scholarly journals A new way to measure milk yield persistency: a genetic point of view with application to Gyr (Bos indicus) cattle

2015 ◽  
Vol 82 (4) ◽  
pp. 385-390 ◽  
Author(s):  
Rodrigo Junqueira Pereira ◽  
Denise Rocha Ayres ◽  
Lenira El Faro ◽  
Aníbal Eugênio Vercesi Filho ◽  
Rui da Silva Verneque ◽  
...  
Keyword(s):  
Milk Yield ◽  
Bos Indicus ◽  
Genetic Correlations ◽  
Deviance Information Criterion ◽  
Information Criterion ◽  
Point Of View ◽  
Quadratic Model ◽  
Cumulative Yield ◽  
Genetic Covariance ◽  
Lactation Length

The objective of this work was to estimate genetic parameters for a measure of persistency of milk yield and to evaluate its association with 305-d cumulative milk yield and lactation length. 12 346 records from 8202 dairy Gyr cows including lactations up to fifth calving were used. The measure of persistency was obtained from one of the parameters of a quadratic model that describes the cumulative yield across lactation as a function of days in milk. A three-trait multivariate analysis was done. Heritability and repeatability for persistency were 0·08 and 0·21, respectively. Deviance Information Criterion provided evidence that the additive genetic covariance between the measure of persistency studied and 305-d cumulative yield is zero. Genetic correlations between persistency and lactation length were 0·50 and 0·27 for first or all lactations, respectively. Milk yield persistency as measured in this study has low heritability. Selection for persistency can increase lactation length. The measure of milk yield persistency studied here is genetically independent of total milk yield and can be included in routine genetic evaluations of dairy cattle.

scholarly journals Model comparison and estimation of genetic parameters for body weight in commercial broilers

2013 ◽  
Vol 93 (1) ◽  
pp. 67-77 ◽  
Author(s):  
G. Maniatis ◽  
N. Demiris ◽  
A. Kranis ◽  
G. Banos ◽  
A. Kominakis
Keyword(s):  
Body Weight ◽  
Akaike Information Criterion ◽  
Model Evaluation ◽  
Model Comparison ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Information Criterion ◽  
Biological Properties ◽  
Genetic Covariance ◽  
Estimation Of Genetic Parameters

Maniatis, G., Demiris, N., Kranis, A., Banos, G. and Kominakis, A. 2013. Model comparison and estimation of genetic parameters for body weight in commercial broilers. Can. J. Anim. Sci. 93: 67–77. The availability of powerful computing and advances in algorithmic efficiency allow for the consideration of increasingly complex models. Consequently, the development and application of appropriate statistical procedures for model evaluation is becoming increasingly important. This paper is concerned with the application of an alternative model determination criterion (conditional Akaike Information Criterion, cAIC) in a large dataset comprising 203 323 body weights of broilers, pertaining to 7 (BW7) and 35 (BW35) days of age. Seven univariate and seven bivariate models were applied. Direct genetic, maternal genetic and maternal environmental (c2) effects were estimated via REML. The model evaluation criteria included conditional Akaike Information Criterion (cAIC), Bayesian Information Criterion (BIC) and the standard Akaike Information Criterion (henceforth marginal; mAIC). According to cAIC the best-fitting model included direct genetic, maternal genetic and c2 effects. Maternal heritabilities were low (0.10 and 0.03) compared to the direct heritabilities (0.17 and 0.21), while c2 was 0.05 and 0.04 for BW7 and BW35, respectively. BIC and mAIC favoured a model that additionally included a direct-maternal genetic covariance, resulting in highly negative direct-maternal genetic correlations (−0.47 and −0.64 for BW7 and BW35, respectively) and higher direct heritabilities (0.25 and 0.28 for BW7 and BW35, respectively). Results suggest that cAIC can select different animal models than mAIC and BIC with different biological properties.

Phenotypic and genetic parameters for milk yield in traditional Nublang cattle (Bos indicus) of Bhutan

2015 ◽  
Vol 57 ◽  
pp. 25-30
Author(s):  
Jigme Dorji ◽  
Dhendup ◽  
Iona M. MacLeod
Keyword(s):  
Milk Yield ◽  
Genetic Improvement ◽  
Genetic Parameters ◽  
Bos Taurus ◽  
Bos Indicus ◽  
Sustainable Utilization ◽  
Dual Purpose ◽  
Lactation Length ◽  
Daily Milk Yield ◽  
Daily Milk

SummaryThe Nublang is a unique dual-purpose breed ofBos indicuscattle found in Bhutan. They have been crossed with Mithun (Bos frontalis) andBos taurusbreeds in an effort to improve milk production leading to a decline in the population of purebred Nublang. An alternative to crossbreeding would be the genetic improvement of milk yield within purebred Nublang, thus allowing conservation and sustainable utilization of the pure breed. It is important to measure the genetic variability (heritability) of milk yield to assess the potential for genetic improvement within Nublang. Therefore this study estimated phenotypic and genetic parameters of milk yield using 2 052 test day milk yields from 66 cows recorded from 1997 to 2013 in the National Nublang Farm, Tashiyangphu. The average daily milk yield (DMY) was 2.12 ± 0.7 litres (N 2 052, range: 0.3–5.0 L, CV: 34 percent). Parity, month in milk and year all had a significant effect on DMY (P< 0.05). The average lactation milk yield (LMY) was 519.2 ± 151 L (N: 261, range: 115–881.7, CV: 29.1 percent) and average lactation length was 239 days. LMY was significantly influenced by parity (P< 0.05) and season of calving. The heritability of DMY and LMY was 0.22 ± 0.16 and 0.13 ± 0.20, respectively. The repeatability estimates were 0.45 ± 0.05 and 0.49 ± 0.08 for DMY and LMY, respectively. Overall the heritability and repeatability estimates of milk yields indicate potential for genetic improvement of milk yield in Nublang cattle through selection. However, it is recommended that a larger dataset is generated to enable more precise estimates of genetic parameters.

scholarly journals Multiple-trait model through Bayesian inference applied to Jatropha curcas breeding for bioenergy

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247775
Author(s):  
Marco Antônio Peixoto ◽  
Jeniffer Santana Pinto Coelho Evangelista ◽  
Igor Ferreira Coelho ◽  
Rodrigo Silva Alves ◽  
Bruno Gâlveas Laviola ◽  
...  
Keyword(s):  
Jatropha Curcas ◽  
Repeated Measures ◽  
Bayesian Model ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Deviance Information Criterion ◽  
Information Criterion ◽  
Monte Carlo Algorithm ◽  
Multiple Trait ◽  
Trait Model

Multiple-trait model tends to be the best alternative for the analysis of repeated measures, since they consider the genetic and residual correlations between measures and improve the selective accuracy. Thus, the objective of this study was to propose a multiple-trait Bayesian model for repeated measures analysis in Jatropha curcas breeding for bioenergy. To this end, the grain yield trait of 730 individuals of 73 half-sib families was evaluated over six harvests. The Markov Chain Monte Carlo algorithm was used to estimate genetic parameters and genetic values. Genetic correlation between pairs of measures were estimated and four selective intensities (27.4%, 20.5%, 13.7%, and 6.9%) were used to compute the selection gains. The full model was selected based on deviance information criterion. Genetic correlations of low (ρg ≤ 0.33), moderate (0.34 ≤ ρg ≤ 0.66), and high magnitude (ρg ≥ 0.67) were observed between pairs of harvests. Bayesian analyses provide robust inference of genetic parameters and genetic values, with high selective accuracies. In summary, the multiple-trait Bayesian model allowed the reliable selection of superior Jatropha curcas progenies. Therefore, we recommend this model to genetic evaluation of Jatropha curcas genotypes, and its generalization, in other perennials.

scholarly journals Genetic Parameters of First Lactation Milk Yield and Fertility Traits in Brown Swiss Cattle

2014 ◽  
Vol 14 (3) ◽  
pp. 545-557 ◽  
Author(s):  
Aziz Şahin ◽  
Zafer Ulutaş ◽  
Asiye Yýlmaz Adkinson ◽  
Robert W. Adkinson
Keyword(s):  
Milk Yield ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Gestation Length ◽  
Yield Traits ◽  
Dry Period ◽  
Brown Swiss ◽  
Lactation Length ◽  
Fertility Traits ◽  
Brown Swiss Cattle

AbstractThis research was carried out to estimate variance components and genetic parameters for first lactation milk yield (lactation milk yield, 305-day milk yield, lactation length, and dry period) and some fertility traits (calving interval, gestation length and number of services per conception) of Brown swiss cattle reared at konuklar state farm located in konya province, turkey. data were collected on milk yield traits of 3, 769 first lactation Brown Swiss cattle during the period from 1990 to 2008. Variance components, genetic parameters, breeding values, and genetic correlations were estimated using multiple trait derivative free restricted maximum likelihood (mtdfreml) fitting an animal model. Heritability estimates were 0.26, 0.25, 0.10, 0.06, 0.07, 0.06 and 0.03 for lactation milk yield (lmy), 305-day milk yield (305 dmy), lactation length (ll), dry period (dp), calving interval (ci), gestation length (Gl), and number of services per conception (nsc), respectively. Genetic correlations between milk yield and fertility traits ranged from 0.31 to 0.95 and phenotypic correlations ranged from –0.026 to 0.75. Breeding values were estimated and used to characterize genetic trends across the time period investigated. The results showed that the first lactation milk yield traits can be used as selection criteria for development of effective genetic improvement programme in turkish Brown swiss cattle. in addition, the results indicate the essential for scheming an effective schedule for growth of genetic variability to improve the milk yield traits of Brown swiss cattle in this farm by way of selection.

scholarly journals Strong support for a heterogeneous speciation decline model in Dinosauria: a response to claims made by Bonsor et al . (2020)

2021 ◽  
Vol 8 (8) ◽  
pp. 202143
Author(s):  
Manabu Sakamoto ◽  
Michael J. Benton ◽  
Chris Venditti
Keyword(s):  
Phylogenetic Tree ◽  
Deviance Information Criterion ◽  
Strong Support ◽  
Information Criterion ◽  
Quadratic Model ◽  
Root Age ◽  
Link Type ◽  
Incomplete Sampling

Through phylogenetic modelling, we previously presented strong support for diversification decline in the three major subclades of dinosaurs (Sakamoto et al . 2016 Proc. Natl Acad. Sci. USA 113 , 5036–5040. ( doi:10.1073/pnas.1521478113 )). Recently, our support for this model has been criticized (Bonsor et al . 2020 R. Soc. Open Sci. 7 , 201195. ( doi:10.1098/rsos.201195 )). Here, we highlight that these criticisms seem to largely stem from a misunderstanding of our study: contrary to Bonsor et al .'s claims, our model accounts for heterogeneity in diversification dynamics, was selected based on deviance information criterion (DIC) scores (not parameter significance), and intercepts were estimated to account for uncertainties in the root age of the phylogenetic tree. We also demonstrate that their new analyses are not comparable to our models: they fit simple, Dinosauria-wide models as a direct comparison to our group-wise models, and their additional trees are subclades that are limited in taxonomic coverage and temporal span, i.e. severely affected by incomplete sampling. We further present results of new analyses on larger, better-sampled trees ( N = 961) of dinosaurs, showing support for the time-quadratic model. Disagreements in how we interpret modelled diversification dynamics are to be expected, but criticisms should be based on sound logic and understanding of the model under discussion.

scholarly journals First Lactation Genetic Parameters of Buffaloes Under Multiple Trait Animal Model

1997 ◽  
Vol 2 ◽  
pp. 27
Author(s):  
M.S. Khan ◽  
K. Z. Gondal ◽  
S. H. Raza ◽  
A. A. Asghar
Keyword(s):  
Animal Model ◽  
Milk Yield ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Calving Interval ◽  
Economic Traits ◽  
Dry Period ◽  
Multiple Trait ◽  
Lactation Length ◽  
The Relationship

There are many computational algorithms available for estimating (co) variance components under multiple trait models. Paternal half-sib correlation is the most commonly used method for estimating genetic parameters of economic traits of buffaloes. The models used are Single trait, ignoring covariances with other traits. The relationship matrices are also ignored. This study was undertaken to estimate genetic parameters of first lactation traits of Nili Ravi buffaloes under a multiple trait animal model. First lactation milk yield was l7% heritable when traits such as age of calving interval were considered. Age at first calving was 18% heritable with very low genetic correlations with other traits. Lactation length, dry period and calving interval were lowly heritable traits. Estimates differed by inclusion or exclusion of traits due to the covariances present among all these traits. A high genetic correlation between mills yield and lactation length (0.74) does not warrant the selection of milk yield as the only trait.

Estimates of genetic parameters for milk and fat yield for the first three lactations in British Friesian cows

1984 ◽  
Vol 38 (3) ◽  
pp. 313-322 ◽  
Author(s):  
Karin Meyer
Keyword(s):  
Milk Yield ◽  
Fixed Effects ◽  
Mixed Model ◽  
Genetic Correlations ◽  
Data Sets ◽  
Lactation Length ◽  
Maximum Likelihood Procedure ◽  
Fat Yield ◽  
Variance And Covariance Components ◽  
Estimate Variance

ABSTRACTA multivariate restricted maximum-likelihood procedure was used to estimate variance and covariance components between and within sires. This method, which considered all lactations simultaneously, accounted for the bias in later lactation records due to selection on dairy performance. Analysis was carried out for a mixed model with herd-year-seasons as fixed and sires as random effects, and fitting lactation length, calving age and month within season of calving as covariables. The data included 26 176 first, 19 978 second and 14 868 third lactation records for 679 test sires, and were analysed in 13 subsets. Additional records for proven sires, treated as fixed effects, were included to improve the data structure.Estimates for all components were higher in later than in earlier data sets, probably, to a large extent, because of a scale effect. Pooled estimates of heritabilities for lactations 1 to 3 were 0·28, 0·19 and 0·24 for milk yield, and 0·27, 0·21 and 0·25 for fat yield. Genetic correlations of 0·91, 0·91 and 0·95 for milk yield, and 0·91, 0·91 and 0·99 for fat yield, were found between lactations 1 and 2, 1 and 3, and 2 and 3, respectively. Results suggest that dairy performance in all lactations is almost identical genetically.

Influence of dietary supplementation and partial suckling on body weight and on lactation and reproductive performance of primiparous Boran (Bos indicus) cows in Ethiopia

1994 ◽  
Vol 123 (2) ◽  
pp. 267-273 ◽  
Author(s):  
A. Tegegne ◽  
A. Geleto ◽  
P.O. Osuji ◽  
T. Kassa ◽  
R. Franceschini
Keyword(s):  
Body Weight ◽  
Milk Yield ◽  
Reproductive Performance ◽  
Milk Fat ◽  
Bos Indicus ◽  
Dietary Supplementation ◽  
Treatment Groups ◽  
Lactation Length ◽  
Daily Milk Yield ◽  
Daily Milk

SummaryThis study was conducted in the central highlands of Ethiopia during 1990–92 to examine the effects of diet and partial suckling on lactation and reproductive performance of Boran (Bos indicus) cows. Primiparous Boran cows were allocated to dietary supplementation or no supplementation with either milking or partial suckling based on body weight at calving. All cows received grass hay ad libitum and the supplemented groups were provided with additional concentrate feed which supplied 222 g/kg DM crude protein and 10 MJ/kg DM energy. Calves were weaned at 8 weeks of age. Mean (±S.E.) dam calving and calf birth weights were 314±11·4 and 25±0·6 kg. Body weights at first postpartum oestrus and at conception were not affected by suckling. Supplemented cows however, were heavier at first oestrus (P = 0·06) and at conception (P < 0·01) than non-supplemented cows. Lactation length was longer (P < 0·01) and mean daily milk yield higher (P < 0·001) in suckled than in milked cows. Diet, however, did not influence either lactation length or daily milk yield. In suckled cows, mean daily milk yield declined sharply after weaning (week 9) and was lower by 38 and 43% of week 8 production in the supplemented and non-supplemented groups, respectively. The overall mean lactation yield was 212·4±64·6 litres; with a significant (P < 0·05) diet × suckling interaction effect. Concentrations of milk fat, total protein and total solids were not affected by either diet or suckling treatment. The postpartum anoestrus interval was longer (P < 0·01) in non-supplemented than in supplemented cows, but did not differ between suckled and milked cows. The percentage of cows cycling by 150 days postpartum was higher (P < 0·05) in supplemented than in nonsupplemented and in milked than in suckled (P > 0·05) cows. By this interval, a higher (P < 0·05) percentage of supplemented-milked (90%) cows cycled than in the other three treatment groups (48·5%). Pregnancy from the first insemination ranged from 45·5 to 63·6% in the four treatment groups. It was concluded that although partial suckling extended the postpartum anoestrus interval, lactation length and milk yield were improved. The negative effects of partial suckling on postpartum reproduction could be overcome with the appropriate dietary supplementation. The economic tradeoff between dietary supplementation, milk yield and reproduction has to be determined in partially suckled cows.

Genetic correlations and heritabilities for milk yield and lactation length of dairy sheep

1998 ◽  
Vol 27 (3) ◽  
pp. 217-221 ◽  
Author(s):  
U.M. El-Saied ◽  
J.A. Carriedo ◽  
J.A. Baro ◽  
L.F. De Le Fuente ◽  
F. San Primitivo
Keyword(s):  
Milk Yield ◽  
Genetic Correlations ◽  
Dairy Sheep ◽  
Lactation Length

scholarly journals Sire Evaluation Based on First Lactation 305 Day Milk Yield and Individual Part Lactation Records in Frieswal Cattle

2021 ◽  
Author(s):  
Rajeev . ◽  
Ravinder Kumar ◽  
Rajbir Singh
Keyword(s):  
Milk Yield ◽  
Estimate Breeding Value ◽  
Genetic Correlations ◽  
Uttar Pradesh ◽  
Breeding Value ◽  
Climatic Regions ◽  
Lactation Length ◽  
Sire Evaluation ◽  
Improvement Programme ◽  
Breed Improvement

Background: Frieswal, the crossbred cattle, between sahiwal and Holstein Friesian breed with 62.50 per cent of exotic (inheritance) with total lactation milk yield of (4000 Kg) with average lactation length 300 days (PDC Annual Report, 2015-16). Presently, the Frieswal Animal is mainly maintained at 36 Military Farms located in various agro-climatic regions in the country.Methods: The present study was undertaken on first lactation 305 days and part lactation records of 1470 Frieswal cows maintained over a period of 10 years (2003-2012) from military farm at CIRC Meerut Uttar Pradesh as well as Ambala. The success of any breed improvement programme depends mainly on the Sire evaluation which involves the estimation of expected breeding value of the bulls on the basis of average first lactation 305-day or less milk yield and part lactation records of their daughters (FL305DMY).Result: The estimate breeding value of 55 Frieswal sires on the basis of first lactation 305-day or less milk yield and individually part lactation records, by LSM, BLUP and DFREML methods were 2701.48 kg and 2660.70 kg, followed by 333.40, kg and 329.17 kg, respectively. A number of 55 Frieswal sires with three or more daughters were evaluated and ranked on the basis of first lactation 305-day milk yield and individual third month part lactation was having better heritability and comparatively higher genetic correlations with the first lactation 305-days or less milk yield. 

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