Senses and social behaviourPigs rely strongly on their sense of smell and hearing. Sows recognize their piglets by smell, and boars smell the sows to check their heat. Voice and hearing are very important in the social behaviour of pigs. Pigs "chat" nearly constantly in quiet grunts to stay in contact with their pack. Warning signals and cries for help are high-pitched and loud. Boars sing a "love song" to attract sows, and the sow's voice signals tell the piglets when milk is available.
|(c) Daily Mail. Check their article about pig slaughtering.|
Unlike many other animals, pigs are contact animals. A sow does not lick its piglets, nor do pigs lick one another. Instead, they eat in groups and sleep side by side, close together. Even mating behaviour is rather straightforward: instead of courting, the boar can just mount the sow. Sows have a standing reflex, which means that in heat it will stand still when pressure is applied to it's loins. In addition to sleeping, eating is also synchronized. Pigs wake up at sunrise, and spend most of their time nosing the ground for food. They eat for 8 hours, and sleep 12-14 hours a day.
Skin care: Pigs have two ways for skin care: wallowing in mud and scratching themselves against walls. Wallowing in mud is not just fun, it also cools the animal on a hot day, rubs away dead skin and removes parasites.
Thermoregulation: Piglets under 3 weeks of age cannot thermoregulate, and in piggeries they depend on heat lamps. In the wild piglets live in a nest built by the sow, so they stay warm. Adult pigs have almost no fur and no sweat glands, so they can thermoregulate only by changing their behaviour.
Parturition and weaningOne or two days before giving birth, sows start to look for a place for a nest. They may wander several kilometers searching for a good spot. 6-12 hours before parturition the sow begins the actual nest building. It digs a shallow hole, and then collects branches, hay, turf and other materials, which it uses to build a nest. 1-2 hours before parturition the sow lays down on her nest. When the piglets are born, the sow lays passively. Domesticated pigs give birth to 10-15 piglets, which are born about 15 minutes from one another. After birth piglets instinctively crawl to the udder and start suckling. If a piglet doesn't get colostrum within few hours of birth, it will die. Colostrum is vital, for the piglets have no antibodies. If the sow is vaccinated before parturition, the piglets will get immunity as well.
For the first three days the piglets fight for teats, but they then develop a clear "teat order": each piglet has its own teat. This is important, because after 12 hours the sow gives milk only once every 45 minutes. It announces milk letting by grunting, and every piglet has about 10 minutes to find a teat and suckle.
|(c) Keith Weller / Shutterstock|
In piggeries sows are not allowed to build nests, and they are often confined to tiny parturition crates for weeks. The crates don't allow the sow to turn around, sometimes not even to stand up. Crates are used so the sow wouldn't lie down on the piglets. Naturally the sow has an anti-crushing behaviour, but in piggeries the sow often cannot hear if a piglet screams when sat on. Studies show that parturition is faster, more piglets are born alive and the sow lets more milk when giving birth freely, compared to birthing crate. Building a having a sest also calms the sow, calms the parturition and improves the relationship beween the sow and the piglets.
Welfare of pigsThe welfare of pigs consists of several basic building blocks:
- air quality and temperature
- Pen structure (size of pen, flooring material)
- availability of litter and other stimuli
- social environment (stable groups)
- feeding (appropriate feed, enough space for all pigs to eat at the same time, enough roughage)
- Attitude and skills of the caretaker
In piggeries, pigs are moved from one department or piggery to one another several times. Each department should take into consideration the needs pigs have at that particular age.
Parturition dept: Since piglets are very sensitive, clean, dry and warm environment is vital for them. During the first few days piglets are castrated, ear-marked, given a tattoo and an iron injection, and their canines are filed. All these cause pain and risk for infections. Parturition dept must have clean space available for these operations. Flooring material is important, so the feces and urine can be cleaned, but the floor isn't too hard or cold for the piglets.
|Intensive piggery, a "hog lot"(c) Wikipedia|
Meat pig farm: For adult pigs, stable groups and enough space are important. They must be able to sleep together and eat together, have separate areas for eating, sleeping and defecating/urinating, and they need space for social behaviour. Stimuli are also important. Temperature can vary more than in previous departments.
Department for pregnant sows: Like the meat pig farm, but pregnant sows need even more space than meat pigs.