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Biomedical subjects

W Sybesma

Publications and source records attributed to W Sybesma.

At least 19 recordsLinked to original sources
PubMed2000

Highly cited article published in the Veterinary Quarterly in 1991.

In early 1991, the Dutch pig industry was struck by the so-called mystery swine disease. Large-scale laboratory investigations were undertaken to search for the aetiological agent. We focused on isolating viruses and mycoplasmas, and we tested paired sera of affected sows for antibodies against ten known pig viruses. The mycoplasmas M. hysonoviae, M. hyopneumoniae, and Acheloplasma laidlawii, and the viruses encephalomyocarditis virus and porcine enterovirus types 2 and 7 were isolated from individual pigs. An unknown agent however, was isolated from 16 of 20 piglets and from 41 of 63 sows. This agent was characterized as a virus and designated Lelystad virus. No relationship between this virus and other viruses has yet been established. Of 165 sows reportedly affected by the disease, 123 (75 per cent) seroconverted to Lelystad virus, whereas less than 10 per cent seroconverted to any of the other virus isolates or to known viral pathogens. Antibodies directed against Lelystad virus were also found in pigs with mystery swine disease in England, Germany, and the United States. We conclude that infection with Lelystad virus is the likely cause of mystery swine disease.

Animals↗
PubMed1997

[Pigs as source animals for humans].

This article reviews the current status of animal-to-human organ transplantation (xenotransplantion). In addition to immunological problems and the risk of disease, ethical issues with regard to both donor animals and humans make this technique not yet practicable. From further progress of this essentially veterinary development veterinary medicine and research will benefit.

Animal Welfare↗
PubMed1981

Use of spermatozoa for artificial insemination. I. Fertilizing capacity of fresh and frozen spermatozoa in sows on 36 farms.

A field trial was conducted on 36 farms in the Netherlands to compare the fertilizing capacity of fresh and frozen-thawed boar spermatozoa. Four-hundred and fifty-one sows were artificially inseminated with semen than that had been frozen and thawed according to the Beltsville Method or diluted in Kiev extender and inseminated on the day of collection. Twelve boars of the Dutch Landrace and Dutch Large White breeds were used. Farrowing rates, total number of pigs per litter and number of live pigs per litter were higher (P less than .0001) for sows inseminated with fresh semen than for sows inseminated with frozen-thawed semen (79.1%, 10.6 and 9.9 vs 47.0%, 7.4 and 7.1, respectively). Farrowing rates for sows inseminated with frozen-thawed semen were higher when semen from Dutch Large White boars was used than when semen from Dutch Landrace boars was used (58.6 vs 40.9%); the pattern reversed for insemination with fresh semen (76.5 vs 81%). Boar differences based on farrowing rate ranged from 62 to 92% for fresh semen and from 29 to 72% from frozen semen. There was no inseminator effect or farm effect on farrowing rate. On the basis of these results, frozen semen used for artificial insemination under practical circumstances can be expected to result in a farrowing rate about 30 percentage points lower and a litter size about three pigs smaller than does fresh semen.

Animals↗
PubMed1976

[Transport of live-stock and process of slaughter (author's transl)].

The introduction on the transport of live-stock and the process of slaughter is mainly confined to transport and stunning as part of the processing of pigs as this presents a fair picture of the problems which also arise in the case of other animals. The study was promoted by problems of welfare both in the animals and in the people involved as well as by the need for modernization. The problems are due particularly to the advent of scale economies in slaughter-houses, the law failing to adjust itselt with sufficient rapidity. These problems will be solved most effectively by a good understanding between and interplay of research institutes and, for instance, the various executive veterinary services.

Abattoirs↗
PubMed1975

[Electrical stunning of pigs intended for slaughter(author's transl)].

The present situation in electrical stunning of pigs intended for slaughter is described. The methods permitted by law are reviewed. In addition, the current situation which is marked by many imperfections, is discussed. These imperfections are due to inadequate awareness of the fact that the condition of the animal to be slaughtered is an important factor but also to matters closely related to the increasing economics of scale which are being adopted in pig slaughter-houses. Methods of restraining pigs at the time of stunning, the stunning apparatus (which often receives scant attention) and the interval between stunning and sticking are discussed. Studies in progress or being initiated in the Netherlands are reviewed; as a result of these studies, legal requirements may acquire that significance which they can be expected to have.

Abattoirs↗
PubMed1975

[Fractures of the scapula in pigs intended for slaughter (author's transl)].

Fractures may be observed in the scapulae of those pigs intended for slaughter, which have undergone electrical stunning. These fractures may be classified into three types. That type in which the fracture is localized in the glenoid cavity is the most injurious one as it is accompanied by haemorrhage and therefore will result in loss of meat. This is liable to cause injuries to the employees engaged in boning out. It was concluded from an inquiry as well as from experimental exposure to stress that fractures of the shoulder are due to the marked tonic contractions of mainly antagonistic muscles, resulting in excessive strain on the shoulder blade and its joints. It is a striking fact that fractures of the shoulder were not observed in pigs stunned electrically while they were in a restraining apparatus.

Abattoirs↗