Oral and Poster Abstracts

4-ipomeanol and 1,4 ipomeanol. These compounds when absorbed into
the animal are further converted by microsomal activity in pneumocytes
to a toxic lung oedema factor, which is responsible for the pulmonary
pathology. The increased use of sweet potatoes for human consumption in
the UK was noted as early as 1975 by Coxon and others. They are now
grown in Europe and increasingly fed as a by-products to cattle. This is
believed to be the first such case published in the UK.
Key words: sweet-potato, toxicity, respiratory, interstitial, pneumonia
531 Key Hepatic Gluconeogenesis Enzymes Activity in Response
to Long-term Glucose Infusion in Dairy Cows
B. Al-Trad 1 , K. Reisberg 1 , T. Wittek 2 , G. Gäbel 1 , M. Fürll 2 ,
J.R. Aschenbach 1
1 Faculty of Veterinary Medicine, University of Leipzig, Institute of
Animal Physiology, Leipzig, Germany
2 Faculty of Veterinary Medicine, University of Leipzig, Medizinische
Tierklinik, Leipzig, Germany
Background and Aims: Periparturient ketosis in dairy cows is
characterized by an imbalance of glucose and lipid metabolism.
Insufficient gluconeogenesis is thought to be primarily caused by a lack
of glucogenic precursors due to negative energy balance. However, it is
not clear whether insufficient catalytic capacity of gluconeogenic
enzymes might contribute to insufficient glucose production
postpartum. The purpose of the present study was to investigate (1)
whether a positive energy balance due to chronic glucose infusion has
a depressive effect on selected gluconeogenesis enzymes activity in
dairy cows and (2) how quick such depressive effect might be reversed
after stopping surplus glucose supply.
Material and Methods: Twelve midlactation dairy cows were
maintained over a 28 d experimental period on continuous intravenous
infusion of either saline (control group, six cows) or 40% glucose
solutions (treatment group, six cows). The infusion dose was calculated
as a percentage of daily energy (NEL) requirements, starting at 1.25%
and increasing by 1.25%/d until a maximum dose of 30% was reached.
Dose was then maintained at 30% for 5 d. No infusions were made
between d 29-32. Blood samples were taken every 2 d and liver
biopsies were taken on d 0, 8, 16, 24, and 32.
Results: Blood glucose and insulin concentrations showed only slight and
occasional increases while NEFA and BUN concentrations decreased by
glucose infusion. Liver glycogen increased progressively during glucose
infusion until reaching plateau between d 16 and 24. Liver glycogen fell
back to baseline values on d 32 after cessation of glucose infusion. During
the infusion period, no significant changes were observed in the activities
of phosphoenolpyruvate carboxykinase and glucose 6-phosphatase.
Fructose 1,6-bisphosphatase decreased and pyruvate carboxylase tended
to decrease in the treatment group during the high dose of glucose infusion
(i.e. infusion dose of 20% & 30% NEL requirements) but quickly returned
to baseline after stopping the infusion.
Conclusion: The activity of key hepatic gluconeogenesis enzymes in
lactating dairy cows is not significantly affected by long-term increases
in glucose supply. Excessive glucose improves body tissues energy
status without impairing the role of liver as the main source of glucose
production in dairy cows. Thus, dysregulation of gluconeogenic
enzymes activity by a positive energy balance pre-partum is likely not
a major cause of postpartum metabolic disturbances.
532 Milk Drop Syndrome in Dairy Ewes: Clinical and Diagnostic
Approach
N. Giadinis 1 , G. Arsenos 1 , G. Fthenakis 2 , P. Tsakos 3 , C. Dovas 1
1
School of Veterinary Medicine, Aristotle University, Thessaloniki,
Greece, Greece
2
University of Thessaly, Thessaloniki, Greece
3
Institute of Infectious and Parasitic Diseases, Centre of Veterinary
Institutes of Thessaloniki, Thessaloniki, Greece
“Milk drop syndrome” in dairy sheep is a problem with considerable
financial implications. However, it has not been thoroughly investigated
and research data are scarce. In this paper, we present the results of a
study, carried out from 2003 to 2007, into the factors involved in milk
drop syndrome reported in 18 flocks of dairy sheep in Northern Greece.
The appropriate clinical and diagnostic approach is also discussed. In
each flock, five adult ewes were selected randomly among those with
reported milk drop. Samples of blood, milk and faecal samples were
collected from these animals throughout a milking period. Their feeding
regime was also evaluated. Evaluation of milk yield was based on data
of previous milking records. In 10/18 flocks, the subclinical mastitis,
caused by coagulase negative Staphylococcus spp. or Streptococcus spp,
was the reason for the reduced milk yield. In other flocks the reasons
were contagious agalactia confirmed by isolation of Mycoplasma
agalactiae in milk cultures (1 flock), inappropriate and unbalanced
nutrition with a ration containing suboptimal protein (1 flock), chronic
ruminal acidosis (1 flock) or Maedi-Visna confirmed by PCR, serum test
for antibodies and histological findings in mammary glands (2 flocks). A
combination of the above factors was observed in 3/18 flocks, while in
one flock these factors were coupled with intense gastrointestinal
parasitism. The results confirm that subcilincal mastitis is the major
reason for reduced milk yield. The role of different pathogens and the
need for proper management of animals in individual flocks imply that
the clinical and diagnostic approach should involve a farm investigation
before any measures are taken.
Key words: dairy ewes, milk, mastitis
533 The Relation of ante Partum Backfat Thickness with
Metabolic Disorders and Fertility Problems in Dairy Cows - a
Long Term Study
H. Pothmann-Reichl 1 , F. Zimmer 2 , I. Sommerfeld-Stur 3 , C. Iben 4
1 University of Veterinary Medicine Vienna, Teaching and Research
Farm, Vienna, Austria
2 Veterinary Clinic, Private Veterinary Practice, Oberkirchen,
Germany
3 University of Veterinary Medicine Vienna, Clinical Department of
Animal Breeding and Reproduction, Vienna, Austria
4 University of Veterinary Medicine Vienna, Department of Veterinary
Public Health and Food Sciences, Vienna, Austria
ObjectivesIn this retrospective study the influence of post partum change
of back fat thickness (BFT) in cattle on fertility, metabolic problems,
mastitis and milk yield was investigated. It is hypothesised that a higher
decrease of back fat thickness post partum (p.p) has a negative impact on
fertility and fat metabolism. Animals, materials and methodsFive dairy
farms in Germany (292 cows) and two farms in Austria (111 cows)
participated in this trial and 1045 lactation periods were analysed. The
back fat thickness was measured with an ultrasound (3.5 MHz) between
the tuber coxae and the tuber ischiadicum at the following days: 8 weeks
ante partum (a.p.), 42 days a.p., day of parturition, 42 days and 100 days
p.p. The programme “Inter-Herd”(Interagri, Earley Gate, UK) was used to
record the data. Statistic evaluation was done by SPSS for Windows
14.0.1 using odds ratio (OR >1 increased risk, OR