• Journal of Animal Science and Technology
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• v.48 no.1
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• pp.39-48
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• 2006

This study utilized test day of somatic cell score data of dairy cattle from 2000 to 2004. The number of data used were 124,635 of first parity, 134,308 of second parity, 77,862 of third parity, 41,787 of forth parity and 37,412 of fifth parity. The data was analyzed by least square mean method using GLM to estimate the effects of calving year, age, lactation stage, parity and season on somatic cell score. Variance component estimation using test day model was determined by using expectation maximization algorithm- restricted maximum likelihood (EM-REML) analysis method. In each parity, somatic cell score was low for younger group and was relatively high in older groups. Likewise, for lactation stage, the score was low in early-lactation and high in late-lactation in first parity and second parity. Nevertheless, for the third, fourth and fifth parity, however, high somatic cell score was observed in mid-lactation. Generally, the score was high in the peak. Although in fourth and fifth parity, the score was low in late-lactation. Environmental effect of season, somatic cell score was generally low from September to November for all parities. The score was high between June and August when the milk production is usually low. The heritability in each parity were 0.05, 0.09, 0.10, 0.05 and 0.05 for parity 1, 2, 3, 4, 5, respectively. Genetic variance value was estimated to be high in second, third and fifth parity in early-lactation and to be low in first and forth parity.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.5
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• pp.580-585
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• 1998

The study was conducted to determine if variation in protein yield can be explained by expressions of early lactation somatic cell score (SCS) and if prediction can be improved by including SCS among the predictors. A data set was prepared (n = 663,438) from Wisconsin Dairy Improvement Association (USA) records for protein yield with sample days near 20. Stepwise regression was used requiring F statistic (p < .01) for any variable to stay in the model. Separate analyses were run for 12 combinations of four seasons and first three parities. Selection of SCS variables was not consistent across seasons or lactations. Coefficients of detennination ($R^2$) ranged from 51 to 61% with higher values for earlier lactations. Including any expression of SCS in the prediction equations improved $R^2$ by < 1 %. SCS was associated with milk yield on the sample day, but the association was not strong enough to improve the prediction of future yield when other expressions of milk yield were in the model.

• Korean Journal of Veterinary Service
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• v.16 no.1
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• pp.1-10
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• 1993

Samples of bulk herd milk, foremilk, last milk (stripping) and individual cow sample were collected and their somatic cell number were counted with Fossomatic counter (FCC), Coulter counter(CC), direct microscopic somatic cell count(DMSCC) and Califormia mastitis test (CMT), The results were compared and summarized as follows : 1. Mean somatic cell counts of 120 bulk herd milk samples obtained by DMSCC, FCC and CC were 433,203, 481,213 and 676,245 respectively. 2. Mean somatic cell counts of 116 foremilk samples obtained by DMSCC, FCC and CC were 515,035, 611,845 and 725,051 respectively 3. Mean somatic cell counts of 87 last milk samples obtained by DMSCC, FCC and CC were 718,506, 839,874 and 1,041,160 respectively. 4. Mean somatic cell counts of 57 individual cow samples obtained by DMSCC, FCC and CC were 449,258, 491,018 and 521,315 respectively. 5. Mean somatic cell counts of all samples increased with the increasing CMT score, and the cell counts were higher by CC than by FCC. 6. The correlation coefficients between the somatic cell counts by CMT and CC were 0.926 in bulk herd milk, 0.707 in foremilk 0.688 in last milk and 0.675 in individual cow sample, respectively 7. The correlation coefficients between the somatic cell counts by CMT and FCC were 0. 945 in bulk herd milk, 0.705 in foremilk 0.694 in last milk and 0.727 in individual cow sample, respectively. 8. The correlation coefficients between the somatic cell counts by CC and FCC were 0.978 in bulk herd milk, 0.997 in foremilk 0.983 in last milk and 0.985 in individual cow sample, respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.2
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• pp.166-171
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• 2007

The objective of this study was to assess the association of polymorphisms in ${\kappa}$-cn, ${\beta}$-lg, ${\beta}$-lg 5′ flanking region, CSN1S2, and IGFBP-3 genes with milk production traits and mastitis-related traits in Chinese Holstein. Traits analyzed were 305 day standard milk yield, protein percentage, fat percentage, the ratio of fat percentage and protein percentage, pre-somatic cell count, somatic cell count, and somatic cell score, respectively. CSN1S2 locus was uninformative because only one genotype BB was found in Chinese Holstein. Allele frequencies of A and B in IGFBP-3 gene were 0.5738 and 0.4262 in Chinese Holstein population, which was different from reported Qinchuan cattle population. The genotypes of animals at IGFBP-3 locus significantly affected 305 day standard milk yield, protein percentage, and somatic cell score. The ${\beta}$-lg genotypes had a significant effect on protein percentage and the ratio of fat percentage and protein percentage. Polymorphism in ${\beta}$-lg 5′ flanking region was associated with 305 day standard milk yield, protein percentage, fat percentage, pre-somatic cell count, and somatic cell count. No significant associations of the polymorphism in ${\kappa}$-cn gene were observed for any trait.

• Journal of Animal Science and Technology
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• v.58 no.10
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• pp.38.1-38.6
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• 2016

Background: Despite the importance of relationships between somatic cell score (SCS) and currently selected traits (milk, fat and protein yield) of Holstein cows, there was a lack of comprehensive literature for it in Iran. Therefore we tried to examine heritabilities and relationships between these traits using a fixed-regression animal model and Bayesian inference. The data set consisted of 1,078,966 test-day observations from 146,765 primiparous daughters of 1930 sires, with calvings from 2002 to 2013. Results: Marginal posterior means of heritability estimates for SCS ($0.03{\pm}0.002$) were distinctly lower than those for milk ($0.204{\pm}0.006$), fat ($0.096{\pm}0.004$) and protein ($0.147{\pm}0.005$) yields. In the case of phenotypic correlations, the relationships between production and SCS were near zero at the beginning of lactation but become increasingly negative as days in milk increased. Although all environmental correlations between production and SCS were negative ($-0.177{\pm}0.007$, $-0.165{\pm}0.008$ and $-0.152{\pm}0.007$ between SCS and milk, fat, and protein yield, respectively), slightly antagonistic genetic correlations were found; with posterior mean of relationships ranging from $0.01{\pm}0.039$ to $0.11{\pm}0.036$. This genetic opposition was distinctly higher for protein than for fat. Conclusion: Although small, the positive genetic correlations suggest some genetic antagonism between desired increased milk production and reduced SCS (i.e., single-trait selection for increased milk production will also increase SCS).

• Animal Bioscience
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• v.34 no.4
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• pp.499-505
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• 2021

Objective: The objective of this study was to evaluate the genetic behavior of a population of Holstein cattle in response to the variation of environmental temperature by analyzing the effects of genotype by environment interaction (GEI) through reaction norms for the somatic cell score (SCS). Methods: Data was collected for 67,206 primiparous cows from the database of the Paraná Holstein Breeders Association in Brazil, with the aim of evaluating the temperature effect, considered as an environmental variable, distinguished under six gradients, with the variation range found being 17℃ to 19.5℃, over the region. A reaction norm model was adopted utilizing the fourth order under the Legendre polynomials, using the mixed models of analysis by the restricted maximum likelihood method by the WOMBAT software. Additionally, the genetic behavior of the 15 most representative bulls was assessed, in response to the changes in the temperature gradient. Results: A mean score of 2.66 and a heritability variation from 0.17 to 0.23 was found in the regional temperature increase. The correlation between the environmental gradients proved to be higher than 0.80. Distinctive genetic behaviors were observed according to the increase in regional temperature, with an observed increase of up to 0.258 in the breeding values of some animals, as well as a reduction in the breeding of up to 0.793, with occasional reclassifications being observed as the temperature increased. Conclusion: Non-relevant GEI for SCS were observed in Holstein cattle herds of southern Brazil. Thus, the inclusion of the temperature effect in the model of genetic evaluation of SCS for the southern Brazilian Holstein breed is not required.

• Journal of Animal Science and Technology
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• v.45 no.5
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• pp.739-748
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• 2003

The objective of this study was to estimate genetic parameters for test-day milk production and somatic cell score using field data collected by dairy herd improvement program in Korea. Random regression animal models were applied to estimate genetic variances for milk production and somatic cell score. Heritabilities for milk yields, fat percentage, protein percentage, solid-not-fat percentage, and somatic cell score from test day records of 5,796 first lactation Holstein cows were estimated by REML algorithm in single trait random regression test-day animal models. For these analyses, Legendre polynomial covariate function was applied to model the fixed effect of age-season, the additive genetic effect and the permanent environment effect as random. Homogeneous residual variance was assumed to be equal throughout lactation. Heritabilities as a function of time were calculated from the estimated curve parameters from univariate analyses. Heritability estimates for milk yields were in range of 0.13 to 0.29 throughout first lactation. Heritability estimates for fat percentage, protein percentage and solid-not-fat percentage were within 0.09 to 0.11, 0.12 to 0.19 and 0.17 to 0.23, respectively. For somatic cell score, heritabilities were within 0.02 to 0.04. Heritabilities for milk productions and somatic cell score were fluctuated by days in milk with comparing 305d milk production.

• Journal of Veterinary Clinics
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• v.24 no.2
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• pp.177-181
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• 2007

In the present study, a total of 547 half milk samples were collected from 274 dairy goats to perform somatic cell counts (SCC) and California mastitis test (CMT). Milk smear was stained with Pyronin Y-Methyl Green stain were classified into either epithelial or blood cells, etc. Of the 547 halves the percentage of CMT negative milk samples were 86%. Among these, 58.2% were CMT negative with SCC<500,000/ml, while 27.8% were CMT negative with SCC>500,000 ml. As expected, CMT score increased with the increase of SCC. The number of epithelial cells decreased with the increasing number of somatic cells, while the opposite was observed with the number of blood cells. These results indicate that the critical point in milk quality & CMT should be considered on the false (pseudo-SC) SCC in dairy goat.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.3
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• pp.303-310
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• 2015

The study was conducted to analyze the genetic parameters of somatic cell score (SCS) of Holstein cows, which is an important indicator to udder health. Test-day records of somatic cell counts (SCC) of 305-day lactation design from first to fifth lactations were collected on Holsteins in Korea during 2000 to 2012. Records of animals within 18 to 42 months, 30 to 54 months, 42 to 66 months, 54 to 78 months, and 66 to 90 months of age at the first, second, third, fourth and fifth parities were analyzed, respectively. Somatic cell scores were calculated, and adjusted for lactation production stages by Wilmink's function. Lactation averages of SCS ($LSCS_1$ through $LSCS_5$) were derived by further adjustments of each test-day SCS for five age groups in particular lactations. Two datasets were prepared through restrictions on number of sires/herd and dams/herd, progenies/sire, and number of parities/cow to reduce data size and attain better relationships among animals. All LSCS traits were treated as individual trait and, analyzed through multiple-trait sire models and single trait animal models via VCE 6.0 software package. Herd-year was fitted as a random effect. Age at calving was regressed as a fixed covariate. The mean LSCS of five lactations were between 3.507 and 4.322 that corresponded to a SCC range between 71,000 and 125,000 cells/mL; with coefficient of variation from 28.2% to 29.9%. Heritability estimates from sire models were within the range of 0.10 to 0.16 for all LSCS. Heritability was the highest at lactation 2 from both datasets (0.14/0.16) and lowest at lactation 5 (0.11/0.10) using sire model. Heritabilities from single trait animal model analyses were slightly higher than sire models. Genetic correlations between LSCS traits were strong (0.62 to 0.99). Very strong associations (0.96 to 0.99) were present between successive records of later lactations. Phenotypic correlations were relatively weaker (<0.55). All correlations became weaker at distant lactations. The estimated breeding values (EBVs) of LSCS traits were somewhat similar over the years for a particular lactation, but increased with lactation number increment. The lowest EBV in first lactation indicated that selection for SCS (mastitis resistance) might be better with later lactation records. It is expected that results obtained from these multi-trait lactation model analyses, being the first large scale SCS data analysis in Korea, would create a good starting step for application of advanced statistical tools for future genomic studies focusing on selection for mastitis resistance in Holsteins of Korea.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.6
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• pp.889-893
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• 2003

Immunomodulatory and therapeutic potential of Enrofloxacin was studied in bovine sub clinical mastitis (SCM). The therapeutic efficacy was adjudged by Somatic cell count and Total bacterial count of the milk, whereas, the immuno modulatory potential of the drug was assessed by measuring myeloperoxidase (MPO) and acid phosphates (ACP) enzyme level in the milk leukocytes. Forty-five cows were divided into three equal groups. Gr I consisting 15 cows served as healthy control, whereas, 30 cows (SCM), Gr II and Gr III, selected on the basis of California Mastitis Test (CMT) positive reaction. Gr II cows received 150 mg of Enrofloxacin, once a day for three days and Gr.III received sterile 5 ml PBS (pH 7.4) for 7days, both the treatment were given by intramammary route. The observation was made up to 30 days post-treatment (PT). The CMT of the healthy milk was negative (0), whereas, it ranged between 1 point score and 2 point score in SCM. The Somatic cell count (SCC) and Total bacterial count (TBC) decreased significantly (p<0.05) on day 3 PT in GrII cows in Enrofloxacin treated group, however, such changes were insignificant in PBS treated group. Traces of MPO and ACP enzyme were found in the healthy milk. The mean ACP level enhanced by 70% on day 3 PT in GrII and only 18.7% in Gr. III cows. The mean MPO level enhanced to 32% in Gr. II and 18 % in Gr. III cows on day 3 PT. Concomitant use of Enrofloxacin in SCM at sub optimal dose was found to reduce the bacterial load by increasing the bactericidal enzyme level in the milk polymorphonuclear cells (PMNs) in bovine SCM, which indicates its immunomodulatory potential in mastitis.