Use of Danish National Somatic Cell Count Data to Assess the Need for Dry-Off Treatment in Holstein Dairy Cattle
In Denmark, PCR testing of dairy cattle is commonly used to select animals for the antibacterial treatment of intramammary infection (IMI) during the dry-off period. IMI is associated with a high somatic cell count (SCC), routinely recorded for milk quality control for most commercial dairy herds. T...
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MDPI AG
2023-08-01
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| Series: | Animals |
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| Online Access: | https://www.mdpi.com/2076-2615/13/15/2523 |
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| author | Maj Beldring Henningsen Matt Denwood Carsten Thure Kirkeby Søren Saxmose Nielsen |
| author_facet | Maj Beldring Henningsen Matt Denwood Carsten Thure Kirkeby Søren Saxmose Nielsen |
| author_sort | Maj Beldring Henningsen |
| collection | DOAJ |
| description | In Denmark, PCR testing of dairy cattle is commonly used to select animals for the antibacterial treatment of intramammary infection (IMI) during the dry-off period. IMI is associated with a high somatic cell count (SCC), routinely recorded for milk quality control for most commercial dairy herds. This study aimed to compare SCC curves over the lactation among dairy cows with positive vs. negative PCR test results for four major IMI pathogens. Data from 133,877 PCR-tested Holstein cows from 1364 Danish conventional dairy herds were used to fit a nonlinear mixed-effects model using a modified four-parameter Wilmink function. We stratified the data into first, second, third or fourth and later parity and fitted Wilmink curves to all SCC observations between 6 and 305 days in milk. The PCR tests were taken before dry-off at the end of the lactation to investigate which animals qualified for selective dry cow therapy. A PCR Ct-value of 37 and below was used to determine if an animal was PCR positive for any of the following IMI pathogens: <i>Staphylococcus aureus</i>, <i>Streptococcus agalactiae</i>, <i>Str. dysgalactiae</i> and <i>Str. uberis</i>. Our findings showed that mean SCC curve fits were higher for PCR-positive animals in all four parity groups and across lactations. The use of SCC data fitted to the entire lactation for multiple lactations enabled quantification of overall differences in SCC curves between cattle with and without detected IMI, adjusted for parity group and stage of lactation. These findings are relevant to the use of SCC to support treatment decisions. |
| first_indexed | 2024-03-11T00:32:28Z |
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| id | doaj.art-99ec8f12f25a4c1a99bfeac9620e5f27 |
| institution | Directory Open Access Journal |
| issn | 2076-2615 |
| language | English |
| last_indexed | 2024-03-11T00:32:28Z |
| publishDate | 2023-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Animals |
| spelling | doaj.art-99ec8f12f25a4c1a99bfeac9620e5f272023-11-18T22:34:12ZengMDPI AGAnimals2076-26152023-08-011315252310.3390/ani13152523Use of Danish National Somatic Cell Count Data to Assess the Need for Dry-Off Treatment in Holstein Dairy CattleMaj Beldring Henningsen0Matt Denwood1Carsten Thure Kirkeby2Søren Saxmose Nielsen3Animal Welfare and Disease Control, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870 Frederiksberg, DenmarkAnimal Welfare and Disease Control, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870 Frederiksberg, DenmarkAnimal Welfare and Disease Control, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870 Frederiksberg, DenmarkAnimal Welfare and Disease Control, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870 Frederiksberg, DenmarkIn Denmark, PCR testing of dairy cattle is commonly used to select animals for the antibacterial treatment of intramammary infection (IMI) during the dry-off period. IMI is associated with a high somatic cell count (SCC), routinely recorded for milk quality control for most commercial dairy herds. This study aimed to compare SCC curves over the lactation among dairy cows with positive vs. negative PCR test results for four major IMI pathogens. Data from 133,877 PCR-tested Holstein cows from 1364 Danish conventional dairy herds were used to fit a nonlinear mixed-effects model using a modified four-parameter Wilmink function. We stratified the data into first, second, third or fourth and later parity and fitted Wilmink curves to all SCC observations between 6 and 305 days in milk. The PCR tests were taken before dry-off at the end of the lactation to investigate which animals qualified for selective dry cow therapy. A PCR Ct-value of 37 and below was used to determine if an animal was PCR positive for any of the following IMI pathogens: <i>Staphylococcus aureus</i>, <i>Streptococcus agalactiae</i>, <i>Str. dysgalactiae</i> and <i>Str. uberis</i>. Our findings showed that mean SCC curve fits were higher for PCR-positive animals in all four parity groups and across lactations. The use of SCC data fitted to the entire lactation for multiple lactations enabled quantification of overall differences in SCC curves between cattle with and without detected IMI, adjusted for parity group and stage of lactation. These findings are relevant to the use of SCC to support treatment decisions.https://www.mdpi.com/2076-2615/13/15/2523PCR testingmastitiswilmink function |
| spellingShingle | Maj Beldring Henningsen Matt Denwood Carsten Thure Kirkeby Søren Saxmose Nielsen Use of Danish National Somatic Cell Count Data to Assess the Need for Dry-Off Treatment in Holstein Dairy Cattle Animals PCR testing mastitis wilmink function |
| title | Use of Danish National Somatic Cell Count Data to Assess the Need for Dry-Off Treatment in Holstein Dairy Cattle |
| title_full | Use of Danish National Somatic Cell Count Data to Assess the Need for Dry-Off Treatment in Holstein Dairy Cattle |
| title_fullStr | Use of Danish National Somatic Cell Count Data to Assess the Need for Dry-Off Treatment in Holstein Dairy Cattle |
| title_full_unstemmed | Use of Danish National Somatic Cell Count Data to Assess the Need for Dry-Off Treatment in Holstein Dairy Cattle |
| title_short | Use of Danish National Somatic Cell Count Data to Assess the Need for Dry-Off Treatment in Holstein Dairy Cattle |
| title_sort | use of danish national somatic cell count data to assess the need for dry off treatment in holstein dairy cattle |
| topic | PCR testing mastitis wilmink function |
| url | https://www.mdpi.com/2076-2615/13/15/2523 |
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