Influence of diet on calcium metabolism, tissue calcification and urinary sludge in rabbits (Oryctolagus cuniculus).

Rabbits absorb more calcium (Ca) from their diet than they require, and excrete surplus via urine, which therefore contains a typical 'sludge'. This makes rabbits susceptible to Ca-containing uroliths. But given the Ca content of diets of free-ranging specimens, and the limited reports of urinary sludge and Ca contents in free-ranging lagomorphs, we can suspect that rabbits are naturally adapted to high urinary Ca loads. We fed four groups of New Zealand hybrid rabbits [n = 28, age at start 5-6 weeks) pelleted diets consisting of lucerne hay only (L, Ca 2.32% dry matter (DM)], lucerne:oats 1:1 (LG, Ca 1.36%), grass hay only (G, Ca 1.04%), or grass:oats 1:1 (GG, 0.83%) for 25 weeks, with water available ad libitum. Diets were not supplemented with Ca, phosphorus, or vitamin D. Rabbits on diets LG and GG had lower food and water intakes, lower faeces and urine output, grew faster and had higher body mass at slaughter (mainly attributable to adipose tissue). Apparent Ca digestibility decreased in the order L-LG-G/GG. Rabbits on L had larger and heavier kidneys, more urinary sediment at sonography, and a higher urinary Ca content than the other groups. No animal showed signs of urolithiasis/calcinosis at X-ray, sonography, or gross pathology. Kidney/aorta histology only sporadically indicated Ca deposits, with no systematic difference between groups. Under the conditions of the experiment, dietary Ca loads in legume hay do not appear problematic for rabbits, and other factors, such as water supply and level of activity may be important contributors to urolithiasis development in veterinary patients. However, due to the lower Ca content of grass hay, the significantly lower degree of urinary sludge formation, and the significantly higher water intake related with grass hay feeding, grass hay-dominated diets are to be recommended for rabbits in which urolithiasis prevention is an issue.

Diseases in chicks and laying hens during the first 12 years after battery cages were banned in Switzerland.

Between 1992 and 2003, a period of 12 years after the definitive ban on battery cages in Switzerland, more than 10,000 replacement chicks and laying hens were examined postmortem. There was a significant decrease in the incidence of viral diseases, mostly due to a reduction in Marek's disease, but there was a marked increase in bacterial diseases, particularly since 1999, mainly due to colisepticaemia in young laying hens. There was a steady decrease in parasitic infections, but the incidence of non-infectious diseases varied from year to year, with no clear trends. There were no significant emerging diseases or economic losses in the alternative housing systems. Vaccination and hygiene were the most effective precautions against infections, and control strategies brought about a marked decline in notifiable diseases, especially for Salmonella Enteritidis. Fifteen years after the ban on battery cages in Switzerland, the health and egg production of laying hens is good.

Choriocarcinoma with metastasis in a rabbit (Oryctolagus cuniculi).

A 3-year-old female rabbit (Oryctolagus cuniculi) presented with apathy and indisposition for 2-3 days. Palpation revealed a mass in the caudal abdomen, namely, in the wall of the uterus. Ovariohysterectomy was performed, and the tissues were submitted for histopathologic examination. The mass consisted of 3 different (trophoblastic, syncytiotrophoblastic, and cytotrophoblastic) neoplastic cell types originating from the uterus. Immunohistochemistry was positive for cytokeratin in all 3 neoplastic cell types, and the syncytiotrophoblasts were positive also for human chorionic gonadotropin. Together these features allow the diagnosis choriocarcinoma. This report documents the first case of a spontaneous choriocarcinoma in a rabbit.