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Conducted
for:
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Sept. 30, 2000 - Feb. 24,
2001
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Phase IPhase I of the trial was a
nursery phase, with the pigs raised in an early-weaning
nursery. A
total of 160 pigs of predominantly Yorkshire breeding were
used in the trial. Each
pig was weighed and individually identified with an ear tag
and then assigned to a pen based on its sex and weight so
that each pen had approximately equal sex ratios and equal
average starting weights.
There were a total of 20 pens of pigs, with 8 per
pen, with the average weight per pen within one-half pound
of the overall mean. Each
pen had four barrows and four gilts, except two pens that
had 5 gilts and 3 barrows.
Pens were then randomly assigned to a treatment group
of either the control ration, or the control ration with 10
pounds of 2X-2-2-5 PLUS substituted for 10 pounds of corn. The only exception
to this was that each treatment group was assigned one of
the two pens with five gilts and three barrows. The pen numbers,
treatment for that pen, average starting and ending weight
for that pen, plus the number of pig deaths per pen are
listed below. The
lightest individual weight was 15 pounds and the heaviest
weight on-test was 29
pounds. Table 1. Phase I Design Data
The design of the nursery
building was such that some pens had access to a single
feeder, while other pens shared a double-sided feeder. The single-feeder
pens were 1, 10, 11 and 20, while the pens sharing a feeder
were 2 and 3, 4 and 5, 6 and 7, 8 and 9, 12 and 13, 14 and
15, 16 and 17, and 18 and 19.
The weight of feed delivered to each feeder was
recorded so that feed efficiency and daily feed consumption
could be recorded. Phase
I lasted for 35 days. . The off-test individual
weights ranged from 45 to 82 pounds. Data was analyzed using
SPSS statistical software.
The model for average daily gain included the mean,
sex and type of feed, whereas the model for feed efficiency
and feed consumption, which were on a pen basis, included
only the mean and type of feed. Following are the means for average daily
gain, feed efficiency and feed consumption for both the
control and yeast groups, with their appropriate
significance level. None of the three traits were
significantly different between the control and yeast groups
for Phase I. Table 2 – Phase I Results
Phase II
The second phase of the study began immediately after the conclusion of Phase I. Using the end weights for phase I, 128 of the pigs concluding Phase I were reallocated, based on weight, sex and Phase I treatment, to one of 16 pens for Phase II. There were four sets of four pens each. The set of four pens consisted of each of the following Phase I/Phase II treatments: Control/Control, Control/Yeast, Yeast/Control, Yeast/Yeast. This allowed the analysis to evaluate the effects of feeding yeast not only for Phase II alone, but for Phase I and Phase II, as well as only receiving the yeast for Phase I. Each pen contained eight pigs – four barrows and four gilts. Each pen contained an individual pen feeder. The on-test individual weight range was from 45 to 82 pounds, and the off-test weight range was from 77 to 150 pounds. The pen numbers, treatment for that pen, average starting and ending weight for that pen are listed below. Table 3. Phase II Design Data
Table 4 – Phase II Results
Feed efficiency approached significance for this interaction, with the pigs receiving the control diet in Phase I but the yeast diet in Phase II having an improved feed efficiency over those pigs fed the control diet throughout Phases I and II. Between the groups fed the yeast diet in Phase I, those fed the yeast diet in Phase II had a slightly better feed efficiency than those the control diet in Phase II, but this difference was not as dramatic as the difference between those pigs fed the control diet in Phase I. The Phase I x Phase II interaction was not significant for average daily gain, nor for average daily feed consumption. Phase III Phase III began immediately at the end of Phase II with pigs in the same pens for Phase III as they were in Phase II. Phase III lasted 77 days and the weight of feed delivered to each pen was recorded. The on-test weight range was from 77 to 150 pounds and the off-test weight range was from 157 to 314 pounds. The average off-test weights for each pen are provided in Table 6. Table 6. Average Off-Test
Weights per pen
There were no significant differences between the
control and yeast-fed pigs for Phase III, although there was
a tendency for the yeast-fed pigs to be more efficient in
converting feed to body weight. The means for the
interaction of Phase I and Phase III treatments for the
three traits analyzed are listed in Table 8. Table 8. Means for the Phase
I x Phase III Interaction
The interaction of Phase I and Phase III diets was not significant for either average daily gain or daily feed consumption. However this interaction approached significance for feed efficiency. While there was little difference between the pigs fed the yeast diet for Phase I, the pigs fed the control diet initially and the Yeast diet in Phase III were more efficient than the pigs fed the control diet throughout Phase III. Phase II and III The data for Phase II and Phase III were then combined, as these two phases were really time intervals of performance under the same penning and treatment scheme. The means for average daily gain, feed efficiency and feed consumption are listed in Table 9 for the combined period of Phase II and Phase III. Table 9 – Phase II and III
Results
During
Phase II and III combined, which is essentially a finishing
period, the yeast-fed pigs were significantly more efficient
in converting feed to body weight. Neither average
daily gain nor average daily feed consumption were
significantly different between the two groups. The means
for the interaction of Phase I and Phase II/Phase III
treatments for the three traits analyzed are listed in Table
10. Table 10. Means for the Phase
I x Phase II/Phase III Interaction
While average daily gain and average daily feed
consumption were not significant for this interaction, feed
efficiency was significantly different. As with Phase II and
Phase III, there was little difference for feed conversion
for the pigs fed yeast during phase I, while for those pigs
fed the control diet during Phase I, the pigs fed Yeast
during Phases II and III were more efficient than the pigs
fed the control ration. Summary There appeared to be little difference between the control and treatment groups for Phase I alone. Difference for feed efficiency became apparent, however, during the finishing phases II and III, with the yeast-fed pigs being more efficient in converting feed to body weight. This trend is particularly noticeable in the interaction of Phase I with Phases II and III, as the pigs fed the control diet in Phase I but the yeast in Phase II were generally more efficient than pigs fed the control diet throughout Phase I, II and III. Thus the addition of 10 pounds of 2X-2-2-5 PLUS yeast product per ton of complete ration appears to improve feed efficiency during the finishing phase. |
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