"What is more uncertain is to exactly what degree heat [from global warming] affects the biology of animals and the promotion of new diseases," said the report. FAO did its last comprehensive review of the livestock sector in 1982.
The researchers underlined that the question of how climate change would alter the already "fragile relationship" between human beings and livestock was "fraught with uncertainty".
About 70 percent of the world's 1.4 billion "extreme poor" - people earning less than US$1.25 per day - are known to depend on livestock for their livelihood.
The livestock population is exploding as demand for meat and milk products grows in developing countries - by 2007 developing countries had overtaken developed countries in meat and egg production, and were closing the gap in milk production, the report said.
|What is more uncertain is to exactly what degree heat [from global warming] affects the biology of animals and the promotion of new diseases|
"During the early stages of intensification of livestock production, large-scale livestock production units tend to be established near to growing urban centres, which places large livestock populations in close proximity to large human populations."
The report noted that city residents in poor countries often kept livestock in cramped and unsanitary conditions close to their homes. "This can foster the emergence and spread of diseases affecting both animals and humans."
Highly infectious diseases that originated in animals, such as severe acute respiratory syndrome (SARS) and the influenza caused by the A (H1N1) virus have recently hit the headlines.
Vaccines and effective treatments might not be available, the report pointed out, and some diseases, such as rabies and new variant Creutzfeldt-Jakob disease, a degenerative neurological disorder, were incurable.
"Vaccination, for example, is relatively simple to apply in large, intensively managed flocks and herds, but tends to be much less cost-effective in small-scale systems because of the costs of delivering it to many small production units."
Small-scale livestock farmers did not always understand the immediate benefits of vaccination drives, and the report underlined the need for strong awareness campaigns to inform communities of new or emerging health threats and how to spot them.
FAO called for urgent measures, such as beefing up surveillance systems by involving villagers and animal health workers, and the development of animal-health protection tailored to local circumstances. It also recommended stronger collaboration between national and international animal health and food safety authorities.