Agriculture Reference
In-Depth Information
behavior lasts for about the first 8 h postpartum (de Passillé
et al.
, 1988a; Graves, 1984).
During this period, each piglet suckles on the average 7 different teats and there is no
preference for anterior teats. Piglets that suckle more teats during the first 8 h have greater
immunoglobulin levels (de Passillé
et al.
, 1988b). During teat sampling, piglets have their
individual suckling rhythms as each of them is active for 2-3 h after birth, then falls
asleep, and resumes activity later (Castrén
et al.
, 1989b). The teat sampling by individual
piglets gradually transforms into synchronized suckling bouts over the first 12 postnatal
hours (de Passillé and Rushen, 1989). Already during parturition, there is a certain degree
of synchrony in suckling and in weight gains by piglets (de Passillé and Rushen, 1989;
Fraser and Rushen, 1992; Rushen and Fraser, 1989). However, these early suckling bouts
occur at short intervals and tend to involve few piglets. At 10 h postpartum, milk intake
occurs during cyclical suckling bouts; however, less than half of the litter is present in
these bouts (de Passillé and Rushen, 1989). By day 1 postpartum, 85% of piglets take part,
on average, in each suckling and complete suckling synchronization of 100% is achieved
on day 3.
13.2.3
Early nursing vocalizations by the sow
Post-parturient sows emit deep rhythmic grunts when they lie in the lateral nursing
position. Peaks in grunting are present already from the onset of farrowing. During the
first 5 h postpartum, the peaks become more frequent and are related to milk ejections.
However, piglets suck the teats also when grunting rate is low (Castrén
et al.
, 1989b), so it
seems that the grunting might mainly attract the piglets to the udder in this period rather
than signal milk ejection. As the cyclic character of nursings gets established over the
first 12 h, the distinctive grunting peaks get linked with synchronous piglet suckling, and
grunting no longer occurs outside the nursing episodes. This pattern is well established
by the 2
nd
day postpartum (Castrén
et al.
, 1989b; de Passillé and Rushen, 1989).
Piglet teat competition
Piglet competition for teats is a prominent aspect of the neonatal behavior. Piglets are
precocial, being capable of active competition within minutes of birth (de Passillé
et
al.
, 1988a; Rushen and Fraser, 1989). Neonatal piglets even possess specifically oriented
canine and incisor teeth for the biting competition with each other (Fraser and
Thompson, 1991). Piglets that are born earlier sample more teats and win more of their
teat disputes than later born litter-mates (de Passillé and Rushen, 1989). Although low-
birth-weight piglets, late-born piglets, and piglets sucking only posterior teats tend to
obtain less colostrum, the differences are small and most piglets obtain an amount of
colostrum consistent with normal serum immunoglobulin concentrations (Fraser and
Rushen, 1992). Birth order has little effect on immunoglobulin G levels, except when
the duration of farrowing exceeds 4-5 h, in which case late-born piglets may be at risk
(Devillers
et al.
, 2011). During the teat sampling period, piglets fight with each other over
any functional teat as they move along the udder. The highest frequency of fighting occurs
at 3 h postpartum. Already during these teat-sampling fights, the pig with the teat in its
mouth wins two thirds of the fights (de Passillé and Rushen, 1989). As individual piglets
gradually restrict the number of teats they suckle, this 'home court' advantage develops
