What question did this study set out to answer?

To develop a cumulative lactation scoring system based on monthly California Mastitis Tests and evaluate its genetic parameters for improving mastitis resistance in dairy cattle.

July 1, 1979Journal of Dairy ScienceOpen Access

Genetic Analysis of California Mastitis Test Records. II. Score for Resistance of Elevated Tests

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Authors

AAA. A. Al-RawiFayoum University RLR.C. LabenUniversity of California, Davis EPE. J. PollakUniversity of Nebraska–Lincoln

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Implication

Genetic analysis reveals moderate heritability for California Mastitis Test resistance scores in dairy cows, suggesting selective breeding can lower mastitis incidence.

Key Points

To develop a cumulative lactation scoring system based on monthly California Mastitis Tests and evaluate its genetic parameters for improving mastitis resistance in dairy cattle.
Evaluated the first nine monthly California Mastitis Tests weighted by number and position of elevated scores (coded 1, 2, or 3 vs normal negative/trace), assigning cumulative scores from 0 to 21.
Analyzed the effects of score and elevation timing on 305-day milk yield and lactation persistency across sire progeny groups.
Estimated heritability values across four lactation groups and calculated the genetic correlation between cumulative score and 305-day milk yield in first-lactation cows.
Heritabilities for the cumulative lactation score were 0.48 ± 0.07 in first, 0.36 ± 0.08 in second, 0.46 ± 0.15 in third, and 0.23 ± 0.12 in fourth or later lactations.
Differences in cumulative lactation score were statistically significant among sire progeny groups.
Genetic correlation between 305-day milk yield and the cumulative lactation score was -0.31 ± 0.13 for first lactation records.

Cite This Study

Al-Rawi et al. (1979) studied this question.

synapsesocial.com/papers/6a7d1767a88f8d6a789ffec8 https://doi.org/10.3168/jds.s0022-0302(79)83385-8

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Implication

Genetic analysis reveals moderate heritability for California Mastitis Test resistance scores in dairy cows, suggesting selective breeding can lower mastitis incidence.

Genetic Analysis of California Mastitis Test Records. II. Score for Resistance of Elevated Tests

Discussion

Member takes

Implication

Key Points

Cite This Study

Genetic Analysis of California Mastitis Test Records. II. Score for Resistance of Elevated Tests

Discussion

Member takes

Implication

Key Points

Cite This Study

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