Piglets from about 6 weeks old were fed on basal diets with P 0, 0.6, 1.2 or 1.8 g/kg, 0, 1.2 or 2.2 g/kg, and 0 or 2.0 g/kg in experiments 1, 2 and 3, respectively. Blood factors did not show a significant response to P intake. Plasma alkaline phosphatase activity was not linearly related to P intake, while regressing the inorganic P content to the quantity of supplemented P resulted in a low fitness of the model (Rsuperscript 2 = 53%). Results from bone fat-free DM, concentration of ash in fat-free DM, amount of ash, concentration of P in ash and bone breaking strength were better (Rsuperscript 2 = 45 to 94%). There were slight differences in the results using tibia, femur or third and fourth metatarsals. However, the highest degree of fit was found using the apparent digestibility of P as the dependent variable (Rsuperscript 2 = 96 to 100%). After relating the criteria to the retention of P, again the apparent P digestibility was the most accurate factor to determine the biological availability of P. Basing the nutritional value of feed phosphates on digestibility of P, significant differences were shown between form and origin of feed phosphate. The values within a type of feed phosphate showed a high repeatability. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Air temperatures were measured every 2 h in 12 growing-finishing pig houses. All houses were operated on the all-in, all-out, principle. Data were collected for two fattening periods in each house. Stocking density, feeding system, pig type, and the farmer's skill were standardized. Every 2 weeks, the houses were visited and live weight, mortality rate, the incidence of coughing and tail biting, and the extent of dirty lying areas were recorded.Air temperature limits could be isolated from the complex of factors affecting behavioural and health problems of pigs observed within these experiments. Sensitive periods within the growth period of the pigs seem to exist. At the onset of the fattening period (20 to 30 kg), pigs which have been transported from other farms need special care. During summer, mortality rate was lowered when the periodicity of the temperature cycles was lowered for 40-to 50-kg pigs, whereas for heavier pigs the mean maximal air temperature was important also. With respect to coughing, a statistically significant negative relation with the air temperature in the pig house was found for all weight classes, with interactions from the number of different temperature cycles within a 24-h period. In order to avoid dirty lying areas for 20-to 40-kg animals, air temperatures should be between 20 to 24°C, whereas for diarrhoea, animals of 40 to 50 kg were especially sensitive to the occurrence of low air temperatures. For minimizing tail biting, an optimal air temperature range of 20 to 22°C is suggested.