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Biomedical subjects

L Elving

Publications and source records attributed to L Elving.

24 records · Page 2Linked to original sources
PubMed1979

[Fertility of dairy cattle in Kenya (author's transl)].

The fertility of dairy cattle was studied on thirty-three government farms in Kenya for five years. Most parameters of fertility showed marked differences between the various farms. Some farms showed considerable annual variations, whereas others continued to have good results during all these years and other farms only obtained results far below average. Dairy cattle fertility was fairly satisfactory with an average conception rate of 51 per cent after first inseminations and averaging two inseminations for each conception. However, the disappointing average calving-interval of 413 days was primarily due to the long parturition-to-first-insemination interval of ninety-three days on an average, and on average of 123 days in 1975. The frequency of normal heat- en service intervals (17-25 days) was too low by approximately 50 per cent, which was caused by the inefficiency of oestrus detection.

Animals↗
PubMed1979

[Relationship between the presence of meconium in newborn lambs and postnatal pH and blood gas tension levels (author's transl)].

The pH of the blood and blood gas tension (PO2 and PCO2) were estimated in thirty-two lambs. Blood was taken from the umbilical vein during labour and blood was collected from the left ventricle after birth (1, 10 and 60 minutes). The findings in twenty-one lambds were used to determine the relationship between the presence of meconium on the fleece and the postnatal changes in pH and blood gas tension. pH, blood gas tension and vitality were found to be identical both in the meconium-stained and in the unstained lambs. Within this experiment, there was no relationship between the length of parturition and pH and blood gas tension levels. The pH, PO2 and PCO2 as determined in the umbilical blood showed that the lambs (both meconium-stained and unstained) continue to be in good condition throughout a normal parturition. Postnatal adjustment is rapid and, following normal ventilation, pH, PO2 and PCO2 respectively attain levels of 7.379; 54.7 and 43.7 within sixty minutes. Diminished vitality, resulting from pathological factors, was observed in four lambs.

Animals↗
PubMed1978

[Criteria for evaluation of methods, systems and interference procedures to which animals are submitted (author's transl)].

Veterinarians can be expected to play a particular role in the relationship between man and animals. Dutch laws and formal agreements on the subject are briefly reviewed. The following main points that should be taken into account are discussed. (1) detailed description of the method, system and interference; (2) their purpose, (3) consequences for the welfare of animals; (4) aspects relevant to human society: importance of purpose, international aspects, significance for public health and environment, public opinion; (5) alternatives, with description of points (1), (3) and (4); (6) considerations of usefulness and necessity from the practical point of view and acceptability from the point of view of ethics; (7) position of the veterinarian; (8) conclusion.

Animals↗
PubMed1975

Oestrus synchronization and fertility in heifers treated with prostaglandin F2alpha.

Oestrus was synchronized with prostaglandin F2alpha in Tham salt buffer (25 mg. and 12.5 mg.) injected intramuscularly on two consecutive days in 41 Dutch Friesian heifers. Thirty-five animals (85,3%) showed heat within 2-5 days of the start of treatment. Degree of synchronization was low if PGF 2alpha was injected before D5. Conception rate was low (31,4%) in the synchronized oestrus, but was normal (58%) at the post-synchronized oestrus. Based on observation for oestrus and rectal palpation of ovaries at 8 hourly intervals, oestrus occurred over a period of 62,1 +/- 3,0 hours and ovulation occurred 29,8 +/- 1,4 hours after the onset of oestrus. The average time from first treatment to ovulation was 93,0 +/- 18,8 hours. The length of the synchronized oestrus was significantly longer (P less than 0,05) than the pretreatment oestrus.

Animals↗
PubMed1975

[Some aspects of fertility following artificial insemination and natural service in dairy cattle (author's transl)].

The difference between the non-return percentage (60-90 days) following 17,086 first inseminations and that after 9,776 first matings in Dutch-Friesian cattle was studied in a random sample of the Netherlands Herd Book records in 1969. The effects of the following factors on this difference in the cases studied are discussed: -- age of bulls and cows, -- frequency of natural service and artificial insemination during each oestrus, -- use of deep-frozen semem --housing and grazing periods. The difference having been corrected for these factors, it was estimated at not more than 9 per cent of non-return 60-90 days in favour of natural service.

Age Factors↗