Intramammary infections and risk factors in freshly calved heifers in dairy herds
2023 (English)In: Journal of Dairy Science, ISSN 0022-0302, E-ISSN 1525-3198, Vol. 106, no 11, p. 7893-7907Article in journal (Refereed) Published
Abstract [en]
Subclinical mastitis can be common among freshly calved heifers (FCH), but the prevalence differs between herds possibly due to variation in risk factors. The aims of this observational study were to identify differences in occurrence of IMI in FCH between herds with documented good or not so good first parity udder health based on cow SCC (CSCC) in early lactation, and to study herd differences in animal factors important for udder health such as udder and hock skin lesions and animal cleanliness. Three groups of herds were included, those with high proportion of FCH with low (≤75,000 cells/ml) CSCC at the first 2 milk recordings after calving (LL), herds with high proportion of FCH with high (>100,000 cells/ml) CSCC at the first and low CSCC at the second recording (HL), and herds with high proportion of FCH with high CSCC at both recordings (HH). Thirty-one herds (13 LL, 11 HL, 15 HH) were visited 3 times during a 12-mo period for observation of cleanliness and hock lesions, and sampling of udder/teat skin using swab cloths of milk-fed calves, early pregnant heifers and late pregnant heifers. In 25 (9 LL, 9 HL, 7 HH) udder quarter samples from colostrum and milk on d 3-4 after calving were taken by the farmers from FCH during one year. The farmers also provided information on calving (individual or group), use of restraint and oxytocin at milking, and presence of teat and udder skin lesions. Bacterial growth in swab samples and quarter samples was investigated by culturing, and a selection of isolates was genotyped using whole genome sequencing (WGS). Cleanliness, hock and udder skin lesions other than udder-thigh dermatitis, and growth of bacteria in swab samples did not differ between herd groups. It was more common that FCH from LL herds, compared with FCH in HH and HL herds, calved in a group of animals. Use of restraint at milking was more common in LL herds than in HH herds while presence of udder-thigh dermatitis was lowest in LL herds. Specific infection was found in 14% of 5,593 quarter samples from 722 FCH. The most common IMI was S. chromogenes. Growth of S. simulans was more common in HH than in LL and HL herds. In colostrum samples, S. haemolyticus was more common in HL and HH than in LL herds. The proportion of quarters with the same specific infection at both samplings was higher in HH than in LL herds and tended to be higher in HH than in HL herds. The proportion of quarters with S. chromogenes IMI at both samplings tended to differ between herd groups and was highest in HH herds. WGS found the same sequence type of S. chromogenes and S. aureus in both samples in almost all quarters with the same infection at both samplings. The differences in IMI between herd groups were in line with the higher SCC in HH herds. The reasons for the predominance of S. chromogenes IMI in FCH need further studies.
Place, publisher, year, edition, pages
Elsevier, 2023. Vol. 106, no 11, p. 7893-7907
Keywords [en]
Mastitis, Staphylococcus chromogenes, cleanliness, skin lesions, whole genome sequencing
National Category
Microbiology in the medical area
Identifiers
URN: urn:nbn:se:oru:diva-105982DOI: 10.3168/jds.2022-22995ISI: 001105235700001PubMedID: 37210369Scopus ID: 2-s2.0-85162218879OAI: oai:DiVA.org:oru-105982DiVA, id: diva2:1758071
Note
The study was financed by the Swedish Farmers' Foundation for Agricultural Research (Stockholm, Sweden).
2023-05-222023-05-222023-12-08Bibliographically approved