A number of Michigan pork producers have questioned whether the “rescue decks” really pay off, according to Barbara Straw, Extension veterinarian at Michigan State University (MSU).

Producers are impressed with the way that disadvantaged pigs perform in the decks in the farrowing house, but question whether those pigs will simply fall back again in the nursery.

Jerry May, MSU Extension swine specialist, set up a trial with a 2,000-sow commercial producer who raised this question.

In the past, it's been common procedure on such an operation to provide supplemental care to pigs that demonstrate slow growth in the first 3-5 days of life.

In this herd studied, routine crossfostering occurs at birth to standardize litter sizes. Then at 3-5 days of age, a litter created from 8-11 undersized pigs is collected from a room of 20 litters. The next gilt to farrow (one of the last in the group to farrow) has all of her piglets removed and transferred to the other remaining newborn litters so she can become a nurse sow for an entirely adopted litter of fallbacks.

In an effort to duplicate the success of using foster litters, an automatic milk feeder was installed to accommodate a litter of healthy piglets. These piglets were moved to the milk feeder to free up their dam to nurse fall-back pigs.

While these foster (fall-back) litters thrived in farrowing, it was unknown whether pigs from these litters would do well in the nursery, or whether they would continue to need special care.

Table 1 depicts the fostering process at the farm for challenged 3-5 day-old pigs. At the same time, 18-day-old pigs were being weaned. The protocol at weaning was to commingle pigs that had received supplemental care in lactation with normal pigs to find out if the supplemented pigs could grow on their own.

In four farrowing rooms at the time of weaning, there were 117 pigs that had been small at 3-5 days of age and placed on foster sows. These pigs were ear tagged to identify them as pigs that had received supplemental care during lactation.

At weaning, 88 of the tagged pigs met the target weight of 13 lb. and were moved to the nursery. Eighteen of the remaining 29 pigs that remained in the farrowing room reached the weaning weight requirement one week later at 25 days of age, while the other 11 pigs died.

To reduce handling stress, weights of tagged and routinely handled pigs were collected one week postweaning, when pigs were vaccinated for Mycoplasmal pneumonia. Pigs were weighed again 35 days postweaning, just prior to movement to the finisher (Table 2).

Overall, three of the undersized pigs died in the nursery (3/106=2.8%), compared to the usual herd nursery mortality of 2.0%. A total of 103 of the undersized pigs completed 35 days in the nursery. And their weight going into the finisher of nearly 40 lb. was no different than normally raised pigs.

In sum, pigs that fail to thrive in the first three days of life are capable of performing adequately if provided supplemental care. These pigs can achieve weights at weaning and at the end of the nursery phase comparable to pigs managed without special care.

Fall-back pigs in this study were due to nutritional deficiencies and not disease, which would have required a different outcome.

Researcher: Barbara Straw, DVM, Michigan State University. Contact Straw by phone (517) 432-5199, fax (517) 432-3450 or e-mail straw@cvm.msu.edu.