Etiology, persistence, and risk factors of subclinical mastitis in a meat-producing sheep flock

Subclinical mastitis, the asymptomatic inflammation of the udder often caused by bacterial infection, is an important economic and welfare concern in meat-producing flocks. We conducted a longitudinal observational study to: (1) characterize the etiology, prevalence, incidence, and persistence of intramammary infections during the first 8 weeks of lactation, and (2) to investigate the potential risk factors of lactation stage, parity, and the number of lambs reared. Duplicate milk samples (n=592) were collected aseptically from each udder half of 37 clinically healthy ewes (9 Hampshire, 22 Polypay, and 6 Targhee) weekly for their first 8 weeks of lactation. A sample was considered a true infection if at least 100 CFU/mL of a bacterial species were isolated. Out of a total of 560 non-contaminated duplicate udder half samples, 186 (33.2%) were infected. The prevalence of subclinical mastitis in the first week of lactation was 26.0% at the udder half level and increased over lactation to 4..., , , # Etiology, persistence, and risk factors of subclinical mastitis in a meat-producing sheep flock

[https://doi.org/10.5061/dryad.9ghx3ffsr](https://doi.org/10.5061/dryad.9ghx3ffsr)

## Description of the data and file structure

These materials provide the data and R script used in this longitudinal observational study of subclinical mastitis in sheep and are referenced in the related article by the same name.

### Files and variables

#### File: Peckler\_etal\_JAS\_SheepMastitisData\_241125.xlsx

**Description:** Excel file containing the bacteriological results from milk samples collected in duplicate from each udder half of 39 ewes weekly over the first 8 weeks of lactation. The second sheet contains descriptions of each column variable. Blank cells indicate NA values.

##### Variables

| Variable | Description ...