Oral and Poster Abstracts

499 Secondary Hepatogenous Photosensitization in Buffalos due
to the Excessive Accumulation of Hepatic Copper
A. Minervino 1 , R. Barreto júnior 2 , F. Rodrigues 1 , L. Reis 1 ,
R. Ferreira 1 , S. Headley 3 , E. Ortolani 1
1
College of Veterinary Medicine, University of Sao Paulo,
Department of Clinical Sciences, Sao Paulo, Brazil
2
Rural Federal University of Semi-Arid, Mossoró, Brazil
3
Faculty of Veterinary Medicine, University of Helsinki, Helsinki,
Finland
Four 1.5 yr-old, male, murrah buffaloes, maintained during six months
with high Cu intake and without direct solar exposure, were transported
to regular farming conditions. Shortly after sunlight exposure, all
buffalos demonstrated clinical manifestations characteristic of
photosensitization: anorexia, apathy and severe cutaneous lesions.
Blood samples were obtained before solar exposure (T0), during the
clinical manifestations (T1), and after recovery (T2) to evaluate
haematological (PCV, Hb, RBC and WBC) and biochemical (total
protein, albumin, g-glutamil transferase (gGT), aspartate amino
transferase (AST), creatine kinase (CK), urea, and creatinine)
parameters. Skin samples obtained by incision biopsy at T0 and T1
were processed for routine histopathology. Treatment consisted of
removal from sunlight exposure and aqueous Zinc oxide solution.
Three animals recovered fullly and 1 died. The hepatic Cu
concentrations and gGT and AST activities before solar exposure were
above normal values. For haematological parameters, only RBC
demonstrated significant difference, being reduced at T1 and returning
to normality at T2. A similar pattern was observed with the total protein
and albumin; but an opposite trend occurred with CK activity. The
buffalo that succumbed had the highest liver of Cu concentration and
more extensive macroscopic skin lesions. At T0 the buffalos had
generalized alopecia, but insignificant histological alterations
(acantholysis and neovascularization). However, at T1
histopathological examination revealed hepatic photosensitization
characterized by diffused, moderate parakeratotic hyperkeratosis,
multifocal moderate acantholysis, degeneration and necrosis of
squamous epithelial cells, sweat gland atrophy, sebaceous gland
hyperplasia, and dermal edema. Although the buffalos demonstrated a
liver insufficiency at T0, the skin lesions indicative of secondary
hepatogenous photosensitization were only triggered after the solar
exposure. In this case, a high Cu intake induced hepatic lesions that
may have caused inefficient metabolization of phylloerythrin resulting
in secondary photosensitization after the sunlight exposure.
Research supported by FAPESP
Key words: buffaloes, hyperkeratosis, photosensitization, hepatic
lesions
500 Trace Elements in Cattle: Copper and it`s “Friends”
A. Mueller, B. Freude, M. Scholz, M. Weiss
IDEXX, Vet Med Labor GmbH, Ludwigsburg, Germany
Prophylactic procedures to prevent diseases become more and more
important in cattle rearing. Adequate supply in trace elements is
required. Copper (Cu) deficiency is regarded as the second most
common mineral deficiency of cattle in the World (Telfer et al, 1996;
Black und French, 2004). Two different copper deficiencies are known:
a primary copper deficiency induced by a simple deficiency of copper
in the diet, and a secondary, resulting from the reduction in copper
absorption or utilization by the antagonistic effects of molybdenum
(Mo) and iron (Fe). 340 cattle samples were analysed as serum/plasma
pairs regarding the concentration of Cu, Mo and Fe with ICP-AES
(Inductively Coupled Plasma Atomic Emission Spectroscopy) during
July 2006 until March 2007. The Cu-plasma analyses showed that only
24% of these samples were below the reference value for Cu (80
Ïg/dL). Compared to these results, 84% of the corresponding serum
samples showed a Cu deficiency (below 80 µg/dL). Serum clotting
reduces Cu by up to 80% compared to the plasma values (in
confirmation to Laven & Livesey, 2006). In contrast to copper the
analyses of Mo in bovine plasma and serum resulted in comparable
values. 4500 bovine serum and plasma samples were analysed for Mo.
80% of Mo-concentrations were below 26 µg/L. Only a few samples (<
1%) showed higher values (max. 3300 µg/L). A correlation between
low Cu and high Mo values in plasma, or low Cu values with high Fe
concentrations could not be found. Additionally, hair analyses of Cu (N
= 173) and Mo (N = 99) were performed. 85 % of the hair samples (3-
30 XXV. Jubilee World Buiatrics Congress 2008
times analyses of each hair sample) showed Cu values between 5 and
20 mg/kg (49%: 6,6-10,4 mg/kg; 4 %: below 6,6 mg/kg), 15 % of the
samples showed higher values up to 100 mg/kg). The Mo
concentrations in the hair samples varied between 0 up to 800 µg/kg or
even higher). The comparison between Cu and Mo in hair (N = 99), or
Cu hair/plasma (N = 107) and Mo hair/plasma (N = 70) showed no
correlation. The analysed cattle samples with low copper plasma
concentrations showed mainly a primary copper deficiency. A
secondary copper deficiency caused by a molybdenum intoxication
could not be found in this set of samples.
501 Effect of chronic glucose infusion on lactation performance
and metabolic profiles in dairy cows
B. Al-Trad 1 , K. Reisberg 1 , T. Wittek 2 , A. Alkaassem 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
Objective: To characterize the metabolic adaptations that occur during
gradual increases of glucose supply via prolonged i.v. glucose
infusions in dairy cows.
Material & methods: Twelve midlactation dairy cows were assigned
randomly to continuous i.v. infusions of either saline (control group,
n=6) or 40% glucose solutions (treatment group, n=6) for 28 d. The
infusion dose started at 1.25% of the daily energy (NEL) requirement
and then gradually increased until a maximum dose of 30% NEL
requirement was achieved at d 23. Then infusion dose was maintained
at 30% for 5 d. The treatment (feed plus infusion) was hypercaloric but
isonitrogenous. Liver and skeletal muscle biopsies were taken on d 0, 8,
16, 24, and 32. Blood samples were taken every 2 d at 10:00 a.m. and
additional 24-h blood samples (6-h intervals) were taken before each
biopsy. Milk and urine samples were also taken on the biopsies days.
Results: No changes occurred in daily feed intake and milk production,
milk lactose and urea concentrations. Milk protein percentage and yield
tended to increase during the high infusion dose (i.e. 20 & 30% NEL
requirement). Decrease in milk fat percentage and yields were
observed in both groups; however, the decrease was numerically higher
in the treatment cows. Body weight and BFT increased in the treated
group. Small and occasional increases in blood glucose and insulin
concentrations were observed in the blood samples taken at 10:00 a.m.
every 2 d. However, at infusion of 30% NEL requirement, five out of
six treated cows had blood glucose concentrations >8 mM at 16:00
p.m., i.e. 1 h postprandially. Glucose infusion decreased serum NEFA,
BHBA and BUN concentrations. Serum liver enzymes, cholesterol,
bilirubin, K and Ca concentrations were not affected by infusion. Less
than 2% changes were observed in serum P, Cl and Na concentrations.
Glucoseuria was detected during the maximum infusion dose. Liver
glycogen increased gradually to reach plateau on d 16 before it fell
back to baseline values on d 32. Skeletal muscle glycogen increased
and liver total lipid tended to increase during the high dosage of
glucose infusion.
Conclusions: Dairy cows on an energy-balanced diet do not direct
excess glucose to increased lactation performance. Excess glucose is
transiently stored as glycogen in the liver and, predominantly,
transferred to body fat. At high dosages, glucose is also stored in
skeletal muscle as glycogen and excreted via the urine.
502 Biochemical Profile of Cattle with Induced Hypocalcaemia
and Subsequently Treated with an Enriched Calcium
Solution
R. Barreto júnior 1 , A. Minervino 2 , F. Rodrigues 2 , E. Meira júnior 2 ,
R. Ferreira 2 , A. Lima 3 , C. Mori 2 , E. Ortolani 2
1 Rural Federal University of Semi-Arid, Mossoró, Brazil
2 College of Veterinary Medicine, University of Sao Paulo,
Department of Clinical Science, Sao Paulo, Brazil
3 Vallée S.A., Sao Paulo, Brazil
Twelve two years-old Holstein heifers were used to study the
biochemical profile during the induction and recovery of
hypocalcaemia. The picture was induced by continuous infusion of a
EDTA solution (5% and pH 7.4) into the jugular vein at the speed of
220 mL/h until the animals presented definitive clinical signs of
hypocalcaemia such as sternal or lateral recumbency; then the infusion