Elimination of selected mastitis pathogens during the dry period

Abstract

We aimed to evaluate the elimination of 4 different mastitis pathogens, Streptococcus agalactiae, Mycoplasma bovis, Staphylococcus aureus, and Streptococcus uberis, from infected udder quarters during the dry period using quantitative PCR. The second purpose of this study was to evaluate the association between milk haptoglobin (Hp) concentration and the presence of udder pathogens (Strep. agalactiae, Staph. aureus, M. bovis, and Strep. uberis) in udder quarter milk samples before and after dry period. Aseptic udder quarter milk samples (n = 1,001) were collected from 133 dairy cows at dry off and at the first milking after calving from 1 large dairy herd. Bacterial DNA of Strep. agalactiae, Staph. aureus, Strep. uberis, and M. bovis in the udder quarter milk samples was identified with commercial quantitative PCR analysis Mastitis 4B (DNA Diagnostic A/S, Risskov, Denmark). Milk Hp concentration (mg/L) was measured from udder quarter milk samples. The elimination rates during the dry period for M. bovis, Staph. aureus, Strep. agalactiae, and Strep. uberis were 86.7, 93.6, 96.2, and 100.0%, respectively. The new IMI rate was 3.0% for M. bovis, 2.9% for Staph. aureus, 2.4% for Strep. agalactiae, and 3.1% for Strep. uberis. The milk Hp concentration was significantly higher in udder quarter milk samples with blood and in samples positive for Strep. agalactiae at dry off and for Staph. aureus postcalving. Elevated milk Hp concentration was not associated with the presence of M. bovis in the udder quarter milk samples. In conclusion, elimination of Staph. aureus, Strep. agalactiae, and Strep. uberis during the dry period was high; the elimination of M. bovis from infected udder quarters was lower, but probably spontaneous. Additionally, milk Hp concentration may be used as a marker for udder inflammation when combined with the bacteriological results at dry off and postpartum.

Pathogen Detection via Quantitative PCR in Milk of Healthy Cows Collected Using Different Sampling Protocols

“…The prevalence of milk samples with no pathogen DNA in STER (58.70%) and DHI (49.30%) resembled the findings of Narayana et al [ 21 ], who performed bacterial cultures on 46,900 quarter-level samples of Canadian Holsteins and reported 54.5% uninfected samples. Using qPCR for the identification of four pathogens, Timonen et al [ 25 ] observed that pathogen DNA was absent in 62.5% of quarter milk samples collected from 133 Holsteins. Moreover, the prevalence of pathogens observed in the present paper ( Table 4 ) agrees with the results of studies that investigated pathogen prevalence in clinically healthy cows [ 21 , 25 ] or in cows with detected or suspected mastitis [ 18 , 26 ].…”

“…Using qPCR for the identification of four pathogens, Timonen et al [ 25 ] observed that pathogen DNA was absent in 62.5% of quarter milk samples collected from 133 Holsteins. Moreover, the prevalence of pathogens observed in the present paper ( Table 4 ) agrees with the results of studies that investigated pathogen prevalence in clinically healthy cows [ 21 , 25 ] or in cows with detected or suspected mastitis [ 18 , 26 ].…”

Comparison of Defined Course Doses (DCDvet) for Blanket and Selective Antimicrobial Dry Cow Therapy on Conventional and Organic Farms

“…This study also demonstrated that cows receiving antimicrobial dry cow therapy (aDCT) had a significantly higher cure rate (86.6%) than cows that did not receive antimicrobial treatment (59.2%), confirming the importance of treating udder disease at this time [15]. Similarly, an Estonian study reported extremely high elimination rates of mastitis pathogens during the dry period when cows were treated with cloxacillin-containing dry cow intramammary injectors, namely 100% for Streptococcus uberis and 93.6% for Staphylococcus aureus [12]. While the antimicrobial treatment of infected cows is therefore essential, a number of countries have attempted to implement a more prudent use of antimicrobials in the dairy sector and some countries such as Finland, the Netherlands and Denmark have effectively banned the prophylactic use of antimicrobials at drying off for all cows (blanket dry cow therapy) if their infection status is not known [16,17,18].…”

“…Since the introduction of the five-point plan for mastitis prevention in 1966 [9], the use of antimicrobial dry cow therapy at drying off in all cows has been a routine herd health procedure worldwide. Indeed, treating cows with persistent high somatic cell counts (SCC) over an extended period with antimicrobials is often the best way to ensure bacterial cure [10,11,12,13,14]. Dairy cows are often already infected with mastitis pathogens at the time of drying off, as shown by, for example, Kiesner and colleagues in a German study where 38.4% of 250 cows from five different farms had intramammary infections (excluding minor pathogens) at this time [15].…”

Application of a dot blot hybridization assay for genotyping Streptococcus uberis from Brazilian dairy herds

“…The risk of IMI increases with teat end contamination, incomplete formation of the keratin plug in the teat, and immunosuppression before and after calving (Bradley and Green, 2004). As well, most new clinical and subclinical infections caused by S. uberis in early lactation originate in the dry period, when risk of infection is increased because of a decrease in immunological defenses and greater exposure to environmental microorganisms (Timonen et al, 2018).…”