Liver Health Index: A potential tool to identify cows at high risk of developing diseases after calving

By Caio Figueiredo, Veterinary Medicine Extension

The transition period is considered one of the most challenging stages in the life of a dairy cow and also one of the most delicate times to manage in dairy herds. Several studies have depicted the importance of a “smooth” transition of cows into lactation on subsequent health, welfare, productive and reproductive performance, and survival. A potential aid in the identification of cows at high risk of developing diseases during the early postpartum period involves the use of negative acute phase proteins and related molecules as an indicator of detrimental inflammation. One diagnostic mechanism is termed the Liver Health Index (LHI = [(Alb − μAlb)/σAlb] + [(Chol − μChol)/σChol] − [(Bili − μBili)/σBili]). Briefly, LHI is calculated using each individual cow’s albumin, cholesterol, and bilirubin values and the sampled population mean and standard deviation. Albumin, cholesterol, and bilirubin are negative acute phase proteins (and related compounds) that indicate liver function and severity of inflammatory status. Although such compounds may not illustrate the biological processes in their entirety, LHI has been associated with differences in biomarkers of energy metabolism (i.e., glucose), liver function (i.e., bilirubin and cholesterol), inflammation (i.e., albumin, ceruloplasmin, haptoglobin, IL-1β, and IL-6), and oxidative stress (i.e., paraoxonase and glutathione).

A recent publication reported that LHI is associated with differences in cow health and performance (Kerwin et al., 2022). More specifically, postpartum cows that were affected by clinical diseases within 2 weeks postpartum had lower LHI compared with cows without clinical diseases (Table 1). Differences in productive and reproductive performance were also associated with LHI (Figure 1).

Other publications have also reported differences in cow health, performance, and behavior associated with LHI. For instance, a greater number of health problems was observed in cows with low LHI compared with cows with high LHI within 30 days postpartum (Trevisi et al., 2012; Zhou et al., 2017). Milk production within 35 days postpartum was also reduced in cows with low LHI compared with cows with high LHI (36.2 vs. 46.3 kg, respectively). Finally, LHI was highly correlated to the number of minutes of rumination per day (r = 0.75), suggesting that LHI could be used as a proxy for cow health and welfare (Calamari et al., 2014). Altogether, LHI may be a useful tool for the identification of cows at higher risk of developing diseases and aid early diagnosis of disease in dairies, particularly for those that do not possess automated activity monitoring systems (i.e., collars or ear tags).

Table 1. Least squares means and standard error of the mean (SEM) of the liver health index for cows diagnosed or not diagnosed with the negative health event of interest for a retrospective cohort study involving 72 farms across the northeastern United States. Adapted from Kerwin et al., 2022.

Figure 1. Summary of findings from Kerwin et al., 2022.