I rT *
Department of Animal Science Florida Agricultural
Research Report No. AL-1975-3 Experiment Station
April, 1975 Gainesville, Florida
,- /INFLUENCE OF FEED LEVEL DURING GESTATION ON THE INCIDENCE
OF MtA, TOTAL REPRODUCTIVE PERFORMANCE, WEIGHT CHANGES,
CULLING RATE OR REPRODUCTIVE LONGEVITY AND FEED COSTS
1 H.\D. Wallace, D. D.,Thieu and G. E. CombsI/
S DUBli past decade much progress and change has been made in the area
oi.s-j.re ing. Foremost among the adjustments has been a "thinner" look and
\jedtced mature weights. This new look has been well accepted as compatible with
more efficient breeding, better farrowing and lactation performance while permitting
a significant saving in sow feed costs.
The primary purpose of the present study was to determine the relationship
of the over-conditioning of sows to susceptibility to MMA mastitiss, metritis
and agalactia). In previous studies the incidence of MMA was not altered by
supplementing the prefarrow and lactation diet with ASP-250 (1) or vitamin K (2)
or by including 15% wheat bran in the diet (3). In another report the inclusion
of 15% alfalfa meal (4) did appear to reduce the incidence of MMA. However, sow
performance was not modified by the latter treatment so the value of alfalfa
meal in preventing MMA remains uncertain. The stress of overconditioning has
long been thought to contribute to farrowing problems and especially to the MMA
complex syndrome. This study was undertaken to obtain more direct and specific
information on the influence of overconditioning. Data were also obtained on
breeding and reproductive performance, weight changes during successive reproduc-
tive cycles, culling rate and productive longevity, and feed costs as related to
level of feeding during gestation.
A total of 44 gilts (Duroc x Yorkshire) were utilized in the study during a
2-year period from July 1971 to May 1973. The gilts, based on litter source and
body weight, were assigned to one of two gestational feed level regimes just
prior to first breeding. The feed levels were 4 and 6 lb. per head daily. The
1/ Data summarized in this report were taken from swine unit experiment No. 207.
?/ Wallace and Combs, Animal Nutritionists; and Thieu, graduate assistant,
Department of Animal Science.
This public document was promulgated at an annual cost of
$ or cents per copy to inform county agricul-
tural directors, ranchers and growers of research results
in swine management and nutrition.
Department of Animal Science
Institute of Food and Agricultural Sciences
,.. -*f,' *<
feed mixture is presented in Table 1. During breeding and gestation the animals
Table 1. Composition of Feed Mixture Fed
to all Animals During all Phases
of the Experiment
Yellow corn meal 59.15
Ground whole oats 20.00
Soybean oilmeal (49%) 18.00
Defluorinated phosphate 2.20
Iodized salt 0.50
Trace mineral mixture (CCC)-1/ 0.10
Vitamin premix (UF)_/ 0.05
1/ Contained 20% zinc, 10% iron, 5.5%
manganese, 1.1% copper, 0.15% iodine,
0.1% cobalt and 2% calcium.
2/ Contained 6,000 mg riboflavin, 20,000
mg niacin, 12,000 mg pantothenic acid,
80,000 mg choline chloride, 10,000 mcg
vitamin 812, 2,500,000 IU vitamin A,
400,000 ICU vitamin D3 and 10,000 IU
vitamin E per lb. of premix.
were maintained in dirt lots with little or no green forage and fed once per day
(AM) on concrete platforms. Water was provided by automatic watering devices.
Breeding was accomplished by a double mating procedure using Hampshire boars.
Each gilt or sow was mated to two littermate boars during an estrus period. All
animals were sprayed every 6 weeks to prevent lice infestation and all sows were
wormed approximately two weeks prior to farrowing. Three days before the expected
farrowing day the animals were scrubbed clean with soap and water, weighed and
placed in individual farrowing stalls in a farrowing building which had been
thoroughly cleaned and disinfected. While in the farrowing barn all sows were
fed 3 lb. of feed twice per day before farrowing and according to appetite during
When each litter of pigs was born, navel cords were tied off, clipped and
the stubs treated with iodine; needle teeth were clipped; tails were docked; and
all pigs were weighed and earnotched for identification. At 3-5 days of age all
piglets were injected with iron to prevent anemia and male pigs were castrated.
Sows were observed for symptoms of the MMA complex prior to, during and for
several days following parturition. Body temperatures of all sows were recorded
.at the time of parturition and 48 hours post parturition. Pig weights were
recorded for experimental comparison when the litters reached two weeks of age.
Most litters were weaned between 2 and 3 weeks of age at which time sow weights
were obtained. As litters were weaned sows were returned to the breeding-
gestation lots and fed their originally designated level of feed (either 4 or
6 lb. per head daily). Rebreeding occurred during the first estrus after weaning.
Statistical analyses of the data involved the use of the analysis of variance
Results and Discussion
Mean sow weights for the three successive reproductive cycles are shown in
Table 2 with a graphical presentation of these differences in Figure 1. During
Table 2. Effect of Gestation Feed Level
on Mean Live Weights of Sows
Gestation feed level,
Ib. per head per day 4 6
Number of gilts 22 22
Initial weight, lb. 283 284
Prefarrowing weight, Ib. 423 513**
Weaning weight, lb. 369 425**
Number of sows 14 12
Prefarrowing weight, Ib. 452 586**
Weaning weight, lb. 392 469**
Number of sows 9 5
Prefarrowing weight, lb. 436 585**
Weaning weight, lb. 416 506**
** Significantly greater (P < .01) than
for sows fed 4 Ib. of feed.
each successive gestation period the sows fed 6 lb. of feed gained significantly
more (P < .01) than sows fed 4 Ib. of feed. The general condition of the sows
on 6 lb. could be described as excessively fat and overweight. Sows fed 4 lb.
were thin to fair in condition, more active and generally easier to work with.
During lactation the sows on the 6 Ib. gestation regime lost significantly more
weight during each lactation (P < .01). This average loss per lactation was
96 lb. per sow compared to 49 lb. per sow for sows fed 4 lb. All sows were fed
according to appetite during lactation and there was a marked difference in
voluntary feed consumption between the two sow groups. Sows on the lower gesta-
tion feed level regime consumed an average of 33 lb. more per head during the
two week lactation period. This greater feed intake largely explains the lower
weight losses by this group of sows during lactation. The heavier, over-condi-
tioned sows in the other group relied heavily on body reserves to fulfill lactation
F = Farrow
W = Wean B = Breed
F WB F
I Is I
T Gestation 2
Effect of Level of Feeding During Gestation
on Weight Changes of Sows During Three
Successive Reproductive Cycles
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Overall reproductive performance data are presented in Table 3. Conception
Table 3. Effect of Feed Level During Gestation on the
Reproductive Performance of Sows
Daily feed level during gestation, Ib. 4 6
Number of matings 46 45
Number of litters farrowed 42 38
Conception percentage 91.3 84.4
Number live pigs per litter 10.33 10.97
Av. weight per pig, lb. 3.08 3.13
Number pigs born dead per litter 0.31 0.39
Number resorbing fetuses per litter 0.45 0.76**
Av. weight of afterbirth, lb. 6.13 6.84
Av. body temperature, Fo 102.6 102.7
Two days post farrowing data
Av. body temperature, FO 103.9 103.2
Total incidence of MMA 10.0 16.0*
Fourteen days post farrowing data
Number of surviving pigs per litter 9.40 9.89
Percentage survival 91.0 89.3
Av. weight per pig, Ib. 8.46 8.93
Statistically significant (P < .10).
** Statistically significant (P < .05).
rate favored the sows on the lower feed regime but the advantage was not statis--
tically significant. The respective conception percentages were 91.3 and 84.4.
The number of live pigs born per litter averaged greater for sows on the higher
level of feed (10.33 vs. 10.97). This difference was not statistically signifi-
cant. Birth weights were very similar for piglets from the two sow groups
(3.08 vs. 3.13). The number of pigs born dead per litter were similar but
significantly more resorbing fetuses (P < .05) were observed from sows fed the
6 lb. of feed during gestation. This observation, coupled with the somewhat
larger litter size at birth suggests that the more liberally fed sows may have
ovulated at a higher level and thus conceived somewhat larger litters initially.
Body temperature data showed no great differences between the two sow
groups. However, a subjective measurement of the incidence of MMA (congested
udders, abnormal vaginal discharge, failure to eat and poor initial milk flow)
indicated that sows fed the higher level of feed during gestation were more
subject to such problems (P < .10). In spite of this these sows weaned more
pigs per litter (9.40 vs. 9.89) and the pigs weighed more at two weeks of age
(8.46 vs. 8.93 lb.). These differences were not statistically significant.
The influence of feed level on reproductive longevity of sows is summarized
in Table 4. An attempt was made to cull sows from the two groups for the usual
reasons in keeping with the normal program at the University of Florida swine
unit. Records of culling were continued for approximately one year beyond the
cut off point for the other data summarized in this report. Sows were maintained
)n the original feed levels during this period of time. More sows were culled
from the high feed level group (7 vs. 10) and the average sow age was less at
time of t-qling (36.3 vs. 32.7 months). A most interesting aspect concerned
productivity of the culled sows. Culled sows in the lower feed level group
produced an average of 4.57 litters per sow compared to only 3.00 for those from
the high feed level group. The main difference in the reasons for culling centered
around failure to conceive. Four sows in the high feed level group failed to
conceive repeatedly and were culled, while no sows on the lower level of feeding
were culled for this reason. The idea that overconditioning of animals tends to
reduce reproductive efficiency, especially conception appears to be augmented by
these data. One sow on the high feed level died in the farrowing barn due to
farrowing complications and/or heat stress. It was noted throughout the study
that this group of sows was more subject to heat stress. Also the day to day
chores associated with herd management were more difficult where the heavy over-
conditioned sows were involved.
Table 4. Influence of Feed Level During Gestation on Culling
Rate and Reproductive Longevity
Daily feed level during gestation, lb. 4 6
Total number of sows 22 22
Number of sows culled 7 10
Number of litters produced
by each culled sow 4.57 3.00
Av. age of culled sows (months) 36.3 32.7
Reasons for culling
Agel 3 2
Poor performance 3 3
Failure to conceive on two or more
successive estrous exposures 0 4
Death 0 1
Injury 1 0
Y/ Over 42 months of age.
2/ Due to complications associated with farrowing and/or
Feed consumption and feed cost data are summarized in Table 5. The experi-
mental design dictated a difference in feed intake during gestation. As
previously indicated however the feeding according to appetite during lactation
resulted in a marked difference between the sow groups in feed intake. Sows fed
4 lb. during gestation averaged 9.8 lb. consumption during lactation while sows
fed 6 lb. during gestation ate only 7.4 Ib. per day during lactation. This
difference was highly significant (P < .01). Accordingly the latter group of
sows lost more weight during lactation as discussed previously.
Average feed costs per sow indicated a saving of $12.47 for each reproductive
cycle or an average of $1.06 for each pig weaned for sows fed on the 4 Ib. regimen.
This advantage would be offset partially by a lower return for the lighter sows
at time of sale. On the other hand an additional feed requirement would be asso-
ciated with the poorer breeding performance of the overconditioned sows. This
was not included in the calculations presented in Table 5.
Table 5. Effect of Feed Levels During Gestation on Total
Feed Consumption and Total Feed Costs of a Sow
for One Complete Reproductive Cycle
Level of feed during gestation, lb. 4 6
Sow feed consumption, Ib.
Total per sow 454 683**
Sow feed per live pig farrowed 44 62**
Lactation (14 days)
Total per sow 137** 104
Breeding to weaning
Total per sow 591 787**'
Sow feed per pig weaned 63 80**
Sow feed cost ($)a/
Total per sow 28.89 43.46
Per live pig farrowed 2.80 3.96
Breeding to weaning
Total per sow 37.61 50.08
Per live pig weaned 4.00 5.06
a/ Sow feed cost estimated at $140.00 per ton.
** Significant (P < .01).
Summary and Conclusions
A study has been conducted to determine the influence of gestation feed
level of sows on the incidence of MMA, total reproductive performance, weight
changes, culling rate or reproductive longevity and feed costs.
The incidence of MMA was significantly greater (P < .10) in sows fed 6 lb.
feed compared to sows fed 4 Ib. feed.
Reproductive performance as measured by number and weights of pigs farrowed
and weaned indicated no significant difference between the two sow treatment
groups. Sows on the higher feed level farrowed slightly more live pigs per
litter that were slightly heavier at birth. They also weaned slightly more
pigs per litter that were slightly heavier. These data indicate that the very
large over-conditioned sows were able to farrow and raise excellent litters.
Sows fed 6 lb. during gestation gained considerably more weight but tended
to eat less feed and lose more weight during lactation than sows on 4 lb. At
the termination of the trial, after 3 successive farrowings and lactations,
there was an average of approximately 100 lb. difference in sow weights between
the two groups.
Culling was more severe in the 6 Ib. group and was due mainly to poorer
Sow feed costs were much higher, $1.06 more per pig weaned at 2 weeks of
age, for the sows fed 6 Ib. of feed during gestation.
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It is concluded that the restriction of feed intake to 4 Ib.of a well
balanced complete feed per sow per day during gestation is better than a more
generous allowance of 6 lb.per day for the following reasons:
less incidence of MMA and other stress associated problems
sows are easier to manage and work with
sows are more active at estrous and conceive more readily
potential for reproductive longevity is greater
feed costs are much lower.
1. Wallace, H. D., D. D. Thieu and G. E. Combs. 1974. Sow farrowing and lacta-
tion performance as influenced by diet fortification with aureomycin,
penicillin and sulfamethazine. Fla. An. Science Research Report No. AL-1974-6.
2. Wallace, H. D., D. D. Thieu and G. E. Combs. 1974. Supplementary vitamin K
for the sow during farrowing and lactation. Fla. An. Science Research Report
3. Wallace, H. D., D. D. Thieu and G. E. Combs. 1974. Wheat bran as a sow
ration ingredient during the farrowing and lactation period. Fla. An. Science
Research Report No. AL-1974-7.
4. Wallace, H. D., D. D. Thieu and G. E. Combs. 1974. Alfalfa meal as
bulky ingredient In the sow diet at farrowing and during lactation.
Science Research Report No. AL-1974-8.