Infectious stunting syndrome associated with disturbances of mineral metabolism and bone development in broiler chickens

On a broiler farm with a rearing capacity of about 200,000 chickens, a disease characterised by growth retardation, variability in chick size, 'leg weakness', diarrhoea and increased mortality at 3 weeks of age occurred repeatedly, in several successive broiler flocks. Gross and histopathological findings were dominated by widening of the hypertrophic and ossification layers of the physes of long bones as well as by thickening, unevenness and defective calcification of the cartilage trabeculae. In the parathyroid gland, vacuolar degeneration of the cytoplasm of glandular epithelial cells, connective tissue proliferation and, here and there, cyst formation were seen. Additional findings included severe cerebellar oedema and neuronal degeneration. The pancreatic, myocardial and intestinal changes typical of infectious stunting syndrome (ISS) occurred only in a mild form. Four-week-old chickens exhibiting 'leg weakness' had significantly lower blood inorganic phosphate concentration and tibial ash content as compared to healthy chickens. The disease was successfully transmitted by oral administration of small intestinal homogenate from affected chickens. In a second experiment, however, the disease could not be transmitted with intestinal homogenate sterilized by irradiation. Large doses of vitamin D3reduced the rate of growth retardation and defective calcification of bones. The digestive enzyme activities of the pancreas and small intestinal mucosa of 'infected' chickens were decreased as is typical of ISS

Massive goitre (Struma parenchymatosa) in geese

In a goose flock consisting of 2300 birds of 6 months of age severe goitre was diagnosed. To the best of our knowledge this is the first report of naturally occurring goitre in geese, which is not related to the feeding of rapeseed meal. The major pathological findings included retarded growth and plumage development, significantly (300%) increased relative thyroid weight, fat accumulation in the mesenteric and abdominal region, and lipid infiltration of liver and kidney cells. Subsequent hormone analysis showed undetectable thyroxine (T4) levels and a dramatic drop in triiodothyronine (T3) plasma levels of the diseased geese. Thy- roidal histology displayed the typical signs of struma parenchymatosa. In order to get more information about the possible causes of the goitre, 10 geese from the affected farm were transferred into the laboratories of the Central Veterinary Institute. The geese were allotted into two groups. Group I received iodine supplementation for 55 days, while the other group served as sick control (Group S). Iodine treatment caused a dramatic improvement in the birds clinical condition except in plumage growth in Group I, while the clinical and main pathological signs of goitre remained unchanged or worsened in the untreated Group S. Contrary to this, the serum levels of thyroid hormones and responsiveness to thyrotropin releasing hormone (TRH) improved not only in Group I but also in Group S. Almost euthyroid biochemical parameters were found after 55 days of iodine treatment in Group I and, surprisingly, a considerable improvement (especially in serum T3 levels) occurred also in Group S. These findings confirm the diagnosis of goitre but also call attention to the fact that iodine deficiency was not the only factor eliciting the disorder. The underlying possible goitrogenic substance could not be traced down

Energy imbalance related predisposition to mastitis in group-fed high-producing postpartum dairy cows

The energy imbalance related predisposition to mastitis was studied in group-fed postpartum dairy cows (n = 333) kept in 4 large-scale units and producing milk of low somatic cell count (SCC). Blood samples were taken on Days 1-3 after calving for assaying some metabolites and hormones related to the negative energy balance (NEB). If mastitis was diagnosed later, aseptic milk samples were taken to identify the pathogens. Considering pathogen types [contagious pathogens: Staphylococcus (S.) aureus, Gram-positive (GP) environmental pathogens, and Gram-negative (GN) environmental pathogens + mastitis with no detectable pathogens (NDP)] separately, stepwise logistic regression was used to analyse the relation between the potential prognostic value of hormones and metabolites and mastitis outbreak. Only the elevated (= 1.00 mmol/l) serum ß-hydroxybutyrate (BHB) levels predisposed the cows to mastitis in the subsequent 4 weeks. This prognostic value of BHB was significant only in GN + NDP mastitis and in cases caused by GP environmental pathogens, but not in S. aureus mastitis (odds ratio: 5.333, 3.600 and 1.333, respectively)