Random regression models to estimate genetic parameters for test-day milk yield and composition in Iranian buffaloes

Abstract. The objective of this study was to estimate genetic parameters for milk yield and milk percentages of fat and protein in Iranian buffaloes. A total of 9,278 test-day production records obtained from 1,501 first lactation buffaloes on 414 herds in Iran between 1993 and 2009 were used for the analysis. Genetic parameters for productive traits were estimated using random regression test-day models. Regression curves were modeled using Legendre polynomials (LPs). Heritability estimates were low to moderate for milk production traits and ranged from 0.09 to 0.33 for milk yield, 0.01 to 0.27 for milk protein percentage and 0.03 to 0.24 for milk fat percentage, respectively. Genetic correlations ranged from −0.24 to 1 for milk yield between different days in milk over the lactation. Genetic correlations of milk yield at different days in milk were often higher than permanent environmental correlations. Genetic correlations for milk protein percentage ranged from −0.89 to 1 between different days in milk. Also, genetic correlations for milk percentage of fat ranged from −0.60 to 1 between different days in milk. The highest estimates of genetic and permanent environmental correlations for milk traits were observed at adjacent test-days. Ignoring heritability estimates for milk yield and milk protein percentage in the first and final days of lactation, these estimates were higher in the 120 days of lactation. Test-day milk yield heritability estimates were moderate in the course of the lactation, suggesting that this trait could be applied as selection criteria in Iranian milking buffaloes.

Download Full-text

Estimation of genetic parameters and comparison of random regression animal and sire models of production traits in the first three lactations of Iranian Holsteins

Biotechnology in Animal Husbandry ◽

10.2298/bah1402261m ◽

2014 ◽

Vol 30 (2) ◽

pp. 261-279 ◽

Cited By ~ 1

Author(s):

A. Mohammadi ◽

S. Alijani

Keyword(s):

Milk Fat ◽

Genetic Parameters ◽

Additive Genetic Variance ◽

Genetic Correlations ◽

Random Regression ◽

Lactation Period ◽

Production Traits ◽

Environmental Variance ◽

In The Beginning ◽

Residual Variances

This study was conducted to compare of random regression (RR) animal and sire models for estimation of the genetic parameters for production traits of Iranian Holstein dairy cows. For this purpose, the test day records were used belonged to first three lactations of cows and for, milk, fat and protein yields traits where, collected from 2003 to 2010, by the national breeding center of Iran. The genetic parameters were estimated using restricted maximum likelihood algorithm. To compare the model, different criterion -2logL value, AIC, BIC and RV were used for considered traits. Residual variances were considered homogeneous over the lactation period. Obtained results showed that additive genetic variance was highest in the beginning and end lactation and permanent environmental variance was highest in beginning of lactation than other lactation period. Heritabilities estimate for milk, fat and protein yields by RR animal and sire models were found to be lowest during early lactation (0.05, 0.04 and 0.07; 0.05, 0.19 and 0.13; 0.14, 0.19 and 0.15, for milk, fat and protein yields and in first, second and third lactation respectively). However, estimated heritabilities during lactation did not vary among different order Legendre polynomials, and also between RR animal and sire models. The variation in genetic correlations estimate in the RR animal and sire models was larger in the first lactation than in the second and third lactations. Thus, based on the results obtained, it can be inferred that the RR animal model is better for modeling yield traits in Iranian Holsteins.

Download Full-text

Estimation the Genetic Parameters for Milk Yield in Romanian Spotted, Simmental Type Cattle Breed

Archiva Zootechnica ◽

10.2478/azibna-2021-0017 ◽

2021 ◽

Vol 24 (2) ◽

pp. 105-121

Author(s):

Rodica Stefania Pelmuș ◽

Mircea Cătălin Rotar ◽

Cristina Lazăr ◽

Răzvan Alexandru Uță

Keyword(s):

Animal Model ◽

Milk Yield ◽

Genetic Parameters ◽

Genetic Correlations ◽

Cattle Breed ◽

Random Regression ◽

Breeding Value ◽

Regression Test ◽

Fat Yield ◽

Heritability Estimates

Abstract The aim of this study was to estimate the genetic parameters for test-day traits milk yield and the breeding value in Romanian Spotted, Simmental type cattle. Random regression test-day animal model was used to estimate the genetic parameters. The number of records were 2062 test-day from 302 cows. The data were obtained from Romanian Breeding Association Romanian Spotted, Simmental type. The heritability estimates values for milk yield ranged between 0.377 and 0.417. The heritability for fat test-day yield in our study was low the values ranged between 0.117 and 0.236 and for protein test-day yield was medium, the values ranged between 0.308 and 0.372. The breeding value for the best ten cows for milk yield ranged from 1946.57 to 3250.38 kg, for fat yield were between 64.92 and 98.86 kg and for protein ranged from 67.26 to 102.21 kg. The correlations between test-day milk yields ranging from 0.28 to 1. Genetic correlations between test day fat and protein yields were high.

Download Full-text

Genetic parameters for milk production and persistency in the Iranian Holstein population by the multitrait random regression model

Archives Animal Breeding ◽

10.7482/0003-9438-57-012 ◽

2014 ◽

Vol 57 (1) ◽

pp. 1-12 ◽

Cited By ~ 2

Author(s):

Khabat Kheirabadi ◽

Sadegh Alijani

Keyword(s):

Milk Yield ◽

Milk Fat ◽

Genetic Correlations ◽

Random Regression ◽

Genetic Dissection ◽

Production Traits ◽

Data Set ◽

Random Regression Model ◽

Regression Test ◽

Fat Yield

Abstract. For genetic dissection of milk, fat, and protein production traits in the Iranian primiparous Holstein dairy cattle, records of these traits were analysed using a multitrait random regression test-day model. Data set included 763 505 test-day records from 88 204 cows calving since 1993. The (co)variance components were estimated by Bayesian method. The obtained results indicated that as in case of genetic correlations within traits, genetic correlations between traits decrease as days in milk (DIM) got further apart. The strength of the correlations decreased with increasing DIM, especially between milk and fat. Heritability estimates for 305-d milk, fat, and protein yields were 0.31, 0.29, and 0.29, respectively. Heritabilities of test-day milk, fat, and protein yields for selected DIM were higher in the end than at the beginning or the middle of lactation. Heritabilities for persistency ranged from 0.02 to 0.24 and were generally highest for protein yield (0.05 to 0.24) and lowest for fat yield (0.02 to 0.17), with milk yield having intermediate values (0.06 to 0.22). Genetic correlations between persistency measures and 305-d production were higher for protein and milk yield than for fat yield. The genetic correlation of the same persistency measures between milk and fat yields averaged 0.76, and between milk and protein yields averaged 0.82.

Download Full-text

Genetic parameters of test day records of British Holstein-Friesian heifers

Animal Science ◽

10.1017/s0003356100037211 ◽

1992 ◽

Vol 55 (1) ◽

pp. 11-21 ◽

Cited By ~ 64

Author(s):

B. L. Pander ◽

W. G. Hill ◽

R. Thompson

Keyword(s):

Maximum Likelihood ◽

Milk Yield ◽

Milk Fat ◽

Genetic Parameters ◽

Genetic Correlations ◽

Lactation Performance ◽

Likelihood Methods ◽

Holstein Friesian ◽

Maximum Likelihood Methods ◽

Heritability Estimates

AbstractEstimates of genetic parameters for test day records of yields of milk, fat and protein and concentrations of fat and protein were obtained on 47 736 British Holstein-Friesian heifers in 7973 herds, progeny of 40 proven (to improve connectedness) and 707 young sires (comprising about one-fifth of the progeny), using multivariate restricted maximum likelihood methods with a sire model.Heritability estimates for lactation yields of milk, fat and protein and concentrations of fat and protein were 0·49, 0·39, 0·43, 0·63 and 0·47, respectively. Estimates for individual test day records of these traits ranged from 0·27 to 0·43, 0·16 to 0·34, 0·22 to 0·33, 0·11 to 0·48 and 0·21 to 0·43, respectively. Generally, heritability estimates for test day records were lowest at start and highest in mid lactation.Estimates of genetic correlations among yields of a trait on different test days ranged from 0·57 to 0·99, and for fat and protein concentrations from 0·34 to 0·99, the correlations being highest for adjacent tests. Phenotypic correlations were lower than genetic correlations. Genetic correlations of test day records with corresponding lactation traits were high (0·76 to 0·99), being highest in mid lactation.Genetic correlations of test day milk yield with test day yields and concentrations of fat and protein throughout the lactation were similar to those for complete lactation.The high heritabilities of test day yields and their high genetic correlations with complete lactation, except for the first 1 or 2 test days, suggest that lactation performance may be predicted from test days in early and mid lactation.

Download Full-text

Genetic parameters for test-day milk yield in tropical Holstein Friesian cattle fitting a multiple-lactation random regression animal model

South African Journal of Animal Science ◽

10.4314/sajas.v47i3.12 ◽

1970 ◽

Vol 47 (3) ◽

pp. 352-361

Author(s):

S. Meseret ◽

E. Negussie

Keyword(s):

Animal Model ◽

Milk Yield ◽

Genetic Improvement ◽

Genetic Parameters ◽

Genetic Correlations ◽

Random Regression ◽

Likelihood Method ◽

Holstein Friesian ◽

Heritability Estimates ◽

Friesian Cattle

Accurate estimates of genetic parameters are essential for genetic improvement of milk yield in dairy cattle and for setting up breeding programmes. Estimates of genetic parameters from test-day models, particularly for Holstein Friesian cattle maintained in tropical environments, are scant in the literature. The objective of this study was therefore to estimate genetic parameters for milk yield by fitting a multiple-lactation random regression animal model (RRM) based on data from Ethiopian Holstein Friesian herds. Data were used from the first three lactations of cows that calved between 1997 and 2013. The data comprised 13 421 test-day milk yield records from 800 cows from two large dairy herds. Variance components were estimated using the average information restricted maximum likelihood method fitting an RRM. Heritability estimates for first, second, and third lactations ranged from 0.20 to 0.26, 0.15 to 0.27, and 0.17 to 0.28, respectively. Heritability estimates ranging from 0.15 to 0.28 indicate that effective genetic improvement should be accompanied by a corresponding improvement of the production environment. Across-lactation genetic correlations between first and second, second and third, and first and third lactations, expressed on a 305-day yield basis, were 0.88, 0.83, and 0.70, respectively. These genetic correlations, less than or equal to 0.88, indicate that different lactations are different traits. For an accurate evaluation of the genetic merit of animals for milk yield, lactations should be treated as different, but correlated traits in a multiple-lactation analysis.Keywords: Genetic correlation, heritability, Legendre polynomial, test-day model

Download Full-text

Estimation of genetic parameters for daily milk yields of primiparous Iranian Holstein cows

Archives Animal Breeding ◽

10.7482/0003-9438-56-044 ◽

2013 ◽

Vol 56 (1) ◽

pp. 455-466

Author(s):

K. Kheirabadi ◽

S. Alijani ◽

L. Zavadilová ◽

S. A. Rafat ◽

G. Moghaddam

Keyword(s):

Milk Fat ◽

Fixed Effects ◽

Genetic Parameters ◽

National Level ◽

Genetic Correlations ◽

Protein Yield ◽

Random Regression ◽

Production Traits ◽

Multiple Traits ◽

Multiple Trait

Abstract. Applying a multiple trait random regression (MT-RR) in national level and for whole test day records of a country is a great advance in animal breeding context. Having reliable (co) variance components is a critical step in applying multiple traits genetic evaluation especially in developing countries. Genetic parameters of milk, fat and protein yields were estimated for Iranian Holstein dairy cows. Data included 276 692 test day (TD) production traits records collected of 30 705 primiparous cows belonging to 619 sires. An animal multi-trait random regression model was employed in the analyses using the restricted maximum likelihood (REML) method. The model included herd-test-date, age-season of calving (by applying a fixed regression for each subclass of this effect) and year of calving as fixed effects and random regression (RR) coefficients for additive genetic (AG) and permanent environmental (PE) effects. Obtained results showed that daily heritabilities ranged from 0.10 to 0.21 for milk, from 0.05 to 0.08 for fat and from 0.08 to 0.18 for protein yield. Estimated heritability for 305-d milk, fat and protein yields were 0.25, 0.20 and 0.25, respectively. Correlations between individual test day records within traits were high for adjacent tests (nearly 1) and decreased as the interval between tests increased. Correlations between yields of milk, fat and protein on a given test day are also high and greater during late lactation than during early or mid-lactation. Genetic correlations between 305-d yield traits ranged from 0.75 to 0.92. The largest genetic correlation, as well as permanent environmental correlation, was observed between milk and protein yield.

Download Full-text

Genetic parameters for production traits in primiparous Holstein cows estimated by random regression models

Revista Brasileira de Zootecnia ◽

10.1590/s1516-35982011000100012 ◽

2011 ◽

Vol 40 (1) ◽

pp. 85-94 ◽

Cited By ~ 6

Author(s):

Igor de Oliveira Biassus ◽

Jaime Araújo Cobuci ◽

Claudio Napolis Costa ◽

Paulo Roberto Nogara Rorato ◽

José Braccini Neto ◽

...

Keyword(s):

Milk Fat ◽

Legendre Polynomials ◽

Regression Models ◽

Genetic Parameters ◽

Genetic Correlations ◽

Random Regression ◽

Holstein Cows ◽

Lactation Period ◽

Production Traits ◽

Residual Variances

The objective of this study was to estimate genetic parameters for milk, fat and protein yields of Holstein cows using 56,508; 35,091 and 8,326 test-day milk records from 7,015, 4,476 and 1,114 cows, calves of 359, 246 and 90 bulls, respectively. The additive genetic and permanent environmental effects were estimated using REML. Random regression models with Legendre polynomials from order 3 to 6 were used. Residual variances were considered homogeneous over the lactation period. The estimates of variance components showed similar trends, with an increase of the polynomial order for each trait. The heritability estimates ranged from 0.14 to 0.31; 0.03 to 0.21 and 0.09 to 0.33 for milk, fat and protein yield, respectively. Genetic correlations among milk, fat and protein yields ranged from 0.02 to 1.00; 0.34 to 1.00 and 0.42 to 1.00, respectively. Models with higher order Legendre polynomials are the best suited to adjust test-day data for the three production traits studied.

Download Full-text

Twinning rate is not genetically correlated with production and reproduction traits in Iranian dairy cows

Animal Production Science ◽

10.1071/an19336 ◽

2020 ◽

Vol 60 (11) ◽

pp. 1402

Author(s):

Seyedeh Samaneh Asadollahi ◽

Navid Ghavi Hossein-Zadeh

Keyword(s):

Dairy Cows ◽

Milk Yield ◽

Milk Fat ◽

Milk Protein ◽

Genetic Correlations ◽

Genetic Selection ◽

Calving Interval ◽

Fat Percentage ◽

Protein Percentage ◽

And Performance

Context Any interruption to the reproductive system can negatively influence animal performance, and suitable animal-management practices should be adopted that will decrease the occurrence of reproductive problems such as may be the case with twinning. Aims The study was designed to estimate genetic parameters for twinning rate (TR) and to estimate genetic correlations between twinning rate and production and reproductive performances in the first lactation of Iranian Holstein cows. Methods The dataset used in this study was collected by the Animal Breeding Center of Iran during 1991–2013 and consisted of 273742 records of calving type (singleton or twin), 435742 records of 305-day milk yield, 424175 records of milk fat percentage, 253901 records of milk protein percentage, 251558 records of first calving interval, and 153632 records of number of days to first service. A single Gibbs sampling chain with 500000 rounds was generated to run linear and threshold animal models. Key results Posterior mean estimates of heritabilities for traits were: TR 0.0028, milk yield 0.28, milk fat percentage 0.33, milk protein percentage 0.38, first calving interval 0.064, and days to first service 0.061. Genetic correlations between TR and performance traits were negligible and varied from –0.08 (between TR and milk yield) to 0.04 (between TR and protein percentage). Conclusions Diminishing TR by genetic selection is a slow task owing to its low heritability. Negligible genetic correlation between TR and performance traits suggests that selection for decreased TR would not cause a significant decrease in milk production, nor is it likely to have a negative impact on the reproductive performance of dairy cows. Implications Dairy cattle breeders should follow genetic selection programs, especially for milk-production traits, without concern for an increase in twinning rate.

Download Full-text

Genetic and phenotypic parameters of some measures of lifetime production and their relationship with milk yield in the first three lactations in Tharparkar cows

The Journal of Agricultural Science ◽

10.1017/s0021859600042015 ◽

1982 ◽

Vol 98 (2) ◽

pp. 461-465

Author(s):

V. K. Taneja ◽

S. B. Basu ◽

D. S. Bhatnagar

Keyword(s):

Milk Production ◽

Milk Yield ◽

Genetic Parameters ◽

Genetic Correlations ◽

Production Traits ◽

Correlated Responses ◽

The Third ◽

Phenotypic Correlations ◽

Genetic And Phenotypic Correlations ◽

Heritability Estimates

SUMMARYThe genetic parameters of lifetime production traits and their relationship with milk yield in first, second and third lactations were estimated from information on 753 Tharparkar cows. The heritability estimates for milk yield in first, second and third lactations were 0·22 ± 0·10, 0·33 ± 0·14 and 0·49 ± 0·17 and for number of lactations completed, lifetime milk production, number of days in milk and herd life 0·58 ± 0·23, 0·51 ± 0·22, 0·54 ± 0·22 and 0·34 ± 0·20 respectively. The genetic and phenotypic correlations among the four lifetime production traits were in the range of 0·83–1·0 and 0·84–0·85 respectively. The phenotypic correlations of milk yield in first, second and third lactations with lifetime production traits were significant and ranged between 0·15 and 0·56. The corresponding genetic correlations ranged between 0·26 and 0·83. For the first three lactations, the genetic correlations of lifetime traits with the third lactation were high and that between lifetime milk yield and yield in third lactation the highest (0·83 ± 0·17). The direct and correlated responses from single trait selection were also estimated.

Download Full-text

Genetic parameters for test day milk yield of first lactation Holstein cows estimated by random regression using Legendre polynomials

Revista Brasileira de Zootecnia ◽

10.1590/s1516-35982008000400003 ◽

2008 ◽

Vol 37 (4) ◽

pp. 602-608 ◽

Cited By ~ 26

Author(s):

Claudio Napolis Costa ◽

Claudio Manoel Rodrigues de Melo ◽

Irineu Umberto Packer ◽

Ary Ferreira de Freitas ◽

Nilson Milagres Teixeira ◽

...

Keyword(s):

Variance Components ◽

Legendre Polynomials ◽

Genetic Parameters ◽

Genetic Correlations ◽

Random Regression ◽

Holstein Cows ◽

Residual Variance ◽

Environmental Variance ◽

Environmental Correlations ◽

Lp Estimates

Data comprising 263,390 test-day (TD) records of 32,448 first parity cows calving in 467 herds between 1991 and 2001 from the Brazilian Holstein Association were used to estimate genetic and permanent environmental variance components in a random regression animal model using Legendre polynomials (LP) of order three to five by REML. Residual variance was assumed to be constant in all or in some classes of lactation periods for each LP. Estimates of genetic and permanent environmental variances did not show any trend due to the increase in the LP order. Residual variance decreased as the order of LP increased when it was assumed constant, and it was highest at the beginning of lactation and relatively constant in mid lactation when assumed to vary between classes. The range for the estimates of heritability (0.27 - 0.42) was similar for all models and was higher in mid lactation. There were only slight differences between the models in both genetic and permanent environmental correlations. Genetic correlations decreased for near unity between adjacent days to values as low as 0.24 between early and late lactation. A five parameter LP to model both genetic and permanent environmental effects and assuming a homogeneous residual variance would be a parsimonious option to fit TD yields of Holstein cows in Brazil.

Download Full-text