The influence of the rearing period on intramammary infections in Swiss dairy heifers: A cross-sectional study

Abstract

Healthy replacement heifers are one of the foundations of a healthy dairy herd. Farm management and rearing systems in Switzerland provide a wide variety of factors that could potentially be associated with intramammary infections (IMI) in early lactating dairy heifers. In this study, IMI with minor mastitis pathogens such as coagulase-negative staphylococci (CNS), contagious pathogens, and environmental major pathogens were identified. Fifty-four dairy farms were enrolled in the study. A questionnaire was used to collect herd level data on housing, management and welfare of young stock during farm visits and interviews with the farmers. Cow-level data such as breed, age at first calving, udder condition and swelling, and calving ease were also recorded. Data was also collected about young stock that spent a period of at least 3 months on an external rearing farm or on a seasonal alpine farm. At the quarter level, teat conditions such as teat lesions, teat dysfunction, presence of a papilloma and teat length were recorded. Within 24h after parturition, samples of colostral milk from 1564 quarters (391 heifers) were collected aseptically for bacterial culture. Positive bacteriological culture results were found in 49% of quarter samples. Potential risk factors for IMI were identified at the quarter, animal and herd level using multivariable and multilevel logistic regression analysis. At the herd level tie-stalls, and at cow-level the breed category "Brown cattle" were risk factors for IMI caused by contagious major pathogens such as Staphylococcus aureus (S. aureus). At the quarter-level, teat swelling and teat lesions were highly associated with IMI caused by environmental major pathogens. At the herd level heifer rearing at external farms was associated with less IMI caused by major environmental pathogens. Keeping pregnant heifers in a separate group was negatively associated with IMI caused by CNS. The odds of IMI with coagulase-negative staphylococci increased if weaning age was less than 4 months and if concentrates were fed to calves younger than 2 weeks. This study identified herd, cow- and quarter-level risk factors that may be important for IMI prevention in the future.

Alternative Practices in Organic Dairy Production and Effects on Animal Behavior, Health, and Welfare

“…In general, heifers are vulnerable to clinical mastitis and IMI during early lactation [ 108 , 109 , 110 , 111 ]. Clinical mastitis is defined by the National Mastitis Council ( (accessed on 9 November 2021)) as “udder inflammation characterized by visible abnormalities in the udder or milk”.…”

Risk and success factors for good udder health of early lactation primiparous dairy cows

“…Because many IMI are already present at calving, risk factors during heifer rearing may be particularly important. Several cow-and herd-level risk factors for IMI and mastitis in early lactation primiparous cows have been identified in studies from various countries (Fox, 2009;De Vliegher et al, 2012;Santman-Berends et al, 2012;Bludau et al, 2014Bludau et al, , 2016, with factors being related to feeding, housing, and milking. In Sweden, only a limited number of studies have been performed.…”

Advancements in the understanding of staphylococcal mastitis through the use of molecular tools

“…In another study, heifers reared at an off-site specialized rearing facility had a lower risk of environmental major pathogen mastitis (Bludau et al, 2016). Reasons for this may be because these specialized farms pay more attention to young stock (Bludau et al, 2016). With respect to season, in Belgium, heifers calving in April to June had a higher risk of having an elevated SCC, as opposed to heifers calving in the other seasons (De Vliegher et al, 2004b).…”

“…Risk factors for S. aureus IMIs in heifers have been evaluated. One risk factor for S. aureus IMI in heifers was the housing system, with a higher prevalence in heifers housed in tie-stall barns (Bludau et al, 2016). Heifers with teat orifices colonized by S. aureus were 3.3 times more likely to have an IMI with S. aureus at parturition than heifers that were not colonized at the teat orifices (Roberson et al, 1994b).…”

“…Bedding type has also been found to be a risk factor, with mammary quarters of primiparous cows bedded on new sand having greater time to a clinical mastitis episode than quarters of those heifers bedded on recycled sand or deep bedded manure solids ( Rowbotham and Ruegg, 2016). In another study, heifers reared at an off-site specialized rearing facility had a lower risk of environmental major pathogen mastitis (Bludau et al, 2016). Reasons for this may be because these specialized farms pay more attention to young stock (Bludau et al, 2016).…”