Differential effect of a single dose of oral Ca based on postpartum plasma Ca concentration in Holstein cows

Even with multiple physiological adaptations in place to maintain normocalcemia, many cows fail to meet this demand without compromising systemic Ca status. As a result, these cows can experience clinical hypocalcemia or, in the absence of clinical symptoms, be categorized as having subclinical hypocalcemia based on blood Ca concentration. Our objectives were to determine: 1) the effect of a single dose of an oral Ca bolus within 24 h after parturition on blood Ca concentration, 2) the response of primiparous (PP) and multiparous (MP) cows to this supplementation strategy, and 3) differential responses to supplementation based on blood Ca concentration at enrollment.