Background: Crossfostering is the transference of piglets to either equalize litter size or to formation of homogeneous litters
according to the birth weight. It is used in order to improve survival rate and weight gain of piglets during lactation. Several
aspects influence the results of crossfostering, as the moment when this management is performed, size of the piglets and parity
order (PO) of biological and adoptive dams. Crossfostering should be performed, preferably between six and 24 h after farrowing,
before teat order has been established and so that piglets can absorb the maximum of colostrum immunoglobulins from their
biological dams. Performance and viability of piglets during lactation depends on the quality of colostrum and milk production
of biological and adoptive dam, which varies according to PO. The aim of the experiment was to assess the performance of
biological and adopted piglets crossfostered in PO 1 and PO 5 females.
Materials, Methods & Results: Thirty females (18 PO 1 and 12 PO 5 females), of Agroceres PIC® genetic, from a Piglet Production
Unit, were used for this experiment. Piglets were crossfostered within eight to 24 h after farrowing. Litters were formed with 11
piglets each, with 1.2 to 1.6 kg at birth. Piglets were individually earmarked at the time they were crossfostered. In PO 1 sows 50%
of their original piglets remained and 50% of piglets were adopted from PO 5 sows. Similarly, PO 5 sows kept 50% of their piglets
and received 50% of adopted piglets from PO 1 sows. For the statistical analysis, four groups were taken into account as
followed: PO1B1 - piglets suckling in their original PO 1 dam; PO1A5 - piglets coming from PO 5 sows but adopted by PO 1 sows;
PO5B5 - piglets suckling in their original PO 5 dam, and PO5A1 - piglets coming from PO 1 sows but adopted by PO 5 sows.
Piglets were weighed at seven, 14 and 18 days old.
Discussion: The mortality rate until 18 days of lactation was 0.9% and was similar among groups (P > 0.05). Within the same PO
there was no difference (P > 0.05) in weight among biological and adopted piglets (2.53 vs. 2.56, 4.07 vs. 4.08, 5.05 vs. 5.06 for litters
of PO 1 sows and 2.84 vs. 2.82, 4.80 vs. 4.78, 5.90 vs. 6.05 for litters of PO 5 sows, at days seven, 14 and 18, respectively). Piglets
nursed by PO 5 sows showed higher weight (P <0.05) than those nursed by PO 1 sows, regardless of being biological or adopted.
Crossfostering performed in the period considered ideal, health status of farm and care given to piglets during lactation may have
contributed to that mortality rate was extremely low in all groups. Performance and viability of piglets during lactation is
dependent on the quality of colostrum and milk production of both adoptive and biological dams. Litters nursed by sows of
higher PO may have immunity for a greater number of antigens and less chance of compromising their performance. Increased
milk and colostrum production can provide to piglets a major input of nutrients and therefore better performance, which was
observable in litters of PO 5 sows. When nursed by dams of the same PO, the performance of biological and adopted piglets was
not affected by crossfostering when it was performed eight to 24 h after farrowing. There was a lower performance of piglets
nursed by PO 1 sows compared to PO 5 sows, regardless of being biological or adopted.
