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September
4, 2003 to February 19, 2004
Milk production
comparison between cows fed live cell yeast and cows fed
dead cell yeast
Investigators:
B.C.
Housewright
C.P. Bagley
K.W. Davenport
S. Stewart
Texas A&M University-Commerce Commerce, TX
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Final Report April 5, 2004
Effects of Pre-partum and Early Post-partum
Supplementation of Western Yeast on Milk Production of
Parlor Fed Dairy Cows
Background
Most researchers agree that yeast
supplementation strategies do have measurable effects on
rumen fermentation. Research is available that indicates
yeast culture supplementation can influence rumen metabolism
(Williams and Newbold, 1990; Dawson, 1992 and Wallace,
1996). These trials indicate that total dry matter digestion
was not affected, however, initial rate of digestion is
markedly improved by live yeast culture addition. Feed
intake can be considered to be a function of initial rates
of fiber digestion and therefore, it may be assumed that
increased initial fiber digestion rates may increase dry
matter intake. Many nutritionists and researchers agree that
dry matter intake is the primary factor in determining milk
production in dairy cattle. Prior studies have been done
with feeding a live yeast culture preparation and have shown
an overall increase of 7.3% in milk production (Dawson,
2000). Increased milk production in these 22 studies ranged
from 3% to 30%, and none showed a loss in production when a
live yeast culture was fed.
Parlor fed dairies show a tendency to
exhibit signs of subclinical acidosis in their cows. This is
due to the slug feeding of grain twice daily in the
parlor. Williams et al. (1991) demonstrated the use of
a live yeast culture on ruminal production of lactic acid.
This would indicate that a drop in rumen pH, as a result of
high grain intake may be somewhat alleviated by feeding a
live yeast culture. Due to the intolerance of fiber
digesting bacteria to low pH, this may be one mechanism by
which the addition of yeast is increasing initial fiber
digestion.
It is these two factors, increased milk
production and decreasing lactic acid production in the
rumen, that make including a live yeast culture product in
parlor rations a necessity.
Research Objectives
The objective of this study was to
determine if there is a difference in milk production
between cows fed live cell yeast culture and cows fed dead
cell yeast culture.
Procedures
The existing dairy at Texas A&M
University-Commerce was used as the research site for this
project. This ensures oversight by the University personnel
to maintain the integrity of the procedures used and receipt
of accurate data.
A total of 20 dairy cows were used in
this experiment. Cows were randomly assigned to one of two
treatment groups, parity differences were taken in account
in order to have each treatment as equal as possible, to
minimize variation. Treatment 1 consisted of the addition of
a dead cell yeast culture of a popular brand, in addition at
56.75 g/hd/d beginning 21 days pre-partum and continuing
through 60 days in milk. Treatment 2 consisted of the
addition of Western Yeast Live Cell Culture (WYC+), in
addition at 56.75 g/hd/d beginning 21 days pre-partum and
continuing through 60 days in milk. During the experiment
all cows were given access to free choice hay and fresh
water.
Cows were randomly assigned treatment
group prior to experiment starting. Each Treatment group was
assigned their own pen, pre-partum, this was to assure that
the cows were receiving the proper treatment. Pre-partum
pens were approximately the same size, and next to each
other, this minimized variations due to location and forage.
Once cows freshened, a leg band was placed on back legs for
proper addition to feed in parlor. Cows in milk were all
under the same conditions to minimize variations.
The trial lasted from September 4, 2003
until February 19, 2004 during which weekly milk production
testing on individual cows, receiving treatment, was done by
DHIA. The use of PCDART, a computer program written to
analyze dairy production records was used to obtain raw
data. Data was analyzed for each period and for an overall
change in milk production over time.
Milking was done as usual procedure in a
double four, herringbone parlor utilizing automatic
take-offs. Individual milk weights were obtained using weigh
jars temporarily installed in the parlor on test days.
Data was analyzed using ANOVA for each
treatment week and also an analysis using ANOVA Repeated
Measures was done to obtain treatment differences for the
entire period.
Results
Data was analyzed as described above and
compared on a weekly basis. In all cases those cows
supplemented with Western Yeast Live Cell Culture (WYC+) had
numerically higher milk production than the cows receiving
the dead cell yeast culture. On average an increase of 14
lbs per cow per day was observed when cows were supplemented
with 56.75 g/hd/d of WYC+. Of the nine total measurements
taken, there was no significant increase in milk production
(p<.05).
In addition to weekly analysis, a total
analysis was done incorporating repeated measures procedures
to analyze for an overall significance in milk production
during the entire treatment period. There were no
significant differences (p<.05) regardless of which yeast
culture the cows were supplemented with. |
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