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The efficiency of manure separation by a conveyor belt under a partially slatted floor for fattening pigs was determined for two types of belts, a fíat belt with an incline of up to 6° transversely and a concave belt with an incline of up to 1° longitudinally. A 31.20% and 23.75% dry matter content of the solid fraction was obtained for the fíat and concave belt, respectively. The fíat belt was more efficient at 6° than other slope angles. The residence time of the manure on the two belt types influenced the separation efficiency from a Uve weight of 63.00 kg upwards. The quantity of residue produced with this system was _ .

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A well-designed environmental control system is the most efficient tool to ensure optimal production in livestock housing. In countries having a hot climate, such as Spain, the former comprises a large proportion of the capital invested in housing, and it deserves a thorough assessment. Most of the research carried out has been done in countries with a temperate climate and considering short hot periods, or even without them. The efficiency of the evaporative cooling system, which is commonly used in hot climate areas, depends upon the pad wetted surface area exposed to the passing air. Keeping the chosen inside temperature requires a definite cooled down of the outdoor air that is related to the 'temperature tolerance', i.e. the difference between inside and incoming air temperatures. The objective of this work was to establish the temperature tolerance when using the steady-state heat balance in commercial poultry housing. The heat balance estimates were imbalanced whenever the difference between indoor and outdoor temperature was less than 2ºC. Substituting the exhaust air temperature for the indoor temperature in the expression that provides the heat drawn out through ventilation balanced the heat equation. The difference between inside and incoming air temperatures, temperature tolerance, has to be at least 2ºC.

The aim was to measure the behaviour of various mortars employed in livestock media in central Spain and to analyse the aggressiveness of pig slurry to cement blended with flyash mortars. To achieve this, mortar specimens were immersed in ponds storing pig slurry. Mortar specimens, of 40 x 40 x 150 mm, were made from four types of cement commonly used and recommended for rural áreas. The types were a sulphate-resistant Portland cement and three cements blended in different proportions with fly ash and limestone fiUer. After 3, 5, 12, 24, 35, 48 and 50 months of exposure, three or four specimens of each cement type were removed from the pond and washed with water. Their compressive strength and microstructure (X-ray diffraction, mercury intrusión pore-symmetry, thermal analysis and scanning electrón microscopy) were then measured. Sulphate-resistant Portland cement (SR-PC), found to be more susceptible to degradation due to its greater proportion of macro-pores and increased total porosity, was found not to be suitable for use with livestock. After 50 months of immersion in the pig slurry médium, CEM II-A (40.3%) mortar retained the greatest compressive strength. Mortars with less than 20% replacement of cement by fly ash were found to be the most durable, with the most suitable mechanical behaviour.