scholarly journals Relationships between longevity and conformation traits in Czech Fleckvieh cows

2009 ◽  
Vol 54 (No. 9) ◽  
pp. 385-394 ◽  
Author(s):  
L. Zavadilová ◽  
E. Němcová ◽  
M. Štípková ◽  
J. Bouška
Keyword(s):  
Variance Component ◽  
Genetic Relationships ◽  
Genetic Correlations ◽  
Variance Component Estimation ◽  
Body Measurements ◽  
Linear Type ◽  
Zero Correlation ◽  
Type Traits ◽  
Component Estimation

The relationships between conformation and longevity traits were analysed in 58 493 Czech Fleckvieh cows first calved from 1994 to 2003. All cows were scored for conformation during the first lactation. Genetic correlations between longevity and conformation traits were estimated by bivariate runs using the VCE 4.0 program for variance component estimation. The values of heritability for conformation traits were in the range from 0.06 to 0.63 and for longevity traits from 0.04 to 0.05. Low or intermediate genetic relationships between recorded linear traits and longevity trait were found. The correlations were lower for functional longevity. Body measurements showed negative genetic correlations with real as well as functional longevity (–0.12 to –0.29). The dairy character negatively correlated with longevity traits (–0.18 to –0.26). The muscularity and udder showed a zero correlation with functional longevity, while the feet and legs were not correlated with real longevity. The highest positive genetic correlations between real longevity and objectively scored linear type traits were found for hock (0.24), rear udder attachment (0.28), fore udder length (0.16) and central ligament (0.11). On the contrary, the correlation between the udder depth and the milk-corrected longevity was positive (0.28) and higher than in the case of real longevity.

scholarly journals Genetic Relationships Among Linear Type Traits and Milk Production Traits of Holstein Dairy Cattle

2015 ◽  
Vol 15 (4) ◽  
pp. 903-917 ◽  
Author(s):  
Mehdi Bohlouli ◽  
Sadegh Alijani ◽  
Mehran Rahimi Varposhti
Keyword(s):  
Dairy Cattle ◽  
Milk Production ◽  
Genetic Relationships ◽  
Genetic Correlations ◽  
Likelihood Method ◽  
Production Traits ◽  
Milk Production Traits ◽  
Linear Type ◽  
Type Traits ◽  
Heritability Estimates

Abstract The aim of this study was to estimate genetic relationships among milk production and linear type traits of Holstein dairy cattle from seven herds in Isfahan province of Iran. Phenotypic data was collected from 2004 to 2012 and included milk yield (MY), fat yield (FY) and protein yield (PY) for first three lactations, six body traits (stature, ST; chest width, CW; body depth, BD; angularity, AN; rump angle, RA; rump width, RW), three feet and legs traits (rear legs side view, RLSV; rear legs rear view, RLRV; foot angle, FA) and eight udder traits (fore udder attachment, FUA; rear udder height, RUH; rear udder width, RUW; central ligament, CL; udder depth, UD; fore teat placement, FTP; rear teat placement, RTP; teat length, TL). The number of animals for each linear type trait was 3505. Multi-trait animal models were used to estimate the (co)variance components based on restricted maximum likelihood method (REML) using WOMBAT software. Heritability estimates of first, second and third lactations for MY were 0.28, 0.41 and 0.36; for FY were 0.22, 0.23 and 0.36 and for PY were 0.31, 0.33 and 0.25, respectively. The heritability estimates ranged from 0.17±0.04 to 0.24±0.04 for body traits, 0.06±0.03 to 0.15±0.04 for feet and leg traits and from 0.12±0.04 to 0.25±0.05 for udder traits. Genetic correlations among the recorded type traits ranged from -0.76±0.01 (between AN and RLRV) to 0.65±0.02 (between AN and RW). The low to moderate positive genetic correlations between AN and FUA with milk production traits indicate that cows with high AN and good FUA have higher milk, fat and protein yields. The results of this study indicated that considerable genetic variation exists for different type traits within this sample of the Iranian Holstein population and additive genetic variability of type traits can provide moderate genetic gains through selection.

GPS-BDS-Galileo double-differenced stochastic model refinement based on least-squares variance component estimation

2021 ◽  
pp. 1-16
Author(s):  
Hong Hu ◽  
Xuefeng Xie ◽  
Jingxiang Gao ◽  
Shuanggen Jin ◽  
Peng Jiang
Keyword(s):  
Stochastic Model ◽  
Least Squares ◽  
Stochastic Models ◽  
Variance Component ◽  
Satellite System ◽  
Variance Component Estimation ◽  
Short Baseline ◽  
Component Estimation ◽  
Zero Baseline ◽  
Global Navigation Satellite

Abstract Stochastic models are essential for precise navigation and positioning of the global navigation satellite system (GNSS). A stochastic model can influence the resolution of ambiguity, which is a key step in GNSS positioning. Most of the existing multi-GNSS stochastic models are based on the GPS empirical model, while differences in the precision of observations among different systems are not considered. In this paper, three refined stochastic models, namely the variance components between systems (RSM1), the variances of different types of observations (RSM2) and the variances of observations for each satellite (RSM3) are proposed based on the least-squares variance component estimation (LS-VCE). Zero-baseline and short-baseline GNSS experimental data were used to verify the proposed three refined stochastic models. The results show that, compared with the traditional elevation-dependent model (EDM), though the proposed models do not significantly improve the ambiguity resolution success rate, the positioning precision of the three proposed models has been improved. RSM3, which is more realistic for the data itself, performs the best, and the precision at elevation mask angles 20°, 30°, 40°, 50° can be improved by 4⋅6%, 7⋅6%, 13⋅2%, 73⋅0% for L1-B1-E1 and 1⋅1%, 4⋅8%, 16⋅3%, 64⋅5% for L2-B2-E5a, respectively.

scholarly journals Selection Response Due to Different Combination of Antagonistic Milk, Beef, and Morphological Traits in the Alpine Grey Cattle Breed

Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1340
Author(s):  
Enrico Mancin ◽  
Cristina Sartori ◽  
Nadia Guzzo ◽  
Beniamino Tuliozi ◽  
Roberto Mantovani
Keyword(s):  
Genetic Correlation ◽  
Functional Traits ◽  
Performance Test ◽  
Genetic Relationships ◽  
Selection Index ◽  
Milk Traits ◽  
Linear Type ◽  
Dual Purpose ◽  
Type Traits ◽  
Selection Indexes

Selection in local dual-purpose breeds requires great carefulness because of the need to preserve peculiar traits and also guarantee the positive genetic progress for milk and beef production to maintain economic competitiveness. A specific breeding plan accounting for milk, beef, and functional traits is required by breeders of the Alpine Grey cattle (AG), a local dual-purpose breed of the Italian Alps. Hereditability and genetic correlations among all traits have been analyzed for this purpose. After that, different selection indexes were proposed to identify the most suitable for this breed. Firstly, a genetic parameters analysis was carried out with different datasets. The milk dataset contained 406,918 test day records of milk, protein, and fat yields and somatic cells (expressed as SCS). The beef dataset included performance test data conducted on 749 young bulls. Average daily gain, in vivo estimated carcass yields, and carcass conformation (SEUROP) were the phenotypes obtained from the performance tests. The morphological dataset included 21 linear type evaluations of 11,320 first party cows. Linear type traits were aggregated through factor analysis and three factors were retained, while head typicality (HT) and rear muscularity (RM) were analyzed as single traits. Heritability estimates (h2) for milk traits ranged from 0.125 to 0.219. Analysis of beef traits showed h2 greater than milk traits, ranging from 0.282 to 0.501. Type traits showed a medium value of h2 ranging from 0.238 to 0.374. Regarding genetic correlation, SCS and milk traits were strongly positively correlated. Milk traits had a negative genetic correlation with the factor accounting for udder conformations (−0.40) and with all performance test traits and RM. These latter traits showed also a negative genetic correlation with udder volume (−0.28). The HT and the factor accounting for rear legs traits were not correlated with milk traits, but negatively correlated with beef traits (−0.32 with RM). We argue that the consequence of these results is that the use of the current selection index, which is mainly focused on milk attitude, will lead to a deterioration of all other traits. In this study, we propose more appropriate selection indexes that account for genetic relationships among traits, including functional traits.

scholarly journals An overview of variance component estimation

Metrika ◽  
1995 ◽  
Vol 42 (1) ◽  
pp. 215-230 ◽  
Author(s):  
Shayle R. Searle
Keyword(s):  
Variance Component ◽  
Variance Component Estimation ◽  
Component Estimation
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