Epidemiology of subclinical hypocalcemia in early-lactation Holstein dairy cows: The temporal associations of plasma calcium concentration in the first 4 days in milk with disease and milk production

Abstract

The objectives of this study were to characterize the epidemiology of subclinical hypocalcemia (SCH) in Holstein dairy cows by assessing the temporal associations of plasma Ca concentrations in the first 4 d in milk (DIM) with the risk of cows being diagnosed with metritis or displaced abomasum (or both), and milk production across the first 15 wk of lactation. A prospective cohort study was conducted in 2 dairy herds in New York State, in which cows had a blood sample collected daily for the first 4 DIM. A total of 396 Holstein cows (137 primiparous and 259 multiparous) were enrolled. Multivariable Poisson regression models were built to evaluate the associations of plasma Ca concentration at each of the 4 d following parturition with the risk of primiparous cows being diagnosed with metritis and multiparous cows being diagnosed with metritis, displaced abomasum, or both. Similarly, generalized linear mixed models were built to evaluate the associations of plasma Ca concentration with milk production across the first 15 wk of lactation. Plasma Ca concentration was assessed on a continuous scale in all models; dichotomization and SCH classification only occurred in the final models if the Ca concentration variable was meaningful by creating an optimized threshold based on receiver operating characteristic curve analysis. Plasma Ca concentration assessed at 1 DIM was not associated with the risk of metritis in primiparous cows, but an association was observed at 2, 3, and 4 DIM (critical thresholds were plasma Ca concentration ≤2.15, 2.10, and 2.15 mmol/L, respectively). Plasma Ca concentration was associated with the risk of metritis or displaced abomasum diagnosis (or both) for 2nd parity animals at 2 DIM (threshold ≤1.97 mmol/L), and at 4 DIM for 3rd and greater lactations (threshold ≤2.20 mmol/L). Reduced plasma Ca concentration was associated with higher milk production when assessed at 1 DIM in primiparous and multiparous cows, and lower milk production when assessed at 4 DIM in multiparous cows only. For primiparous cows, plasma Ca concentration was not associated with lower milk production at any of the DIM assessed. In conclusion, assessments of SCH at the individual cow level must take into account the DIM of Ca concentration measurement and parity of the cow, as the epidemiology of the disorder was demonstrated to be highly dependent on these variables. This study advances the knowledge of the epidemiology of SCH and better establishes thresholds for optimizing SCH diagnosis.

Effects of postpartum oral calcium supplementation on milk yield, milk composition, and reproduction in multiparous Jersey and Jersey × Holstein crossbreed cows

“…The sample size available to assess the treatment by serum calcium concentration effect, as well as the degree of hypocalcemia in the study herds may have limited the power of the present study to detect the effects of serum calcium concentration before supplementation on treatment response. Recent research suggests that the time relative to parturition when blood calcium concentration is assessed plays a role on its association with productive and health outcomes (Neves et al, 2018); thus, it is plausible that the serum calcium concentration assessed within the first 5 h following parturition may not have the strongest association with the evaluated productive and reproductive outcomes. In addition, the improved calcemia following oral calcium supplementation observed in the former study by our group was only evident up to 2 DIM (Valldecabres et al, 2018); the limited size or absence of effects observed for the evaluated productive and reproductive outcomes may also indicate that calcemia within the first 48 h following parturition may not be strongly associated with the evaluated outcomes.…”

Review: Regulation of gastrointestinal and renal transport of calcium and phosphorus in ruminants

“…The physiological response to transient hypocalcaemia is an increase in bone mobilisation followed by enhanced gastrointestinal absorption (van´t Klooster, 1976). If these mechanisms are compromised, either the extent or the duration of hypocalcaemia is exacerbated resulting in increased risks of developing different diseases in early lactation depending on the duration of hypocalcaemia (Neves et al, 2018). Reliable data on the prevalence of peripartum hypocalcaemia in small ruminants are scarce.…”

The effect of an organic rumen-protected fat supplement on performance, metabolic status, and health of dairy cows

“…All of these disorders have adverse effects on animal welfare, milk production, reproduction, and farm profitability [9,10].…”