Biomedical subjects

N A de Visser

Publications and source records attributed to N A de Visser.

4 recordsLinked to original sources

PubMed1988

Consequences of failure of the reticular groove reflex in veal calves fed milk replacer.

A number of problems seen in veal calves are associated with insufficient adaptation to the changes in husbandry connected with the fattening system. These problems include chronic tympanitis, chronic vomiting, cachexia, unthriftiness, abomasal erosions and ulcers. Some of these problems are associated with failure of the reticular groove reflex, and result in ruminal drinking. Persistent ruminal drinking causes a syndrome characterised by a variety of symptoms such as unthriftiness, severe growth retardation, inappetence, recurrent tympany, abdominal distension, a long dry haircoat and clay-like faeces. Clinical studies performed to investigate the pathogenesis of the syndrome are described. It was found that the milk was stored in the rumen and was partly broken down. The presence of milk in the rumen induced typical changes in the ruminal mucosa (hyper/parakeratosis) and also inhibited casein clot formation in the abdomasum. The small intestinal mucosa showed villous atrophy. After training, the reticular groove reflex was re-established in a number of patients but the growth rate of these calves did not return to normal.

Animal Feed↗

PubMed1987

Enteric infections in veal calves: a longitudinal study on four veal calf units.

Forty-five calves on four veal calf units were monitored during the first four weeks after their arrival. Faecal samples were collected on alternate days and screened for the presence of rotaviruses, bovine coronavirus, Cryptosporidium oocysts, K99 positive strains of E. coli and Salmonella spp. Rotaviruses and Cryptosporidium were the most commonly detected agents (78% and 60% respectively of the calves). Bovine coronavirus was detected in the faeces of 18% of the calves, whilst K99 positive E. coli was only found in 2 samples from one calf. Salmonella spp. were not isolated from any of the 646 faecal samples examined. Shedding of rotaviruses occurred in a bimodal pattern beginning in the first week of the survey. Cryptosporidium oocysts were detected most frequently in the interval between the two peaks of rotavirus shedding. The presence of rotaviruses or Cryptosporidium oocysts in faeces was not strongly associated with scour, nor were combined infections with these agents or the cases of bovine coronavirus infection. The condition of the calves throughout the survey was generally satisfactory.

Animals↗

PubMed1985

[Gentamicin: various pharmacotherapeutic aspects in comparison with other aminoglycosides].

Gentamicin may be used in the treatment of infection with gram-negative bacteria including Pseudomonas spp and Proteus spp. Resistance will only appear in suboptimal or too prolonged courses of treatment and usually is due to 'multi-step mutation'. This resistance may be prevented, among others, by combined treatment with gentamicin and an antibiotic of the beta lactam group. When gentamicin is used correctly, it will have few toxic side-effects. Thus, 3 mg/kg of body weight three times daily will usually be indicated to ensure an optimum therapeutic effect. Parenteral administration of gentamicin would only appear to be useful in cases of bacteraemia and/or bacterial infection of the kidney and/or urinary excretory ducts; in the last-named case, the dose given at one time may be reduced by fifty per cent. Local treatment, the most recent method of which consists in administration by I(ntra-)T(racheal) route, apparently offers more prospects.

Administration, Topical↗

PubMed1984

[Ruminal drinkers and clay defecators].

In this clinical lecture, attention is drawn to the phenomenon of young milk-fed calves showing irregular appetites and recurrent bloat. These patients often produce faeces which are too dry and too light in colour. These symptoms are preceded by inadequate closing of the oesophageal groove during milk intake, which causes an inflow of milk into the rumen rather than into the abomasum. The present authors introduced the term 'Ruminal Drinkers' to describe this type of patient. The identification of ruminal drinkers as well as the clinical findings are reviewed. The effects of ruminal drinking, the therapy indicated and a number of preventive measures are discussed.

Animals↗