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Biomedical subjects

R E Larsen

Publications and source records attributed to R E Larsen.

32 records · Page 2Linked to original sources
PubMed1980

The search for viruses in bovine semen, a review.

Viruses reported in bovine semen include those of foot and mouth disease, bluetongue, bovine leukemia, infectious bovine rhinotracheitis, bovine viral diarrhea, ephemeral fever, and lumpyskin disease. Bovine enteroviruses, a parapoxvirus (paravaccinia), and several uncharacterized viruses have also been isolated. Their presence in semen has been recognized by a variety of animal inoculation and cell culture techniques. The prevalence of viruses in semen and the attendant impact on fertility is largely unknown. The widespread distribution of frozen semen, an ideal system for preserving viral infectivity, indicates this product could serve as an important vehicle for transmission of viruses to uninfected herds or areas. This concern has placed restrictions on international movement of semen. Improved methods for detecting viruses in semen are necessary to assess the importance of the problem and to develop realistic precautionary measures.

Journal Article↗
PubMed1980

Prediction of silage digestibility and intake by chemical analyses or in vitro fermentation techniques.

Chemical analyses and in vitro fermentations were on three corn silages, four legume-grass silages, and four corn-hay crop silage mixtures which had been fed to sheep for 21 days. In vivo data were collected for voluntary silage intake and apparent digestibility of energy. Forage nutritive value was expressed as digestible energy intake. Multiple regression equations were developed to determine the more reliable methods to evaluate voluntary intake, digestibility, and nutritive value of silage. Equations for quadratic response surfaces accounted for 71 to 79% of variation in in vivo data compared to 54 to 70% of variability accountable by simple linear regression equations. Dry matter, crude protein, cell wall, acid-detergent fiber, and acid-detergent lignin contents of silage accounted for greater variability in silage intake, digestibility, and nutritive value than did any in vitro method either alone or in combination with chemical analysis. The results support Crampton's concept of nutritive value index, which is now expressed in the relative feed value system proposed by the American Forage and Grassland Council for differences between forages.

Animal Feed↗
PubMed1980

Semen changes in boars after experimental infection with pseudorabies virus.

Two groups of adult boars were inoculated with a field strain of pseudorabies virus (PRV) by intranasal droplet; one group was given 5 x 10(5) median tissue culture infective doses (TCID50), and the other, 5 x 10(6) TCID50. (A third group was maintained as controls.) Ejaculates were examined twice a week for volume, sperm numbers, sperm morphology, and presence of PRV. Severe clinical disease with fever followed administration of the larger virus dose. Death (one boar), testicular degeneration, and transient elevation in spermatozoa with proximal cytoplasmic droplets were seen in different members of this group. The smaller dose resulted in seroconversion, but did not produce signs of disease. In this group, volume, sperm numbers, and sperm morphology did not decline when compared with base-line values or data of control animals. The virus was not isolated from semen. Effects of PRV infection on semen quality in boars seem to be related to the associated clinical signs of systemic disease.

Animals↗
PubMed1979

Breeding studies reveal segregation of a canine Robertsonian translocation along Mendelian proportions.

Six matings of golden retriever-type mongrel dogs with a 13/23 Robertsonian translocation were studied. Three matings between normal dogs and dogs heterozygous for the translocation produced 12 normals and 11 heterozygotes. In three matings between heterozygotes, the distribution of normal, heterozygous, and homozygous proteny was Mendelian (8:12:5). No gross phenotypic anomalies were observed with the exception of congenital inguinal hernia in two female homozygotes. Nondisjunction in the form of trisomic or monosomic individuals for either autosome 13 or 23 was not observed.

Animals↗
PubMed1978

Postanaesthetic postural stability following thiopental or propanidid anaesthesia.

Using a quantitative Romberg-test performed on a computerized force-plate-system, postural stability was tested in 39 patients before and 3 hours after general anaesthesia with either thiopental (20 patients) or propanidid (19 patients). Sway-tendencies in the sagittal and the transversal direction were recorded. Comparing pre- and postoperative test results, patients anaesthetized with thiopental had a decreased postural stability 3 hours after anaesthesia, indicated by a significantly (P less than 0.05) increased sway-tendency of 22.6% in the sagittal direction. No change occurred in sway-tendency in the transversal direction in this group. In the propanidid group no significant differences were found between pre- and postoperative test results.

Adolescent↗
PubMed1978

Centric fusion of autosomal chromosomes in a bitch and offspring.

A fertile Golden Retriever cross had a chromosome number of 77, with 3 large metacentric chromosomes representing the 2 X chromosomes and a centric fusion of 2 autosomes. The known reproductive history of the bitch included litters of 6, 5, 13, and 10 pups during 4 consecutive estrous cycles. A total of 16 pups and their sire were located and karyotyped. The sire and 9 of the pups were of normal karyotype. Seven of the 16 pups were found to be carriers of the translocation. The translocation was determined to be a fusion of chromosomes 13 and 17, utilizing G-banding techniques. Although centric fusion has been reported in dogs with congenital disease, the dogs in the present study were not phenotypically unique or abnormal.

Animals↗