Effect of calcium intake and the dietary cation-anion difference during early lactation on the bone mobilization dynamics throughout lactation in dairy cows

Abstract

This study investigated the consequences of a low supply of dietary Ca with or without a low dietary cation-anion difference (DCAD) during early lactation on bone mobilization and reconstitution during lactation and on the dynamics of milk Ca content. Fifteen multiparous Holstein cows were distributed among 3 treatments 5 weeks before their expected calving date. These treatments differed based on the provision of diets through the first 10 weeks of lactation. During this period, the control treatment (NCa) consisted of a diet providing 100% of the Ca requirement, with a DCAD of 200 mEq/kg dry matter (DM). The LCa (low Ca) and LCaLD (low Ca, low DCAD) treatments consisted of diets providing 70% of the Ca requirement, with a DCAD of 200 and 0 mEq/kg DM, respectively. After 10 weeks, all cows received the same total mixed ration, which was formulated to meet 100% of the Ca requirement. LCa and LCaLD tended to decrease the body retention of Ca at 3 weeks of lactation compared with NCa but affected neither the dynamics of the blood biomarkers of bone formation and resorption during lactation nor the body retention of Ca at 17 weeks of lactation. Cows almost entirely compensated for the decrease in Ca supply caused by LCa and LCaLD by increasing their apparent digestive absorption of Ca at 3 weeks of lactation, whereas their apparent digestive absorption was unaffected by the treatments at 17 weeks of lactation. Milk production tended to be lower throughout lactation with LCa and LCaLD compared with NCa, with a mean difference of 2 kg/d. The results of this study also indicated that measuring the dynamics of milk Ca content during lactation cannot be considered effective for indirectly estimating the dynamics of bone mobilization in cows. The results also suggested that limited Ca intake at the beginning of lactation may have deleterious effects on milk production.

Biochemical Bone Markers During the Transition Period Are Not Influenced by Parenteral Treatment With a High Dose of Cholecalciferol but Can Predict Milk Fever in Dairy Cows

“…Results from this study indicate that bone metabolism was increased after calving, in response to high Ca demand in early lactation. Similar conclusions were made by other studies using CTx or other bone resorption markers (11,37,41,42). In a study where biochemical bone markers between healthy and cows with milk fever were compared, higher values of bALP and lower values of CTx were observed in milk fever cows, however, the differences were not statistically significant (33).…”

“…However, they found ALP was highest in early lactation (8-50 day after calving), while we observed a fall at 10-20 day after calving. Both specific biochemical bone markers increased after calving and were highest 10-20 days after calving (11). Except for bALP in the winter group.…”

“…The objective of this study was to evaluate the effect of a single high-dose parenteral administration of vitamin D 3 , between 10 and 2 days before calving and season on blood biochemical bone markers, blood minerals, total alkaline phosphatase, estradiol, and milk yield in standard lactation during the transition period compared to untreated cows during the winter housed period. Few studies have investigated the effect of different milk fever prevention methods on selected parameters to such extent (6,(9)(10)(11). The hypothesis was that vitamin D 3 administration would increase bone resorption, raise blood mineral content, reduce the incidence of milk fever and increase milk production compared to untreated groups.…”

Effect of calcium intake and dietary cation anion difference in early lactation on bone mobilization dynamics all over lactation in dairy cows

“…In our experiment, the diet offered to the cows during the first 10 weeks of lactation was also intentionally formulated with a high dietary PDI to NE L ratio, with the objective being to maximize the milk production capacity by the mammary gland and perhaps the necessity of bone mobilization (20). Primiparous cows were excluded from the experiment, and special care was applied to balance the average parity between treatments because parity is, in dairy cows, a strong determinant of bone formation and resorption throughout lactation (11,25,35) and digestive absorption of Ca (36).…”

“…Mid-infrared spectra technology allows a rapid and inexpensive way to determine the milk Ca content (23,24). Data collected during several stages of lactation in dairy cows with different parities (25) suggested that milk Ca and P contents could be related to the plasma concentrations of biomarker of bone formation and resorption. However, whether those variations are specifically related to the cycle of bone formation and mobilization or other interfering effects is unknown.…”