The correct answer is young female cattle before 1st parturition. Heifer refers to a young female cattle which have not given birth. Heifer is 6 months to 3 years of age. If the heifer gives birth to a calf, it is known as a cow. If the calf is male, it becomes a bull calf or bullock, or steer. If the calf is female, it becomes a heifer. ?Additional Information TerminologiesDefinitionBovineRefers cattle or buffaloCalfYoung cattle of any sexBull CalfYoung male calfHeiferYoung female calfBullAdult male that not castratedSteer or BullockMale that is castratedOxBullock after 2-3 years of castrationCowAdult female that had a calfSireFather bullDamMother cowMilch cow or dairy cowMilk producing cow that gave birth to a calf Important PointsParturition or Calving is the process of giving birth to a calfLactation is the process of secretion and yielding of milk to their calf