Effects of Altering Dietary Cation-Anion Difference on Calcium and Energy Metabolism in Peripartum Cows

Abstract

Our objective was to determine the effects of varying dietary cation-anion differences (DCAD: meq[(Na + K) - (Cl + S)]/100 g of dry matter) in prepartum diets on Ca, energy, and endocrine status prepartum and postpartum. Holstein cows (n = 21) and heifers (n = 34) were fed diets with varying amounts of CaCl2, CaSO4, and MgSO4 to achieve a DCAD of +15 (control), 0, or -15 meq/100 g of dry matter for the last 24 d before expected calving. Dietary Ca concentration was increased (by CaCO3 supplementation) with decreasing DCAD. Plasma ionized Ca concentrations prepartum and at calving in both cows and heifers increased with reduced DCAD in the diet. At calving, plasma ionized Ca concentration was 3.67, 3.85, and 4.35 for cows and 4.44, 4.57, and 4.62 mg/dl for heifers fed diets containing +15, 0, and -15 DCAD, respectively. All heifers had normal concentrations of plasma ionized Ca (>4 mg/dl) at calving. Also at calving, plasma concentrations ofparathyroid hormone and calcitriol were less in cows and heifers fed diets containing reduced DCAD, but the plasma concentration of hydroxyproline was not affected by diet. Prepartum dry matter intake, energy balance, and body weight gains were lower and concentration of liver triglyceride was higher for heifers but not cows fed the -15 DCAD diet. Also, nonesterified fatty acids the last week prepartum were positively correlated with liver triglyceride for heifers but not cows. Feeding of anionic salts plus CaCO3 to reduce DCAD to -15 and increase Ca in prepartum diets prevents hypocalcemia at calving in cows, but decreases prepartum dry matter intake and increases the concentration of liver triglyceride in heifers. That heifers maintained calcium homeostasis at calving regardless of diet but ate less when fed the -15 DCAD diet suggests that they should not be fed anionic salts before calving.

Hipocalcemia no deslocamento de abomaso de bovinos: estudo de 39 casos

“…A DACD ideal parece estar em torno de -10mEq/100g de matéria seca. Entretanto, alguns autores observaram que a dieta aniônica promoveu o aumento nas concentrações plasmáticas de cálcio nas primeiras 24 horas pós-parto, sem contudo influenciar na incidência de hipocalcemia clí-nica ou subclínica (Moore et al 2000, Kurosaki et al 2007, Ramos-Nieves et al 2009). Por ser um cátion com forte poder alcalinizante, monitorar os níveis de potássio na forragem é outra estratégia que deve ser considerada na prevenção da hipocalcemia.…”

Acidification of urine by feeding anionic products to non-lactating dairy cows

“…Furthermore, administration of vitamin D or its metabolites often requires the proper timing of multiple doses and the possibility of toxicity exists (Littledike and Horst 1980). Manipulation of dietary cation-anion difference (DCAD) to below -5 meq 100 g dry matter -1 (DM) has also been shown to reduce the incidence of milk fever (Block 1984;Moore et al 2000). Dietary cation-anion difference is a systematic way to predict the overall difference in the acid-base status within the cow.…”

“…A urine pH below 6.5 has been shown to minimize parturient hypocalcemia (Jardon 1995;Moore et al 2000). Anionic products are commercial supplements that can be fed to cows to rapidly depress urine pH (Goff and Horst 1998a) and it is recommended that spot samples of urine be used to verify the acid-base metabolic status of individual cows receiving anionic supplements.…”

Effects of feeding anionic products to non-lactating dairy cows on urine pH

“…Reducing the cation-anion difference of diets fed to prepartum cows to below -5 mequiv 100 g -1 dry matter (DM) can greatly reduce or completely eliminate the incidence of milk fever postpartum (Block 1984;Moore et al 2000). Dietary cation-anion difference (DCAD) is a method used to calculate the acid-base status of the diet based on the levels of specific anions and cations contained within the diet.…”

“…Monitoring urine pH is a common measure used to evaluate the acid-base condition of non-lactating cows consuming anionic products (Jardon 1995;Goff and Horst 1998a;Vagnoni and Oetzel 1998). Urine pH of 6.5 or lower is thought to be required to decrease the risk of milk fever (Jardon 1995;Moore et al 2000). Current field recommendations specify that the optimum time to measure urine pH from non-lactating cows is 3 to 4 h post-feeding.…”