Blood Mineral, Hormone, and Osteocalcin Responses of Multiparous Jersey Cows to an Oral Dose of 25-Hydroxyvitamin D3 or Vitamin D3 Before Parturition

Abstract

Twenty-seven multiparous Jersey cows were randomly assigned to receive an oral bolus containing corn starch (control, CON), corn starch plus 15 mg of 25-hydroxyvitamin D(3) (25-OH), or 15 mg of cholecalciferol (D(3)) at 6 d before expected parturition. Cows were maintained in individual box stalls from 20 d before expected parturition and fed a common diet. Jugular blood samples were collected at -14, -13, -5, -4, -3, -2, -1 d before expected calving, at calving, and at 1, 3, 5, 7, 9, 11, 13, 28, 56, and 84 d postcalving. After calving, cows were housed in 1 pen in a free-stall barn and consumed a common diet. Colorimetric assays were used to analyze Ca, P, and Mg concentrations in serum. Serum concentrations of osteocalcin (OC), an indicator of bone formation, serum 25-hydroxyvitamin D(3), and parathyroid hormone (PTH) were determined in samples obtained from d -5 through d 13. The 9 control multiparous cows and 5 untreated primiparous cows were used to evaluate the effect of parity on the variables that were measured. There was no effect of parity on Ca, PTH, or 25-OH concentration. Compared with second-lactation cows and older cows (>2 lactations), first-lactation cows had greater serum OC (22.3, 32.0, and 48.3 ng/mL, respectively), indicating that younger animals were forming more bone. Blood Ca, P, and Mg decreased near the time of calving and then increased over time. Serum 25-hydroxyvitamin D(3) was greater for cows dosed with 25-OH (119.0 ng/mL) compared with those dosed with D(3) (77.5 ng/mL) or CON (69.3 ng/mL). Cows dosed with 25-OH tended to have lower serum PTH concentration, but treatments did not affect serum Ca, P, or Mg. Serum OC was greater in second-lactation cows compared with cows entering their third or fourth lactation but OC was unaffected by treatment. Although results indicated a 60% increase in serum 25-hydroxyvitamin D(3) due to a single oral dose of 25-OH before calving, the amount administered in this study apparently was not sufficient for initiation of any improvement in Ca homeostasis at parturition.

Impact of parity on bone metabolism throughout the reproductive cycle in sows

“…The higher OC concentrations in primiparous sows compared to multiparous sows were in agreement with the expectations, because OC reflects osteoblast activity in bone formation and these decreased with age (Liao et al, 1990), and were in accordance with other species such as goats and sheep (Liesegang et al, 2007) and cows (van Mosel and Corlett, 1990;Kamiya et al, 2005;Taylor et al, 2008). Though, the concentration of bone markers may vary independently of bone metabolism, as reported in Sato et al (2013).…”

“…At this reproductive phase, despite the increased absorption efficiency, the minerals absorbed from feed may not meet the increased nutrient requirements to facilitate Ca and P demands for foetal development and milk production (Liesegang et al, 2005;Counotte et al, 2009;Donangelo and King, 2012). In other studies, serum Ca concentrations decreases consequently and stimulates PTH and 1,25-(OH) 2 D 3 secretion to support Ca transport and mobilisation (Liesegang et al, 2000;Taylor et al, 2008;Counotte et al, 2009), thereby increasing bone resorption and decreasing bone formation (Halloran and DeLuca, 1980;Liesegang et al, 2005 and2006). In the present study, sows were fed close to ad libitum feed intake during lactation, which is in accordance with conventional practices.…”

“…Although increased bone remodelling is conceivable in sows during reproduction as well as in other production animals, the effect of parity on bone mineralisation has not been studied in breeding sows. In other animal species, parity did influence bone mineralisation (cattle: Taylor et al, 2008;Sato et al, 2011 andsheep and goats: Liesegang et al, 2007). Since primiparous sows are still growing and lack a preceding lactation period, we hypothesised that hormonal profiles differ between primiparous and multiparous sows.…”

“…These processes are largely regulated by parathyroid hormone (PTH) and 1,25-dihydroxyvitamin D 3 (1,25-(OH) 2 D 3 ) hormone secretion (Peterson et al, 2005;Liesegang et al, 2006;Taylor et al, 2008). The latter hormone increases an active calcium (Ca) and phosphorus (P) intestinal epithelial transport and mobilisation.…”

Perfil mineral de vacas mestiças Girolanda no período de transição em sistema semi-intensivo em duas estações do ano

“…Quando as concentrações de cálcio são menores que o intervalo de referência, como observada nos animais próximo ao parto, ocorre à liberação do paratormônio, que aumenta a reabsorção óssea e ativa a 1,25-dihidroxivitamina D. A vitamina D atua aumentando a reabsorção tubular renal e a absorção intestinal de cálcio (DeGaris & Lean 2008, Taylor et al 2008, Goff 2009). Porém, em algumas situações esses mecanismos falham e ocorre a hipocalcemia (NRC 2001).…”