Phenotypic relationship of female sexual precocity with production and reproduction traits in beef cattle using multivariate statistical techniques

Figures & data

Figure 1. Proportional distribution of visual scores of conformation (CS), finishing precocity (FP), muscling (MS), and size (SS) in 13,105 Nellore females.

Table 1. Descriptive statistics for the traits used in both principal component and factor analysis.

Traits	Mean	Min	Max	SD	CV %
WWG, kg	0.74	0.29	1.25	0.13	17.55
YWG, kg	0.41	0.10	0.88	0.14	35.02
BFT, mm	2.78	0.90	8.10	1.17	41.95
AFC, mo	30.51	21.53	38.66	5.79	18.99
DSC, d	325.96	270.0	365.0	19.07	5.85
LONG, mo	42.65	16.90	92.25	19.71	46.19
CP, kg/year	104.96	16.20	288.54	48.73	46.42

WWG: weaning weight gain; YWG: yearling weight gain; BFT: backfat thickness at yearling; AFC: age at first calving; DSC: days to second calving; LONG: longevity; CP: cumulative productivity; SD: standard deviation; CV: coefficient of variation.

Table 2. Eigenvalues (${\mathit{\lambda }}_{\mathit{i}}$), variance percentage (VP), and cumulative variance percentage (CVP) explained by principal components.

Principal components	${\lambda }_i$	$\mathrm{V}\mathrm{P}$	$\text{CVP}$
PC1	1.4655	30.68	30.68
PC2	1.0965	17.18	47.86
PC3	1.0590	16.02	63.88
PC4	0.9789	13.69	77.57
PC5	0.8277	9.79	87.36
PC6	0.7355	7.73	95.08
PC7	0.5866	4.92	100.00

Table 3. Correlation coeficients between traits with the three first principal components.

Traits	PC1	PC2	PC3
LONG	–0.0528	0.5114	–0.6355
YWG	–0.5743	0.1807	0.0889
WWG	0.1350	–0.4932	–0.6506
CP	–0.2771	–0.5710	0.1844
AFC	0.5486	0.1456	0.0965
DSC	0.1343	–0.3395	–0.2258
BFT	–0.5033	–0.0098	–0.2659

Values in bold represent the coefficients showing the discriminant variables for each component.

LONG: longevity; YWG: yearling weight gain; WWG: weaning weight gain; CP: cumulative productivity; AFC: age at first calving; DSC: days to second calving; BFT: backfat thickness.

Figure 2. Distribution of the precocious (1) and non-precocious (0) dams, and of the traits: weight gain from birth to weaning (WWG), weight gain from weaning to yearling (YWG), backfat thickness at yearling (BFT), age at first calving (AFC), days to second calving (DSC), cumulative productivity (CP), and longevity (LONG), considering the first two principal components (PC1 and PC2).

Table 4. Factors after rotation and its corresponding values.

Traits	Factor 1	Factor 2	Factor 3
LONG	0.100	0.016	0.541
YWG	0.764	–0.327	0.035
WWG	0.031	0.978	0.068
CP	0.269	0.087	–0.376
AFC	–0.735	0.027	0.121
DSC	–0.088	0.118	–0.053
BFT	0.622	0.000	0.074

Values in bold represent the factor coeficients showing the discriminant variables for each factor.

LONG: longevity; WWG: weaning weight gain; YWG: yearling weight gain; CP: cumulative productivity; AFC: age at first calving; DSC: days to second calving; BFT: backfat thickness.

Table 5. Mean of the precocious (P) and non-precocious (NP) dams for the scores in each factor and for the growth, reproduction, and production traits.

Factor	Mean^a		Traits^b	Mean
	P	NP		P	NP
Factor 1	0.808^A	–0.652^B	YWG (kg)	0.498	0.335
			AFC (mo)	24.20	35.61
			BFT (mm)	3.37	2.30
Factor 2	–0.047^A	0.038^A	WWG (kg)	0.735	0.742
Factor 3	–0.130^A	0.105^B	LONG (mo)	42.96	42.41

^a Factor means in row followed by same letter do not differ by F test (p < .01).

^b Mean values of each discriminant trait according to each factor.

YWG: yearling weight gain; AFC: age at first calving; BFT: backfat thickness; WWG: weaning weight gain; LONG: longevity.

Figure 3. Distribution of the precocious dams (1) and non-precocious (0), and of the traits: weight gain from birth to weaning (WWG), weight gain from weaning to yearling (YWG), backfat thickness at yearling (BFT), age at first calving (AFC), days to second calving (DSC), cumulative productivity (CP), and longevity (LONG), considering the first and the third principal components (PC1 and PC3).

Figure 4. Perceptual map, dimensions 1 and 2 (D1 and D2) and their respective inertia for the traits: early pregnancy (EP), stayability (STAY), success (1), and failure (0) scores, measured at yearling and ranging from 1 to 5, of conformation (CS), finishing precocity (FP), muscling (MS), and size (SS).