Identification and characterization of dairy cows with different backfat thickness antepartum in relation to postpartum loss of backfat thickness: A cluster analytic approach

The objectives of this study were (1) to characterize the interindividual variation in the relationship and subsequent BFT loss during early lactation in a large dairy herd using cluster analysis; (2) to compare the serum concentrations of metabolites (nonesterified fatty acids, beta-hydroxybutyrate), metabolic hormones (leptin and adiponectin), and an inflammatory marker to compare lactation performance and uterine health status in the different clusters. An additional objective was (4) to investigate differences in these serum variables and in milk yield of overconditioned (OC) cows that differed in the extent of BFT loss. Using data from first selected those animals from which serum samples and d 31 (+/- 3 d) postpartum (pp). The remaining 713 cows (parity of 2 to 7) were then subjected to cluster analysis: different approaches based on the BFT of the learning algorithm) clustering based on BFT-ap alone between BFT-ap and BFT-pp (Delta BFT) also revealed 5 clusters: extreme loss (17-23 mm Delta BFT, n = 16), mod-erate loss (9-15 mm, n = 119), little loss (4-8 mm, n = 326), no loss (0-3 mm, n = 203) , gain (-8 to -1 mm, n = 51). Based on the blood variables measured, our results confirm that cows with greater BFT losses had higher lipid mobilization , ketogenesis than cows with less BFT loss. The serum variables of cows that gained BFT did not differ from normal cows. Milk yield was affected by the BFT-ap cluster, but not by the Delta BFT cluster. Cows categorized as VF had lesser milk yield than other clusters. We further compared the OC cows that had little or no BFT loss (i.e., 2% of VF, 12% of JF, and 31% of SF, OC-no loss, n = 85) with the OC cows that lost BFT (OC-loss, n = 135). Both NEFA and BHB pp concentrations and milk yield were greater in OC-loss cows compared with the OC-no loss cows. The serum concentration of leptin ap was greater in OC-loss than in the OC-no loss cows. Overall, OC cows lost more BFT than normal or lean cows. However, those OC cows with a smaller loss of BFT produced less milk than OC cows with greater losses.

Automated summary

This study aimed to characterize the interindividual variation in BFT loss during early lactation in a large dairy herd and evaluate its relationship with serum metabolites, metabolic hormones, and inflammatory markers. The results showed that cows with greater BFT losses had higher lipid mobilization and ketogenesis, and milk yield was affected by the BFT-ap cluster.