The feeding system used for sows has a significant effect on the availability of sows’ key resource: food. Feeding systems are categorized as either competitive or non-competitive, depending on how feed is presented. These systems differ in initial cost, floor space requirements, group size and management requirements, thus it is important to select a system that works for your barn, herd size and management style. Planning is important, and in general you get what you pay for. Cutting costs during the renovation phase can result in a system that requires more labor and/or feed to operate in the long run.
Competitive Feeding Systems
In competitive feeding systems, feed is provided in a common area, typically on a solid floor area or in short stalls, with all sows having access to feed at once. In competitive feeding, sows can gain access to more feed through aggression, or winning a fight. These systems are managed with smaller groups (from 5 to 30 sows per group) and require more hands-on management, including careful selection of uniform groups, and daily checks on sows during feeding to monitor health and body condition. Another drawback is that more feed is used in these systems to ensure that subordinate sows can access sufficient feed. One positive attribute is that they are typically less expensive to install than non-competitive systems, often using existing feed lines.
Examples of competitive systems include shoulder stalls, open feeding stalls or floor feeding.
We define competitive feeding systems as those in which an animal can obtain more feed by winning a fight. However, this does not necessarily mean that you will observe a lot of fighting in such a system. Often, the majority of fighting will occur within a couple of hours after mixing. Once a sow’s dominance status has been established by aggression (fighting), it is often maintained by very subtle agonistic behaviour. These behaviours include threats through head movements and body posture by the dominant animals, and, for subordinate sows, moving in such a way as to avoid dominant animals. One study even referred to the social order among sows in a group to be one of ‘avoidance’ rather than ‘dominance’ (Jensen, 1982). However, if a sow is able to obtain more feed by any of these means, it is a competitive feeding system. Some feeding systems, such as gated stalls and ESF stations, protect a sow while she is eating and eliminate the possibility of obtaining more feed by fighting. We will discuss these in later articles. In this article we will discuss the ultimate competitive feeding system, floor feeding, and non-gated feed stalls that reduce but don’t eliminate competition.
Competition is a characteristic of the social system within a group of animals. In its simplest form we have dominant/subordinate relationships among the animals. The definition of dominance is that it results in priority of access to limited and defendable resources. Pig producers are generally comfortable with group housing if the resource (feed) is not limited: e.g. finishing pigs fed ad-lib. But sows are almost always limit fed to control their body condition, and so we have the possibility of competition. Our management of competitive systems is such that we attempt to reduce the dominant sows’ ability to control the resource. We do this in two ways: social and physical management. We will look at different competitive systems and how they can be managed most effectively
Non-Competitive Feeding Systems
In non-competitive feeding systems, sows are isolated and fed individually, so opportunities to gain more feed through aggression are limited. Electronic Sow Feeding (ESF) systems and free-access stalls are the most common non-competitive systems, with free access ESF systems being another recently developed option. The main advantage of non-competitive systems is the fact that they significantly reduce feeding aggression and allow greater control over individual feed intake. However, although ESFs do allow individual feeding, there can still be competition for access to the feeder. Controlling competition by not overstocking feeders and by designing pens and feeders to reduce multiple feeder entries by sows is important for the success of these systems.
Training of new sows and gilts is another important aspect of ESF systems. Animals may be reluctant to enter the feeder initially, as they may feel threatened in enclosed or dark spaces. Training pens using a standard ESF feeder, or gates to simulate the feeder entrance, can be used to familiarize new animals to the system. See gilt and sow training for more information.