Oral and Poster Abstracts

2
Freie Universität Berlin, Veterinary Clinical Sciences, Berlin,
Germany
3
Miner Agricultural Research Institute, Chazy, United States
4
University of Illinois, animal sciences, Urbana - Champaign, United
States
Hypophosphatemia and disturbed liver function are common findings
in dairy cows during early lactation. Low serum phosphorus (P)
concentrations have been associated with altered liver function and
decreased regenerative capacity of the liver. To our knowledge,
neither the liver P content nor the relationship between serum P
concentration ([P]) and liver P content have been studied in
periparturient dairy cows. We therefore investigated the change
in hepatocellular P content in dairy cows from late gestation to early
lactation. Liver biopsy samples of 6 dairy cows were obtained at -65,
-30, -14, +1, +14, +28 and +49 days relative to calving. Amounts of
P, potassium (K) and magnesium (Mg) in liver were determined using
inductively coupled plasma-mass spectrometry and expressed as
mg/g or µg/g liver dry weight. The amount of DNA in the biopsy
sample was determined in order to explore the potential confounding
effect of changes in cell volume on liver P content. Serum [P] was
measured at -50, -36, -14, +1, +14, +28 and +49 d relative to calving.
The amount of P in wet weight liver (PW), non fat wet weight
(PNFW) liver, and per cell (indexed to DNA; PDNA) was calculated;
similar values were calculated for K and Mg. Repeated measures
ANOVA was used to identify changes in measured and calculated
values over time. Liver P decreased significantly from 12.4±1.1 mg/g
at -14d to 8.2±1.4 mg/g at +14d, increasing thereafter to 11.7±1.5
mg/g at +49 d. Similar changes in dry weight liver were observed for
Mg and K. PW and PDNA showed the same pattern of change over
time with similar trends for the Mg and K content in wet liver tissue
as well as indexed to DNA. In contrast, the amounts of K and Mg in
non fat wet tissue remained constant over time whereas a significant
decline of PNFW at +14d was determined. Serum [P] tended to
increase from calving to +14d and did not reflect changes in liver P
content over time. Our findings indicate that time-dependent changes
of the electrolyte contents in dry liver weight are largely due to
changes in hepatic water and fat content. As indicated by the P, Mg
and K content in non-fat wet liver weight, the cytosolic
concentrations of Mg and K were stable throughout the study period
whereas the cytosolic P concentration significantly declined at +14 d.
Our findings further indicate that serum [P] cannot be used to
estimate liver P content.
282 Effect of Vitamin D on the Bone Metabolism of Dairy Cattle
with Hypophosphatemia
JT. Wang, JL. Li, SW. Xu, FQ. Shi
Northeast Agricultural University, College of Veterinary Medicine,
Harbin, China
The morbidity of mineral metabolic obstacle in cows was very high in
Daqing and Anda regions in China, especially in some areas of Anda in
which most areas belonged to alkaline soil which was composed of
high content of NaHCO 3. There was 5mg/kg available phosphorus in
soil roughly. Dairy cattle in these areas were found to have
hypophosphatemia with detecting the content of phosphorus in serum,
and they showed dyskinesia and low productive ability for long time.
The aim of this study was to find out the method which prevented and
cured dairy cattle with hypophosphatemia, and illuminated the effect of
vitamin D on the bone metabolism of cows with hypophosphstemia. 30
cows with obvious clinical symptoms which were hypophosphatemia,
dyskinesia was assigned randomly. 10 cows as control feed low phosphorus
grass (p0.2%), 10 cows as group 2: feed high phosphorus grass (p>0.2%),
and got vitamin D3 (2.5x10 6 IU, weekly) by intramuscular injection and
one capsule of vitamin D 3 (10mg/500kg, daily) by oral. Blood samples
(serum) were withdrawn on 1d, 30d, 60d, 90d and 120d. The content of
vitamin D (including vitamin D, 25-OH-D, 1,25-(OH) 2-D), calciumphosphorus-
CT and BGP in the serum of group 2 were higher, and
APK activity was lower than control and group 1. However, these items
are near between control and group 1: the content of serum protein,
GOP and GPT activity in serum had no difference in three groups.
After 120 days the clinical symptom of 10 cows in group 2 was
obviously slight, 10 cows in group 1 were better than control. These
results clearly demonstrated that the content of calcium-phosphorus-
CT, BGP, vitamin D3 and its metabolism activity in serum of the cows
with hypophosphstemia were changed obviously with adding vitamin
D and high phosphorus grass. With enhanced the content of calcium,
phosphorus, CT and BGP in serum, vitamin D could effect the bone
metabolism of dairy cattle with hypophosphstemia, and prevented
dairy cattle hypophosphatemia
Key words: cows, hypophosphstemia, vitaman D, bone metabolism
283 Changes T3 and T4 Plasma Concentrations in Dairy Cows
during Lactation
K. Sinka, J. Illek, D. Kumprechtova, P. Novak
Veterinary and Pharmaceutical University Brno, Clinic of Ruminant
Diseases, Brno, Czech Republic, Czech Republic
Objective: The objective of this study was to determine plasma
concentrations of T3 and T4 hormones in dairy cows in preparturient
period (20 to 10 days prepartum), in early lactation (15 to 20 days in
milk -DIM), peak lactation (60 to 80 DIM), and late lactation (220 to
250 DIM).
Material and methods: The study was performed in a Holstein herd
with average milk yield of 10,650 kg per 305 day lactation. Cows
were housed loose in pens and fed total mixed ration consisting of
maize silage, clover-grass silage, meadow hey, straw and
concentrate. Proportions of TMR components and nutrient contents
reflected the lactation phases and were in accordance with standard
recommendations.
Selected cows from different phases of calving to calving interval were
withdrawn blood from the coccygeal vein, using the HEMOS tubes
with heparin. Group A: late pregnancy cows (10-20 days prepartum),
Group B: early lactation (15- 20 days prepartum), Group C: peak
lactation (60-80 DIM), Group D: late lactation (220-250 DIM). In each
group 10 cows without clinical disease signs and in optimum body
condition were monitored. Hormones T3 and T4 were measured by
chemiluminiscence, using the automatic analyzer IMMULITE 1000.
Results were statistically evaluated.
Results: The late pregnancy cows (A) showed the lowest T3
concentrations and the highest T4 concentrations. In early lactation there
was a significant decrease in T4 and non-significant increase in T3. In
peak lactation, T4 levels were still low but non-significantly higher than in
the early lactation. In late lactation there was a significant increase in T4
and significant decrease in T3. The late lactation values were similar to
those measured in late pregnancy cows.
Table 1. T3 and T4 plasma concentrations (nmol/l)
Group A B C D
T3 T4 T3 T4 T3 T4 T3 T4
X 1.71 74.64 1.93 36.9 1.95 43.96 1.77 63.96
S.D. 0,179 8,562 0,183 3,157 0,135 7,096 0,095 7,592
C.V. 0,105 0,115 0,095 0,086 0,069 0,161 0,054 0,119
T-test A-B A-B B-C B-C C-D C-D
** *** N.S. ** *** ***
(P