Relationship between dairy cows' hind leg activity and vacuum records during milking.

In a number of dairy farms, a restlessness of hind legs of cows during milking can be observed for no apparent reason. Previous studies have associated the hind leg activity of cows with mental or physical discomfort. Aim of this study was to investigate whether the observed hind leg activity was influenced by the milking process. The analysis was performed for total milking period and also separately for the following milking periods: let-down, main milk flow and over-milking. The following variables were analyzed for their influence on dairy cows' hind leg activity: the vacuum level in the MPC and SMT, the length of the milking periods, the vacuum curve type, bimodal curves and the presence of teat-end hyperkeratosis. In turn, it was also investigated whether the cows' hyperkeratosis is influenced by milking duration, length of milking periods or by the vacuum level in the SMT. Measurements and observations were done in ten milking parlors, each visited twice. Four milking units per parlor were equipped with vacuum loggers (VaDia 2.0, BioControl AS, Norway). One observer recorded hind leg activity per up to four cows, using the following categories: (1) stepping (claw raised < 15 cm) and (2) kicking (claw raised > 15 cm). A powerful, purposive kick to milking unit/milker was classified as p-kick (3) initially. Due to a small number of p-kicks, they were added to the number of kickings for further analysis. The analyses showed that none of the milking process-related variables had a significant influence on the dairy cows' prevalence to show hind leg activity. Although the prevalence was not influenced, the type of hind leg activity was. The hind leg activity kicking was observed at significantly higher average mouthpiece chamber vacuum levels than steppings. Cows showing kickings had a higher degree of teat-end hyperkeratosis than those showing steppings. The degree of teat-end hyperkeratosis was related to the milking duration.

Evaluation of three methods to assess the degree of milk-out in dairy cows.

The assessment of the completeness of milk-out in dairy cows is one of the indicators used to evaluate and optimise the milking process. A number of different methods and thresholds are available for this purpose, but procedures and validation of the methods are not always described in detail, and may vary between studies. The objective of this study was to introduce and evaluate a new, precisely defined hand-milking method (DEFINED) and to compare its outcome with two commonly applied methods to assess the completeness of milking: visual scoring of the degree of quarter filling (VISUAL) and quantitative assessment of the number of easy strips (EASYSTRIPS). Each of the three methods was applied in 131 Holstein cows of six dairy herds in northern Germany. The assessment of milk-out was carried out by three experienced but non-regular milkers (evaluators). Each evaluator visited the six herds once during afternoon milking. To avoid any transitions, the interval between visits of two evaluators was at least 2 days. Maximum hand-milking time per cow was set to 60 s. The total strip yield collected in 60 s (SY60) by the application of a strip frequency of 1 Hz was used as a reference for the amount of milk left in the investigated quarter after machine-milking. The three methods were evaluated by analysing their statistical relationship with SY60, and by ranking their suitability for quantitative or qualitative assessment of milk-out. VISUAL and SY60 were not related, indicating that VISUAL was unsuitable for estimating the amount of milk left actually in the udder quarters. The strip yield in 15 s (DEFINED) and SY60 was significantly related, but results varied among evaluators. With regard to EASYSTRIPS, a significant relationship with SY60 was found, but the results were influenced by evaluator and herd. The findings of this study imply that DEFINED allows a rapid and farm-independent quantitative estimate of the post-milking strip yield. Likewise, EASYSTRIPS was meaningful in assessing milk-out of quarters in a given herd, whereas VISUAL allowed neither a quantitative nor a qualitative assessment of post-milking strip yield or milk-out. Thresholds for complete or incomplete milk-out by DEFINED must be lower than those commonly applied in 15 s of post-milking.

Suitability of feeding and chewing time for estimation of feed intake in dairy cows.

Monitoring of feeding and rumination behaviour can provide useful information for dairy herd management. The feeding behaviour of dairy cows can be recorded by different techniques, such as video cameras, weighing troughs or chewing sensors. Among feeding characteristics, individual feed intake of cows is of utmost interest, but as weighing troughs have high space and cost requirements they are used primarily in research studies. The objective of the present study was to evaluate whether records on feeding time or chewing activity or a combination of both contain enough information to estimate feed intake with sufficient accuracy. Feed intake and feeding time per cow were recorded by means of weighing troughs. Concurrently, chewing activity of seven cows was recorded by MSR-ART pressure sensors during five to eight measuring days per cow. Feeding and chewing behaviour were evaluated in time slots (1 min) and additionally assigned to feeding bouts for further analysis. The 1 min time slots were classified into feeding/no feeding or chewing/no chewing by the two systems, and agreement was found in 92.2% of the records. On average, cows spent 270±39 min/day at the feeding troughs and chewed 262±48 min/day. The average fresh matter intake (FMI) was 49.6±5.1 kg/day. Feed intake was divided into 9.7 bouts/day during which cows fed in average 27.8±21.7 min/bout and chewed 27.0±23.1 min/bout. The correlation between FMI and feeding time was r=0.891 and between FMI and chewing time r=0.780 overall cows. Hence, both systems delivered suitable information for estimating feed intake.

Feeding characteristics and rumination time of dairy cows around estrus.

Against the background of decreasing reproduction efficiency, estrus detection is gaining increased importance. The objective of this study was to evaluate changes of feeding characteristics and rumination time in dairy cows in the days around estrus. Feeding characteristics were recorded by weighing troughs, and rumination time by acoustic sensors. Analysis included data from 25 primiparous and 37 multiparous cows, which were successfully inseminated (day of insemination=d 0). Feeding time and rumination time were decreased on d -1 and 0, feed intake, and feeding rate on d 0. Primiparous and multiparous cows differed in their reference values, but their feeding and rumination times on the day of insemination were reduced to similar extents. Rumination time was reduced in a time frame of 30 h around estrus whereby the main drop was found during the time period between 0600 h on d -1 and 1200 h on d 0. The change of almost all evaluated feeding characteristics and rumination time around estrus indicated their potential for useful addition in early detection of estrus.

Pressure load on specific body areas of gestating sows lying on rubber mats with different softness.

Rubber mats offer a possibility to increase lying comfort for sows with positive effects on sow lying behavior and health. However, until now, no information has been reported about the relationship between the softness of rubber mats and the pressure load on certain body areas of sows. We used a total of 68 (40 multiparous, 28 primiparous) German Landrace × German Landrace sows with a BW within the range of 90 to 330 kg (divided in 3 weight classes) to measure peak force and distribution of pressure during lying in the sternal and half recumbent position. Measures were done in an experimental pen that was equipped with a pressure sensor map system (5400 NTL; Tekscan Inc., Boston, MA). Three rubber mats differing in softness (penetration depth: hard mat, 4.0 mm [HM]; soft mat, 14.6 mm [SM]; very soft mat, 43.0 mm [VSM]) were tested and compared to concrete floor (CF) as a reference. Pressure load was analyzed in the sternal position for the sternum, belly, and ham body regions and also in the half recumbent position for the shoulder. For each lying position we determined the body region with the highest pressure load and analyzed the peak force (PF) and the contact area (CA) using a mixed model ANOVA (MIXED procedure of SAS Enterprise, version 4.3., SAS Inst. Inc., Cary, NC) with floor type, weight class of sows, and their interaction as fixed factors. Overall, the highest values for PF in the sternal position were found on the sternum (median: 1.62 N/cm(2)) and in the half recumbent position on the shoulder (median: 2.72 N/cm(2)). In the sternal position PF on the sternum was lower on VSM compared to CF (P = 0.001). In the half-recumbent position PF on the shoulder was lower on VSM compared to CF (P = 0.013) and compared to HM (P = 0.011). The weight of the sows affected PF on the sternum in the sternal position, with lower values in weight class 1 compared to weight class 2 (P = 0.001) and weight class 3 (P = 0.002). Contact area under the sternum was larger on SM (P = 0.016) and VSM (P = 0.008) compared to CF in the sternal position, and this was affected by weight class (P = 0.0002). In the half-recumbent position floor type did not affect CA under the shoulder, but CA was larger in weight classes 2 and 3 compared to weight class 1 (all P < 0.05). Assuming that a reduced PF in combination with pressure distributed over a larger area will increase lying comfort, hard rubber mats do not seem to offer a high lying comfort with regard to pressure load on debited body regions such as the sternum or shoulder.

Accuracy of in-line milk composition analysis with diffuse reflectance near-infrared spectroscopy.

Knowledge of daily milk composition changes can assist in monitoring dairy cow health and can help to detect nutritional imbalances. An analytical tool offering the possibility of analyzing milk during the daily milking routine would provide such information. Near-infrared (NIR) spectroscopy can analyze multiple constituents in a given substrate at the same time. In this study, a special NIR in-line milk-analyzing device was designed, and its ability to predict the contents of fat, protein, lactose, and urea and the somatic cell count in milk during the milking process was evaluated. The NIR spectra were acquired with a diode array spectrometer in diffuse reflection in the wavelength range 851 to 1649 nm. The spectra originated from a total of 785 partial milkings out of 84 composite milkings. Corresponding subsamples of the composite milkings were used for reference analysis (n=785). Excellent validation results were obtained with regard to the coefficients of determination (R(2)=0.99, 0.98, and 0.92), and standard errors of prediction (0.09, 0.05, and 0.06) for fat (%), protein (%), and lactose (%), respectively. Satisfying results were achieved for urea content (mg/L) and logarithmically transformed SCC in milk, with R(2) of 0.82 and 0.85 and standard errors of prediction of 19.3 and 0.18, respectively. The accuracy of predicting protein, lactose, and urea contents was in accordance with international recommendations for reproducibility specified for in-line analytical devices.

Sevoflurane as a potential replacement for halothane in diagnostic testing for malignant hyperthermia susceptibility: results of a preliminary study.

BACKGROUND: To diagnose malignant hyperthermia (MH) susceptibility, muscle bundles are exposed to halothane and caffeine. We investigated whether sevoflurane, which is more clinically relevant but less potent of an anesthetic, could replace halothane in diagnostic MH testing. METHODS: With prior written consent, muscle bundles from 6 malignant hyperthermia susceptible (MHS) and 5 non-susceptible (MHN) individuals were exposed to increasing concentrations of sevoflurane (1.3; 2.6; 5.2 vol%). In addition, muscles from 9 MHS and 8 MHN were tested with a rapid exposure to 8 vol% of sevoflurane. Maximal contractures were measured and statistically analyzed (Mann-Whitney-U-test; P<0.05). RESULTS: There were no differences in weight, length or pre-drug tension of the muscle bundles. Incremental sevoflurane concentrations induced no differences in contracture between susceptible and non-susceptible muscles. The rapid application of sevoflurane induced significant contractures in all malignant hyperthermia susceptible compared with non-susceptible individuals. CONCLUSION: The rapid application of a high sevoflurane concentration but not an increasing stepwise application allowed for the diagnostic discrimination of susceptible individuals.

Invited review: technical solutions for analysis of milk constituents and abnormal milk.

Information about constituents of milk and visual alterations can be used for management support in improving mastitis detection, monitoring fertility and reproduction, and adapting individual diets. Numerous sensors that gather this information are either currently available or in development. Nevertheless, there is still a need to adapt these sensors to special requirements of on-farm utilization such as robustness, calibration and maintenance, costs, operating cycle duration, and high sensitivity and specificity. This paper provides an overview of available sensors, ongoing research, and areas of application for analysis of milk constituents. Currently, the recognition of abnormal milk and the control of udder health is achieved mainly by recording electrical conductivity and changes in milk color. Further indicators of inflammation were recently investigated either to satisfy the high specificity necessary for automatic separation of milk or to create reliable alarm lists. Likewise, milk composition, especially fat:protein ratio, milk urea nitrogen content, and concentration of ketone bodies, provides suitable information about energy and protein supply, roughage fraction in the diet, and metabolic imbalances in dairy cows. In this regard, future prospects are to use frequent on-farm measurements of milk constituents for short-term automatic nutritional management. Finally, measuring progesterone concentration in milk helps farmers detect ovulation, pregnancy, and infertility. Monitoring systems for on-farm or on-line analysis of milk composition are mostly based on infrared spectroscopy, optical methods, biosensors, or sensor arrays. Their calibration and maintenance requirements have to be checked thoroughly before they can be regularly implemented on dairy farms.

Airborne biological hazards in different pig fattening systems.

In this research project two organic and two conventional housing systems for fattening pigs are assessed in regard to the emission of microorganisms, endotoxins and dust. The concentrations of microorganisms and endotoxins varied between the different housing systems while no distinct differences for the dust concentrations were observed. Endotoxins concentrations reached up to 14 495 EU/cubic meter median) in deep litter stable, indicating the high exposure with biological agents during farm work. The differences between the stables could not be assigned to the organic or conventional kind of husbandry but to the management of the systems.

[No potentiation of fentanyl by use of transdermal buprenorphine in patients undergoing fast-track anesthesia for open-heart surgery]. / Kein Opioidüberhang bei Patienten mit transdermalem Buprenorphin und Fast-Track-Anästhesie nach Eingriffen am offenen Herzen.

OBJECTIVE: Simultaneous use of opioids with a different pharmacological profile may lead to unexpected prolongation of effects. In an open label study possible overhang in post-operative respiratory effects and vigilance was determined in a group of patients (n = 22) carrying a transdermal buprenorphine patch for at least 2 months for treatment of chronic pain, undergoing a fentanyl-based fast-track enflurane anesthetic technique for open-heart operation. Data was compared with another randomised group (n = 21) undergoing similar open-heart procedures with no other opioid than fentanyl on board. METHODS AND RESULTS: Following induction with fentanyl and a barbiturate, depth of anesthesia with enflurane (Fi 0.5) was guided using the bispectral index (BIS). Additional doses of fentanyl were given when blood pressure and/or heart-rate increased 20% above pre-induction levels. Early postoperative extubation was initiated once the cardiovascular system was stable and there were no signs of respiratory impairment. Following a similar time of operation and anesthesia and a similar total dose of fentanyl (0.69 mg +/- 0.23 SD versus 0.67 mg +/- 0.16 SD), postoperatively, there were no significant differences between the buprenorphine- and the control group regarding the time till extubation (25.2 min +/- 6.1 versus 33.3 min +/- 5.0) and the arterial blood gases under oxygen inhalation (paO2 136 torr +/- 48 SD versus 128 torr +/- 35 SD; paCO2 43.3 torr +/- 3.3 SD versus 41.9 torr +/- 1.2 SD and the post-anesthetic vigilance and recovery score (6.8 +/- 1.0 versus 7.5 +/- 0.8) 60 minutes after end of anesthesia. Contrary to the control group, there was a lower and significant (p < 0.01) incidence of PONV in patients with transdermal buprenorphine. CONCLUSION: Patients using a buprenorphine patch for the relief of chronic pain cannot be regarded as opioid naïve. Due to adaptive mechanisms and the development of tolerance, there is no prolongation of the respiratory depression induced by intraoperative fentanyl. Long-term use of transdermal buprenorphine does not lead to potentiation or prolongation of opioid effects in cardiac surgery patients.

Determination of the dynamics of the odour release from a pig house, using an electronic odour sensor.

The widely fluctuating operating conditions in pig husbandry, due to climatic and biological changes (changes in temperature and air flowrate between day and night, as well as between summer and winter, increasing animal mass during the fattening process, etc.) exert a significant influence on the amount of actual odour emission. The project presented here comprised the measurement of seasonal (fattening course), daytime-related, and short-term (feeding) dynamic effects of odour release, as well as the identification of potential factors which influence the amount of odour emitted. In parallel with "classic" olfactometry, an electronic odour sensor with a chemosensor array of ten metal oxide sensors was employed. The highest odour emissions are measured on hot summer days, while the lowest emissions were determined on cold winter days. On the one hand, the sensor signals of the electronic odour sensor exhibited considerable differences on days with large volume flow alterations. On the other hand, continuous measurement with the electronic odour sensor allowed changes in the gas- and odorant composition of the exhaust air during feeding times to be shown. From the measurement results, recommendations for odour sampling, the consideration of seasonal odour emission fluctuations, and the use of electronic odour sensors for the evaluation of odour emissions have been derived.

Placebo-controlled comparison of effervescent acetylsalicylic acid, sumatriptan and ibuprofen in the treatment of migraine attacks.

Acetylsalicylic acid (ASA) in combination with metoclopramide has been frequently used in clinical trials in the acute treatment of migraine attacks. Recently the efficacy of a new high buffered formulation of 1000 mg effervescent ASA without metoclopramide compared to placebo has been shown. To further confirm the efficacy of this new formulation in comparison with a triptan and a nonsteroidal anti-inflammatory drug (ibuprofen) a three-fold crossover, double-blind, randomized trial with 312 patients was conducted in Germany, Italy and Spain. Effervescent ASA (1000 mg) was compared to encapsulated sumatriptan (50 mg), ibuprofen (400 mg) and placebo. The percentage of patients with reduction in headache severity from moderate or severe to mild or no pain (primary endpoint) was 52.5% for ASA, 60.2% for ibuprofen, 55.8% for sumatriptan and 30.6% for placebo. All active treatments were superior to placebo (P < 0.0001), whereas active treatments were not statistically different. The number of patients who were pain-free at 2 h was 27.1%, 33.2%, 37.1% and 12.6% for those treated with ASA, ibuprofen, sumatriptan or placebo, respectively. The difference between ASA and sumatriptan was statistically significant (P = 0.025). With respect to other secondary efficacy criteria and accompanying symptoms no statistically significant differences between ASA and ibuprofen or sumatriptan were found. Drug-related adverse events were reported in 4.1%, 5.7%, 6.6% and 4.5% of patients treated with ASA, ibuprofen sumatriptan or placebo. This study showed that 1000 mg effervescent ASA is as effective as 50 mg sumatriptan and 400 mg ibuprofen in the treatment of migraine attacks regarding headache relief from moderate/severe to mild/no pain at 2 h. Regarding pain-free at 2 h sumatriptan was most effective.

Multicentre evaluation of in vitro contracture testing with bolus administration of 4-chloro-m-cresol for diagnosis of malignant hyperthermia susceptibility.

BACKGROUND AND OBJECTIVE: The in vitro contracture test with halothane and caffeine is the gold standard for the diagnosis of susceptibility to malignant hyperthermia (MH). However, the sensitivity of the in vitro contracture test is between 97 and 99% and its specificity is 78-94% with the consequence that false-negative as well as false-positive test results are possible. 4-Chloro-m-cresol is potentially a more specific test drug for the in vitro contracture test than halothane or caffeine. This multicentre study was designed to investigate whether an in vitro contracture test with bolus administration of 4-chloro-m-cresol can improve the accuracy of the diagnosis of susceptibility to MH. METHODS: Three hundred and fifty-two patients from 11 European MH laboratories participated in the study. The patients were first classified as MH susceptible, MH normal or MH equivocal by the in vitro contracture test according to the European MH protocol. Muscle specimens surplus to diagnostic requirements were used in this study (MH susceptible = 103 viable samples; MH equivocal = 51; MH normal = 204). 4-Chloro-m-cresol was added to achieve a concentration of 75 micromol L(-1) in the tissue bath. The in vitro effects on contracture development and muscle twitch were observed for 60 min. RESULTS: After bolus administration of 4-chloro-m-cresol, 75 micromol L(-1), 99 of 103 MH-susceptible specimens developed marked muscle contractures. In contrast, only two of 204 MH-normal specimens showed an insignificant contracture development following 4-chloro-m-cresol. From these results, a sensitivity rate of 96.1% and a specificity rate of 99.0% can be calculated for the in vitro contracture test with bolus administration of 4-chloro-m-cresol 75 micromol L(-1). Forty-three patients were diagnosed as MH equivocal, but only specimens from 16 patients developed contractures in response to 4-chloro-m-cresol, indicating susceptibility to MH. CONCLUSIONS: The in vitro contracture test with halothane and caffeine is well standardized in the European and North American test protocols. However, this conventional test method is associated with the risk of false test results. Therefore, an improvement in the diagnosis of MH is needed. Regarding the results from this multicentre study, the use of 4-chloro-m-cresol could increase the reliability of in vitro contracture testing.

Efficacy and tolerability in migraine prophylaxis of flunarizine in reduced doses: a comparison with propranolol 160 mg daily.

This was a phase-IV double-blind equivalence trial designed to assess the efficacy and tolerability of two doses of flunarizine (10 mg o.d.=FLU 10 mg and 5 mg o.d.=FLU 5 mg) in the prophylaxis of migraine, in comparison with slow-release propranolol (160 mg o.d.). A total of 808 subjects were treated in a treatment period of 16 weeks. 142 subjects discontinued the trial prematurely, mainly because of adverse events (n=58). The mean attack frequency in the double-blind period was 2.0 for the FLU 5 mg group, 1.9 for the FLU 10 mg group, and 1.9 for the propranolol group. The mean attack frequency in the last 28 days of the double-blind period was 1.8 for FLU 5 mg, 1.6 for FLU 10 mg, and 1.7 for propranolol. Both flunarizine groups were at least as effective as propranolol (P<0.001 in one-sided test). The percentage of responders (defined as subjects for whom attack frequency decreased by at least 50% compared to run-in) in the last 28 days of the double-blind period was 46% (118/259) for FLU 5 mg, 53% (141/264) for FLU 10 mg, and 48% (125/258) for propranolol. Statistical analysis showed that FLU 10 mg is at least as effective as propranolol (P<0.001) and showed a trend for noninferiority of FLU5 and propranolol (P=0.053). No statistically significant differences between the treatment groups were found for any of the secondary parameters. Overall, 190 subjects reported one or more adverse events during the run-in phase: 54 (20.5%) in the FLU 5 mg group, 76 (27.7%) in the FLU 10 mg group and 60 (22.3%) in the propranolol group. The results of this equivalence trial show that 10 mg flunarizine daily with a drug-free weekend is at least as effective as 160 mg propranolol in the prophylaxis of migraine for all evaluated parameters (one-sided equivalence tests) after 16 weeks of treatment. In addition, 5 mg flunarizine proves to be at least as effective as 160 mg propranolol when looking at the mean attack frequency for both the whole double-blind period and the last 28 days of treatment. However, in the analysis of responders, 160 mg propranolol seems to be slightly better than 5 mg flunarizine. In addition, no significant differences between the three treatments were found with regard to safety: all three treatments were generally well-tolerated and safe.

Reduction potential of microbial, odour and ammonia emissions from a pig facility by biofilters.

The intention of this study was the determination of the potential to reduce specific microbial bioaerosol (cultivable bacteria and fungi, total cell counts of microbes, airborne endotoxins and microbial volatile organic compounds, MVOC), odour and ammonia emissions from a pig facility by biofilters. Five identical biofilter units in half technical scale were filled with different filter materials (Biochips, coconut-peat, wood-bark, pellets + bark and compost) and connected in parallel to a piggery. The results showed obvious differences between the filter materials. Numbers of airborne cultivable bacteria were decreased by ca. 70 to 95% and the total counts of bacterial cells from ca. 25 to (>) 90%. The total amount of fungal cells was reduced by at least 60%, although the percentage of cultivable moulds in the air after passing the filters was sometimes higher than before. Airborne endotoxins and MVOC were effectively reduced by all filter materials to at least 90%. Regarding odour, the average reduction was between 40 and 83%, whereas only one of the filters proved to be capable of slightly reducing the ammonia emissions. No relationships between odour/ammonia and microbial bioaerosols with regard to the reduction efficiency of the different filter materials or the total load of the emitted air could be established. A tendency could be shown, that biofilters best capable to reduce odour emitted slightly more airborne bacteria, both cultivable and total cell counts.

A comparative study of oral acetylsalicyclic acid and metoprolol for the prophylactic treatment of migraine. A randomized, controlled, double-blind, parallel group phase III study.

This study was a multinational, multicentre, double-blind, active controlled phase III trial designed to investigate efficacy and safety of 300 mg acetylsalicyclic acid (ASA) (n = 135) vs. 200 mg metoprolol (n = 135) in the prophylaxis of migraine. In total 270 (51 male and 219 female) patients, aged 18-65 years, suffering between two and six migraine attacks per month were recruited. The main objective was to show equivalence with respect to efficacy, defined as a 50% reduction in the rate of migraine attacks. A run-in phase was carried out with placebo for 4 weeks, followed by a 16-week drug phase. In both treatment groups the median frequency of migraine attacks improved during the study period, from three to two in the ASA group and from three to one in the metoprolol group; 45.2% of all metoprolol patients were responders compared with 29.6% with ASA. Medication-related adverse events were less frequent in the ASA group (37) than in the metoprolol group (73). The findings from this trial show that metoprolol is superior to ASA for migraine prophylaxis but has more side-effects. Acetylsalicylic acid is better tolerated than metoprolol. Using a strict responder criterion ASA showed a responder rate comparable with the placebo rate in the literature.

Influence of different pig housing systems on odor emissions.

The odor emissions from two different housing systems were determined during three fattening periods from October 1999 to November 2000 by analyzing weekly samples by means of dynamic olfactometry. The objects of the investigations were a standard housing system with fully slatted floor and forced ventilation (FF) compared with a kennel housing system with natural shaft ventilation (KN) in parallel operation. Only little data but with a wide range of odor emission values are available from the literature and these are difficult to compare and interpret, because of missing standards in presenting the results and experimental conditions. Therefore minimum requirements for measuring odor emissions from livestock buildings have been derived. In the scope of the measurements during the first two fattening periods (October 1999 to June 2000), no differences in odor emissions could be determined with mean values related to the livestock units (1 LU = 500 kg life weight) of 85 (FF) /87 (KN) in period A and 60 (FF) / 61 (KN) (OU/s)LU(-1) in period B. The overall range of the results of all measurements in periods A and B was 4 to 355 (OU/s)LU(-1). In period C (August-November 2000), the system FF showed higher odor emissions with 193 (28-550) compared to system KN with 105 (25-218) (OU/s)LU(-1). The air flow rates and odor concentrations at the three different naturally ventilated exhaust shafts of system KN differed considerably from each other. Odor measurement techniques with a higher temporal resolution than olfactometry are necessary to give evidence for the main factors influencing the odor formation and release.

Biofilters--the influence of different filter materials and different operating conditions on the reduction efficiency.

A series of biofilter materials were tested for performance efficiency in treating ventilation air from pig sheds. Two different phases were conducted. In phase A five different biofilter materials were tested with the aim of selecting the best material regarding the odor reduction and over all efficiency. In conclusion of phase A, biochips, a new filter material, was selected due to its high average odor reduction (81%) in combination with a very low flow resistance (less than 30 Pa for filter volume loads of 600 m3 h(-1) m(-3)). In phase B, biochips and coconut fiber peat were tested under different operating conditions. Biofilters number 3 and 4 each with down-flow air supply could realize a higher average odor reduction than biofilter 5 with up-flow air supply. All three filter materials had the same moisture, however the two biofilters with down-flow air supply showed a more homogenous moisture distribution but they also used approximately three times more water than biofilter 5. Like in phase A the specific odor cleaning efficiency was mainly influenced by the specific odor loading rate and showed only slight differences between the five biofilters differing in bulk layer height (0.5 m and 1.0 m) and air supply mode. All in all the investigation showed that the efficiency of biofilters can be optimized by using an new filter material and a appropiate operating mode.

Detection of the dynamics of odour emissions from pig farms using dynamic olfactometry and an electronic odour sensor.

The dynamics of odour emissions from a pig house was investigated by olfactometry and using an electronic odour sensor. In addition, several suggested influencing factors on the odour emission were measured to get insight into the reasons for the fluctuation of the odour emission. Odour emission tended to increase over the fattening period f rom August to November 2000 by a factor of two to three, although temperature and air-flow rate decreased according to the seasons. Feeding caused a significant temporary rise in animal activity, dust and odour concentration resulting in an increase of odour emission. The sensor signals of an electronic odour sensor increased simultaneously and showed a good relation to the odour concentration. There is a promising potential of electronic odour sensors to detect the dynamic and the level of odour concentrations. Further investigation will be done, to ensure a standardised measuring protocol and to obtain a calibration of electronic odour sensor signals direct to odour concentrations.