New low-stress PECVD poly-SiGe layers for MEMS

Thick poly-SiGe layers, deposited by plasma-enhanced chemical vapor deposition (PECVD), are very promising structural layers for use in microaccelerometers, microgyroscopes or for thin-film encapsulation, especially for applications where the thermal budget is limited. In this work it is shown for the first time that these layers are an attractive alternative to low-pressure CVD (LPCVD) poly-Si or poly-SiGe because of their high growth rate (100-200 nm/min) and low deposition temperature (520/spl deg/C-590/spl deg/C). The combination of both of these features is impossible to achieve with either LPCVD SiGe (2-30 nm/min growth rate) or LPCVD poly-Si (annealing temperature higher than 900/spl deg/C to achieve structural layer having low tensile stress). Additional advantages are that no nucleation layer is needed (deposition directly on SiO/sub 2/ is possible) and that the as-deposited layers are polycrystalline. No stress or dopant activation anneal of the structural layer is needed since in situ phosphorus doping gives an as-deposited tensile stress down to 20 MPa, and a resistivity of 10 m/spl Omega/-cm to 30 m/spl Omega/-cm. With in situ boron doping, resistivities down to 0.6 m/spl Omega/-cm are possible. The use of these films as an encapsulation layer above an accelerometer is shown

Klebsiella pneumoniae can be highly prevalent in the environment of cows without causing mastitis

Introduction: Bulk milk coli count is one of the parameters of Flemish milk quality control. In surveillance of the coli count subclinical Klebsiella mastitis turns out to be an emerging problem in well-managed Flemish dairy herds. This is in contrast with various outbreak reports with high production losses or lethal outcome in other countries. Bedding materials and faeces are frequently pinpointed as potential sources of mastitic Klebsiella. This study was designed to further elucidate Klebsiella pneumoniae transfer to quarter milk with a molecular typing technique of high discriminating power. Materials and Methods: A longitudinal study was carried out in 6 Flemish dairy herds from May 2008 until May 2009. In each herd 10 cows were randomly selected (4 cows of first, 3 cows of second and 3 cows of third or higher parity). All cows were housed in free-stalls with sawdust bedded cubicles. Each month, coliforms were isolated from sawdust stock, sawdust bedding, faeces, and quarter milk. Isolates which tested positive for Klebsiella pneumonia by PCR were further typed to strain level by Pulsed Field Gel Electrophoresis (PFGE). Band patterns were clustered with the BioNumerics version 5.10 software (Applied Maths, Sint-Martens-Latem, Belgium). Results: Of 73 sawdust stock and 73 sawdust bedding samples 6 and 20 contained K. pneumoniae, respectively. In faeces 121 of 566 samples contained K. pneumoniae while in the 2796 quarter milk samples only two turned out to be positive. In total 108 different K. pneumoniae strains were typed. The six isolates from sawdust stock belonged to six different strains. In sawdust bedding 18 different strains were detected (1 to 5 per herd) and in faeces 92 different strains were observed (1 to 27 per herd). The two isolates from milk were from the same herd (not from the same cow or quarter) but differed in PFGE pattern. However, the same PFGE type of one of these isolates was also present in one sawdust bedding sample of that herd. No similarity was found between strains of sawdust stock and strains of other sources. Discussion: Monthly sampling, bacterial isolation and typing of K. pneumoniae strains with a highly discriminating genotypic method as PFGE on cow and environmental level in 60 cows of 6 well managed dairy farms could not reveal a strong transfer pattern of K. pneumoniae towards udder quarters. The low incidence of K. pneumoniae intramammary infection in an environment where K. pneumoniae is highly prevalent, suggests that infection with K. pneumoniae can be facilitated by failure of cow defence mechanisms rather than by K. pneumoniae pathogenicity factors

Does cleanliness, body condition or gait score effect on udder health? An observational study

Although the cleanliness of beef cattle is assessed for food hygiene reasons in slaughtering houses, cleanliness scoring in dairy cattle is less common. However, unhygienic environmental conditions could result in environmental evoked disease (such as foot and udder disorders) and reduced animal welfare. Therefore, the cleanliness of dairy cattle could also be implemented as a parameter for several health issues (e.g. mastitis, gait, welfare). To investigate to which extend the cleanliness, body condition and gait of dairy cattle influences the udder health, the following experiment is conducted. Ten randomly selected dairy cows are monitored during one year on six Flemish dairy herds. Monthly, the cleanliness, body condition and gait score of these cows will be determined by two independent trained persons. In contrast with traditional cleanliness scoring systems scoring the whole animal, this scoring system will focus on five specific udder related parts of the cow. Cleanliness was scored on a scale of 0 (no dirt) to 2 (dirty on 100% of the area). A 3 point method was used to score the gait of the cows and the body condition scores. In addition, udder quarter milk samples are collected monthly for somatic cell count. This observational study will end in April 2009 and results will be presented during the congress. This study is part of a larger project which aims to clarify the complex relationships between different factors explaining the mastitis status of cows and quarters and their evolution over time

If ten points are no longer sufficient: an observational study on factors related to udder health and milk quality in Flanders, Belgium

In Flanders, a shift of the distribution of mastitis pathogens towards coagulase-negative staphylococci (CNS) and coliforms has been observed and this may be the cause of the recent problems of increasing bulk milk somatic cell counts and/or decreasing milk quality. Ten randomly selected cows are monitored during one year on 6 Flemish dairy herds. For comparison, three farms with and three without specific coliform problems are included in the study. Milk samples are cultured for presence of mastitis bacteria and somatic cell counts are measured. Monthly climate variations (temperature, humidity, gas concentrations, dust) are investigated with innovative techniques. At the cow level, zootechnical information is complemented with recording of cleanliness, body condition, gait and milking characteristics, and at the quarter level teat conformation, teat apex condition and teat cleanliness are observed with recently developed digital image-analysis technology. These monthly observations will contribute to the clarification of the complex relationships between different factors explaining the mastitis status of cows and quarters and its evolution over time

OUTLINE OF AN OBSERVATIONAL STUDY ON UDDER HEALTH AND MILK QUALITY IN FLANDERS, BELGIUM

In Flanders, a shift of the distribution of mastitis pathogens towards coagulase-negative staphylococci (CNS) and coliforms in dairy cattle has been observed in recent years. This may partially explain the recent problems of increasing bulk milk somatic cell counts, decreasing milk quality or both. To clarify the complex relationships between different factors explaining the mastitis status of cows and quarters and their evolutions in time, the following protocol and research tools were developed and optimized. Ten randomly selected dairy cows of six Flemish dairy herds (n=60) are monitored during one year. For comparison, three farms with and three without former specific coliform problems are included in the study. On this farms udder health is observed and potential environmental or animal related risk factors are monthly assessed at three different levels (farm, cow and quarter). Teat swabs, quarter milk samples and barn samples (air, floor, bedding materials, feces) are cultured for presence of mastitis bacteria. Molecular identification and typing techniques are used to detect CNS strains and to identify the main sources of CNS infections. At farm level the milking process is monitored by on the one hand, a monthly technical review of the milking machine and on the other hand, by a video controlled milking routine registration. Information on additional management factors is registered using a questionnaire. Additionally climatic variations (temperature, humidity, gas concentrations, dust) in the barn are investigated with innovative instruments. At cow level, zootechnical information (age, parity, oestrus, pregnancy, production) is complemented with records of cleanliness, body condition, gait and milking characteristics. At the quarter level, the conformation, teat apex condition and cleanliness of the teats are observed with an image processing program developed in Halcon (Halcon 8.0, MVTec Software GmbH, München, Germany). All of the presented measurement methods have been developed and optimised for routine detection and have been proven to be robust enough for monthly monitoring

Short communication: Subtyping of Staphylococcus haemolyticus isolates from milk and corresponding teat apices to verify the potential teat-skin origin of intramammary infections in dairy cows

Coagulase-negative staphylococci (CNS) are a major cause of intramammary infections (IMI) in dairy cows and they colonize the teat skin. Staphylococcus haemolyticus, one of the more common CNS, has been identified as a highly versatile opportunistic species. The aim of the present study was to gain better insight into the adaptation of S. haemolyticus subtypes to the udder ecosystem with respect to IMI development. During a longitudinal observational study conducted over 13 mo on 6 Flemish dairy herds, S. haemolyticus isolates were recovered from milk and teat apices. A total of 44 S. haemolyticus isolates originating from milk (24 isolates) and teat apices (20 isolates) of 6 selected udder quarters were singled out and analyzed using a combined methodology of (GTG)(5)-PCR and amplified fragment length polymorphism (AFLP) fingerprinting to determine intraspecies differences. Combining both fingerprinting methods, 4 S. haemolyticus subtypes were obtained (I to IV). Subtypes I, II, and IV were recovered from both milk and teat apex samples and were found to be associated with persisting IMI. Subtype III, not apparently related to IMI, was isolated solely from teat apices and not from milk. In general, S. haemolyticus subtypes found in milk from infected quarters could be recovered from the corresponding teat apices, although the latter could be colonized with up to 3 different subtypes. Comparing subtypes from milk and teat apices indicates that the IMI-causing agent likely originates from the teat skin

Sources other than unused sawdust can introduce Klebsiella pneumoniae into dairy herds

A longitudinal study was carried out to detect intramammary infections caused by Klebsiella pneumoniae and to identify potential sources of this bacterial species in the environment of the cows. The study was performed in 6 well-managed Belgian dairy herds from May 2008 to May 2009. Monthly (n = 13), unused and used sawdust bedding samples as well as individual quarter milk and feces samples were collected from 10 randomly selected cohort cows in each herd. Cases of clinical mastitis of all lactating cows in the 6 herds were also sampled (n = 64). From the 3,518 collected samples, 153 K. pneumoniae isolates were obtained, of which 2 originated from milk (clinical mastitis cases). In feces (n = 728), used bedding (n = 73), and unused bedding (n = 73), respectively, 125 (17.2%), 20 (27.4%), and 6 (8.2%) isolates were found. The isolates were fingerprinted by means of pulsed field gel electrophoresis. In total, 109 different pulsotypes were differentiated, indicating a high degree of genetic diversity within the isolates. All isolates from unused bedding belonged to pulsotypes other than those from the other sources, suggesting that sources other than unused sawdust may introduce K. pneumoniae into the herd. Only 2 pulsotypes contained isolates originating from different sources. Pulsotype 10 was found in milk and used bedding and pulsotype 21 was found in feces and used bedding. The 2 milk isolates originated from 2 cows in the same herd but they belonged to a different pulsotype. The results indicate that K. pneumoniae can be prevalent in the environment without causing significant mastitis problems. Most cows were shedding K. pneumoniae in feces, substantiating findings under very different conditions (i.e., American dairy herds). Contamination of used bedding in the cubicles with K. pneumoniae from feces was confirmed, whereas unused bedding was not an important source of K. pneumoniae for the environment of the cows