E. Groeneveld - Academia.edu (original) (raw)

Papers by E. Groeneveld

Livestock Production Science, 2002

The covariance structure was estimated by REML for a joint genetic evaluation of traits from fiel... more The covariance structure was estimated by REML for a joint genetic evaluation of traits from field test, station test and litter recording with data from the Czech Landrace (LA, 86 833 records) and the Slovak White Meaty breed (WM, 58 348 records). Production traits from the field test (average daily gain [ADGF], lean meat percentage [LMF], and backfat thickness [BFF]) and from the station test (average daily gain [ADGS], valuable cuts [VCS], and backfat thickness [BFS]) as well as reproduction traits (number of piglets born alive in the first litter [NBA1] and number born alive in the second and higher litters [NBA2 1 ] as a trait with repeated measurements) were analyzed jointly in a six-trait (LA) or seven-trait (WM) animal model. The estimated genetic correlations between NBA1 and NBA2 1 (0.83 for LA and 0.78 WM) support the decision to treat first and further litters separately in genetic evaluation. The proportions of variances and correlations were also estimated for nongenetic effects in the models for both breeds (herd or herd-year-season, station-year-season, litter effects, and permanent effect of sow). For ADGF, a very high proportion of variance (0.43) was observed in WM for the herd-year-season effect and in LA (0.27) for the herd effect. The herd-year-season effects for reproduction traits were low (0.05-0.06 in WM, 0.01-0.02 in LA). The estimated genetic correlations between production and reproduction traits were small with the highest absolute values between NBA2 1 and ADGS (20.12 for LA and 2 0.28 for WM). As not all of them were zero, a separate genetic evaluation of reproduction would be incorrect. Also, because of the low heritabilities of the reproduction traits any additional information will be useful making a joint evaluation of production and reproduction traits preferable. Covariance estimates and parameters for genetic and nongenetic effects in the models were widely discussed with special attention to the most recent literature sources. 

Livestock Production Science, 1987

ABSTRACT Developments in the use of microelectronics have occurred rapidly over the last 10 years... more ABSTRACT Developments in the use of microelectronics have occurred rapidly over the last 10 years, often from origins outside agriculture. The most important development could be that of a unique, permanent, individual identification system which also transfers data automatically. There is probably a need for a code of practice providing minimum criteria for ID systems to be approved in national schemes. Developments enable more accurate measurement of existing traits and the potential for measuring new traits. New traits range from efficiency in ruminants and the in vivo estimation of lean meat and, possibly meat quality to the monitoring of blood metabolite and hormone levels. Microelectronics affords greater control of the environment for some species, and more efficient monitoring of environmental changes, which makes it possible to adjust for such affects. Data handling has benefited considerably from microelectronics, but the development of on farm systems could lead to the isolation of data sets with obvious consequences to some breeding programmes. There is a need for a code of practice defining traits, in order to prevent isolation of data sets. The effects of microelectronic developments on breeding structure are discussed, and the potential cost benefits are briefly considered.RésuméL'utilisation de la microélectronique s'est développée rapidement au cours des dix dernières années, souvent à partir d'origines extérieures à l'agriculture. Le développement le plus important pourrait être celui d'un système d'identification individuel unique et permanent qui transférerait aussi les donnèes de façon automatique. Il y a probablement besoin d'un code d'usage fournissant un maximum de critères pour que ces systèmes soient agrées dans les plans nationaux. Leur utilisation permet de mesurer les caractères habituels avec plus de précision et offre la possibilité d'en mesurer de nouveaux. Ces derniers vont de l'efficacité (chez les ruminants), l'évaluation in vivo du maigre et peut être de la qualité de la viande jusqu' à l'enrigistrement des concentrations sanguines en métabolites et hormones. La microélectronique permet de mieux maîtriser le milieu environnant pour certaines espèces et de suivre plus efficacement ses modifications, ce qui offre la possibilité de s'adapter à ces dernières. Le traitement des données a beaucoup bénéficié de la microélectronique mais le développement des systèmes à la ferme pourrait conduire à l'isolement de séries de données avec des conséquences évidentes sur certains programmes de sélection. Il y a besoin d'un code d'utilisation définissant les caractères afin de prévenir l'isolement de séries de données. Les conséquences des développements de la microélectronique sur la structure de la sélection sont discutées et les coûts et bénéfices potentiels brièvement examinés.ZusammenfassungDie Anwendung von Mikroelektronik hat in den letzten 10 Jahren eine stürmische Entwicklung genommen, wobei die Anstöβe in der Regel aus dem nichtlandwirtschaftlichen Bereich kommen. Am wichtigsten könnte die Entwicklung eines eindeutigen, permanenten, individuellen Identifikationssystems, das zugleich Daten automatisch überträgt, sein. Es gibt wahrscheinlich einen Bedarf, die Mindestanforderungen an ein Identifikatinssystem zu definieren, bevor dieses in einem nationalen Programm eingesetzt wereden kann. Neue Entwicklungen werden genauere Messungen bereits existierender Merkmale und ein Potential für die Messung neuer Merkmale bieten. die Spannweite neuer Merkmale reicht von der Effizienz bei Wiederkäuern über die in vivo Schätzung des Fleischanteils und möglicherweise der Fleischqualität bis zur Erfassung von Blutmetaboliten und Hormonspiegeln. Die Mikorelektronik gestattet eine bessere Regulung der Umweltbedingungen fr̈ einige Spezies und eine effizientere Überprüfung von Umweltveränderungen mit der Möglichkeit, für solche die Daten zu korrigieren. Die Datenbearbeitung hat beträchlich von der Mikroelektronik profitiert, die Entwicklung betriebsinterner Systeme könnte allerdings zu einer Isolierung von Datenbeständen mit offensichtlichen Konsequenzen für einige Zuchtprogramme führen. Es wird die Notwendigkeit einer Vereinbarung zur Definition von Merkmalen gesehen, um der Isolation von Datenbeständen entgegenzuwirken. Der Effekt der Entwicklung im Bereich der Mikroelektronik auf die Zuchtstrukturen wird diskutiert und potentielle Kostenvorteile kurz gewürdigt.

Livestock Science, 2010

The objective of this study was to identify and quantify the influence of F (inbreeding coefficie... more The objective of this study was to identify and quantify the influence of F (inbreeding coefficient) on weaning weight (WW), weight gain from weaning to 18 months of age (WG345), finishing visual score (precocity) at 18 months of age, muscling visual score at 18 months of age (MUS), hip height (HH), scrotal circumference at 18 months of age (SC), heifer probability of pregnancy at 14 months of age (PP14), and stayability (STAY) in Brazilian Nellore cattle. The complete pedigree included 417,552 animals born between 1984 and 2007 on 12 farms located in the states of Mato Grosso do Sul, São Paulo and Bahia. Following the observation of a statistically significant effect (P b 0.05) of the covariates individual inbreeding coefficient (F) and maternal inbreeding coefficient, regression analysis of each trait, adjusted for all other effects, was performed as a function of the linear and quadratic effect of F and maternal F (when significant). Inbreeding negatively affected all traits studied (P b 0.05), except for muscling. A quadratic effect of individual F on WW, WG345, HH and PP14, and a quadratic effect of maternal F on WG345 and HH were observed. Levels of inbreeding higher than 7-11% affected negatively growth and reproductive performance of Nellore cattle. Therefore, inbreeding should be avoided, except for purposes of genetic breeding whose main objective is the fixation of certain alleles in the population.

Livestock Production Science, 2002

The covariance structure was estimated by REML for a joint genetic evaluation of traits from fiel... more The covariance structure was estimated by REML for a joint genetic evaluation of traits from field test, station test and litter recording with data from the Czech Landrace (LA, 86 833 records) and the Slovak White Meaty breed (WM, 58 348 records). Production traits from the field test (average daily gain [ADGF], lean meat percentage [LMF], and backfat thickness [BFF]) and from the station test (average daily gain [ADGS], valuable cuts [VCS], and backfat thickness [BFS]) as well as reproduction traits (number of piglets born alive in the first litter [NBA1] and number born alive in the second and higher litters [NBA2 1 ] as a trait with repeated measurements) were analyzed jointly in a six-trait (LA) or seven-trait (WM) animal model. The estimated genetic correlations between NBA1 and NBA2 1 (0.83 for LA and 0.78 WM) support the decision to treat first and further litters separately in genetic evaluation. The proportions of variances and correlations were also estimated for nongenetic effects in the models for both breeds (herd or herd-year-season, station-year-season, litter effects, and permanent effect of sow). For ADGF, a very high proportion of variance (0.43) was observed in WM for the herd-year-season effect and in LA (0.27) for the herd effect. The herd-year-season effects for reproduction traits were low (0.05-0.06 in WM, 0.01-0.02 in LA). The estimated genetic correlations between production and reproduction traits were small with the highest absolute values between NBA2 1 and ADGS (20.12 for LA and 2 0.28 for WM). As not all of them were zero, a separate genetic evaluation of reproduction would be incorrect. Also, because of the low heritabilities of the reproduction traits any additional information will be useful making a joint evaluation of production and reproduction traits preferable. Covariance estimates and parameters for genetic and nongenetic effects in the models were widely discussed with special attention to the most recent literature sources. 

Genetics Selection Evolution, 1993

Genetic parameters of 7 traits measured in central test stationsaverage daily gain (ADG1), feed c... more Genetic parameters of 7 traits measured in central test stationsaverage daily gain (ADG1), feed conversion ratio (FCR) and backfat thickness (ABT) measured on candidates for selection, and average daily gain (ADG2), dressing percentage (DP), estimated carcass lean content (ECLC) and meat quality index (MQI) measured in slaughtered relativeswere estimated for the Large White (LW) and French Landrace (LR) breeds using a derivative free restricted maximum likelihood (DF-REML) procedure applied to a multiple trait individual animal model. The data consisted of 2 sets of records (3 671 and 3 630 candidates, 3 039 and 2 695 slaughtered animals in, respectively, LW and LR breeds) collected at 3 different stations from [1985][1986][1987][1988][1989][1990] (LW) or 1980-1990 (LR). The models included additive genetic value, common environment of birth litter and residual random effects, a fixed year x station x batch or year x station x slaughter date effect and, for traits measured in slaughtered animals, a fixed sex effect and a covariable (weight at the beginning or at the end of the test period). Heritabilities of ADG1, ABT, FCR, ADG2, DP, ECLC and MQI were respectively 0.30, 0.64, 0.22, 0.52, 0.39, 0.60, 0.33 in the LW and 0.34, 0.56, 0.25, 0.46, 0.31, 0.68, 0.23 in the LR breed. Common litter effects ranged from 5% (ABT in LW breed) to 16% (ADG2 in LR breed) of phenotypic variance.

Genetics and Molecular Research, 2014

Data from 69,525 animals were used to compare two types of analyses, one of them having the weani... more Data from 69,525 animals were used to compare two types of analyses, one of them having the weaning management group (WEMANG) included as an effect in the contemporary group (F_ WEMANG) and the other considering the weaning management group as a random effect, not related to the mathematical model (R_WEMANG) for post-weaning traits. The components of (co)variance were estimated for pre-weaning traits: birth weight and weaning weight and for postweaning traits: scrotal circumference (SC), weight gain from weaning to 18 months of age (WG) and muscle score (MUSC) in Nellore cattle, based on a complete animal model. Heritability of SC, WG and MUSC for the F_WEMANG model was equal to 0.46 ± 0.02, 0.38 ± 0.03 and V.B. Pedrosa et al.

Journal of Animal Breeding and Genetics, 2001

Changes in variance component estimates in growing sets of performance data in two pig breeds wer... more Changes in variance component estimates in growing sets of performance data in two pig breeds were investigated. Data was used from the ®eld and station test of Czech Landrace (LA: 75 099 observations) and the Slovakian breed, White Meaty swine (WM: 32 203 observations). In LA the traits analysed were estimated lean meat content (LM) and average daily gain (ADGF) on ®eld test and average daily gain (ADGS) and weight of valuable cuts (VCW) on station test. In WM the traits analysed were backfat thickness on ®eld and station test (BFF, BFS, respectively), proportion of valuable cuts (VCP) on station test, ADGF and ADGS. Covariance components were estimated from four-and ®ve-trait animal models using the VCE software. Omitting data from factor levels with a low number of records led to 4.2% of LA records and 21.7% of WM records being deleted. Changes in genetic and residual variance estimates were less than 5% for all traits in LA and less than 12% for all traits except ADGS in WM. The changes in estimated genetic variances caused by 18 months (LA) or 24 months (WM) of new data were 2±25% and the changes in estimated residual variances were less than 5% in LA and less than 20% in WM. In both breeds, changes in heritability estimates did not exceed 0.06 in absolute value. In LA, it is reasonable to use genetic parameter estimates for 3 years before re-estimation. In WM the time interval should be shorter because of changes in the estimates caused by their lower accuracy arising from the smaller size of the data-set and smaller frequency of station testing.

Livestock Production Science, 2002

The covariance structure was estimated by REML for a joint genetic evaluation of traits from fiel... more The covariance structure was estimated by REML for a joint genetic evaluation of traits from field test, station test and litter recording with data from the Czech Landrace (LA, 86 833 records) and the Slovak White Meaty breed (WM, 58 348 records). Production traits from the field test (average daily gain [ADGF], lean meat percentage [LMF], and backfat thickness [BFF]) and from the station test (average daily gain [ADGS], valuable cuts [VCS], and backfat thickness [BFS]) as well as reproduction traits (number of piglets born alive in the first litter [NBA1] and number born alive in the second and higher litters [NBA2 1 ] as a trait with repeated measurements) were analyzed jointly in a six-trait (LA) or seven-trait (WM) animal model. The estimated genetic correlations between NBA1 and NBA2 1 (0.83 for LA and 0.78 WM) support the decision to treat first and further litters separately in genetic evaluation. The proportions of variances and correlations were also estimated for nongenetic effects in the models for both breeds (herd or herd-year-season, station-year-season, litter effects, and permanent effect of sow). For ADGF, a very high proportion of variance (0.43) was observed in WM for the herd-year-season effect and in LA (0.27) for the herd effect. The herd-year-season effects for reproduction traits were low (0.05-0.06 in WM, 0.01-0.02 in LA). The estimated genetic correlations between production and reproduction traits were small with the highest absolute values between NBA2 1 and ADGS (20.12 for LA and 2 0.28 for WM). As not all of them were zero, a separate genetic evaluation of reproduction would be incorrect. Also, because of the low heritabilities of the reproduction traits any additional information will be useful making a joint evaluation of production and reproduction traits preferable. Covariance estimates and parameters for genetic and nongenetic effects in the models were widely discussed with special attention to the most recent literature sources. 

Livestock Production Science, 1987

ABSTRACT Developments in the use of microelectronics have occurred rapidly over the last 10 years... more ABSTRACT Developments in the use of microelectronics have occurred rapidly over the last 10 years, often from origins outside agriculture. The most important development could be that of a unique, permanent, individual identification system which also transfers data automatically. There is probably a need for a code of practice providing minimum criteria for ID systems to be approved in national schemes. Developments enable more accurate measurement of existing traits and the potential for measuring new traits. New traits range from efficiency in ruminants and the in vivo estimation of lean meat and, possibly meat quality to the monitoring of blood metabolite and hormone levels. Microelectronics affords greater control of the environment for some species, and more efficient monitoring of environmental changes, which makes it possible to adjust for such affects. Data handling has benefited considerably from microelectronics, but the development of on farm systems could lead to the isolation of data sets with obvious consequences to some breeding programmes. There is a need for a code of practice defining traits, in order to prevent isolation of data sets. The effects of microelectronic developments on breeding structure are discussed, and the potential cost benefits are briefly considered.RésuméL'utilisation de la microélectronique s'est développée rapidement au cours des dix dernières années, souvent à partir d'origines extérieures à l'agriculture. Le développement le plus important pourrait être celui d'un système d'identification individuel unique et permanent qui transférerait aussi les donnèes de façon automatique. Il y a probablement besoin d'un code d'usage fournissant un maximum de critères pour que ces systèmes soient agrées dans les plans nationaux. Leur utilisation permet de mesurer les caractères habituels avec plus de précision et offre la possibilité d'en mesurer de nouveaux. Ces derniers vont de l'efficacité (chez les ruminants), l'évaluation in vivo du maigre et peut être de la qualité de la viande jusqu' à l'enrigistrement des concentrations sanguines en métabolites et hormones. La microélectronique permet de mieux maîtriser le milieu environnant pour certaines espèces et de suivre plus efficacement ses modifications, ce qui offre la possibilité de s'adapter à ces dernières. Le traitement des données a beaucoup bénéficié de la microélectronique mais le développement des systèmes à la ferme pourrait conduire à l'isolement de séries de données avec des conséquences évidentes sur certains programmes de sélection. Il y a besoin d'un code d'utilisation définissant les caractères afin de prévenir l'isolement de séries de données. Les conséquences des développements de la microélectronique sur la structure de la sélection sont discutées et les coûts et bénéfices potentiels brièvement examinés.ZusammenfassungDie Anwendung von Mikroelektronik hat in den letzten 10 Jahren eine stürmische Entwicklung genommen, wobei die Anstöβe in der Regel aus dem nichtlandwirtschaftlichen Bereich kommen. Am wichtigsten könnte die Entwicklung eines eindeutigen, permanenten, individuellen Identifikationssystems, das zugleich Daten automatisch überträgt, sein. Es gibt wahrscheinlich einen Bedarf, die Mindestanforderungen an ein Identifikatinssystem zu definieren, bevor dieses in einem nationalen Programm eingesetzt wereden kann. Neue Entwicklungen werden genauere Messungen bereits existierender Merkmale und ein Potential für die Messung neuer Merkmale bieten. die Spannweite neuer Merkmale reicht von der Effizienz bei Wiederkäuern über die in vivo Schätzung des Fleischanteils und möglicherweise der Fleischqualität bis zur Erfassung von Blutmetaboliten und Hormonspiegeln. Die Mikorelektronik gestattet eine bessere Regulung der Umweltbedingungen fr̈ einige Spezies und eine effizientere Überprüfung von Umweltveränderungen mit der Möglichkeit, für solche die Daten zu korrigieren. Die Datenbearbeitung hat beträchlich von der Mikroelektronik profitiert, die Entwicklung betriebsinterner Systeme könnte allerdings zu einer Isolierung von Datenbeständen mit offensichtlichen Konsequenzen für einige Zuchtprogramme führen. Es wird die Notwendigkeit einer Vereinbarung zur Definition von Merkmalen gesehen, um der Isolation von Datenbeständen entgegenzuwirken. Der Effekt der Entwicklung im Bereich der Mikroelektronik auf die Zuchtstrukturen wird diskutiert und potentielle Kostenvorteile kurz gewürdigt.

Livestock Science, 2010

The objective of this study was to identify and quantify the influence of F (inbreeding coefficie... more The objective of this study was to identify and quantify the influence of F (inbreeding coefficient) on weaning weight (WW), weight gain from weaning to 18 months of age (WG345), finishing visual score (precocity) at 18 months of age, muscling visual score at 18 months of age (MUS), hip height (HH), scrotal circumference at 18 months of age (SC), heifer probability of pregnancy at 14 months of age (PP14), and stayability (STAY) in Brazilian Nellore cattle. The complete pedigree included 417,552 animals born between 1984 and 2007 on 12 farms located in the states of Mato Grosso do Sul, São Paulo and Bahia. Following the observation of a statistically significant effect (P b 0.05) of the covariates individual inbreeding coefficient (F) and maternal inbreeding coefficient, regression analysis of each trait, adjusted for all other effects, was performed as a function of the linear and quadratic effect of F and maternal F (when significant). Inbreeding negatively affected all traits studied (P b 0.05), except for muscling. A quadratic effect of individual F on WW, WG345, HH and PP14, and a quadratic effect of maternal F on WG345 and HH were observed. Levels of inbreeding higher than 7-11% affected negatively growth and reproductive performance of Nellore cattle. Therefore, inbreeding should be avoided, except for purposes of genetic breeding whose main objective is the fixation of certain alleles in the population.

Livestock Production Science, 2002

The covariance structure was estimated by REML for a joint genetic evaluation of traits from fiel... more The covariance structure was estimated by REML for a joint genetic evaluation of traits from field test, station test and litter recording with data from the Czech Landrace (LA, 86 833 records) and the Slovak White Meaty breed (WM, 58 348 records). Production traits from the field test (average daily gain [ADGF], lean meat percentage [LMF], and backfat thickness [BFF]) and from the station test (average daily gain [ADGS], valuable cuts [VCS], and backfat thickness [BFS]) as well as reproduction traits (number of piglets born alive in the first litter [NBA1] and number born alive in the second and higher litters [NBA2 1 ] as a trait with repeated measurements) were analyzed jointly in a six-trait (LA) or seven-trait (WM) animal model. The estimated genetic correlations between NBA1 and NBA2 1 (0.83 for LA and 0.78 WM) support the decision to treat first and further litters separately in genetic evaluation. The proportions of variances and correlations were also estimated for nongenetic effects in the models for both breeds (herd or herd-year-season, station-year-season, litter effects, and permanent effect of sow). For ADGF, a very high proportion of variance (0.43) was observed in WM for the herd-year-season effect and in LA (0.27) for the herd effect. The herd-year-season effects for reproduction traits were low (0.05-0.06 in WM, 0.01-0.02 in LA). The estimated genetic correlations between production and reproduction traits were small with the highest absolute values between NBA2 1 and ADGS (20.12 for LA and 2 0.28 for WM). As not all of them were zero, a separate genetic evaluation of reproduction would be incorrect. Also, because of the low heritabilities of the reproduction traits any additional information will be useful making a joint evaluation of production and reproduction traits preferable. Covariance estimates and parameters for genetic and nongenetic effects in the models were widely discussed with special attention to the most recent literature sources. 

Genetics Selection Evolution, 1993

Genetic parameters of 7 traits measured in central test stationsaverage daily gain (ADG1), feed c... more Genetic parameters of 7 traits measured in central test stationsaverage daily gain (ADG1), feed conversion ratio (FCR) and backfat thickness (ABT) measured on candidates for selection, and average daily gain (ADG2), dressing percentage (DP), estimated carcass lean content (ECLC) and meat quality index (MQI) measured in slaughtered relativeswere estimated for the Large White (LW) and French Landrace (LR) breeds using a derivative free restricted maximum likelihood (DF-REML) procedure applied to a multiple trait individual animal model. The data consisted of 2 sets of records (3 671 and 3 630 candidates, 3 039 and 2 695 slaughtered animals in, respectively, LW and LR breeds) collected at 3 different stations from [1985][1986][1987][1988][1989][1990] (LW) or 1980-1990 (LR). The models included additive genetic value, common environment of birth litter and residual random effects, a fixed year x station x batch or year x station x slaughter date effect and, for traits measured in slaughtered animals, a fixed sex effect and a covariable (weight at the beginning or at the end of the test period). Heritabilities of ADG1, ABT, FCR, ADG2, DP, ECLC and MQI were respectively 0.30, 0.64, 0.22, 0.52, 0.39, 0.60, 0.33 in the LW and 0.34, 0.56, 0.25, 0.46, 0.31, 0.68, 0.23 in the LR breed. Common litter effects ranged from 5% (ABT in LW breed) to 16% (ADG2 in LR breed) of phenotypic variance.

Genetics and Molecular Research, 2014

Data from 69,525 animals were used to compare two types of analyses, one of them having the weani... more Data from 69,525 animals were used to compare two types of analyses, one of them having the weaning management group (WEMANG) included as an effect in the contemporary group (F_ WEMANG) and the other considering the weaning management group as a random effect, not related to the mathematical model (R_WEMANG) for post-weaning traits. The components of (co)variance were estimated for pre-weaning traits: birth weight and weaning weight and for postweaning traits: scrotal circumference (SC), weight gain from weaning to 18 months of age (WG) and muscle score (MUSC) in Nellore cattle, based on a complete animal model. Heritability of SC, WG and MUSC for the F_WEMANG model was equal to 0.46 ± 0.02, 0.38 ± 0.03 and V.B. Pedrosa et al.

Journal of Animal Breeding and Genetics, 2001

Changes in variance component estimates in growing sets of performance data in two pig breeds wer... more Changes in variance component estimates in growing sets of performance data in two pig breeds were investigated. Data was used from the ®eld and station test of Czech Landrace (LA: 75 099 observations) and the Slovakian breed, White Meaty swine (WM: 32 203 observations). In LA the traits analysed were estimated lean meat content (LM) and average daily gain (ADGF) on ®eld test and average daily gain (ADGS) and weight of valuable cuts (VCW) on station test. In WM the traits analysed were backfat thickness on ®eld and station test (BFF, BFS, respectively), proportion of valuable cuts (VCP) on station test, ADGF and ADGS. Covariance components were estimated from four-and ®ve-trait animal models using the VCE software. Omitting data from factor levels with a low number of records led to 4.2% of LA records and 21.7% of WM records being deleted. Changes in genetic and residual variance estimates were less than 5% for all traits in LA and less than 12% for all traits except ADGS in WM. The changes in estimated genetic variances caused by 18 months (LA) or 24 months (WM) of new data were 2±25% and the changes in estimated residual variances were less than 5% in LA and less than 20% in WM. In both breeds, changes in heritability estimates did not exceed 0.06 in absolute value. In LA, it is reasonable to use genetic parameter estimates for 3 years before re-estimation. In WM the time interval should be shorter because of changes in the estimates caused by their lower accuracy arising from the smaller size of the data-set and smaller frequency of station testing.