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A B S T R A C TThe environmental impacts of livestock production are attracting increasing attention, especially the emission of greenhouse gases (GHGs). Currently, pork is the most widely consumed meat product in the world, and its production is expected to grow in the next few decades. This paper deals with the production of carbon dioxide (CO 2 ), methane (CH 4 ) and nitrous oxide (N 2 O) by animals and by manure from pig buildings, with a focus on the influence of rearing techniques and nutrition. GHG emissions in piggeries originate from animals through CO 2 exhalation and CH 4 enteric fermentation, and from manure through the release of CO 2 , CH 4 and N 2 O. The level of the CO 2 exhalation (E-CO 2, pig ) depends on the physiological stage, the body weight (BW), the production level and the feed intake of the animals concerned. Enteric CH 4 (E-CH 4, pig ) is principally related to dietary fibre intake and the fermentative capacity of the pig's hindgut. Based on a review of the literature, the following equations are proposed in order to estimate E-CO 2, pig (in kg day À1) and E-CH 4,pig (in g day À1 ) for fattening pigs: E-CO 2,; E-CH 4,pig = 0.012 Â dRes; with BW (in kg) and dRes for digestible residues (in g day À1 ). Numerous pathways are responsible for GHG production in manure. In addition, the microbial, physical and chemical properties of manure interact and modulate the level of emissions. Influencing factors for removal systems for both liquid and solid fractions of manure have been investigated. A large range of parameters showing an impact on the level of GHG production from pig houses has been reported. However, few of these can be considered unquestionably as GHG mitigation techniques because some strategies have shown contradictory effects depending on the gas, the circumstances and the study. Nevertheless, frequent manure removal seems to be an efficient means to reduce concurrently CO 2 -, CH 4 -and N 2 O-emissions from pig buildings for both slatted and bedded floor systems. Manure removal operations may be associated with specific storage conditions and efficient treatment in order to further reduce emissions. Several feeding strategies have been tested to decrease GHG emissions but they seem to be ineffective in reducing emissions both significantly and durably. In general, good management practices that enhance zootechnical performance will have beneficial consequences on GHG emission intensity. Taking into account the results described in the literature regarding CO 2 -, CH 4 -and N 2 Oproduction from animals and manure in pig houses, we estimate total GHG emissions to 448.3 kg CO 2 equiv. per slaughter pig produced or 4.87 kg CO 2 equiv. per kg carcass. The fattening period accounts for more than 70% of total emissions, while the gestation, lactation and weaning periods each contribute to about 10% of total emissions. Emissions of CO 2 , CH 4 and N 2 O contribute to 81, 17 and 2% of total emissions from pig buildings, representing 3.87, 0.83 and 0.11 kg CO 2 equiv. per kg carcass, re...

SUMMARYStandardized methods were used to make quantitative and qualitative assessments of respirable dust and aeroallergens in feed and bedding for horses.Concentrations of airborne dust were measured by using a Rion particle counter, and levels of major aeroallergens implicated in chronic obstructive pulmonary disease were measured by using an Andersen sampler. Laboratory conditions allowed comparison of the different sources of forage, supplements, and bedding without external influences such as ventilation, external temperature and horse activity affecting the result. Crass silages of approximately 50 % dry matter and alfalfa pellets appeared to be very good sources of forage with low levels of dust and aeroallergens. The studied good quality straw was significantly less dusty with fewer allergens than the wood shavings. Supplements, such as whole grains and molassed concentrates, contained many respirable particles and aeroallergens. Rolled grains were significantly more dusty than good hay.

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