Relaciones entre calcio, ácidos grasos no esterificados, e insulina sanguínea en preparto y leche bovina perdida en el inicio de la lactancia.

Introduction: The objective was to determine the relationship between the serum concentrations of Calcium (Ca2+), non-esterified fatty acids (NEFA), and insulin 10 days prepartum with losses in milk yield (MY) at 10 and 20 days of lactation. Method: Two hundred forty-three Holstein-Friesian cows (780 ± 36 kg PV, with more than two lactations) were sampled by coccygeal puncture several times before, during and after parturition. Results: When Ca2+ levels were low 10 days before parturition and were related to MY at 10 days postpartum, it was observed that 77.11% of the cows lost 2.20 kg of milk; while on day 20, 66.41% of the cows lost 1.40 kg animal-1 day-1. In contrast, when NEFA were high 10 days before calving and were related to MY, 67.40% of cows showed a risk of losing 0.80 kg, whereas at 20 days postpartum, 22.00% of cows lost approximately 0.90 kg cow-1 day-1. The determination of low prepartum insulin and MY on days 10 and 20 of lactation indicated that 6.02% of cows lost 0.80 and 0.70 kg of milk-1 animal-1 day-1 for days 10 and 20 of lactation. Conclusion: In conclusion, low blood levels of calcium, high levels of NEFA, and low insulin 10 days before parturition were associated with milk yield losses at 10 and 20 days after parturition. It was also observed that low calcium could cause greater milk losses than excesses of nonesterified fatty acids and serum low insulin concentrations. [ABSTRACT FROM AUTHOR]