questions: query regarding  oestrous of a cow 
 answers: insemination should generally  be done after 16-18 hrs of onset of oestrous ( sometime 24 hrs ) . liver tonic calcium supplement should be  given orally or in injectable form, calcium supplement should slightly increased in first & last trimester of pregnancy. before insimination , deworming should be done , liver tonic is essential to improve portal circulation , since there is a close attachment with umbilicus .