الفهرس 
Dedication
Aims of the studyOnly 14 pages are availabe for public view
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Abstract
Periparturient period is a very important period in dairy cattle industry and as a critical period in the production cycle. It extends from start of dry period through early lactation. During this period, dairy cowssubjected to severe metabolic modification and load, which effect ongeneral health of cows and predispose them to metabolic diseases.
Themain objectives of this study to throw a light on the metabolic profile of, insulin resistance and oxidative stress for dairy cows during periparturient period.
The present study was carriedout on a dairy farm in Assiut Governorate from November 2015 to May 2016. The total number of dairy cows in this study was 38 multiparous dairy cows aged 3-11 years. The suggested design of the study was examination of selected animals at different time periods as following, from 1 month before parturition proceeding the examination till 2 months after parturition with 2wks interval between each sample. However, as a result of variation between the expected and the actual time of calving all animals were examined and sampled at average time of 25±8 days prepartum then followed up to 64±5 days postpartum.This difference between expected and actual time was due to errors in herd health programs including faults in management, inadequate insemination technique of natural mating without accurate timing and dates of calving, also improper herd books. Both ultrasound measurement of BFT and blood sampleswas done concurrently with clinical examination. Samples were obtained from the jugular vein at days –25±8, –12±8, 16±6, 32±5, 48±5, and 64±5 relative to parturition. The samples were drawn always at the same time in the morning. Tubes supplemented with K3EDTA and sodium fluoride (NaF) tubes were used to collect whole blood samples.
Furthermore,after parturition and according to health state of dairy cows animals were classified into four groups, clinically healthy (n=16), subclinical ketotic (n=10), clinical mastitic (n=6) and cows with retained placenta (n=6). Backfat thickness measurement was used as a clinical and objective tool for assessment of body condition of dairy cows. To investigate metabolic profile in these cows (NEFA, BHBA, Glucose and Insulin) were measured. Furthermore, RQUICKI was calculated to determine insulin resistance, besides that, for oxidative stress indices TAC and MDA were measured in this study.
The main results obtained in the present study could be summarized as following:
1. Backfat thickness (BFT, mm):
BFT showed a significant increase in mastitic group at 30 and 15 days prepartum and significant decrease in the same group at 60 postpartum.
2. Non-esterified fatty acids (NEFA, µmol/l):
NEFA showed a significant increase in cows that develop RP after calving and SCK group at 2wks prepartum and 2wks postpartum, respectively.
3. β- hydroxybutyric acid (BHBA, µmol/l):
BHBA showed a significant increase in cows that develop RP after calving
and SCK group at 2wks prepartum and 2wks postpartum, respectively.
4. Glucose (mg/dl):
Glucose showed a significant decrease in SCK group at 2wks postpartum.
5. Insulin(µIU/ml):
Insulin showed a significant decrease in SCK group at 4wks postpartum and significant increase in mastitic group 6wks postpartum.
6. RQUICKI:
RQUICKI showed a significant decrease in cows that develop RP after calving and SCK group at 2wks prepartum and 2wks postpartum, respectively.
7. Malondialdehyde (MDA, nmol/ml):
MDA showed a significant increase in cows that develop RP after calving and SCK group at 2wks prepartum and 2wks postpartum, respectively.
8. Total antioxidant (TAC, mmol/l):
TAC showed a significant decrease in cows that develop RP after calving and mastitic group at 2wks postpartum and 6wks postpartum, respectively.