Serum osteocalcin and alkaline phosphatase concentrations in replacement heifers
S.G.A. van der Drift*, A. Koopmans, R. Grotentraast, and M.M.C. Holstege
Royal GD, Arnsbergstraat 7, 7418 EZ Deventer, The Netherlands
*Presenting author
Aim of the study
Materials & Methods
• Serum samples were collected between October 2020 and January 2021 from 317 replacement heifers of 2 to 4 months (3 animals/farm) and 12 to 14 months of age (3 animals/farm) on 53 Dutch dairy farms (study design in Figure 1).
• OC concentrations in serum were analysed with a N-MID Osteocalcin test kit on an IDS-iSYS Multi-Discipline Automated System (IDS).
• ALP concentrations in serum were analysed with an enzymatic method on a UniCel DxC 600 Synchron Clinical System (Beckman Coulter); results from hemolytic samples were rejected (n=22).
• Only complete records from animals that met the age criteria were included in the final dataset (257 observations from 52 farms).
• Differences in serum parameters between age groups were investigated with a Wilcoxon Rank Sum Test and associations between serum parameters were described with a Spearman rank correlation coefficient (Statistix Version 8.0; significance level P<0.05).
• Reference intervals were calculated using Reference Value Advisor (1).
Results
• Serum OC and ALP concentrations were larger in younger than in older replacement heifers (P<0.001; Table 1 and Figure 2 and 3).
• Correlation coefficients for OC and ALP concentrations in younger and older replacement heifers were rs = 0.32 and r s = 0.30, respectively (P<0.001).
Conclusions
• Age-specific reference values are necessary for correct interpretation of serum ALP and OC concentrations in replacement heifers from different age groups.
Reference
1. Geffre, A., Concordet, D., Braun, J.P., Trumel, C. 2011. Reference Value Advisor: a new freeware set of macroinstructions to calculate reference intervals with Microsoft Excel. Vet. Clin. Pathol. 40(1): 107–112.
53 farms
Sampling of 317 replacement heifers from two age groups
Analysis of serum OC and ALP concentrations
Serum concentrations of (bone-specific) alkaline phosphatase (ALP) and bone biomarkers such as osteocalcin (OC) can be used to monitor bone metabolism in animals. The objectives of this study were to investigate serum concentrations of OC and ALP in 2- to 4-month-old and 12- to 14-month-old replacement heifers and to calculate reference intervals for these age groups.
Reference interval calculation 2 to 4 months of age 12 to 14 months of age
257 complete & valid animal records (52 farms)
Table 1: Descriptive statistics and reference intervals for serum concentrations of alkaline phosphatase (ALP, in U/L) and osteocalcin (OC, in ng/mL) in replacement heifers of different age groups from 52 Dutch dairy farms.
Figure 2: Serum concentrations of alkaline phosphatase (ALP) in replacement heifers of two to four months of age (n=126) and 12 to 14 months of age (n=131) from 52 Dutch dairy farms.
Figure 3: Serum concentrations of osteocalcin (OC) in replacement heifers of two to four months of age (n=126) and 12 to 14 months of age (n=131) from 52 Dutch dairy farms.
Figure 1. Design of the study