Manageable risk factors associated with bacterial and coliform counts in unpasteurized bulk milk in Flemish dairy herds

Abstract

Associations between herd management practices and both bacterial counts (BC) and coliform counts (CC) from 254 and 242 dairy herds in Flanders (Belgium), respectively, were studied. Data were analyzed using multivariable, multilevel linear regression analysis, allowing variance components analyses. Both BC and CC fluctuated throughout the year, although the milk quality parameters followed an opposite pattern. Bacterial count values decreased with each increase of the cleaning frequency of the cubicles (once per week, once per day, twice per day, or more than twice per day) between January and March. Herds with a conventional milking parlor had substantially lower BC than herds where the cows were milked using an automatic milking system. Lower BC were observed when the milking parlor was equipped with an automatic cluster removal system, when premilking teat disinfection was applied, when the dry cows were supplemented with a mix of minerals and vitamins, and when the teats were prepared either first wet and dried or via an automatic milking system. Milking cows with a high-pipeline milking parlor setup or with an automatic milking system was associated with substantially higher CC values. Herds where prepartum heifers were often treated with antimicrobials before calving had a lower CC than farms where heifers were either not or only rarely treated. Most variation in BC and CC resided at the herd level rather than at the observation level, indicating that management is important in the control of both BC and CC. Still, only a small proportion of the total variance was explained by factors capturing information related to the milking, herd health, and dry cow management, which suggests that the bacteriological milk quality and, in particular, CC is primarily driven by other factors than the ones included in this study.

Scientific Opinion on the public health risks related to the consumption of raw drinking milk

“…Nada et al (2012) observed that an improvement in the quality of raw milk from cows through implementation of GAP on farms with respect to a range of factors including feeding, animal health and welfare, sanitation, milking and maintenance of equipment and the cooling and storage and transport of raw milk. Piepers et al (2014) found management practices influence bacteria counts and coliform counts in raw milk but that information relating to milking, animal health and dry cow management suggest that there are other unidentified factors which may also be important in contamination of the milk. Jorritsma and Hofste (2011) found that less hygienic on-farm practices were risk factors for persistent presence of salmonella antibodies in bulk tank milk in the Netherlands.…”

“…Dirty teats and udders are possible sources of bacteria and poor udder preparation prior to milking can increase the numbers of bacteria in the milk. Pre-milking teat disinfection has been associated with a reduction in the total aerobic count and coliform count (Galton et al, 1986;Pankey, 1989;Piepers et al, 2014) and total bacteria and anaerobic spore counts (Rasmussen et al, 1991). Schreiner and Ruegg (2003) reported that dirty cows were 1.5 times more likely to be infected with a major mastitis pathogen than clean cows.…”

“…The authors concluded that implementing and maintaining a few simple hygienic practices in terms of barn cleaning and milking procedures (forestripping, pre-dipping and post-dipping) can significantly improve the microbiological quality of cow's milk under intensive farming conditions in northern Italy where animals are kept in the barn all year. Piepers et al (2014) examined risk factors associated with bacterial and coliform counts in raw bulk milk in Flemish dairy herds. A decrease in bacterial counts was related to a number of factors including increased frequency of cubicle cleaning, use of an automatic cluster removal system in the milking parlour and when pre-milking teat disinfection was used.…”

Modelling relationships between raw milk quality parameters and climatic conditions - the case study of a 3-years survey in Serbia

“…Although milk is sterile in the mammary gland, different bacteria might contaminate raw milk as a result of direct contact with soil, air, workers hands, faeces, grass and excretion from the udder of an infected animal (Lejeune & Rajala-Schultz, 2009), but also with contaminated surfaces during storage and transport of raw milk (Millogo, Sjaunja, Ouedraogo, & Agenas, 2010) and occasionally by milking of mastitic cows (Hayes et al, 2001;Pantoja, Reinemann, & Ruegg, 2009). Microbiological quality of raw milk is assessed by total plate count (TPC) and somatic cell count (SCC), and these parameters are used for the comparison and estimation of milk quality (Piepers, Zrimsek, Passchyn, & De Vliegher, 2014;Smigic et al, 2012). SCC is an important measure of milk quality, reflecting the health status of the mammary gland, the increased risk of non-physiological changes to milk composition and reduced milk yield (More, Clegg, Lynch, & O'Grady, 2013).…”

The Size of the Farm and Its Influence at Cleanliness of the Cows and Milk Hygiene

“…Every increase in the number of somatic cells in milk above 100,000 / ml is connected with a decrease in milk production, and it has an impact on the quality of milk products (Katic, 2007). High bacterial levels in milk, whether originating from the cow or the environment, substantially affect the quality, safety, and consumer acceptance of milk and dairy-derived products (Piepers et al, 2014). The aim of this paper is to examine whether there is an influence of the size of farms (number of cows) on the subjective cow cleanliness and hygienic quality of milk.…”