64 research outputs found
Produktie van Ethylbenzeen door middel van katalytische destillatie
No full textDocument(en) uit de collectie Chemische ProcestechnologieDelftChemTechApplied Science
Effect of moving dairy cows at different stages of labor on behavior during parturition
No full textCows are often moved from a group to an individual maternity pen just before calving. However, it is unclear whether moving cows during labor may alter their behavior or affect the progress of labor. The aim of this study was to determine if moving cows to a maternity pen at different stages of labor would influence calving behavior or the length of the second stage of labor. Seventy-nine multiparous Holstein dairy cows were moved from 1 of 2 group pens to 1 of 10 maternity pens adjacent to each group pen either 3 d before expected calving date or when one or more behavioral or physical signs of labor were observed. These signs were noted, and were used to retrospectively categorize cows into 1 of 3 movement categories: (1) moved before labor, (2) moved during early stage I labor (signs of suddenly tense and enlarged udder, raised tail or relaxed pelvic ligaments; could also be immediately prelabor), or (3) moved during late stage I labor (signs of viscous, bloody mucus or abdominal contractions; could also be transitioning to stage II labor). Calves were weighed within 12h of birth and remained with their dam for 3 d. The length of the second stage of labor (the time between first abdominal contractions to the delivery the calf) and the total time of abdominal contractions, lying time, and number of position changes from standing to lying made by the cow in the hour before calving were recorded. A single blood sample was taken from the jugular vein of cows 3 to 27h after calving to determine content of haptoglobin, a marker of systemic inflammation. The effect of movement category on length of the second stage of labor and behavioral variables was tested with ANOVA; category was a fixed effect and calf body weight (BW) and cow parity were covariates. The relationship between haptoglobin and the length of the second stage of labor was tested in a model with time of sampling relative to calving as a covariate. Cows moved during late stage I had the longest labor, but did not have longer contractions compared with cows in the other categories. These same cows spent half as much time lying in the 1h before calving compared with cows in the other categories, but did not differ in the number of position changes from standing to lying. We did not have the power to test the effect of movement category on haptoglobin, but cows with longer stage II labor had higher haptoglobin postcalving. Moving cows to a maternity pen during the late part of the first stage of labor caused a delay in the second stage of labor, and this was likely driven by altered lying behavior
Mesoscopic electrochemistry in nanofluidic devices
No full textThis thesis describes nanofluidic devices capable of detecting small numbers of redox-active molecules and even single molecules. The detection relies on redox cycling, in which diffusive molecules rapidly transfer electrons between two parallel electrodes embedded in a thin, solution-filled channel. This high sensitivity permits studying the mesoscopic regime of electrochemistry in which the discreteness of molecules and statistical fluctuations can no longer be ignored.Kavli Institute of NanoscienceApplied Science
The effect of dystocia on the dry matter intake and behavior of Holstein cows
No full textDairy cows that have a difficult calf delivery (dystocia) are more likely to develop health complications after calving, reducing productivity and welfare. Understanding the behavioral cues of dystocia may facilitate prompt obstetric assistance and reduce the long-term effect of the challenging delivery. The aim of this study was to describe the effects of dystocia on dairy cow behavior during the period around calving and to assess the use of these behaviors as potential indicators of dystocia. Individual dry matter intake, water intake, feeding and drinking time, meal size, standing time, and number of transitions from standing to lying positions (bouts) were recorded during the 48-h period before and after the time of calf delivery for 22 Holstein cows [11 cows with dystocia and 11 cows with unassisted delivery (eutocia)]. Cows with dystocia consumed 1.9 kg less during the 48 h before calving compared with cows with eutocia (14.3 ± 1.0 vs. 16.2 ± 1.0 kg, respectively), and this difference increased to 2.6 kg in the 24 h before calving (8.3 ± 0.7 vs. 10.9 ± 0.7 kg/d). There were no differences in drinking time between the groups, but cows with dystocia consumed less water 24 h before calving (22.4 ± 4.4 vs. 36.2 ± 4.4 kg/d, respectively) and consumed more water during the 24-h period after calving (56.9 ± 3.1 vs. 48.7 ± 3.1 kg/d) compared with cows with eutocia. Cows with dystocia transitioned from standing to lying positions more frequently than cows without dystocia beginning 24 h before calving (10.9 ± 0.7 vs. 8.3 ± 0.7 bouts/d). Dry matter intake and standing bouts in the 24 h before calving were the most accurate variables in discriminating between cows with and without dystocia, suggesting that cows with dystocia begin to alter their behavior beginning 24 h before calving
Behavior during transition differs for cows diagnosed with claw horn lesions in mid lactation
No full textClaw horn lesions, including sole hemorrhages and sole ulcers, are a major cause of lameness in dairy cattle. These lesions often develop in the weeks around calving and become visible 8 to 12 wk later. The aim was to determine whether cows that are diagnosed with claw horn lesions several weeks after calving behave differently during the calving period when the lesions are thought to first develop. The claws of 26 multiparous Holstein dairy cows were scored for sole hemorrhage severity and presence of sole ulcers 2 wk before calving, 3 wk after calving, and every 4 wk thereafter until 15 wk after calving. Of the 26 cows, 13 cows had no or low lesion scores up to 15 wk and 13 cows had at least 1 new severe lesion or sole ulcer diagnosed between 7 and 15 wk after calving. Behavior (dry matter intake, feeding time and rate, number and size of meals, standing time, number and duration of standing bouts, location of standing, and displacements at the feed bunk) was recorded from 2 wk before calving to 3 wk after calving. Behavior during the 2 wk before calving, first 24h after calving, 1 wk after calving, and 2 to 3 wk after calving was compared between cows with and without lesions in mid lactation. Multivariate regression was used to determine the predictive value of each behavior and combination of behaviors on lesion diagnosis. Cows diagnosed with lesions in mid lactation spent more time standing than cows without lesions during the 2 wk before (832+/-29 vs. 711+/-29 min/d) and 24 h after (935+/-46 vs. 693+/-46 min/d) calving. These differences were driven by an increase in the time spent perching with front feet in the stall (241+/-22 vs. 147+/-22 min/d at 2 wk before calving) and an increase in standing bout duration (101+/-10 vs. 56+/-10 min/bout at 24 h after calving). Compared with cows without lesions, cows with lesions consumed feed at a faster rate (86+/-3 vs. 77+/-3 g/min) during the 2 wk before calving and consumed more feed (17.9+/-0.9 vs. 12.3+/-0.9 kg/d) during the 24 h after calving. The number of displacements at the feeder was not different between groups. These results indicate that a combination of feeding and standing behavior during the transition can serve as early indicators of claw horn lesions in mid lactation
Exposure to an unpredictable and competitive social environment affects behavior and health of transition dairy cows
No full textSocial factors are important determinants of disease in humans and and laboratory animals, but less research has been done using farm animals. The objective of this study was to determine if an unpredictable and competitive social environment affects behavior and health during the transition period when dairy cows are at high risk of disease. Five weeks before calving, 64 cows were assigned to a predictable and noncompetitive social environment (predictable) or an unpredictable and competitive social environment (unpredictable) using 8 groups of 4 animals per treatment. Each group consisted of 3 multiparous and 1 primiparous cow. At first enrollment (baseline; 5 wk before calving), all groups had access to 4 electronic feed bins. At 4 wk before calving, cows in the predictable groups were given access to 6 feed bins, and cows in the unpredictable groups were moved into a new pen with 4 resident cows each trained to consume feed from one bin. Each cow in the unpredictable group was then provided access to only 1 of the 4 feed bins which they shared with 1 resident cow (resulting in 2 cows/bin), creating a competitive feeding environment. To create an unpredictable environment, access to morning feed was delayed 0, 1, 2, or 3 h every other day. On alternate days, the cows in unpredictable groups were assigned to feed from a new feed bin (and thus had to compete with a new resident partner). Feeding and social behavior were collected electronically from the feed bins. Blood was sampled at baseline (wk −5), wk −2, wk −1, and wk +1 relative to calving to measure inflammatory (haptoglobin and tumor necrosis factor-α) and metabolic (nonesterified fatty acids, β-hydroxybutyrate, calcium, and glucose) biomarkers. Uterine cytology was performed 3 to 5 wk after calving to diagnose cytological endometritis. Data were analyzed using mixed models including baseline data as a covariate, week as a repeated measure, treatment as a main effect, and a treatment by week interaction. The probability of cytological endometritis at the group level was analyzed using Mann-Whitney U tests. Parity was included in separate models to determine any parity × treatment interactions. Cows from both treatments consumed the same amount of feed, but cows in the unpredictable group spent less time feeding and had a higher rate of feed intake. Cows in the unpredictable groups also visited the feed bins less often, consumed more feed during each visit, and were involved in more social replacements at the feed bin compared with predictable groups. Cows in the unpredictable groups had higher serum concentrations of nonesterified fatty acids and tumor necrosis factor-α, but lower β-hydroxybutyrate compared with predictable groups. Multiparous cows in unpredictable groups were more likely to be diagnosed with cytological endometritis after calving compared with cows in the predictable groups, but primiparous cows in unpredictable groups showed a tendency for the opposite response. These results suggest that an unpredictable and competitive social environment before calving causes changes in feeding and social behavior, some physiological indicators of metabolism and inflammation, and increases the risk of uterine disease in multiparous cows after calving
Investigation on the required processor capability necessary for carrying out the MLS procedural interception using conventional indicators
No full textDit rapport beschrijft het volgende: - Benodigde instrumenten en extra 'annunciators' om een zgn. MLS procedurele interceptie uit te voeren. - Minimum 'Capability' van het processorsysteem welke benodigd is om deze instrumenten aan te sturen. - De eisen aan een (digitaal) filter, nodig om een rustig aanwijsgedrag van de instrumenten te bewerkstelligen als gevolg van het foutgedrag van het MLS. - De parametersets van het gekozen filter.Electrical Engineering, Mathematics and Computer ScienceTelecommunicatie- en Verkeersbegeleidingssysteme
Competition at the feed bunk changes the feeding, standing, and social behavior of transition dairy cows
No full textTransition dairy cows are vulnerable to the negative consequences of depressed feed intake around calving. Competition can decrease feeding activity in midlactation cows, but the effects of competition on the transition cow are not well understood. The objective was to test the effect of competition on the behavior and feed intake of transition cows. Standing behavior, feeding behavior, and dry matter intake were monitored from 1 wk before to 2 wk after calving for 36 Holstein dairy cows. Displacements at the feed bins were recorded the week before calving. Cows were assigned to either competitive (2:1 cows:feed bin) or noncompetitive (1:1 cow:feed bin) treatments. Treatment groups were balanced for parity and baseline feeding measures, resulting in 8 primiparous and 10 multiparous cows per treatment. Competition increased the number of displacements at the feed bins for both primiparous and multiparous cows. Primiparous cows had no change in feed intake or standing time when fed in a competitive environment, but did increase the time spent for each meal during the week before calving (28 +/- 1.5 vs. 24 +/- 1.5 min/meal). In the week before and after calving, competitively fed multiparous cows had a lower feeding time per visit than noncompetitively fed cows (4.2 +/- 0.5 vs. 5.8 +/- 0.5 kg/visit and 5.3 +/- 0.7 vs. 7.0 +/- 0.7 kg/visit, respectively). Multiparous cows ate at a faster rate 2 wk after calving (142 +/- 11 vs. 105 +/- 11 g/min). Multiparous cows in the competitive treatment increased the time they spent standing (without eating) during the week after calving compared with cows in the noncompetitive treatment (820 +/- 44 vs. 649 +/- 44 min/d). Feeding rate was correlated with a displacement index in multiparous cows, whereby cows with lower displacement indices ate more rapidly. Results indicate that restricting access to feed increases displacements regardless of parity, and alters the feeding and standing behavior of primiparous and multiparous cows differently
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