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Department of Animal Science Florida Agricultural
Mimeograph Series No. AN67-9 Experiment Station
June, 1967 Gainesville, Florida
THE INFLUENCE OF LEVEL OF FEEDING DURING
LATE GESTATION ON PIG BIRTH WEIGHTS AND
SOW PERFORMANCE DURING LACTATION
H. D. Wallace and G. E. Combsl/
Management of the sow gestation feeding program to provide the necessary nutri-
tion without permitting excessive gains is one of the more challenging aspects of
swine production. It is generally agreed that feed restriction is necessary. Most
swine nutritionists recommend 3-5 lb. of complete feed per head per day during ges-
tation for both sows and gilts. If forage is available, less concentrates are of-
Fetal nutritional requirements are greatest, at least quantitatively, during
the last part of the gestation period. Thus it would seem logical to offer more nu-
trients to the sow at this stage of gestation.
The present study was undertaken to determine if a more liberal feeding during
the last 4 weeks of gestation would be beneficial. Hopefully, this procedure might
increase birth weights and vigor of the pigs and improve survivability.
The study consisted of two trials. Trial 1 was conducted during 1959-1960 and
Trial 2 was conducted during 1965-66.
All animals were maintained in pasture lots throughout gestation. In Trial 1
the animals were fed 4 lb. of complete feed per head per day from the time of breed-
ing to four weeks prior to farrowing. At this time the animals were divided into
two groups according to age, breed and previous performance. One group was contin-
ued on 4 lb. of feed and the other group was increased to 6 lb. of feed for the dur-
ation of gestation. All sows were fed according to appetite, up to a maximum of ten
pounds of feed per head per day during lactation.
In Trial 2 the same procedure was followed, except the feeding levels were 3
and 6 lb., respectively, during the gestation period. Feed mixtures for the two
trials are presented in Table 1.
S JUL 20 1967
S.F.AS. Univ. of Floridc i
1/ Wallace, Animal Nutritionist, and Combs, Associate Animal Nutritionist, Animal
Table 1. Composition of diets
Trial 1 Trial II
Ingredients & lactation Gestation Lactation
Ground yellow corn 37.00 61.19 65.09
Ground whole oats 36.00 20.00 10.00
Soybean oilmeal (44%) 14.00 ----
Soybean oilmeal (50%) ---- 14.30 20.30
Alfalfa meal (18%) 10.00 --- ----
Ground limestone 1.00 0.75 0.75
Steamed bonemeal 1.00 1.00 1.00
Iodized salt 0.50 0.50 0.50
Trace mineral supplementa 0.10 0.06 0.06
B-vitamin supplement --- 0.10 0.20
Vitamin B12 supplementc ---- 0.10 0.10
Vitamin A and D supplement 2.00 2.00
a Calcium Carbonate Co. swine mix. Added the following to the ration (ppm):
Manganese (35.5), iron (43.8), copper (3.0), cobalt (1.0), zinc (50.4) and
b Contained 2,000 mg. riboflavin, 4,000 mg. pantothenic acid, 9,000 mg. nia-
cin and 10,000 mg. choline chloride per pound of supplement.
c Contained a minimum of 9 mg. B12 per pound of supplement.
d Contained 14 gm. vitamin A supplement (10,000 I.U./gm.), 4 gm. vitamin D sup-
plement (9,000 I.U./gm.) and 890 gm. yellow corn.
Results and Summary
Farrowing and lactation performance data are presented in Table 2.
In Trial 1 the sows fed the increased level of feed (6 lb.) during the last 4
weeks of gestation averaged more live pigs per litter (8.57 vs. 9.33) and the aver-
age birth weight of the pigs was considerably greater (2.73 vs. 2.91). Sows fed the
increased level also weaned more pigs per litter (7.52 vs. 8.21). Percent survival
was approximately the same for the two treatment groups.
In Trial 2 the sows fed the increased feed level farrowed fewer live pigs
(11.10 vs. 10.51), with similar birth weights (3.01 vs. 3.03). Sows fed the in-
creased feed level weaned 9.27 pigs per litter, compared to 9.58 for the control
group. Survival rate was about as observed in Trial I with no great difference be-
tween the feeding levels. Sow weight losses from pre-farrowing to weaning were ap-
proximately the same for the two groups.
Results of the two separate trials are rather different. In Trial 1 a benefit
from increasing feed level seemed apparent, but not so in Trial 2. The differing
results are not readily explained. Chance allotment probably played a role because
of the many factors that can influence sow productivity. Initial sow condition,
forage availability and season of year may also have been important factors.
Although the data reported here are not overwhelmingly convincing, it seems
feasible to recommend that any extra conditioning of the sow be accomplished during
the latter part of gestation, rather than during early gestation. Published data
suggest that high energy intake during early gestation does not favor embryo sur-
vival. Thus, a low feed level during early gestation (3-4 lb. per head per day)
with an increase during the last 4-5 weeks, is the best recommendation that can be
offered at present.
Table 2. Summary of farrowing and
Feeding level during last
4 weeks of gestation, lb. 4 6 3
Number of litters
Average number live pigs per
Average birth wt. per pig, lb.
Average number pigs weaned
(2 weeks of age)
Average sow wt. loss, lb.
(pre-farrow to weaning)
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