Aarnink A.J.A.,Senior Researcher Livestock Environment |
Aarnink A.J.A.,Wageningen UR Livestock Research |
Landman W.J.M.,GD Animal Health Service Ltd. |
Landman W.J.M.,University Utrecht |
And 4 more authors.
Transactions of the ASABE | Year: 2011
Two studies were conducted to assess the efficiency of air scrubbers to reduce airborne microorganisms in the exhaust air from animal houses. First, in a field study, the effects of a bio-scrubber and an acid scrubber on total bacterial counts were assessed. Higher bacterial counts were found in the outlet air compared to the inlet air of a bio-scrubber (increase from 6.1 × 104 to 2.4 × 105 CFU m -3), while an acid scrubber with sulfuric acid reduced bacterial emissions from 2.7 × 105 to 8.4 × 104 CFU m -3. Second, in a laboratory study, the effects of three disinfectants, added to the circulating water of an experimental air scrubber, on reductions of bacteria and virus were tested and compared with the effect of using only water. The air to the scrubber was extracted from four isolators each harboring seven roosters. Enterococcus faecalis and Gumboro vaccine virus were aerosolized in the air of one of the isolators. Hydrogen peroxide (H 2O 2; 0.6%), peracetic acid (CH 3CO 3H; a solution of 0.13% acetic acid, 0.6% peroxide, and 0.13% peracetic acid), or ozone (O3; 0.015%) were used as disinfectants. Peracetic acid was the only disinfectant that reduced bacteria and virus concentrations to below the sampler detection limits. We conclude that an acid scrubber with sulfuric acid is very useful at reducing ammonia emissions to the atmosphere but cannot significantly prevent emissions of microorganisms. Peracetic acid has a high potential to reduce these emissions and could replace or supplement sulfuric acid in existing scrubbers during periods of high risk of disease outbreak. © 2011 American Society of Agricultural and Biological Engineers ISSN 2151-0032.
Brouwer H.,GD Animal Health Service Ltd. |
Bartels C.J.M.,GD Animal Health Service Ltd. |
Stegeman A.,University Utrecht |
van Schaik G.,GD Animal Health Service Ltd.
BMC Veterinary Research | Year: 2012
Background: More and more countries hold databases on cattle movements. The primary purpose of the registration of cattle movements is to provide data for quick tracing of contagious animals in case of disease outbreaks and food safety scares. Nevertheless, these data can also be used for analytical studies to get insight into the nature of the contact structure between and within cattle holding types. This paper focuses on the effect post-2001 FMD movement regulations have had on the number of cattle movements between different and within the same cattle holding types. Important characteristics and dynamics of cattle movement patterns of Dutch cattle holding types were identified using data on cattle movements after the 2001 FMD outbreak.Results: The results showed that in 2001, just after the FMD outbreak when strict movement restriction regulations were in force, a reduced number of cattle movements was seen compared to before the FMD outbreak. However, the number of cattle movements off-farm for live trade and the number of imported cattle increased in the period 2002-2004 to higher levels than expected, i.e. to levels almost as high as before the FMD outbreak, despite operative movement restriction regulations. As the number of cattle movements to and from traders strongly decreased just after the FMD outbreak in 2001, traders regained their central role again in the network in the years 2002-2004.Conclusions: Quantifying the Dutch cattle contact structure between and within holding types up to 3.5 years after the FMD outbreak gave evidence that the post-FMD movement restriction regulations were not able to reduce the number of cattle movements in the longer term. With that the risk of a large epidemic increased. Quantifying contact structures based on animal movement data between different and within the same cattle holding types is important for targeting disease control and for assessing compliance with legislation. © 2012 Brouwer et al.; licensee BioMed Central Ltd.
Jansen J.,Wageningen University |
van Schaik G.,GD Animal Health Service Ltd. |
Renes R.J.,Wageningen University |
Lam T.J.G.M.,GD Animal Health Service Ltd. |
Lam T.J.G.M.,Dutch Udder Health Center
Journal of Dairy Science | Year: 2010
Over the years, much effort has been put into implementing mastitis control programs in herds. To further improve utilization of such programs, there needs to be an understanding of the attitudes, knowledge, and behavior of farmers regarding udder health, and the way this can be influenced by mastitis control programs. This study aimed to explore the effect of a national mastitis control program on Dutch farmers' attitudes, knowledge, and behavior regarding mastitis. A total of 378 dairy farmers completed a survey on attitudes, knowledge, and behavior regarding mastitis before the start of a national mastitis control program in 2004, and 204 completed a similar survey in the final year of the program (2009). Although the average annual bulk milk somatic cell count (BMSCC) remained the same, the farmers' self-reported attitudes, knowledge, and behavior changed significantly. The problem level of BMSCC decreased from 285,000 cells/mL in 2004 to 271,000 cells/mL in 2009. More farmers perceived that they had sufficient knowledge about the prevention of mastitis (34% in 2004 vs. 53% in 2009) and they more often perceived that they knew the cause of a mastitis problem (25% in 2004 vs. 37% in 2009). The use of gloves for milking increased from 15 to 46%, the use of a standardized mastitis treatment protocol increased from 7 to 34%, and freestalls were cleaned more often (2.28 vs. 2.51 times/d) in 2009 compared with 2004. Most changes in attitudes, knowledge, and behavior did not differ between groups of dairy farmers whose herds had an initially low (≤162,000 cells/mL), medium (163,000 to 205,000 cells/mL), or high (>206,000 cells/mL) BMSCC. The high BMSCC group significantly decreased their annual BMSCC level by 15,000 cells/mL. Regression analysis showed that the decrease in BMSCC was associated with a change in farmers' perceptions (e.g., increased perceived knowledge about the effect of the milking machine on mastitis) and with a change in certain management practices (e.g., disinfecting all teats after milking). The results showed that a national mastitis control program affected the attitudes, knowledge, and behavior of farmers regarding mastitis and could contribute to udder health improvement in the long term. © 2010 American Dairy Science Association.
Backer J.A.,Central Veterinary Institute of Wageningen UR |
Brouwer H.,GD Animal Health Service Ltd. |
van Schaik G.,GD Animal Health Service Ltd. |
van Roermund H.J.W.,Central Veterinary Institute of Wageningen UR
Preventive Veterinary Medicine | Year: 2011
Early detection of the introduction of an infectious livestock disease is of great importance to limit the potential extent of an outbreak. Classical Swine Fever (CSF) often causes non-specific clinical signs, which can take considerable time to be detected. Currently, the disease can be detected by three main routes, that are all triggered by clinical signs. To improve the early detection of CSF an additional program, based on mortality data, aims to routinely perform PCR tests on ear notch samples from herds with a high(er) mortality. To assess the effectiveness of this new early detection system, we have developed a stochastic model that describes the virus transmission within a pig herd, the development of disease in infected animals and the different early detection programs. As virus transmission and mortality (by CSF and by other causes) are different for finishing pigs, piglets and sows, a distinction is made between these pig categories. The model is applied to an extensive database that contains all unique pig herds in The Netherlands, their herd sizes and their mortality reports over the CSF-free period 2001-2005. Results from the simulations suggest that the new early detection system is not effective in piglet sections, due to the high mortality from non-CSF causes, nor in sow sections, due to the low CSF-mortality. In finishing herds, the model predicts that the new early detection system can improve the detection time by two days, from 38 (27-53) days to 36 (24-51) days after virus introduction, when assuming a moderately virulent virus strain causing a 50% CSF mortality. For this result up to 5 ear notch samples per herd from 8 (0-13) finishing herds must be tested every workday. Detecting a source herd two days earlier could considerably reduce the number of initially infected herds. However, considering the variation in outcome and the uncertainty in some model assumptions, this two-day gain in detection time is too small to demonstrate a substantial effect of the new early detection system based on mortality data. But when the alertness of herd-owners and veterinarians diminishes during long CSF-free periods, the new early detection system might gain in effectiveness. © 2010 Elsevier B.V.