Shibu SimonNaveen Kumar, R. H.2019-06-262019-06-262017-08-16KVASU REFERENCE CITATIONhttp://krishikosh.egranth.ac.in/handle/1/5810110048With an aim to compare two methods of early pregnancy diagnosis by ultrasonography and progesterone assay a study was conducted at ULF and FRDS, Mannuthy. Twelve apparently healthy post-partum dairy cows with normal cyclicity and body condition score were selected for the study. Trans-rectal ultrasonographic examination was performed from day eight post insemination to day 30 on alternate days. The animals were grouped as pregnant and non-pregnant based on ultrasonographic findings and return to oestrus. Further, the pregnant animals were ultrasonograhically evaluated till day 60 at five days interval. Blood samples were collected on days 0, 2, 4, 8, 17, 21 and 24 for estimation of serum progesterone level. Size of CL had no significant difference between days 8 to 60 in pregnant animals. When CL changes were compared between pregnant and nonpregnant animals, no significant difference was observed between these two groups till day 16. Thereafter, significant reduction in size was observed in nonpregnant animals. The mean day of disappearance of CL cavity was 16.55 and 15.5 in pregnant and non-pregnant animals, respectively. The CL blood flow was the same in pregnant and non-pregnant animals till day 15. But, on day 16 blood flow was increased in non-pregnant animals than pregnant animals. Thereafter, it was reduced in non-pregnant animals, whereas, in pregnant animals it was maintained at same level. Earliest day on which foetal/extrafoetal structures were visualised is as follows; anechoic area (16 d), amniotic vesicle (22 d), embryo (22 d), heart (24 d), placentome (26 d), CRL (28 d), vertebral column (35 d), limb buds (40 d), BPD (40 d), liver (45 d), spleen (45 d), tail bud (45 d), BD (45 d) and UD (45 d), cloven feet (50 d), orbit (50 d) and brain ventricles (50 d), Bladder (55 d), Falx cerebri (55 d) and each vertebrae and ribs were easily distinguishable by (60 d). The PI and RI values for umbilical blood flow had no significant difference between days. Pregnancy could be detected as early as day 24 by B-mode ultrasonography, whereas, when Colour Doppler ultrasonography was combined with B-Mode ultrasonography, pregnancy can be diagnosed as early as day 18. Although based on progesterone assay pregnancy could be diagnosed as early as day 18 it may not be confirmatory as serum progesterone level could be enhanced in some pathological conditions also.ennullThesis