The main aim of this study was to evaluate the effectiveness of repeated inoculations
of a Corynebacterium cutis lysate (Ultra-Corn®) - a non-specific immune-stimulant,
to reduce the milk SCC in commercial dairy cows. An additional aim was to evaluate
if these inoculations had any detrimental effects on milk quality.
This study was performed in two separate trials, using Holstein cows with SCCâs
over 250 000 cells/ml of milk at different stages of lactation from two commercial
dairy farms in the Free State Province. On each farm, cows were paired according
days in milk and SCC, in order to obtain two homogeneous groups of experimental
animals. The two groups of cows in each farm were randomly allocated to a
treatment or a control group. Both groups in the same farm were managed under
the same conditions for the entire trial periods. The only difference was that cows
from the treatment group received 3 weekly inoculations of Corynebacterium cutis
lysate(Ultra-Corn® ), while those from the control group received distilled water for
injection (the same volume as the cows in the treatment group). Two similar trials were conducted, using the same basic experimental design.
Differences were only in the dose of the Corynebacterium cutis lysate inoculated per
cow treated, number of experimental animals and duration of the observation
periods. In Trial 1, cows from the treated group received 3 weekly vaccinations of
Ultra-Corn® (4 ml per cow, thus 80mg of Corynebacterium cutis lysate per cow)
injected subcutaneously (sc), while those from the control group received 3 weekly
sc injections of 4 ml distilled water. This was followed by 8 weeks of observation of
the effect of treatment on milk SCC and composition. In Trial 2, the three doses of
Corynebacterium cutis lysate administered weekly per cow for the treated group was
2ml/100kg, thus 40mg Corynebacterium cutis lysate/100 kg per cow. This was
followed by 8 weeks of observation of the effect of treatment on milk SCC and
composition.
Individual quarter milk samples were collected weekly from all cows and analysed for
SCC and a combined milk sample (from the measuring bottle in the milk parlour)
from each cow was also taken for butterfat, protein, lactose and urea content. The
results were compared between the two groups per farm, using ANOVA procedures
for repeated measures analysis, using the 95% confidence level (SAS, 2004).
The two farms were evaluated separately, due to the possible differences between
general management conditions, which could introduce serious confounding factors
if the results from the two farms were combined. However, it can be considered that
both dairy farms used an acceptable level of commercial dairy management
practices and produced an acceptable yield per cow under South African commercial
conditions.
In general no significant differences were recorded between the treated and control
groups of cows in both farms in both trials in terms of milk SCC, butterfat, protein,
lactose and urea content of the milk. In this study, the immuno-stimulant effect of
Ultra-Corn®, a Corynebacterium cutis lysate could not be confirmed in lactating
cows. Although this inoculant does not seem to have any detrimental effects on the main solids of the milk, its use cannot be justified as it did not significantly reduce
somatic cell counts in lactating cows.
Further research is warranted to develop and evaluate the effectiveness of vaccines
against mastitis causing organisms, in order to control SCC and mastitis in dairy
cows. However, when such studies are conducted it is advisable to use very high
number of experimental units and proper control trials should be conducted. All
efforts should be done to ensure minimum environmental changes during these
trials, which can introduce serious confounding effects in the experimental design.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ufs/oai:etd.uovs.ac.za:etd-09202010-114049 |
| Date | 20 September 2010 |
| Creators | Pretorius, Christa |
| Contributors | Prof JPC Greyling, Dr LMJ Schwalbach |
| Publisher | University of the Free State |
| Source Sets | South African National ETD Portal |
| Language | en-uk |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.uovs.ac.za//theses/available/etd-09202010-114049/restricted/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University Free State or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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