Early versus late body condition score loss in dairy cows: reproductive performance.
2023
PFEIFER, L. F. M. | LIMA, R. A. DE | NAKASHIMA, S. H. | SILVA, J. T. DA | SCHMITT, E. | LUIZ FRANCISCO MACHADO PFEIFER, CPAF-RO; RHUAN AMORIM DE LIMA, CPAF-RO; SIDNEI HIROKI NAKASHIMA, DELAVAL BRASIL LTDA; JACKELINE THAÍS DA SILVA, DELAVAL BRASIL LTDA; EDUARDO SCHMITT, UNIVERSIDADE FEDERAL DE PELOTAS.
This study aimed to compare milk production and reproductive performance in high yield Holstein cows that lose BCS early and late in the postpartum period. Lactating dairy cows (n = 76) were received frst timed AI at 60 to 75 DIM using the farm-managed estradiol-progesterone-GnRH?based timed AI protocol. The BCS of all cows was daily evaluated by automated BCS cameras. Aiming to evaluate the efect of the days in milk (DIM) in which a cow reached the nadir BCS on the reproductive parameters, cows were separated into two groups: early BCS loss (n = 42), cows that reached the nadir BCS ≤ 34 DIM, and late BCS loss (n = 34), cows that reached the nadir BCS > 34 DIM. The optimal cut-of point for determining the relationship between days to nadir BCS and pregnancy by 150 DIM (P150) was calculated using the receiver operating characteristic (ROC) curve. From the ROC analysis, the cut-of was 34 DIM (Se, 80.9%; Sp, 66.7%; AUC, 0.74; P < 0.01). No diferences (P>0.05) were detected between groups on the BCS and milk production. The average of milk production in both groups was 46.65 ± 6.15 Kg/day. Cows that reached the nadir BCS early postpartum presented lower (P < 0.01) calving interval and greater (P < 0.01) pregnancy at frst AI and P150. In summary, cows that lost BCS early had better reproductive performance and had similar milk yield compared with cows that lost BCS late in the postpartum period.
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