Symposium review: Transition cow calcium homeostasis—Health effects of hypocalcemia and strategies for prevention

Abstract

The effects of subclinical hypocalcemia have been explored in numerous observational and mechanistic studies in recent years. Besides obvious, well-known effects on muscle contractility, the role of Ca with respect to immune function and intermediary metabolism explains the contribution of subclinical hypocalcemia to the development of several diseases observed in early lactation and underlines its importance in highperforming dairy cows. The present review aims at integrating recent scientific progress, such as discoveries about the role of the mammary gland in regulating bone mobilization, into generally accepted aspects of the endocrine control of Ca homeostasis. We will discuss Ca transport mechanisms through absorption, resorption, secretion, and mobilization, as well as the physiological regulation of Ca through parathyroid hormone, 1,25-dihydroxyvitamin D, fibroblast growth factor 23, and serotonin, in addition to dietary mineral requirements. To improve hypocalcemia prevention strategies, our knowledge of the physiological mechanisms necessary to maintain normocalcemia and their endogenous regulation should be combined with data derived from herd-level studies. Using such studies, we will discuss prepartum nutritional strategies aimed at reducing the incidence of subclinical hypocalcemia, as well as options for postpartum Ca supplementation and their effects on early-lactation health and production. Especially in respect to approaches that might interfere with endogenous adaptation processes, such as supple-mentation with vitamin D metabolites or large doses of Ca, a thorough understanding of the underlying mechanisms that might induce unwanted hypocalcemia rebound effects will be crucial to ameliorate our future management of transition cows. Continued efforts by researchers to understand the interaction of Ca homeostasis with prevention strategies is necessary to optimize cow health and support copious milk production.

The TRPV3 channel of the bovine rumen: localization and functional characterization of a protein relevant for ruminal ammonia transport

“…11b). Given the robust evidence supporting transport of Ca 2+ by TRPV3 [37,45,48,63], bTRPV3 also clearly emerges as a candidate mediating electrogenic Ca 2+ transport by the ruminal epithelium [27,61,62].…”

“…Given that certain plantderived compounds modulate the activity of TRPV3 [55], this has implications both for the development of new drugs and for new feeding strategies [8]. Ruminants absorb considerable amounts of Ca 2+ from the rumen to meet the high demand involved in milk production [61]. Based on electrophysiological data, a ruminal channel for Ca 2+ has long been postulated [27,62], although the typical epithelial calcium channels TRPV5 and TRPV6 are not expressed in the ruminal epithelium [45,60].…”

“…Based on electrophysiological data, a ruminal channel for Ca 2+ has long been postulated [27,62], although the typical epithelial calcium channels TRPV5 and TRPV6 are not expressed in the ruminal epithelium [45,60]. Intriguingly, TRPV3 channels are activated by intracellular protons [36], which may explain the welldocumented stimulatory effects of short-chain fatty acids on ruminal calcium uptake [61].…”

Research on the Applications of Calcium Propionate in Dairy Cows: A Review

“…It is well-known that calcium is essential for the formation of skeletal tissue, transmission of nervous tissue, muscle contractility, and essential minerals for blood and milk. In contrast, the role of calcium with respect to the immune function and intermediary metabolism explains the contribution of subclinical hypocalcemia to the development of several diseases observed in early lactation and underlines its importance in high-performing dairy cows [20]. Oral calcium supplementation with calcium propionate, which is a calcium source in solution, can be greatly absorbed by the rumen and increase the ionized calcium concentration in the blood.…”

Fatores Maternos De Vacas Leiteiras De Baixa Produção Que Podem Influenciar Nas Concentrações De Paraoxonase-1 Do Neonato

“…O papel do cálcio e do magnésio se estende a implicações endócrinas e de função imune e déficits desses sistemas em vacas periparturientes são um dos fatores que contribuem para ocorrência de doenças nesses animais (WILKENS et al, 2020). Além disso, a concentração sérica de cálcio da vaca influencia na saúde do bezerro, sendo bezerros nascidos de vacas hipocalcêmicas mais predispostos a desenvolver diarreia quando comparados a bezerros nascidos de vacas normocalcêmicas (WILHELM et al, 2017).…”