A novel model to explain dietary factors affecting hypocalcaemia in dairy cattle

Abstract

Most dairy cows exhibit different degrees of hypocalcaemia around calving because the gestational Ca requirements shift to the disproportionately high Ca requirements of lactation. Ca homeostasis is a robust system that effectively adapts to changes in Ca demand or supply. However, these adaptations often are not rapid enough to avoid hypocalcaemia. A delay in the reconfiguration of intestinal Ca absorption and bone resorption is probably the underlying cause of this transient hypocalcaemia. Several dietary factors that affect different aspects of Ca metabolism are known to reduce the incidence of milk fever. The present review describes the interactions between nutrition and Ca homeostasis using observations from cattle and extrapolations from other species and aims to quantitatively model the effects of the nutritional approaches that are used to induce dry cows into an early adaptation of Ca metabolism. The present model suggests that reducing dietary cation -anion difference (DCAD) increases Ca clearance from the blood by dietary induction of systemic acidosis, which results in hypercalciuria due to the loss of function of the renal Ca transient receptor potential vanilloid channel TRPV5. Alternatively, reducing the gastrointestinal availability of Ca by reducing dietary Ca or its nutritional availability will also induce the activation of Ca metabolism to compensate for basal blood Ca clearance. Our model of gastrointestinal Ca availability as well as blood Ca clearance in the transition dairy cow allowed us to conclude that the most common dietary strategies for milk fever prevention may have analogous modes of action that are based on the principle of metabolic adaptation before calving.

Elevation of circulating serotonin improves calcium dynamics in the peripartum dairy cow

“…In the dairy cow, smooth muscle contraction is responsible for rumen and gut motility as well as uterine and teat sphincter contraction (Kimura et al 2006, Goff 2008. Dysregulation of these physiological functions as a result of low calcium leads to many other common transition period diseases, including ketosis and fatty liver, displaced abomasum, dystocia, metritis, and mastitis (Kimura et al 2006, Goff 2008, Martín-Tereso & Verstegen 2011, Chapinal et al 2011. In addition, subclinical hypocalcemia specifically has been linked to greater risk of fever, as well as decreased pregnancy rates and longer intervals to pregnancy (Martinez et al 2012).…”

Peripartal alterations of calcitonin gene‐related peptide and minerals in dairy cows affected by milk fever

“…Milk fever (MF) or periparturient paresis is a common and economically important metabolic disorder of dairy cows occurring at the onset of lactation. It is characterized by a rapid decline of calcium (Ca) concentrations in plasma . This disease has been described for more than 2 centuries, with the first reports in the literature about MF dating back to 1793 .…”

“…Different hypotheses have been generated over the years to explain the etiopathogenesis of MF; however, the underlying mechanisms of MF are not well understood. The hypothesis that has gained most support to date is that MF is a perturbation of Ca homeostasis at or near parturition . Despite many advances made in prevention of MF, its incidence, as indicated by most recent epidemiologic studies, is relatively high.…”

“…It is characterized by a rapid decline of calcium (Ca) concentrations in plasma. 1,2 This disease has been described for more than 2 centuries, with the first reports in the literature about MF dating back to 1793. 3 Different hypotheses have been generated over the years to explain the etiopathogenesis of MF 3,4 ; however, the underlying mechanisms of MF are not well understood.…”

“…The hypothesis that has gained most support to date is that MF is a perturbation of Ca homeostasis at or near parturition. [2][3][4][5] Despite many advances made in prevention of MF, 5 its incidence, as indicated by most recent epidemiologic studies, is relatively high. For example, it was shown that on a herd level, this condition affected between 4 and 8% of cattle in the USA, 5 between 4 and 9% in the UK, 4 and between 2 and 5% in Australia.…”