.18	0.17	0.26
$h_{m 2}^{2}$	0.07	0.07	0.01	0.02
r_a12	0.45	0.66	0.56	0.73

(Co) variance	WC	WP	WM	YC	YP	YM	MW	FIND
$σ_{a 1}^{2}$	653.40±28.20	670.98±29.54	672.40±29.62	680.21±27.67	679.63±29.35	678.12±29.52	683.08±26.84	649.24±28.64
$σ_{m 1}^{2}$	–	–	–	–	–	–	–	–
$σ_{p 1}^{2}$	–	–	–	–	–	–	–	–
$σ_{e 1}^{2}$	815.43±24.89	794.01±25.86	791.97±25.91	797.89±24.26	787.68±25.65	787.98±25.80	803.64±23.62	794.36±25.24
σ_am1	–	–	–	–	–	–	–	–
$σ_{a 2}^{2}$	0.18±0.0	0.22±0.0	0.20±0.0	0.22±0.01	0.27±0.01	0.26±0.01	153.21±6.82	21.49±0.13
$σ_{m 2}^{2}$	0.06±0.0	0.07±0.0	0.081±0.0	0.01±0.00	–	0.01±0.0	11.93±2.30	–
$σ_{p 2}^{2}$	0.14±0.0	0.15±0.0	0.17±0.0	–	–	–	0.00±2.36	–
$σ_{e 2}^{2}$	0.61±0.0	0.67±0.0	0.70±0.0	0.65±0.00	0.72±0.00	0.75±0.0	385.41±4.68	0.53±0.05
σ_am2	0.01±0.0	–	0.11±0.0	–	–	–	22.76±2.69	–
σ_a12	6.86±0.47	1.65±0.59	1.69±0.58	7.78±0.49	2.56±0.55	2.06±0.56	237.32±12.32	45.14±1.73
σ_a1m2	1.67±0.26	1.53±0.31	1.39±0.31	0.66±0.24	0.74±0.27	0.67±0.28	41.50±6.28	–
$h_{a 1}^{2}$	0.44	0.45	0.45	0.46	0.46	0.46	0.45	0.44
$h_{m 1}^{2}$	–	–	–	–	–	–	–	–
$h_{a 2}^{2}$	0.17	0.19	0.17	0.25	0.27	0.25	0.26	0.97
$h_{m 2}^{2}$	0.06	0.06	0.06	0.01	–	–	0.02	–
r_a12	0.62	0.13	0.14	0.62	0.18	0.15	0.73	0.38

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[1] * Corresponding author: celsokoetzjr@yahoo.com.br