[Artificial insemination].
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Animal Husbandry↗
Biomedical subjects
J A van Lieshout
Publications and source records attributed to J A van Lieshout.
The serological BHV1 status of dams determines the precolostral status of their calves.
Precolostral calves and their dams were serologically investigated for the presence of antibodies against Bovine Herpesvirus 1 in diagnostic tests with a very high sensitivity and specificity. Although the syndesmo-chorial type of placenta of ruminants does not transfer gamma globulins, a large number of calves had antibodies, in most cases in a very low concentration. Significant correlations were found between the serological status of the dam, the status of the calf, and the titre of antibodies. Oral intake of maternal blood by the calf at birth or transmission or leakage of maternal antibodies during pregnancy might be possible causes of precolostrally positive calves. From the results it is concluded that to reduce the risk of obtaining BHV1-positive calves, BHV1-negative dams should be selected for breeding purposes.
Animals↗
A subclinical infection of bulls with bovine herpesvirus type 1 at an artificial insemination centre.
A subclinical bovine herpesvirus type 1 (BHV1) infection affected bulls at an artificial insemination centre for at least six months. The virus was detected in semen samples from 43 out of 116 bulls examined; 27 of them shed virus during one consecutive period of up to 10 days and 16 shed the virus intermittently. The virus titres ranged between 10 and 100,000 TCID50/ml. Vaccinated bulls tended to excrete the virus less frequently than unvaccinated bulls. Approximately 50 per cent of the bulls that had an increase in neutralising antibody titre to BHV1 shed the virus in their semen.
Animals↗
Spread of bovine virus diarrhoea virus in a herd of heifer calves.
A calf persistently infected and immunotolerant to Bovine Virus Diarrhoea virus (BVD virus) was, on purpose, introduced to a herd of heifer calves over 4 months of age that had been reared as recipients for embryo transplantation. All calves were brought in contact with the persistently infected animal. In total, 240 calves were involved in this experiment, 22 of which were serologically negative when introduced. These serologically negative animals developed antibodies against BVD virus within 5 months after introduction. At short distances from the persistently infected BVD virus shedder, negative calves seroconverted within 2 months, but at greater distances the moment of seroconversion was unpredictable. The calves that had undergone a natural infection with BVD virus received embryos after transportation to an allied farm. In total, 14 calves were born after embryo transplantation, all of which were free of BVD virus, in spite of the presence of BVD-virus on the latter farm.
Animals↗
Practical experiences with prostaglandins in heifers and dairy cows.
This paper describes the extent to which utilisation of prostaglandins (PG) to achieve synchronisation of oestrus can influence certain economic results. Special attention is paid to the fertility status (FS) and calving index in dairy cows, where PG-treated groups are compared with untreated groups. With regard to these parameters a significant difference exists in favour of the PG treated group. In heifers the pregnancy rate after the first insemination has been determined in a PG treated group. The result compare very well with other published data. On large farms, where heat detection is poor, the routine use of PGs in the total herd is economically attractive. On those farms where the practitioner is involved in a fertility guidance system and where optimum heat detection takes place, the routine use of PGs in dairy cows would seem to offer advantages from a financial point of view.
Animal Husbandry↗
[The teaser bull (author's transl)].
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Animals↗
[Aujezky's disease in the field and vaccination against the disease (author's transl)].
A rather extensive outbreak of Aujeszky's disease in the area served by the above veterinarians is reported. Of 252 pig-breeding farms, eighty-two were contaminated. The other herds (170) were partly (81) vaccinated against the disease with the Bartha strain. Unlike de non-vaccinated group, the immunized herds showed few of any losses. In view of this fact it is concluded that Aujeszky's disease vaccination is a useful procedure (even in a contaminated environment).
Animals↗