Animal welfare complementing or conflicting with other sustainability issues
Systems for the production of food, or other products for human use, should be sustainable. This means that the system should be acceptable now and its expected future effects should be acceptable, in particular in relation to resource availability, consequences of functioning and morality of action. However, there are many components of sustainability. People who consider only one aspect may not advocate the best solution. If the focus is entirely on: animal welfare, preservation of rare wildlife species, maximising local biodiversity or minimising greenhouse gas production may cause other harms. When an agricultural or other product is considered, life cycle analyses can take account of every contributory factor. Every externality of the system should be evaluated and the value of each balanced. Some actions that improve animal welfare may also have positive environmental effects and each aspect can be measured. If straw from cereal production is burned, carbon dioxide is released but if it is used as bedding or for manipulation welfare is improved and the greenhouse gas effect can be reduced. Taking wild animals to keep as pets leads to poor welfare and wild populations are reduced. Stray dogs have a negative impact on the populations and welfare of some wild animals. Stray dog welfare is often poor because of disease and malnutrition so humanely killing the dogs can prevent poor welfare and benefit conservation. The land-sparing argument, encouraging intensive animal production so more land is available for nature reserves, would favour feedlots for beef production but the welfare of the cattle in feedlots is often poor and water usage and pollution can be high. However, semi-intensive silvopastoral systems are very efficient and their use of shrubs and trees greatly increases biodiversity, reduces greenhouse gas production per unit of production, reduces conserved water usage and improves welfare. Conserving land for hunting wild animals increases biodiversity but the hunting usually causes poor welfare. Where endangered species cannot adapt well to captive conditions, captive breeding might preserve the species but the welfare of the captive animals is poor. When a system is being evaluated, each of the many components of sustainability should be measured precisely: welfare, biodiversity, worker satisfaction, water use, greenhouse gas production and harmful accumulation of pollutants like nitrogen and phosphorus. Decision-making may involve developing units for comparison of each positive and negative consequence or considering any negative that is so great that no counter-balancing would ever be acceptable to the public.