Description:
Three trials with wethers and four trials with steers were
conducted to determine some of the effects of sodium bicarbonate,
calcium hydroxide and/or transfer of ruminal contents on ruminant
adjustment to abrupt changes to concentrate rations.
Lambs fed a basal concentrate diet plus sodium bicarbonate had
the highest average feed intake, the highest pH and Lowest lactic acid
level for the first ten days, but went off-feed after buffer removal
(Trial I). The lambs receiving buffer plus rumen fluid had the highest
overall average feed intake for the trial. Basal fed lambs went off-feed
the second day of the trial at which time rumen and urine pH
decreased and lactic acid levels increased. Lambs given rumen fluid
developed diarrhea, went off-feed, had low rumen pH and total VFA
values and elevated lactic acid levels in the rumen. Significant
correlations occurred between rumen pH and acetic to propionic acid
(P < .05) and acetic to butyric (P < .10) acid ratios. Also, lactic
acid and feed intake were correlated (P < .05). A negative correlation (P < .01) between rumen pH and lactic acid levels also existed.
Lambs fed buffered rations had the highest average intake, ADG,
rumen pH at the second collection and final total VFA levels (Trial II).
Lambs given buffer plus rumen fluid and those fed basal rations performed
similarly overall, but basal fed lambs went off-feed. A
negative correlation (P < .05) was found between rumen pH and total
VFA. Rumen pH and acetic to propionic acid (P < .01) and acetic to
butyric (P < .05) acid ratios were correlated.
Calcium hydroxide added to the ration reduced feed intake and
ADG in Trial III. Calcium hydroxide plus rumen fluid resulted in
improved gains and feed efficiency. Average pH at the second collection
was increased by this treatment. The sodium bicarbonate group
had the highest overall feed intake but rumen pH decreased after buffer
withdrawal. Correlations between rumen pH and acetic to propionic
were the same as in Trial I.
Steers fed a buffered ration and given rumen fluid had lower
rumen pH values, but higher feed intake and ADG than steers fed a
buffered ration (Trial IV). Average pH was increased significantly
(P < .05) in both groups, by the addition of sodium bicarbonate to the
ration. The lactic acid level was higher in the buffer plus rumen fluid
group. Negative correlations (P < .05) in this trial existed between rumen pH and lactic acid and rumen pH and total VFA levels.
There were no significant differences in average feed intake,
ADG or average feed conversion in Trial V. Although rumen pH was
increased by addition of buffers to the diet both groups went off-feed
when the buffers were removed. There were negative correlations
(P< .01) between rumen pH and total VFA levels and total VFA levels
and lactic acid. Also, rumen pH and lactic acid were correlated
(P < .01).
In Trial VI there were no significant differences in animal
performance. Rumen pH in the buffer plus rumen fluid group was
higher than that of the basal fed group. Average rumen pH, total VFA
levels and acetic to propionic acid ratios were significantly (P < .01)
lower at the end than at the beginning of the trial for both groups.
Rumen pH and acetic to butyric acid ratios were correlated (P < .01).
Rumen pH and total VFA were negatively correlated (P < .05).
The buffer fed group had a higher average intake than the basal
fed group in Trial VII. One steer in the basal fed group developed
acute indigestion on the second day of the trial. Rumen pH decreased
and lactic acid level increased at that time. There were negative
correlations (P < .01) between rumen pH and lactic acid, between
rumen pH and acetic to propionic acid ratios and between lactic acid
and total VFA levels.
Subject:
Sheep -- Feeding and feeds
Cattle -- Feeding and feeds
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Record Title:
Ruminant and microbial physio-chemical response to abrupt ration changes as influenced by chemical and/or biological means
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