Abstract
Antibiotic stewardship on dairy farms can be heightened through the implementation of selective dry-cow therapy (SDCT). However, some producers are concerned that this practice may be related to poor udder health outcomes in cows with high milk production at the time of dry-off. The objective of this study was to evaluate if the effect of culture-guided SDCT (Cult-SDCT) and algorithm-guided SDCT (Alg-SDCT) on dry-period intramammary infection (IMI) dynamics and postcalving udder health and performance [when compared with blanket dry-cow therapy (BDCT)] varied according to milk production level before dry-off. Data were compiled from clinical trials conducted in the United States and Canada that compared Cult-SDCT and Alg-SDCT to a positive control, i.e., BDCT. In those trials, cows were enrolled 1–2 d before dry-off, randomized to their dry-cow therapy strategy and followed until 120 d in milk of the subsequent lactation. The number of cows and quarters in the final data set were 1,485 and 5,097, respectively. Measured outcomes included quarter-level antibiotic use at dry-off, quarter-level IMI prevalence after calving, quarter-level dry-period IMI cure risk, quarter-level dry-period new IMI risk, cow-level clinical mastitis and removal from the herd during 1–120 d in milk, and somatic cell count and milk yield during 1–120 DIM. The primary objective of analysis was to investigate if the effect of Cult-SDCT and Alg-SDCT on these outcomes, when compared with BDCT, varied according to milk production level before dry-off. To do this, each cow was classified as having low, mid or high production, based on her milk yield tertile group at the most recent herd test before enrollment (low: <23.7 kg/d, mid: 23.7 to 30.4 kg/d, and high >30.4 kg/d). Multivariable generalized estimating equations were used to estimate risk differences and differences in means, and Cox regression was used to estimate hazard ratios. For Cult-SDCT, the proportion of quarters treated with dry-cow antibiotics within each milk production level were 40.7% (low), 41.7% (mid) and 47.2% (high). For Alg-SDCT, the proportions were 60.6% (low), 38.7% (mid), and 35.1% (high). Measures of udder health were not markedly different when comparing Cult-SDCT to BDCT and Alg-SDCT to BDCT. This was consistently observed in low, mid and high producing cows. In conclusion, the findings from this study indicate that Cult-SDCT and Alg-SDCT can be successfully implemented in cows of all milk production levels.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1953-1967 |
| Number of pages | 15 |
| Journal | Journal of Dairy Science |
| Volume | 106 |
| Issue number | 3 |
| DOIs | |
| State | Published - Mar 2023 |
Bibliographical note
Funding Information:Fieldwork conducted in the United States funded by the United States Department of Agriculture – NIFA (Award # 2018-67015-28298) and was supported by an in-kind donation of product (Spectramast DC, Orbeseal) from Zoetis (Parsippany, NJ). Fieldwork in Canada was supported by Agriculture and Agri-Food Canada (Ottawa, Ontario, Canada), and by additional contributions from Dairy Farmers of Canada (Ottawa, Ontario, Canada), the Canadian Dairy Network (Guelph, Ontario, Canada), and the Canadian Dairy Commission (Ottawa, Ontario, Canada) under the Agri-Science Clusters Initiative, through the Canadian Bovine Mastitis and Milk Quality Research Network (Saint Hyacinthe, Quebec, Canada) research program, by Zoetis (Kirkland, Quebec, Canada), and by one of the authors (Dufour) NSERC-Discovery grant funds (RGPIN/435637-2013, Saint Hyacinthe, Quebec, Canada). Fidele Kabera was also supported by the NSERC-CREATE in Milk Quality program and the Fonds de recherche du Québec-Nature et technologies (FRQNT). As per the research agreement, aside from providing financial support, the funders have no role in the design and conduct of the studies, data collection and analysis, or interpretation of the data. The authors wish to acknowledge the important contributions of co-authors from the US and Canadian studies: Pat Gorden (Iowa State University), Alfonso Lago (Dairy Experts Inc. California), Amy Vasquez (Danone, New York), Erin Royster (University of Minnesota), Jennifer Timmerman (University of Minnesota), Mark Thomas (Dairy Health and Management Services, New York), Greg Keefe (University of Prince Edward Island, Canada), and Marguerite Cameron (University of Prince Edward Island, Canada). The Minnesota Easy 4Cast plate is manufactured by the University of Minnesota (St. Paul, MN). However, the study investigators have no financial interest in the sale of this plate. The authors have not stated any other conflicts of interest.
Funding Information:
Fieldwork conducted in the United States funded by the United States Department of Agriculture – NIFA (Award # 2018-67015-28298) and was supported by an in-kind donation of product (Spectramast DC, Orbeseal) from Zoetis (Parsippany, NJ). Fieldwork in Canada was supported by Agriculture and Agri-Food Canada (Ottawa, Ontario, Canada), and by additional contributions from Dairy Farmers of Canada (Ottawa, Ontario, Canada), the Canadian Dairy Network (Guelph, Ontario, Canada), and the Canadian Dairy Commission (Ottawa, Ontario, Canada) under the Agri-Science Clusters Initiative, through the Canadian Bovine Mastitis and Milk Quality Research Network (Saint Hyacinthe, Quebec, Canada) research program, by Zoetis (Kirkland, Quebec, Canada), and by one of the authors (Dufour) NSERC-Discovery grant funds (RGPIN/435637-2013, Saint Hyacinthe, Quebec, Canada). Fidele Kabera was also supported by the NSERC-CREATE in Milk Quality program and the Fonds de recherche du Québec-Nature et technologies (FRQNT). As per the research agreement, aside from providing financial support, the funders have no role in the design and conduct of the studies, data collection and analysis, or interpretation of the data. The authors wish to acknowledge the important contributions of co-authors from the US and Canadian studies: Pat Gorden (Iowa State University), Alfonso Lago (Dairy Experts Inc., California), Amy Vasquez (Danone, New York), Erin Royster (University of Minnesota), Jennifer Timmerman (University of Minnesota), Mark Thomas (Dairy Health and Management Services, New York), Greg Keefe (University of Prince Edward Island, Canada), and Marguerite Cameron (University of Prince Edward Island, Canada). The Minnesota Easy 4Cast plate is manufactured by the University of Minnesota (St. Paul, MN). However, the study investigators have no financial interest in the sale of this plate. The authors have not stated any other conflicts of interest.
Publisher Copyright:
© 2023 American Dairy Science Association
Keywords
- antimicrobial resistance
- antimicrobial stewardship
- dry-cow therapy
- mastitis
PubMed: MeSH publication types
- Randomized Controlled Trial, Veterinary
- Journal Article