author(s)
Maradona Nath, KC Deka, KC Nath, P Borah, BK Sarmah and DP Bora

abstract
A total of 800 breedable cows maintained at Instructional Livestock Farm, C.V.Sc., Khanapara and at different private farms around the college campus were taken to record the incidence of prolonged oestrus, which was recorded to be16.75 per cent. Out of which 20 apparently healthy prolonged oestrus and 6 normal duration of oestrus cow were taken to study the blood biochemical and haematological parameters. The behavioural signs and the physical signs of oestrus were also studied. These signs were subside on day 5^th except swelling of vulva (10.00 %). The occurrence of relaxed and open cervix, good to very good uterine tone, palpable Graafian follicle, tense and soft follicular wall in prolonged oestrus cows were observed even up to the 3^rd day of oestrus. The level of serum inorganic phosphorus was significantly (P<0.01) lower in prolonged oestrus cows at all days of oestrus. Level of serum cholesterol varies significantly (P<0.01) between days of oestrus, highest level being recorded on 10^th day and the serum glucose level varies significantly (P<0.01) between oestrus duration groups as well as between days of oestrus. The haematological parameters viz. Hb, PCV, TEC, TLC, lymphocyte, monocyte and total granulocyte count were found to be within the normal physiological range and there was no significant difference of haematological parameters between the groups and different days of oestrus.