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Biomedical subjects

E O Oen

Publications and source records attributed to E O Oen.

13 recordsLinked to original sources
PubMed1995

Description and analysis of the use of cold harpoons in the Norwegian minke whale hunt in the 1981, 1982 and 1983 hunting seasons.

Until 1984, cold harpoons, i.e. harpoons with no detonating device, were used to hunt minke whales in Norway. To investigate the effectiveness of such harpoons and compare them with alternatives, data on kills using cold harpoons were collected as part of a project dealing with alternative killing techniques for whales. Data on 353 whale kills were collected in 1981-83. The criteria used to determine the time of death were cessation of flipper movement, that the mandible relaxed, or that the whale hung immobile from the harpoon line. These criteria do not take into account any movements caused by spinal reflexes. About 17% of the animals died instantaneously (< or = 10 s). The median survival time was 570 s. Animals died most rapidly if hit in the brain, heart or major blood vessels. If only the lungs were injured, minke whales died less rapidly than terrestrial mammals. For whales that did not die immediately, shooting range, animal size and the angle of the shot all influenced the time to death. The efficiency of cold harpoons could be improved, but their use was no longer considered acceptable, and they were replaced by harpoons with penthrite grenades in 1984.

Animals↗
PubMed1995

A Norwegian penthrite grenade for minke whales: hunting trials with prototypes and results from the hunt in 1984, 1985 and 1986.

A penthrite grenade to replace cold harpoons in the Norwegian minke whale hunt was developed in 1983-1985. Data on survival times for 259 minke whales were collected from the trials in the 1984-86 hunting seasons, when 3 different prototypes were used. About 45% of the whales were killed instantaneously. The median survival time was 72 s. A substantially higher percentage of instantaneous deaths was recorded for penthrite grenades than for cold harpoons. The criteria for death were cessation of flipper movement, relaxation of the mandible, or sinking without any active movement. Some animals dived before the criteria could be controlled. If the central nervous system, heart, lungs or main vessels were damaged, a high percentage of the animals died instantaneously. In most cases, hits and detonations outside the thorax and central nervous system resulted in longer survival times than hits in the thorax. Survival time increased with whale size and range for animals not killed instantaneously. Marksmanship, technical and functional reliability of equipment and hunting techniques were all crucial to a good result. Better training of gunners, improved weapons and hunting equipment and more rapid reshooting of wounded animals would reduce the proportion of long survival times.

Animals↗
PubMed1990

Plasma progesterone in reindeer in relation to ovariectomy and hysterectomy.

Four semi-domesticated reindeer were ovariectomized and 3 both ovariectomized and hysterectomized, 30-70 days before expected parturition. Anaesthesia with etorphine/propyonylphenthiazine was followed by an increase in the plasma concentration of progesterone of peripheral blood. The concentration of progesterone returned to pre-anaesthetic values before ovariectomy. Ovariectomy did not result in any substantial change in the plasma progesterone concentration within an observation period of 35-120 min. Hysterectomy was followed by a marked decrease in peripheral plasma progesterone within 60 min. The progesterone concentration in ovarian venous blood was slightly higher than the jugular venous blood in 1 animal and 150 and 400 times higher in the 2 other animals examined. Thus, despite lack of marked changes of progesterone in jugular venous blood upon ovariectomy, it is concluded that the ovaries are a major production site of progesterone in pregnant reindeer. The progesterone in uterine venous blood was close to that in the jugular vein in 1 animal, and slightly higher in 2 others. This observation, and the maintenance of pregnancy in spite of ovariectomy in 2 out of 4 animals, point to the foeto-placental unit as an additional source of progesterone production.

Animals↗
PubMed1977

The oral administration of megestrol acetate to postpone oestrus in cats.

During 1974, megestrol acetate tablets were distributed to 397 cat owners in the Oslo district for use as an oestrus suppressing agent in cats. A weekly dose of 2.5 mg megestrol acetate was given for at least 30 weeks. Treatment was carried out according to plan in 244 cats. Results are shown in Table I. The course of birth was abnormal in two cats which were pregnant before the trial began. Pregnancy was not registered in any of the remainder. Heat was observed during the period of treatment in 21 of the 244 cats treated according to plan without pregnancy being registered. As regards side effects of the preparation, increased appetite, weight increase and changes of temperament were the most pronounced. One cat developed pyometra after three years of treatment with the preparation.

Administration, Oral↗
PubMedDate not supplied

Electrical whaling--a review.

Theoretically, for anatomical reasons, the use of electric current should be an efficient killing method on whales, and a number of experiments with electric harpoons have therefore been previously carried out. Even though killing time was reduced in relation to the use of the detonating grenade harpoon, results were inconsistent, mainly because of technical problems. The method therefore seems to be too uncertain to be used as an alternative to present catching methods.

Animals↗
PubMedDate not supplied

Killing times of minke whales in the Norwegian coastal whaling in the 1981 and 1982 seasons.

During the whaling seasons of 1981 and 1982 16 inspectors were on the whaling grounds to collect data about weapons and equipment, shooting facilities, hitting areas, reaction to hits, tissue and organ damage and killing times. The inspectors were instructed to confirm the criteria of death by personal observation before reading the time. Consequently the recorded times are appreciably longer than real killing time for a number of whales. The average killing time according to this method was 11 min 50 sec in the 1981 season and 12 min 40 sec in the 1982 season (Table I). 22.4% and 21.8% died instantaneously in the two seasons. Hitting the CNS or the heart was most effective. Hits in the abdominal cavity or the musculature prolonged the killing times considerably.

Animals↗
PubMedDate not supplied

Drug immobilization and anaesthesia of a lynx in connection with a broken leg.

The drug immobilization of a lynx, Felis(Lynx)lynx using ketamine hydrochloride injected intramuscularly by means of a blowpipe is described. Immobilization was satisfactory in six of a total of seven attempts. The primary immobilization dose varied from 11--28 mg ketamine hydrochloride per kg and the time elapsing before ataxia varied between 3 to 20 minutes. Undesirable side effects were not seen. In addition, inhalation anaesthesia with halothan was employed during surgery on three separate occasions.

Anesthesia, Inhalation↗