Serum osteocalcin and CTX-I concentrations in transition dairy cows
S.G.A. van der Drift1*, A. Koopmans1, L. Kroon2, R. Grotentraast1, and M.M.C. Holstege1
1Royal GD, Arnsbergstraat 7, 7418 EZ Deventer, The Netherlands
2Schothorst Feed Research B.V., Meerkoetenweg 26, 8218 NA Lelystad, the Netherlands
*Presenting author
Aim of the study
Bone metabolism can be monitored by serum biomarkers such as osteocalcin (OC; indicator bone formation) and CTX-I (degradation products of C-terminal telopeptides of Type I collagen; indicator bone resorption). The aim of this study was to investigate serum concentrations of OC and CTX-I in transition dairy cows.
Materials & Methods
• The study was performed in 2019 – 2020 at the dairy farm of Schothorst Feed Research B.V. (Lelystad, the Netherlands).
• A total of 44 cows of different parities were enrolled in the study.
• Serum samples were collected at different time points relative to parturition (Figure 1).
• OC and CTX-I concentrations in serum were analyzed using N-MID Osteocalcin and CTX-I test kits on an IDSiSYS Multi-Discipline Automated System.
• Serum results were available for 35 to 41 cows per sampling moment.
• Differences in OC or CTX-I concentrations 1) between sampling days and 2) between parity groups (within sampling day) were investigated using a Kruskal-Wallis test followed by a Dunn’s test with Bonferroni correction (Stata version 17.0, 2021; significance level P<0.05).
Results
• OC and CTX-I results are shown in Table 1.
• Heifers had larger serum OC concentrations than cows from third or higher parity at all time points (P<0.05) and larger OC concentrations than second parity cows at day 7 and 28 (P<0.05).
• Serum CTX-I concentrations were larger in heifers than in cows from third or higher parity from day -10 until day 7 (P<0.05).
• Heifers tended to have smaller serum OC/CTX-I-ratios than second parity cows (P<0.10) and older cows (P<0.05) before parturition, but had larger OC/CTX-Iratios at day 7 and 28 postpartum (P<0.05).
Conclusions
• Serum OC en CTX-I concentrations seem to follow a pattern around parturition, but parity-specific reference intervals are necessary for correct interpretation of OC and CTX-I concentrations in transition cows.
Figure 1: Design of the study.
Table 1: Concentrations (mean and standard deviation) of osteocalcin (OC; ng/mL), CTX-I (ng/mL), and their ratio in transition cows at different sample moments relative to parturition at the dairy farm of Schothorst Feed Research (the Netherlands).
*Results with different superscripts in the same column differ significantly from each other (P<0,05). Moment of sampling No. of cows
Figure 2: Serum concentrations of osteocalcin in heifers (1), second parity (2), and older parity (>=3) cows at different sampling moments shown as days relative to parturition (day 0).
Figure 3: Serum concentrations of CTX-I in heifers (1), second parity (2), and older parity (>=3) cows at different sampling moments shown as days relative to parturition (day 0).
