Body condition score (BCS) is a quick, cheap and reliable tool that helps determine fat reserves. BCS at calving and changes in BCS after calving have been consistently associated with milk yield, diseases, and fertility in dairy cows, yet, the dynamics of BCS during the dry period has been less studied. The objective was to assess the change in BCS within the far-off (dryoff to −21 d prepartum) and close-up (−21 d prepartum to calving) and its association with postpartum diseases. The study analyzed 22,000 lactations from 28 dairies from Argentina. BCS was assessed with a scale of a 1/4 unit from 1 (emaciated) to 5 (obese). BCS was carried out by 2 of the authors creating 4 groups. G1: cows that maintained or gained BCS during far-off and close-up; G2: cows that maintained or gained BCS during far-off and lost BCS during close-up; G3: cows that lost BCS during far-off and maintained or gained BCS during close-up; G4: cows that lost BCS during far-off and close-up. Diseases were compared among groups by conducting logistic regression. Dependent variable was the incidence of the disease (yes, no). Three models were run, comparing G1 vs G2, G1 vs G3, and G1 vs G4, correcting for year, BCS at calving, lactation and farm. Group was not associated with the incidence of milk fever and lameness; however, cows gaining or maintaining BCS across the entire dry period (G1) were less likely to experience RFM, metritis, subclinical ketosis (BHB ≥1.2 mmol/L), clinical mastitis, and culling than cows losing BCS during the close-up period (G1 vs. G2; and G1 vs. G4). The impact of losses of BCS during the far-off period was less dramatic (G1 vs. G3) than during the close-up period. Table 1 (Abstr. 161).

Model	Milkfever	RFM	Metritis	Ketosis	Mastitis	Lame	Culling	Disease
G1 vs. G2	0.890.72–1.12	0.760.63–0.92	0.680.54–0.86	0.750.54–1.06	0.780.68–0.90	1.020.83–1.27	0.860.74–1.00	0.820.74–0.92
G1 vs. G3	1.220.93–1.60	0.850.68–1.06	1.200.68–1.84	0.850.60–1.20	0.920.79–1.09	0.950.74–1.22	0.840.70–1.00	0.970.86–1.11
G1 vs. G4	1.020.65–1.60	0.740.53–1.04	0.910.59–1.41	1.020.54–1.92	0.800.62–1.03	0.890.60–1.30	0.660.50–0.86	0.720.58–0.89