Metabolic profile of Holstein × Gyr cows: effects of parity and body condition score at calving.

This study aimed to evaluate the effects of parity and body condition score at calving on the metabolic profile of high-producing Holstein × Gyr cows during the transition period. Cows were divided into groups according to the parity: primiparous (n = 20), biparous (n = 20), multiparous (n = 20); and according to the BCS at calving: high (HBCS; > 3.5; n = 20), normal (NBCS; 3.0 - 3.5; n = 21), and low (LBCS; < 3.0; n = 15). BCS, serum non- esterified fatty acids (NEFA), beta-hydroxybutirate (BHB), cholesterol, total protein (TP), albumin, blood urea nitrogen (BUN), total calcium (Ca), phosphorus (P), magnesium (Mg), aspartateaminotransferase (AST), gamma-glutamyltransferase (GGT), and plasma glucose levels were measured on -21, -7, 0, 7, 21, and 42 days relative to parturition. Differences between parity groups were observed for most metabolites; however, these differences occurred at a few time points and were more frequent at 7 and 21 days in milk (DIM). At 21 DIM, primiparous cows had lower BCS, BHB, cholesterol, and TP values and intermediate NEFA and Mg values. Multiparous cows exhibited lower Ca values at calving than primiparous cows. Differences between groups according to BCS at calving were observed mainly at parturition and during early lactation. HBCS cows had significantly differences in NEFA values than LBCS cows at calving and in BHB values than LBCS cows at calving and at 7 and 21 DIM. Subclinical hypocalcemia at calving was the main imbalance (53.1%) mainly affecting multiparous cows. It can be concluded that well-nourished high-producing Holstein × Gyr cows are metabolically balanced, and that parity and BCS at calving do not significantly impact the metabolic profile of Holstein x Gyr cows.