scholarly journals Milking-to-Milking Variability for Milk Yield, Fat and Protein Percentage, and Somatic Cell Count

2008 ◽  
Vol 91 (9) ◽  
pp. 3412-3423 ◽  
Author(s):  
M.A. Quist ◽  
S.J. LeBlanc ◽  
K.J. Hand ◽  
D. Lazenby ◽  
F. Miglior ◽  
...  
Keyword(s):  
Somatic Cell ◽  
Cell Count ◽  
Milk Yield ◽  
Somatic Cell Count ◽  
Protein Percentage

scholarly journals Genetic Aspects of Somatic Cell Count in Holstein Dairy Cows in Iran

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1637
Author(s):  
Hadi Atashi ◽  
Miel Hostens
Keyword(s):  
Dairy Cows ◽  
Somatic Cell ◽  
Cell Count ◽  
Genetic Correlation ◽  
Milk Yield ◽  
Somatic Cell Count ◽  
Random Regression ◽  
Fat Percentage ◽  
Protein Percentage ◽  
Holstein Dairy Cows

The aim of this study was to estimate the genetic parameters of somatic cell count (SCC) and its relationship with production traits in the first three parities in Iranian Holstein dairy cows. Data were 1,891,559 test-day records of SCC, milk yield, and milk compositions on 276,217 lactations on 147,278 cows distributed in 134 herds. The number of test-day records in the first, second and third parities were 995,788 (on 147,278 cows), 593,848 (on 85,153 cows), and 301,923 (on 43,786 cows), respectively. Test-day SCCs were transformed to somatic cell scores (SCS). A random regression test-day animal model through four-trait three-lactation was used to estimate variance components for test-day records of SCS and lactation traits were included. Gibbs sampling was used to obtain marginal posterior distributions for the various parameters using a single chain of 200,000 iterates in which the first 50,000 iterates of each chain were regarded as a burn-in period. The mean heritability estimates for SCS (0.15 to 0.18) were lower than those for milk yield (0.36 to 0.38), fat yield (0.30 to 0.31), protein yield (0.31 to 0.32), fat percentage (0.21 to 0.25), and protein percentage (0.21 to 0.22). Low negative genetic correlations ranging from −0.05 to −0.30 were found between SCS and yield traits (milk, fat, and protein yields). The genetic correlation found between SCS and fat percentage was close to zero, however, a low positive genetic correlation ranging from 0.12 to 0.17 was found between SCS and protein percentage. Based on the results, it can be concluded that genetic selection for decreasing SCS would also increase lactation yield. The estimates found in this study can be used to perform breeding value estimations for national genetic evaluations in Iranian Holsteins using a multiple-trait, multiple-lactation random regression model.

scholarly journals Hyperketonemia Predictions Provide an On-Farm Management Tool with Epidemiological Insights

Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1291
Author(s):  
Ryan S. Pralle ◽  
Joel D. Amdall ◽  
Robert H. Fourdraine ◽  
Garrett R. Oetzel ◽  
Heather M. White
Keyword(s):  
Somatic Cell ◽  
Cell Count ◽  
Milk Yield ◽  
Milk Fat ◽  
Somatic Cell Count ◽  
Past Research ◽  
Management Tool ◽  
Milk Analysis ◽  
Linear Regression Models ◽  
High Throughput Detection

Prediction of hyperketonemia (HYK), a postpartum metabolic disorder in dairy cows, through use of cow and milk data has allowed for high-throughput detection and monitoring during monthly milk sampling. The objective of this study was to determine associations between predicted HYK (pHYK) and production parameters in a dataset generated from routine milk analysis samples. Data from 240,714 lactations across 335 farms were analyzed with multiple linear regression models to determine HYK status. Data on HYK or disease treatment was not solicited. Consistent with past research, pHYK cows had greater previous lactation dry period length, somatic cell count, and dystocia. Cows identified as pHYK had lower milk yield and protein percent but greater milk fat, specifically greater mixed and preformed fatty acids (FA), and greater somatic cell count (SCC). Differential somatic cell count was greater in second and fourth parity pHYK cows. Culling (60d), days open, and number of artificial inseminations were greater in pHYK cows. Hyperketonemia prevalence decreased linearly in herds with greater rolling herd average milk yield. This research confirms previously identified risk factors and negative outcomes associated with pHYK and highlights novel associations with differential SCC, mixed FA, and preformed FA across farm sizes and production levels.

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