Study of clinical mastitis in British dairy herds with bulk milk somatic cell counts less than 150,000 cells/ml

Abstract

A 12-month prospective study of clinical mastitis was conducted in 482 British dairy herds with a bulk milk somatic cell count (BMSCC) of less than 150,000 cells/ml. The mean proportion of cows in the herd with clinical mastitis was 23.1 per cent (range 0 to 80), with a mean of 1.50 quarter cases per cow. The mean incidence rate of clinical mastitis was 36.7 quarter cases per 100 cow years (range 0 to 208.2). Twelve per cent of the quarter cases showed systemic signs, including inappetence and severe lethargy. Over 22 per cent of quarter cases occurred in the first seven days of lactation and over 50 per cent occurred in the first 90 days of lactation. Cluster analysis indicated that the main difference between herds with a low and average incidence of mastitis was the proportion of clinical cases occurring in the first seven days of lactation, 14 per cent compared with 44 per cent, respectively. The risk of severe clinical mastitis compared with mild clinical mastitis decreased significantly as the individual cow somatic cell count (SCC) in the month before clinical mastitis was diagnosed increased.

Relationship between the probability of veterinary-diagnosed bovine mastitis occurring and farm management risk factors on small dairy farms in Austria

“…In the GLMM used here, we found that the risk of mastitis increased in association with lactation number (i.e., age), which is to be expected and has been reported by several authors (Busato et al, 2000;Peeler et al, 2002;Taponen et al, 2017). Similarly, another common finding, which was confirmed by our statistical analysis, was that farms on which herd veterinarians assessed the cows' udders as being generally moderately to severely soiled had a tendency for a higher risk of mastitis occurring during the LP (OR = 1.47, P = 0.062) compared with farms on which udders were assessed as clean.…”

Influence of Dry Period Bacterial Intramammary Infection on Clinical Mastitis in Dairy Cows

“…An alternative explanation is that the previous bacterial infection increases the risk of subsequent infection. Quarter susceptibility may occur because of anatomical features such as short wide teat canals (Grega and Szarek, 1985;Grindal et al, 1991) or immunological characteristics, such as poor white cell function (Hill, 1981) or low white cell number (Peeler, 2001). Alternatively, previous infection may cause damage or alteration to the mammary environment in some way and reduce innate defense mechanisms.…”

Energy imbalance related predisposition to mastitis in group-fed high-producing postpartum dairy cows

“…However, in the early weeks of lactation GN bacteria may be the predominant mastitis pathogens in herds producing milk of low (< 150,000-250,000/ml) SCC (Hogan et al, 1989;Schukken et al, 1989;Green et al, 1996;Miltenburg et al, 1996;Beaudeau et al, 2002;Peeler et al, 2002), as well as their prevalence is known to increase also in the spring and summer months (Sandholm and Pyörälä, 1995;Zerocelli and Piccinini, 2002), mainly in cows heavily and persistently contaminated with faeces (Ward et al, 2002). So this trial was carried out in large-scale dairy herds producing low SCC milk for many years, individuals with healthy udder were involved, and most of the sampling series were conducted in seasons supposed to provide the most suitable environmental conditions for GN pathogens.…”