Animal Flow Strategies
There are two main types of animal flow strategies: all in-all out (AIAO) and continuous flow.
This room houses nursery pigs only, from 3 to 9 or 10 weeks of age. It flows strictly AIAO - the room is completely emptied between groups of pigs. Each new group of pigs arrives in a freshly disinfected environment, and stays there for the entire nursery phase. The facility has a separate room for each week's weanings, and the same number of rooms as the length of the nursery phase, in weeks.
- AIAO means that animals of the same age or size are housed together in order to decrease the opportunities for disease entities to spread. This housing may be the same room in a barn, or ideally, the same barn, with no other ages of animals in it.
- Advantages: disease spread can be better contained, animals are less stressed when they remain with a familiar social group throughout development, and cleaning and disinfecting between groups is possible.
- Disadvantages: animals must be put into space which must be large enough to house them when they have grown. Space is less efficiently allocated.
- When you are ready to view the AIAO animation, please keep in mind that you are looking at 5 pens which will house pigs of the same age and the pigs will grow up together and then all leave together at which time the facilities are cleaned and disinfected.
In a continuous flow barn, young pigs (right) may be penned adjacent to older pigs (left). Note the size difference - pigs in these two pens are dissimilar ages.
- Continuous flow means that animals are trickle-added to a group as they are old enough or large enough. Animals of many different stages of development may be housed in close proximity to one another. The facilities are never empty.
- Advantages: space is efficiently used, because pigs can be moved to larger pens as they grow, and new arrivals can replace them in the smaller pens.
- Disadvantages: animals of varying immunocompetence are housed together facilitiating disease spread, stress levels can be heightened with changing social groups, adequate cleaning and disinfecting are not feasible.
This is a continuous flow nursery/finisher barn. The young pigs are in the foreground and older pigs are in the background. This barn houses 1200 pigs ranging in age from 10 to about 26 weeks of age.
- When you are ready to view the continuous flow animation, note that you are watching different size pigs grow up next to one another. Pens empty in a staggered fashion, and the facilities are never empty.
The AIAO and contiuous flows may be viewed together. Use the opportunity to get a feel for the differences in the flows.
Copyright ©1997 by the University of Pennsylvania School of Veterinary Medicine
Faculty: Dr. Paul Pitcher
Student: Sandra Springer,'99