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 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 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.

scholarly journals Genetic evaluation for length of productive life in Slovak Pinzgau cattle

2008 ◽  
Vol 51 (5) ◽  
pp. 438-448 ◽  
Author(s):  
G. Mészáros ◽  
C. Fuerst ◽  
B. Fuerst-Waltl ◽  
O. Kadlečík ◽  
R. Kasarda ◽  
...  
Keyword(s):  
Milk Production ◽  
Proportional Hazards ◽  
Genetic Evaluation ◽  
Data Set ◽  
Final Model ◽  
Breeding Values ◽  
Age At First Calving ◽  
Clear Tendency ◽  
Productive Life ◽  
Increasing Risk

Abstract. The proportional hazards method was used to estimate breeding values for functional length of productive life within the endangered Slovak Pinzgau population. The analyzed data set contained 21,985 cows, daughters of 254 sires. The risk of culling was higher for cows with lower milk production relative to herd average, higher age at first calving and in herds decreasing in size. In the first lactation the culling risk was highest at the beginning, and decreased during lactation. From second lactation onwards an increasing risk was observed. The effect of breed composition was found insignificant, and was not included into final model. A heritability of 0.05 was estimated for functional length of productive life. The average reliability of estimates was 0.25. No clear tendency in average breeding values by year of birth of bulls was observed.

Milk production in Awassi and Hungarian Merino sheep in Iraq

1971 ◽  
Vol 76 (3) ◽  
pp. 507-511 ◽  
Author(s):  
H. A. Karam ◽  
K. H. Juma ◽  
M. Al-Shabibi ◽  
J. Eliya ◽  
H. N. Abu Al-Ma'ali
Keyword(s):  
Birth Weight ◽  
Correlation Coefficient ◽  
Milk Production ◽  
Milk Yield ◽  
Correlation Coefficients ◽  
Multiple Correlation Coefficient ◽  
Lactation Period ◽  
Weaning Weight ◽  
Stage Of Lactation ◽  
Effect Of Age

SUMMARYOn the Abu-Ghraib Experiment Station, milk production was investigated in 31 Awassi ewes of different ages and 12 newly imported Hungarian Merino ewes, two years old, together with the effect of age, lactation period, number of lambs born and reared and stage of lactation on milk production in the Awassi ewes. The relationships between milk production, birth weight and weaning weight of lambs were also investigated.First-lactation milk yield during the suckling period (90 days) based on 12 h milking interval was 114·58 kg in the Merino and 75·29 kg in the Awassi.Age had no significant effect on milk production in Awassi ewes although first-lactation yield was lower than that from subsequent lactations. Ewes that produced and nursed twins gave significantly more milk than ewes that produced and nursed single lambs.Milk yield in Merino and Awassi ewes increased with the decrease of milking interval from 12 to 4 h. The correlation coefficients between milk yield during 12 and 4 h were positive and significant.Correlation coefficients between birth and weaning weights and milk production were positive in both breeds. The correlation coefficient between weaning weight and milk production was 0·78 in the Awassi (P <0·01) and 0·65 in the Merino (P <0·05). The multiple correlation coefficient between weaning weight and birth weight and milk production was 0·67 in the Awassi and 0·43 in the Merino.

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 Effect of Age at First Calving on First Lactation Milk Yield, Lifetime Milk Production And Longevity of Cows

2019 ◽  
Vol 19 (1) ◽  
pp. 189-200
Author(s):  
Anna Sawa ◽  
Kamil Siatka ◽  
Sylwia Krężel-Czopek
Keyword(s):  
Dairy Cows ◽  
Milk Production ◽  
Milk Yield ◽  
Considerable Decrease ◽  
Age At First Calving ◽  
Productive Life ◽  
Active Population ◽  
Holstein Friesian ◽  
Effect Of Age ◽  
Friesian Cows

AbstractThe objective of the study was to analyse the effect of age at first calving (AFC) on first lactation milk yield, lifetime milk production and longevity of dairy cows. The study used SYMLEK data on the milk yield and culling of 111 857 Polish Holstein-Friesian cows from the active population in Pomerania and Kujawy, Poland. The cows first calved during 2000–2009 and were used or removed from the herds until the end of 2015. For each cow, calculations were made of first lactation milk yield, lifetime milk production, first lactation milk yield per milking day, lifetime milk production per day, as well as the lifespan (length of productive life, duration of rearing) and number of calvings. Based on the age at first calving (duration of the rearing period), the cows were grouped as follows: ≤22, 22.1–24.0, 24.1–26.0, 26.1–28.0, 28.1–30.0, 30.1–32.0 and >32 months. The GLM, CORR PEARSON and FREQ procedures from the SAS package were used in the statistical calculations. Considering first lactation milk yield, lifetime milk production and longevity, it is recommended that the cows should be first milked between 22.1 and 26.0 months of age. This is supported by the approximately 24% higher lifetime milk production in relation to the latest calving cows (P<0.01). Late commencement of the first milking (especially after 28 months) causes a considerable decrease in the first lactation milk yield and lifetime milk production, shortens the productive period, reduces the number of calvings, and increases culling rate due to low milk yield and udder diseases.

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 &times; stage of lactation, within-herd standard deviations of milk production, herd &times; year &times; season interaction, change of herd size with respect to the previous year, age at first calving, and sire and maternal-grandsire effects. Parity &times; 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. &nbsp;

Influence of age at first lambing on reproductive and productive performance of Lacaune dairy sheep under an intensive management system

2011 ◽  
Vol 78 (2) ◽  
pp. 160-167 ◽  
Author(s):  
Fernando Hernandez ◽  
Laura Elvira ◽  
Juan-Vicente Gonzalez-Martin ◽  
Antonio Gonzalez-Bulnes ◽  
Susana Astiz
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Intensive Management ◽  
Productive Performance ◽  
Sequence Group ◽  
Dairy Sheep ◽  
Productive Life ◽  
Total Milk ◽  
Group A ◽  
Effect Of Age

The present study investigated the effect of age at first lambing (AFL) on the performance of Lacaune sheep under intensive management conditions. Records from 3088 maiden sheep from one farm, for the period 2005–2010, were classified into four experimental groups: group E (early) ewes with AFL ⩽390 d; group M (middle) with AFL of 391–450 d; group L (late) with AFL of 451–510 d; and group A (aged) with AFL ⩾511 d. The higher the number of lactations, the lower were the yield/lactation and yield/Day in Milk. Ewes from group M up to 450 days old lambed 0·2 times more often and had 0·25 more lactations than the ewes from group L; in addition, the former group lambed 0·5 times more often and had 0·49 more lactations than ewes from group A. Group A had the lowest yield per lifetime; the yield followed the sequence: group E (1032 l) >group M (1051 l) >group L (989 l) > group A (859 l) (P<0·0001). Yield/lactation was affected by AFL during the first three lactations (P<0·05). Group E produced significantly less milk in the first lactation than ewes from groups M, L and A. AFL correlated negatively with the number of lactations in life (r= −0·26; P<0·0001) and with total milk yield (r= −209; P<0·0001). The productive performance between the ewes that reached puberty early (n=404) or late (n=2684) in life were different (P<0·0001) with the early sheep having a lower total milk yield (591 v. 1073 l, P<0·0001). In conclusion, the current study indicates that the optimal AFL for the Lacaune breed under an intensive dairy system is between 390 and 450 d. Ewes with AFL earlier than 390 d or later than 450 d are likely to have a shorter productive life and a lower lifetime milk production.

Economics of respiratory disease in dairy replacement heifers

2020 ◽  
Vol 21 (2) ◽  
pp. 143-148
Author(s):  
Michael W. Overton
Keyword(s):  
Respiratory Disease ◽  
Milk Production ◽  
Incident Case ◽  
Data Set ◽  
Dairy Heifers ◽  
The Usa ◽  
History Of ◽  
On Farm ◽  
The Impact ◽  
Selective Culling

AbstractBovine respiratory disease (BRD) is a frequent disease concern in dairy cattle and is most commonly diagnosed in young dairy heifers. The impact of BRD is highly variable, depending on the accuracy and completeness of detection, effectiveness of treatment, and on-farm culling practices. Consequences include decreased rate of weight gain, a higher culling risk either as heifers or as cows, delayed age at first service, delayed age at first calving, and in some cases, lower future milk production. In this data set of 104,100 dairy replacement heifers from across the USA, 36.6% had one or more cases diagnosed within the first 120 days of age with the highest risk of new cases occurring prior to weaning. Comparison of the raising cost for heifers with BRD and those without a recorded history of BRD resulted in an estimated cost per incident case occurring in the first 120 days of age of $252 or $282, depending upon whether anticipated future milk production differences were considered or not. Current market conditions contributed to a cost estimate that is significantly higher than previously published estimates, driven in part by the losses associated with selective culling of a subset of heifers that experienced BRD.

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