After around 115 days, a female domestic pig usually gives birth to about 10-14 piglets. Three to four days before the birth, the sow will become restless. In nature or in free-range systems, she leaves the group and looks for her own place to create a litter nest. Other pigs are no longer tolerated, and the sow is behaving highly aggressive towards them.
Pregnant sows, standing on slatted floors, have no nesting material available. If your freedom of movement is restricted in the box stall, your stress level increases. The animals therefore show several behavioural disorders such as the stereotypical "empty digging" or "bar biting". If the sows are offered straw as bedding, their restlessness decreases.
Piglets can suffocate without straw
The birth (farrowing) takes about three to four hours. The very advanced piglets are born with open eyes and ears and can run just a few minutes after birth. They free themselves from the pericarp (placenta). Rough litter, such as straw, makes this process easier and in the absence of such material, the piglets can suffocate by the placenta material within a very short time.
Immediately after birth, the sow briefly leaves the nest to defecate and urinate. If she is prevented from doing so, as in the crate, it often happens that she retains the defecation for so long that it may arise to a blockage.
A suckling order begins to form shortly after birth: the front teats of the sow are occupied by the strongest and most vital piglets, the weakest piglets on the rear teats. The piglets spend the first week close together in the nest. In the second week they leave the nest for the first time to explore the area and play with other animals in the group.
Lack of enrichment in stables causes tail biting in piglets
After about two weeks, the sows and their piglets are put together in one group. Cross-litter rank relationships between piglets are established in a playful way. During this time, the sow and her piglets are constantly in visual and acoustic contact. If a piglet is lost, they would call for their mother. In nature, or in free-range husbandry systems, the piglets stay with the sow until they are about three months old. Although piglets rely on breast milk for the first seven weeks, they start eating solid foods and drink water in the second week.
If the piglets are weaned at the age of three to five weeks, as in intensive husbandry systems, they are weaned off, thus suffering from the loss of their mother. In addition, their suckling demand remains unsatisfied. The piglets then carry out substitute actions and suck lifeless objects or the soft parts of their siblings' bodies.
This means that the tail of other piglets in the group, due to the lack of stimulus, represents a very attractive, flexible conversion stimulus. Initially still playful, the behaviour of the piglets becomes rougher over time. This can result in serious injuries, infections, or even in complete amputation of the tail. In the worst case, a complete paralysis of the hindquarters occurs after an infection and abscesses in the spine. For this reason, various interventions are carried out on pigs in intensive systems to adapt them to the husbandry, but unfortunately not vice-versa, thus the underlying needs remain, and interventions do not reach their goal - one of these unsuccessful interventions is 'tail docking'. Learn more about the mutilations performed on pigs to adapt them to the husbandry systems here.