Genetic parameters for visual scores, growth and carcass traits in Nellore Cattle

doi:10.21203/rs.3.rs-1516960/v1

Growth and carcass traits are essential selection criteria for beef cattle breeding programs. However, it is necessary to combine these measurements with body composition traits to meet the demand of the consumer market. This study aimed to estimate the genetic parameters for visual scores, growth (pre and post-weaning weights), and carcass (rib eye area (REA), back and rump fat thickness) traits in Nellore cattle using Bayesian inference. Data from 12,060 animals belonging to the HoRa Hofig Ramos farm were used. Morphological traits were evaluated by the MERCOS methodology. The heritability estimates obtained ranged from low to high magnitude, from 0.15 to 0.28 for visual scores, 0.13 to 0.44 for growth, and from 0.42 to 0.46 for carcass traits. Genetic correlations between traits of visual scores and growth were generally of moderate to high magnitudes, however, visual scores showed low correlations with carcass traits, except between REA and sacral bone and structure. Selection for visual score traits can lead to favorable responses in body weight and vice versa. Morphological categorical traits can be used as complementary tools that add value to selection.

Bayesian methods

genetic association

morphological traits

weight performance

Zebu Cattle

Table 3 is available in the Supplementary Files section

Table 1 Distribution (%) for the traits of visual scores in Nellore cattle.

Traits	Visual Scores
Traits	1	2	3^*1	4	5^*2
Muscling	0.00	12.81	40.12	43.55	3.53
Physical structure	0.00	8.98	55.13	35.00	0.89
Racial Aspects	3.26	31.57	48.77	16.02	0.38
Conformations	0.72	20.17	48.60	29.58	0.93
Omphalos	1.44	25.65	64.43	7.95	0.53
Sacrum	11.71	79.90	8.38	---	---

*1 Ideal score for omphalos (navel) and sacrum;

*2 Ideal score for muscle, physical structure, racial aspects and conformation.

Table 2 Descriptive statistics for growth traits, carcass and visual scores in Nellore cattle.

Traits	N°	Bulls	Cows	Min.	Max.	Median	Mode	SD	CV (%)	N° CG	Median of CG
W120 (kg)	7131	129	4466	69	199	137.29	138.00	19.46	14.18	103	27
W210 (kg)	6879	127	4622	100	279	204.08	206.00	25.99	12.74	106	23
W365 (kg)	5287	121	3745	162	408	260.00	260.00	34.63	13.32	50	47
W450 (kg)	4220	110	3157	182	476	300.83	269.00	47.09	15.65	40	43
REA (cm²)	2177	81	1222	31	88	58.92	60.00	9.31	15.80	45	15
BFT (mm)	2173	81	1222	1	11	3.50	3.00	1.65	47.11	45	15
RFT (mm)	2172	81	1222	1	15	5.16	5.00	2.17	4.14	45	15
M	4170	101	3066	2	5	2.38	4.00	0.75	31.52	23	182
E	4154	101	3055	2	5	2.28	3.00	0.63	27.70	23	182
R	4175	101	3069	1	5	2.79	3.00	0.76	27.24	23	182
C	4175	101	3069	1	5	3.10	3.00	0.74	24.02	23	182
O	4175	101	3069	1	5	2.80	3.00	0.61	21.88	23	182
SAC	4175	101	3069	1	3	1.97	2.00	0.45	22.73	23	182

No.: number of observations; Min.: minimum values; Max.: maximum values; SD: standard deviation; CV: coefficient of variation; No. CG: number contemporary groups; Average of n° obs. CG: mean of animals per GC; W120: weight at 120 days of age; W210: weight at 210 days of age; W365: weight at 365 days of age; W450: weight at 450 days of age; REA: rib eye area; BFT: backfat thickness; RFT: rump fat thickness; M: musculature; E: physical structure; R: racial aspects; C: conformation; O: omphalos (navel); SAC: sacrum.

Table 4 Posteriori estimates of genetic, residual, and phenotypic correlations between visual scores traits in Nellore cattle.
Parameters	Genetic Correlations				Residual Correlations	Phenotypic Correlations
Parameters	Median ± SD	Mode	Median	CI (95%)	Residual Correlations	Phenotypic Correlations
M x E	0.79 ± 0.08	0.80	0.80	0.62 - 0.92	0.65	0.51
M x R	0.37 ± 0.14	0.36	0.37	0.08 - 0.62	0.41	0.36
M x C	0.89 ± 0.06	0.94	0.90	0.74 - 0.98	0.60	0.59
M x O	0.50 ± 0.13	0.54	0.51	0.23 - 0.73	0.18	0.20
M x SAC	0.44 ± 0.15	0.49	0.45	0.12 - 0.68	0.44	0.33
E x R	0.63 ± 0.10	0.65	0.64	0.41 - 0.81	0.29	0.32
E x C	0.64 ± 0.11	0.67	0.64	0.4 - 0.82	0.48	0.45
E x O	0.63 ± 0.11	0.68	0.64	0.37 - 0.81	0.12	0.18
E x SAC	0.25 ± 0.17	0.29	0.26	0.00 - 0.56	0.34	0.23
R x C	0.54 ± 0.12	0.56	0.55	0.27 - 0.75	0.42	0.36
R x O	0.51 ± 0.14	0.52	0.51	0.21 - 0.75	0.11	0.17
R x SAC	0.36 ± 0.15	0.38	0.37	0.05 - 0.63	0.33	0.24
C x O	0.65 ± 0.12	0.69	0.67	0.38 - 0.85	0.24	0.18
C x SAC	0.57 ± 0.14	0.63	0.58	0.24 - 0.80	0.37	0.35
O x SAC	-0.01 ± 0.19	-0.07	-0.01	-0.30 - 0.35	0.19	0.09

M: muscle; E: physical structure; R: racial aspects; C: conformation; O: omphalos (navel); SAC: sacrum.

Table 5 A posteriori estimates of genetic, residual, and phenotypic correlations between visual score and growth traits in Nellore cattle.
Parameters	Genetic Correlations				Residual Correlations	Phenotypic Correlations
Parameters	Median ± SD	Mode	Median	CI (95%)	Residual Correlations	Phenotypic Correlations
M x W120	0.37 ± 0.24	0.39	0.36	(-0.09) - 0.85	0.09	0.04
M x W210	0.44 ± 0.18	0.47	0.45	0.05 - 0.76	0.11	0.08
M x W365	0.57 ± 0.13	0.58	0.57	0.33 - 0.80	0.19	0.29
M x W450	0.39 ± 0.11	0.40	0.40	0.17 - 0.59	0.21	0.27
E x W120	0.35 ± 0.20	0.41	0.37	(-0.06) - 0.72	0.13	0.08
E x W210	0.41 ± 0.19	0.44	0.42	0.04 - 0.76	0.15	0.14
E x W365	0.46 ± 0.11	0.47	0.46	0.22 - 0.67	0.21	0.30
E x W450	0.43 ± 0.10	0.45	0.43	0.23 - 0.63	0.29	0.23
R x W120	-0.35 ± 0.18	-0.38	-0.36	(-0.65) - 0.05	0.14	0.02
R x W210	-0.34 ± 0.21	-0.25	-0.32	(-0.69) - 0.05	0.12	0.06
R x W365	0.05 ± 0.12	0.06	0.06	(-0.19) - 0.28	0.08	0.15
R x W450	0.10 ± 0.13	0.13	0.10	(-0.17) - 0.35	0.22	0.14
C x W120	0.24 ± 0.23	0.18	0.24	(-0.21) - 0.65	-0.04	0.13
C x W210	0.05 ± 0.21	0.03	0.05	(-0.40) - 0.44	0.03	0.12
C x W365	0.31 ± 0.25	0.34	0.32	0.01 - 0.60	0.13	0.21
C x W450	0.10 ± 0.13	0.13	0.10	(-0.17) - 0.35	0.22	0.22
O x W120	0.08 ± 0.21	0.07	0.08	(-0.36) - 0.47	0.09	0.08
O x W210	-0.13 ± 0.22	-0.13	-0.13	(-0.60) - 0.31	0.14	0.12
O x W365	0.26 ± 0.13	0.26	0.27	(-0.01) - 0.50	0.01	0.20
O x W450	0.13 ± 0.12	0.16	0.14	(-0.12) - 0.36	0.07	0.21
SAC x W120	0.20 ± 0.23	0.25	0.21	(-0.26) - 0.62	-0.12	-0.08
SAC x W210	-0.08 ± 0.20	-0.06	-0.07	(-0.47) - 0.28	0.00	-0.07
SAC x W365	0.08 ± 0.16	0.13	0.08	(-0.26) - 0.39	0.03	0.00
SAC x W450	-0.04 ± 0.14	-0.04	-0.04	(-0.31) - 0.22	0.07	0.00

M: muscularity; E: physical structure; R: racial aspects; C: conformation; O: omphalos (navel); SAC: sacrum; P120: weight at 120 days of age; P210: weight at 210 days of age; P365: weight at 365 days of age; P450: weight at 450 days of age.

Table 6 Posteriori estimates of genetic, residual, and phenotypic correlations between visual score and carcass traits in Nellore cattle.
Parameters	Genetic Correlations				Residual Correlations	Phenotypic Correlations
Parameters	Median ± SD	Mode	Median	CI (95%)	Residual Correlations	Phenotypic Correlations
M x REA	0.03 ± 0.17	0.03	0.03	(-0.29) - 0.34	0.26	0.32
M x BFT	0.14 ± 0.17	0.15	0.14	(-0.19) - 0.49	0.10	0.25
M x RFT	0.05 ± 0.15	0.06	0.05	(-0.24) - 0.34	0.13	0.24
E x REA	0.22 ± 0.17	0.24	0.22	(-0.11) - 0.53	0.14	0.13
E x BFT	0.02 ± 0.18	0.01	-0.02	(-0.35) - 0.33	0.12	0.01
E x RFT	0.02 ± 0.16	-0.01	-0.02	(-0.31) - 0.31	0.14	0.05
R x REA	0.10 ± 0.15	0.06	0.10	(-0.19) - 0.39	-0.01	0.00
R x BFT	0.14 ± 0.17	0.14	0.14	(-0.21) - 0.46	-0.10	-0.04
R x RFT	0.02 ± 0.15	0.05	0.02	(-0.25) - 0.31	0.00	-0.01
C x REA	0.09 ± 0.17	0.06	0.08	(-0.24) - 0.41	0.04	0.25
C x BFT	0.14 ± 0.19	0.15	0.14	(-0.22) - 0.50	0.08	0.25
C x RFT	0.16 ± 0.17	0.20	0.17	(-0.15) - 0.47	0.05	0.29
O x REA	0.18 ± 0.18	0.15	0.18	(-0.16) - 0.52	0.04	0.24
O x BFT	0.17 ± 0.20	0.18	0.18	(-0.22) - 0.53	-0.07	-0.04
O x RFT	0.28 ± 0.19	0.28	0.28	(-0.07) - 0.66	-0.06	-0.08
SAC x REA	-0.37 ± 0.20	-0.39	-0.37	(-0.78) - 0.02	0.14	0.00
SAC x BFT	0.10 ± 0.21	0.12	0.10	(-0.31) - 0.49	0.04	0.00
SAC x RFT	0.14 ± 0.18	0.16	0.14	(-0.22) - 0.47	0.00	0.01

REA: rib eye area; BFT: backfat thickness; RFT: rum fat thickness; M: muscularity; E: physical structure; R: racial aspects; C: conformation; omphalos (navel); SAC: sacrum.

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Genetic parameters for visual scores, growth and carcass traits in Nellore Cattle

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