scholarly journals Estimation of breeding values for functional productive life in the Slovak Holstein population

2014 ◽  
Vol 59 (No. 2) ◽  
pp. 54-60 ◽  
Author(s):  
E. Strapáková ◽  
P. Strapák ◽  
J. Candrák
Keyword(s):  
Herd Size ◽  
Proportional Hazard ◽  
Breeding Values ◽  
Productive Life ◽  
Stage Of Lactation ◽  
Weibull Proportional Hazard ◽  
Season Interaction ◽  
Maternal Grandsire ◽  
Genetic Standard Deviation ◽  
Interaction Change

Genetic evaluation of length of functional productive life was carried out using a Weibull proportional hazard sire-maternal grandsire model. The database included 405 624 Holstein cows with 19.24% censoring. The analyzed effects were parity × stage of lactation, within-herd standard deviations of milk production, herd × year × season interaction, change of herd size with respect to the previous year, age at first calving, and sire and maternal-grandsire effects. Parity × stage of lactation had the most important influence on functional productive life. The results of the analysis confirmed more intensive selection at the beginning of each lactation, whereby the risk ratio increased with each other lactation. Heritability of functional productive life was 0.13 on the original scale. Breeding values of sires were expressed as relative breeding values with a mean of 100 and genetic standard deviation of 12.  

scholarly journals Genetic evaluation of the functional productive life in Slovak Simmental cattle

2013 ◽  
Vol 56 (1) ◽  
pp. 797-807
Author(s):  
E. Strapáková ◽  
J. Candrák ◽  
P. Strapák ◽  
A. Trakovická
Keyword(s):  
Milk Production ◽  
Herd Size ◽  
Genetic Evaluation ◽  
Independent Effect ◽  
Proportional Hazard ◽  
Productive Life ◽  
Stage Of Lactation ◽  
Standard Deviations ◽  
Weibull Proportional Hazard ◽  
Maternal Grandsire

Abstract. Genetic evaluation of sires based on length of functional productive life of their daughters was carried out using a Weibull proportional hazard sire-maternal grandsire model. The data consisted of 214634 registered Slovak Simmental cows with censoring of 21.34%. Besides the random sire and maternal grandsire effects, the model included time dependent effects parity × stage of lactation interaction, within-herd standard deviations of milk production, herd × year × season interaction, change of herd size with respect to the previous year, and time independent effect age at first calving. Within-herd, the standard deviations of milk production had the most important influence on functional productive life. The highest risk of culling was found in cows with the lowest milk production class (uncompleted lactation). Risk of culling decreased with an increasing milk production class. Estimated heritability of functional productive life was 0.05 on the original scale. Breeding values of sires expressed as a risk ratio of their daughters were between −0.57 and 0.53.

scholarly journals Genetic evaluation of the length of productive life in Holstein cattle in the Czech Republic

2011 ◽  
Vol 50 (No. 11) ◽  
pp. 493-498 ◽  
Author(s):  
E. Páchová ◽  
L. Zavadilová ◽  
J. Sölkner
Keyword(s):  
Milk Production ◽  
Random Effect ◽  
Independent Effect ◽  
Data Set ◽  
The Czech Republic ◽  
Productive Life ◽  
Stage Of Lactation ◽  
Original Scale ◽  
Season Interaction ◽  
Effect Of Age

Survival Kit V3.12 was used to analyse the length of productive life of cattle in theCzechRepublic. The data set consisted of 230 028 registeredHolstein cows. The model included the time-dependent effects parity × stage of lactation interaction, herd × year × season interaction, class of milk production within herd and year, breed within years and the time-independent effect of age at first calving and the random effect of sire. The highest risk of culling was found for cows at the beginning and at the end of the first lactation and at the end of any other lactation. The risk of culling decreased with parity. The risk of culling of cows assigned to the lowest milk production class was five times higher than that of cows assigned to the average milk production class. Risk of culling diminished with a decreasing percentage ofHolstein breed. Cows younger at first calving showed a lower risk of culling. Breeding values for sires expressed as a risk ratio of their daughters were between 0.7 and 1.45. Estimated heritability of functional longevity was 0.025 on the log scale and 0.041 on the original scale.  

scholarly journals Survival analysis of productive life in Brazilian holstein using a piecewise Weibull proportional hazard model

2016 ◽  
Vol 185 ◽  
pp. 89-96 ◽  
Author(s):  
Elisandra Lurdes Kern ◽  
Jaime Araujo Cobuci ◽  
Claudio Napolis Costa ◽  
Vincent Ducrocq
Keyword(s):  
Survival Analysis ◽  
Hazard Model ◽  
Proportional Hazard ◽  
Proportional Hazard Model ◽  
Productive Life ◽  
Weibull Proportional Hazard

scholarly journals Fleckscore system of exterior evaluation as a more accurate indirect predictor of longevity in Slovak Simmental dairy cows

2021 ◽  
Author(s):  
Eva Strapáková ◽  
Peter Strapák ◽  
Juraj Candrák ◽  
Ivan Pavlík ◽  
Katarína Dočkalová
Keyword(s):  
Dairy Cows ◽  
Reference Group ◽  
Proportional Hazard ◽  
Proportional Hazard Model ◽  
Productive Life ◽  
Body Conformation ◽  
Individual Traits ◽  
Weibull Proportional Hazard ◽  
Relationship Of ◽  
The Relationship

The goal of the work was to discover the influence of conformation traits evaluated by the Fleckscore system on the length of productive life of Slovak Simmental dairy cows. Evaluation of body conformation traits according to the Fleckscore system was performed on 3 452 cows. The relationship of individual traits to longevity was analysed using the Weibull proportional hazard model. The results confirmed that smaller and longer cows, which were well muscular and with a deeper body, had a lower risk of early culling than cows in the reference group. Hock angularity, pastern and hoof height scored with low or high marks were associated with an early culling of cows. In terms of the length of productive life, a slightly more elastic pattern is required. Cows with a deeper udder and a stronger and tighter fore udder attachment, which were also average in notching and height central ligament and centrally placed teats, reached a longer productive life.  

scholarly journals Phenotypic relationships between type traits and productive life using a piecewise Weibull proportional hazard model

2018 ◽  
Vol 75 (6) ◽  
pp. 470-478 ◽  
Author(s):  
Elisandra Lurdes Kern ◽  
Jaime Araujo Cobuci ◽  
Cláudio Napolis Costa ◽  
Vincent Ducrocq
Keyword(s):  
Hazard Model ◽  
Proportional Hazard ◽  
Proportional Hazard Model ◽  
Productive Life ◽  
Type Traits ◽  
Weibull Proportional Hazard

scholarly journals Genetic evaluation for longevity of Croatian Simmental bulls using a piecewise Weibull model

2013 ◽  
Vol 56 (1) ◽  
pp. 89-101
Author(s):  
S. Jovanovac ◽  
N. Raguž ◽  
J. Sölkner ◽  
G. Mészáros
Keyword(s):  
Milk Production ◽  
Weibull Model ◽  
Fixed Time ◽  
Herd Size ◽  
Genetic Evaluation ◽  
Genetic Trend ◽  
Data Set ◽  
Breeding Values ◽  
Age At First Calving ◽  
Productive Life

Abstract. Genetic evaluation of sires for functional longevity was conducted using survival analysis techniques. The data set consisted of 49 659 Simmental cows with first calving from 1997 to 2008. A piecewise Weibull sire model was used to estimate breeding values of 251 bulls for functional length of productive life of their daughters. The model was stratified by parity i.e. a separate baseline hazard was computed for each stratum. Besides the random sire effect, the model included the fixed time independent effects of age at first calving, herd size and region as well as the time dependent effects of relative milk production and year*season of first calving. The highest impact on longevity was found for relative milk production. Cows with the lowest milk yields were at approximately 2.7 times higher risk of culling compared to cows with average milk production. Effects of age at first calving, herd size and country region had lower impact on longevity. Sire variance was 0.023 which results in a heritability of 0.06 for functional length of productive life. The average approximate reliability of estimated breeding values was 0.49. Genetic trend showed no clear tendency by year of birth of bulls.

scholarly journals Genetic evaluation for functional longevity in Polish Simmental cattle

2017 ◽  
Vol 62 (No. 7) ◽  
pp. 276-286 ◽  
Author(s):  
M. Morek-Kopeć ◽  
A. Zarnecki
Keyword(s):  
Fixed Effects ◽  
Proportional Hazards ◽  
Proportional Hazards Model ◽  
Average Length ◽  
Selection Index ◽  
Herd Size ◽  
Genetic Evaluation ◽  
Productive Life ◽  
Stage Of Lactation ◽  
Fat Yield

The Weibull proportional hazards model was applied for genetic evaluation of functional longevity in Polish Simmentals. Data consisted of production and disposal records for 12 527 Simmental cows, daughters of 294 sires, calving for the first time from 1995 to 2014 in 286 herds. Length of productive life of cows was calculated as number of days from the first calving to culling or censoring. Average length of productive life of 4462 cows with complete (uncensored) survival records was 1198 days (39.3 months); mean censoring time for the remaining 8065 cows was 1093 days (35.8 months). Functional longevity was defined as length of productive life corrected for production. The model included time-independent fixed effect of age at first calving, time-dependent fixed effects of year-season, parity-stage of lactation, annual change in herd size, relative fat yield and protein yield, and random herd-year-season and sire effects. Likelihood ratio tests showed a highly significant impact of all fixed effects on longevity, except for relative fat yield. Estimated sire variance was 0.069, resulting in the equivalent (accounting for censoring level) heritability of 0.09. Standardized relative breeding values (RBV) ranged from 71 to 139 (mean 101.4, SD 9.12). Average reliability of RBVs was 0.47. Moderate heritability supports the possibility of effective selection for functional longevity, which will be included in the total selection index for Polish Simmentals.

scholarly journals Analysis of longevity in the Slovak Pinzgau population – extension to the animal model

2013 ◽  
Vol 58 (No. 7) ◽  
pp. 289-295 ◽  
Author(s):  
G. Mészáros ◽  
O. Kadlečík ◽  
R. Kasarda ◽  
J. Sölkner
Keyword(s):  
Animal Model ◽  
Milk Production ◽  
Fixed Effects ◽  
Herd Size ◽  
Size Change ◽  
Breeding Values ◽  
The Third ◽  
Stage Of Lactation ◽  
Increased Risk ◽  
High Age

Breeding values for length of productive life in Slovak Pinzgau cattle were estimated using survival analysis. As the results were corrected for milk production, the final breeding values represented the ability of cows to avoid culling from reasons other than milk production. In addition to the relative milk yield, the risk of culling was also studied in connection with the herd and year of calving, parity and stage of lactation, herd size change and age at the first calving. Among the fixed effects, the low milk production, high age at the first calving, and decreasing herd size were associated with increased risk of culling. The risk was non-linear for parity &times; stage of lactation classes, decreasing within the first parity and increasing during later parities. Two genetic random effects were considered in separate models: the sire of the cow and the animal itself, both with the corresponding pedigree records up to the third generation. The genetic effects were estimated in separate runs, but the rest of the model remained unchanged. Heritability was h<sup>2 </sup>= 0.08 for sire model, confirming the results of an earlier study in the Slovak Pinzgau population. The computational feasibility of the animal model for estimation of breeding values for cows was confirmed in this study. The new breeding values could be computed for each cow, accounting for all relationships within the population. The estimated heritability for the animal model was h<sup>2 </sup>= 0.11, which should be used later on for animal breeding purposes. &nbsp;

scholarly journals Factors affecting the functional length of productive life in Slovak Pinzgau cows

2008 ◽  
Vol 53 (No. 3) ◽  
pp. 91-97 ◽  
Author(s):  
G. Mészáros ◽  
J. Wolf ◽  
O. Kadlečík
Keyword(s):  
Milk Production ◽  
Linear Increase ◽  
Production Level ◽  
Proportional Hazard ◽  
Proportional Hazard Model ◽  
Age At First Calving ◽  
Factors Affecting ◽  
Productive Life ◽  
The Impact ◽  
Effect Of Age

A proportional hazard model was used to analyze the impact of the most important factors on the length of productive life in 44 796 Slovak Pinzgau cows. The calculations were carried out with Survival Kit 3.12. The milk production level within a herd was the most important factor. The relation between the milk production level and the culling risk was strongly non-linear. Cows with extremely low milk production (less than 1.5 standard deviations below average) had a 4.8 times higher culling risk than average cows. The culling risk for the highest yielding cows was about one half of the risk of average cows. In the first lactation the culling risk was highest at the beginning and decreased in the course of lactation whereas in subsequent lactations the culling risk was highest at the end of lactation. The risk decreased with parity. The effect of age at first calving did not have a large influence on the length of productive life, although a linear increase in culling risk was observed as the age at first calving increased. Cows from expanding herds were at lower risk to be culled compared to cows in herds of stable and decreasing size.

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