Per Peetz Nielsen

Tetramine: occurrence in marine organisms and pharmacology

The occurrence of tetramethylammonium ion (TMA) in marine organisms is reviewed. The pharmacological action of TMA is also discussed, with special emphasis on the sign and symptoms experienced by oral poisonings. It is concluded that the major manifestations of TMA poisonings may be attributed to interactions with the autonomous nervous system. Fatal intoxications are due to neuromuscular blockade.

The toxin tetramine from the “edible” whelk Neptunea antiqua

The chemical nature of extracts of the marine gastropod Neptunea antiqua collected in the North Sea has been investigated. Amino acid analysis and spectroscopical studies (FAB MS, 1H NMR, 13C NMR and IR) on fractions purified by Biogel P-2 and Amberlite IR 120 column chromatography allowed the identification of 19 components. It was established that the water-soluble toxin responsible for poisonings, following ingestion of this snail, is tetramine (the tetramethylammonium ion present as an unknown salt). Contrary to what occurs in other Neptunea species (N. arthritica and N. intersculpta), tetramine was found not only in the salivary gland, but also in the remaining part of the animal, albeit in smaller concentration. In the isolated guinea-pig ileum assay, synergistic effects with other main components present (betaine, homarine) could not be demonstrated. Choline esters, believed to act synergistically in other Neptunea species, were not detected in Neptunea antiqua.

Personality-Guided Treatment for Alcohol Dependence: A Quasi-Randomized Experiment

Personality disorders are highly prevalent among alcohol-dependent populations and result in a seriously elevated risk for non-responding to treatment; therefore, they represent a major challenge for professionals providing treatment for alcohol dependence. Personality-guided Treatment for Alcohol Dependence (PETAD), an approach that integrates cognitive therapy for addictive behaviors with strategic intervention for maladaptive personality features, may be helpful for patients with co-morbid alcohol dependence and personality disorders. Clients admitted for inpatient treatment for alcohol dependence at Ringgaarden, Denmark (n = 108) were allocated to either standard inpatient treatment with cognitive therapy for alcohol dependence, or PETAD. Both treatments were manualized. Clients were followed up by mail at six months post-treatment and administered the MCMI-I and II and the SCL-90 at intake, post-treatment, and at follow-up. PETAD was associated with better retention, longer time to first relapse, and less time spent drinking post-treatment, although few differences reached statistical significance. Differences in results were mainly found in the subgroup with higher levels of PD. The study suggests that PETAD is a promising approach that warrants further study.

Poisonings from flesh of the Greenland shark Somniosus microcephalus may be due to trimethylamine

The flesh of the Greenland shark, Somniosus microcephalus, especially in fresh condition, is toxic to both dog and man. Analysis of the toxic fractions indicates the presence of large amounts of trimethylamine oxide (TMAO) but no other substances that could be directly responsible for the poisoning. The symptoms appear to be due to an acute trimethylamine (TMA) poisoning arising from intestinal reduction of TMAO to TMA. TMA stimulates contraction of the guinea-pig ileum (antagonized by atropine but not hexamethonium). Low concentrations of TMA increase contraction of the rat phrenic nerve-diaphragm preparation, whereas higher concentrations cause blockade.

Technical note: Variation in daily milk yield calculations for dairy cows milked in an automatic milking system

An accurate estimation of the daily milk yield of dairy cows milked in an automatic milking system is not obvious because of variations in milking intervals and frequencies. Daily harvested milk varies substantially, and developing a method to be used for estimating daily milk production is of great importance. Three calculation methods (simple, semiadvanced, and advanced) were used. The simple method calculated rough daily milk production by summing up the yield per day. The semiadvanced used yield in combination with time since last milking to calculate the milk production per hour between milking; an average of the milk production per hour over the day was calculated and multiplied by 24. The advanced method calculated the milk production from midnight to midnight by using information about yield and time since last milking to calculate the exact milk production. The results show a clear preference for the advanced calculation method because the variation [variation for the advanced method=ln(1.79) for first lactation and ln(2.28) for later lactations] between days was reduced significantly (3 to 4 times lower compared with the simple method). Variation in daily harvested milk can be used as a management tool.

The Effects of Teat Bar Design and Weaning Method on Behavior, Intake, and Gain of Dairy Calves

The aim of the present study was to investigate the effects of teat-feeding method and weaning method on behavior, milk and concentrate intake, and weight gain of group-housed dairy calves. Forty-eight calves were housed in groups of 4 and offered 6 L of whole milk per calf in 2 daily feedings. In 6 of the 12 group pens, the calves were offered the milk in a teat bar with a separate milk compartment for each teat, whereas in the remaining 6 pens, the calves were offered the milk in a teat bar with all teats connecting to 1 shared milk compartment. Calves were gradually weaned off milk by reducing the volume of milk over a 10-d period, starting at an average age of 47 d. In 6 pens (3 pens with each of the 2 milk-feeding treatments), calves were weaned by volume reduction, whereas in the remaining pens, the calves were weaned by diluting the milk with water (WD) and maintaining the same total volume of liquid. Daily concentrate intake per pen was recorded during weaning and 1 wk after weaning. Behavior was recorded around milk feeding, by direct observation on 1 occasion before and on 1 occasion during weaning, and by video on 1 occasion before and 2 occasions during weaning. Furthermore, the behavior was recorded during the 15 h of light on 1 occasion during weaning. Individual milk intake was measured twice by weighing the calves immediately before and after milk feeding. The calves fed via a separate teat bar switched between teats more often than calves fed with a shared teat bar. There was greater variation in the duration of ingesting milk within groups fed via a separate teat bar, but no effect of teat bar design was found on the variation in milk intake within the groups. Calves fed via a separate teat bar took longer to start eating concentrate after milk feeding than calves fed with a shared teat bar. The WD calves had a lower concentrate intake during weaning than weaned by volume reduction calves. The WD calves were lying down less during the 30 min after milk feeding and during the 15 h of light, although they had a shorter latency to lie down after milk feeding. In conclusion, a separate teat bar increased teat switching, increased variation in duration of ingesting milk, and increased the latency to eat concentrates after milk feeding. There was no effect of the teat bar design on feed intake or weight gain. However, weaning the calves by gradually diluting the milk with water reduced lying during weaning and reduced the concentrate intake during and after weaning.

First-night effect on sleep time in dairy cows

In human sleep studies, the probability of discomfort from the electrodes and the change in environment usually results in first-night recordings being discarded. Sleep recordings from the first night in human subjects often differ in amount of REM (rapid eye movement) sleep and the overall sleep architecture. This study investigated whether recordings of sleep states in dairy cows also show a first-night effect. Non-invasive electrophysiological recordings were carried out on nine cows of the Swedish Red breed during three consecutive 24-hour periods (recording days 1–3). Overall, cows spent 12.9 ± 1.4 hours awake, 8.2 ± 1 hours ruminating, 57.2 ± 20.3 min drowsing, 44.1 ± 20.2 min in REM sleep and 64.3 ± 38.1 min in NREM (non-rapid eye movement) sleep (mean ± SD) and there were no significant differences between recording days in total duration for any of the sleep and awake states. However, the bouts of REM sleep and rumination were longer, and the awake bouts were shorter, at night time compared to daytime, regardless of recording day. The awake bouts also showed an interaction effect with longer bouts at daytime during day 1 compared to daytime on day 3. Data on sleep and awake states recorded in adult dairy cows during three consecutive 24-h periods showed great variation in sleep time between cows, but total time for each state was not significantly affected by recording day. Further and more detailed studies of how sleep architecture is affected by recording day is necessary to fully comprehend the first-night effect in dairy cows.

Technical note: Validation and comparison of 2 commercially available activity loggers

To validate the accuracy of 2 commercially available activity loggers in determining lying, standing, walking, and number of steps in dairy cows, 30 cows were fitted with the CowScout Leg (GEA Farm Technologies, Bönen, Germany) system and the IceTag (IceRobotics Ltd., Edinburgh, Scotland) system. The CowScout Leg logger reports standing and lying in 15-min periods, whereas the IceTag logger reports standing and lying every second. To make data comparable, the IceTag data were therefore also summarized over 15-min periods corresponding to the paired CowScout Leg sensor. These data from the 2 systems were then analyzed (more than 1,000 cow days in total). Video recordings of a total of 29.5 h were used for labeling the behaviors of the selected cows (n = 10) and these labels were used as a gold standard to determine the accuracy with which these 2 loggers can record behavioral states lying, standing, walking, and the behavioral event number of steps. A concordance correlation coefficient analysis showed that both the standing and lying durations obtained with the 2 systems were almost perfectly correlated with the video labeling (IceTag: ρc = 0.999 and 0.999, respectively; CowScout Leg: ρc = 0.995 and 0.996, respectively). However, both loggers performed poorly regarding number of steps (classified as an event; IceTag: ρc = 0.629; CowScout Leg: ρc = 0.678) and CowScout Leg did not detect walking (classified as a state) very accurately (ρc = 0.860). The IceTag system does not measure walking behavior. When comparing the 2 loggers, the correlation between them for standing and lying was substantial (ρc = 0.953 and ρc = 0.953, respectively). The number of steps poorly correlated between the 2 loggers (ρc = 0.593), which might be due to the CowScout Leg logger being attached to the front leg and the IceTag logger being attached to the hind leg. We conclude that both the IceTag and the CowScout Leg logger are able to record standing and lying almost perfectly, but the step counting by both loggers and the walking recording by the CowScout Leg logger are not very accurate.

It is warm outside today: How temperature affects dairy cows’ willingness to be on pasture

ABSTRACT The effect of Temperature Humidity Index (THI) on dairy cows’ willingness to be on pasture was examined. Information for 2 years regarding weather, milk production, and time for voluntarily passing a gate between the barn and pasture of cows milked with an automatic milking system was studied. When the THI exceeded 72 during the day, more cows spent time on pasture compared to when the THI was less than 72 (27.0% vs. 19.2% of cows on pasture, respectively). However, the time of day influenced the proportion of cows on pasture, and when the THI exceeded 72, more cows were on pasture at night and less during the afternoon compared to days when the THI was less than 72. In conclusion, even under Swedish conditions, THI might have an effect on cows’ behaviour. However, when the cows have free access to roughage and pasture, an increased THI does not affect milk production.