IMPROVING PREWEANING SURVIVAL OF PIGS
Duane E. Reese, Gary R. Parker, Dennis O. Liptrap, Tim S. Stahly and
Gary L. Cromwell
The loss of baby pigs before weaning
is an enormous waste of resources. Recent data from 49 Kentucky farrow-to-finish
swine farms indicate that an average of 80 percent of pigs born alive survive
to weaning. Most of these losses occur during the first 23 days following
The survival rate of young pigs improves
as birth weight increases. In addition, birth weights are partially dependent
on the amount of feed consumed by the sow during gestation (Table 1). Restricting
feed intake too severely during gestation will result in lighter weight
pigs at birth and hence lower survivability. In order to achieve adequate
material and fetal weight gain during pregnancy, it is important to adjust
feed intake during gestation according to the physical condition of the
sow and the environmental conditions in which she is maintained. Sows with
adequate body fat reserves that are individually confined in an environmentally
regulated building may need only 3 1/2 to 4 pounds of a corn-soybean meal
diet daily; those in relatively poor condition and/or housed outdoors during
the winter may need 5 to 7 pounds daily.
Table 1. Effect of gestation feeding level on pig birth weight1,2
1Adapted from Henry and Etienne, 1978.
Avg. pig birth weight, lb
2Based on 29 experiments involving over 5,000 liters.
3Based on a corn-soy diet.
Since fetal growth increases significantly
during the final trimester of gestation, it would seem beneficial to increase
the sow's feed during this time. Based on recent data, increasing the sow's
intake of a corn-soybean meal diet by 3 pounds per day during the last
3 weeks of gestation results in larger pigs at birth and improved survival
rate (Table 2). The magnitude of a response to elevated feed levels in
late gestation is probably related to overall sow herd condition and the
average birth weight of pigs in the herd. Therefore, in herds which experience
low birth weights (and lower piglet survival) increasing late gestation
feed levels should yield benefits.
Table 2. Effect of additional feed during late gestation on reproduction
1 Cromwell et al., 1982.
|Pig birth wt, lb
2 4-5 lbs of a corn-soy diet/day during entire gestation.
3 During final 23 days of gestation period.
Therapeutic levels of an absorbable
antibiotic are generally considered to be beneficial at farrowing time
and during early lactation. Table 3 illustrates the value of antibiotics
fed 3 to 5 days prior to farrowing through 7 to 21 days of lactation on
young pig survival. Incorporating antibiotics in the diet at these times
slightly improved Survival rate and the number of pigs weaned. It is expected
that the response to antibiotics in the sow's diet would depend on the
disease level in the herd.
Table 3. Effect of Antibiotics in the pre-farrowing and Lactation
Diet for Sows1,2
1 Cromwell, 1983
|Pigs born live/litter
2 Summary of 7 experiments, 787 litters.
3Tetracyclines, ASP-250, Tylosin or copper sulfate fed
from 3-5 days prepartum through 7 to 21 days of lactation.
Fat additions to the sow's diet during
late gestation and early lactation slightly improves survival rate. Fat
increases the energy density and yield of sow milk. The greatest response
to added fat in the sow's diet occurs in herds with survival rates below
80 percent. For best results, sows should consume at least 2.2 pounds of
supplemental fat before farrowing and continue to consume fat during early
lactation. "Dried-fat" products are readily available to help incorporate
fat into swine diets.
As previously discussed, pigs with
lower birth weights have a reduced chance of surviving to weaning. This
is partially because smaller pigs are unable to effectively compete with
larger pigs for colostrum and/or milk. Newborn pigs have low energy reserves;
therefore, they must have a warm (90° F), draft-free environment and
obtain adequate and regular nutrition from the dam if they are to maintain
a constant body temperature. The intake of colostrum during the first few
hours of life also protects young pigs from certain disease organisms.
Cross-fostering pigs to even up birth
weights within litters as soon as possible after farrowing improves survival
rate. Naturally, cross-fostering is best accomplished when there is batch-farrowing.
Another method to improve survival of small pigs is to dose them with a
milk replacer or split-suckle a litter of pigs when cross-fostering can't
Unsanitary conditions in the farrowing
house can predispose baby pigs to various health problems. Improving sanitation
in the farrowing house will pay large dividends. A European study indicated
that switching from continuous usage to all-in-a]l-out management of the
farrowing house improves survival rate by 5 percent. An all-in-all-out
scheme allows a facility to be cleaned and disinfected between groups of
sows. Of course, only strictly adhering to a predetermined breeding and
weaning schedule can you accomplish all-in-all-out management of the farrowing
house. You also can improve sanitation by washing and disinfecting sows
before farrowing and keeping manure buildup in the crate to a minimum by
regular cleaning. These procedures, in addition to using farrowing crates
with wire floors, will reduce the incidence of diarrhea and improve survival.
Studies representing over 17,000 litters indicate that preweaning survival
increased by about 7 percent when using farrowing crates with wire floors
that provide a cleaner and drier environment than do farrowing crates with
flooring materials that provide less open area.
Preweaning survival rates also depend
on the genetic make-up of the sow and pigs. More crossbred pigs survive
until weaning than purebred ones, while pigs nursing crossbred sows have
a higher survival rate than those raised by purebred sows. Therefore, breeding
systems that use crossbred sows are recommended for commercial swine production.
Producers are encouraged to keep production
records to help identify problem areas in their swine operations. With
proper records, the preweaning survival rate can be monitored for each
farrowing group. A realistic goal for a commercial swine operation should
be a preweaning death loss of 12 percent or less. By incorporating some
of these management practices, producers should be able to decrease the
preweaning death loss in their herds.