Dietary Ca concentration to minimize the risk of hypocalcaemia in dairy cows is affected by the dietary cation–anion difference (original) (raw)
Related papers
Journal of Dairy Science, 2009
Forages low in dietary cation-anion difference (DCAD) can be used to decrease the DCAD in prepartum diet but the extent to which DCAD needs to be reduced is of recent interest. The objective of this study was to evaluate the effectiveness of timothy hays differing in DCAD at maintaining Ca homeostasis. Six nonlactating and nonpregnant multiparous Holstein cows were fed diets containing timothy (Phleum pratense L.) hay with DCAD values of 4.1 ± 3.6 (LOW), 14.1 ± 3.0 (MED), or 25.1 ± 2.5 (HIGH) mEq per 100 g of DM in a duplicated 3 × 3 Latin square design with 14-d experimental periods. The LOW and MED hays were produced by fertilizing established timothy fields at a rate of 224 kg CaCl 2 per ha, and HIGH hay was obtained from the same field where LOW hay was produced, but from a section not fertilized with CaCl 2 . Experimental diets, containing LOW, MED, or HIGH timothy hay at 71% of dietary DM, had DCAD values of 0.7, 7.3, and 14.4 mEq per 100 g of DM, respectively. Animals were fed at 6% of metabolic body weight, which provided 108% of their daily energy requirement. For each period, after a 12 d diet adaptation, cows were subjected to an EDTA challenge (3 cows each on d 13 and 14). Infusion of EDTA solution into the jugular vein decreases the concentration of blood ionized Ca, and the EDTA challenge protocol determined the resistance time and recovery time: the time required for the blood ionized Ca concentration to decrease to 60%, and the time required to recover to 90% of the prechallenge concentrations, respectively. Urine pH was lower when cows were fed LOW compared with HIGH diet (6.88 vs. 7.83), but urine pH when cows were fed MED diet (7.15) did not differ from that when cows received the LOW or HIGH diet. However, immediately before the EDTA challenge, blood pH was lower when cows were fed LOW or MED compared with HIGH diet (7.44 vs. 7.47). Although the resistance time was not affected by treatments, the recovery time was shorter when cows were fed the LOW compared with MED or HIGH diet (185 vs. 248 and 263 min, respectively). Blood pH decreased when cows were fed the LOW or MED diet, but the capability to maintain Ca homeostasis was enhanced only when cows received the LOW diet, in which the DCAD value was decreased to 1 mEq per 100 g of DM.
Comparative Clinical Pathology, 2019
Two experiments were carried out in order to evaluate the efficacy of a partially decreased dietary cation-anion difference (pDCAD) of dry period rations of dairy cattle ((DCAD~0 mEq/Kg DM) in prevention of postpartum subclinical hypocalcemia (SCH). The primary goal of the Experiment I was to compare the efficacy of a pDCAD strategy in minimizing SCH against a full DCAD (fDCAD~− 50 mEq/Kg DM) and a low calcium diet (LCD) in late (21 days (d)) pregnancy in Farm 1, using 66 multiparous cows (parity ≥ 3). The primary goal of Experiment II was to evaluate the effect of extension of a pDCAD to whole dry period (expDCAD-60 days), enrolling 40 cows (parity ≥ 3) to compare a pDCAD vs. expDCAD strategy. In both experiments, a primiparous heifers group was included as well. Serum Ca, Pi, Mg, and energy status indicators β-hydroxybutyrate (BHB) and non-esterified fatty acids (NEFA) were monitored pre-and post-partum, serially. Experiment I showed a significantly lower Ca, a numerically higher prevalence of SCH, and significantly lower NEFA and BHB in pDCAD vs. fDCAD. The prevalence of subclinical ketosis (SCK) was significantly higher in fDCAD peripartally. In Experiment II, a significantly higher Ca and lower prevalence of SCH were observed in expDCAD vs. pDCAD postpartum, while BHB, NEFA, and the prevalence of SCK were not significantly different. The prevalence of SCH in primiparous heifers in both experiments was about 30%. Overall, compared to common ordinary fDCAD strategy, pDCAD could be potentially regarded as a practical intervention, when the adverse effects of fDCAD are unavoidable.
Australian Veterinary Journal, 2018
BackgroundAdjusting the dietary cation–anion difference (DCAD) is one of the most efficient ways to stimulate calcium homeostasis in periparturient dairy cattle. However, adjusting DCAD to the recommended negative values (−100 to −150 mEq/kg) is associated with decreased food intake and metabolic acidosis. The critical conditions of the animals at peripartum (i.e. drastic hormonal changes, decreased appetite and negative energy balance) can be detrimental to the health, productivity and welfare of the animals if combined with decreased feed intake caused by unpalatable acidogenic salts.MethodsIn a cross‐sectional study, we analysed the ration of eight small to large dairy herds with intensive husbandry systems, including 6949 dry cows. Sodium, potassium, chlorine and sulfur concentrations in the feed were determined and DCAD was calculated. The DCAD of the ration of the farms ranged from –33.5 to +24.7 mEq/kg. Parturient paresis (PP, or milk fever) prevalence was investigated and co...
Journal of dairy science, 2003
It was hypothesized that a reduction in the dietary cation-anion difference (DCAD) before calving, combined with an increase in Ca intake after calving, would reduce the incidence of periparturient hypocalcaemia and increase milk production in pasture-based dairy cows. Cows (n = 40) were assigned to one of two DCAD levels before calving (i.e., +7 and +50 mEq/100 g). Each group was then assigned to one of two dietary Ca concentrations after calving (i.e., 1.0 and 0.7%) in a 2 x 2 factorial design. The lower DCAD resulted in a nonrespiratory reduction in systemic pH as indicated by a lower urine pH. This acidosis resulted in an increased concentration of Ca in urine before calving. The lower precalving DCAD helped prevent the decline in blood Ca caused by the onset of lactation, even though blood Ca concentration was lower before calving compared with cows receiving a high DCAD. Supplementation of cows with Ca after calving increased plasma Ca concentration on the day of calving and d...
Hypocalcemia in dairy cows: meta-analysis and dietary cation anion difference theory revisited
Journal of dairy science, 2006
Data from 137 published trials involving 2,545 calvings were analyzed using random effects normal logistic regression models to identify risk factors for clinical hypocalcemia in dairy cows. The aim of the study was to examine which form, if any, of the dietary cation anion difference (DCAD) equation provided the best estimate of milk fever risk and to clarify roles of calcium, magnesium, and phosphorus concentrations of prepartum diets in the pathogenesis of milk fever. Two statistically equivalent and biologically plausible models were developed that predict incidence of milk fever. These models were validated using data from 37 trials excluded from the original data used to generate the models; missing variables were replaced with mean values from the analyzed data. The preferred models differed slightly; Model 1 included prepartum DCAD, and Model 2 included prepartum dietary concentrations of potassium and sulfur alone, but not sodium and chloride. Other factors, included in bot...
Journal of Dairy Science, 2000
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 CaCl 2 , CaSO 4 , and MgSO 4 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 CaCO 3 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 of parathyroid 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 CaCO 3 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 2095 calving regardless of diet but ate less when fed the −15 DCAD diet suggests that they should not be fed anionic salts before calving. (Key words: prepartum diet, anionic salts, energy balance, hypocalcemia)
Journal of Dairy Science, 1994
Our objective was to examine whether feeding low cation-anion diets altered the Ca status of the growing calf. Holstein calves (n =32; 16 males) were blocked at 56 to 70 d after birth according to sex and birth date and assigned randomly to dietary treatments containing Ca content and cation-anion balances as mi11iequivalents of (Na + K) -(Cl + S)/loo g of dietary DM of .42% and -18, .52% and -18, .42% and 13, and .52% and 13. Feed intake did not differ among treatments. Calves fed the diet with cationanion balance of 13 had higher gain (.85 vs..71 kg/d) than those fed the diet with balance of -18. Venous blood pH (7.374 vs. 7.323), partial pressure of C02 (47.9 vs. 45.6 mm Hg), and bicarbonate (28.3 vs. 23.3 mmollL) were higher for calves fed the 13 versus -18 balances. Plasma Ca and P were unaffected by Ca or cation-anion balance. Urinary pH was higher for calves fed the high than the low balance (7.442 vs. 6.047). Urinary Cl and Ca excretion was higher for calves fed the low than the high balance. Breaking strengths for 7th and 9th ribs were higher for calves fed the high balance and higher for the 7th rib only for calves fed the high Ca diet. Cation-anion balance altered Ca metabolism, but it is unclear whether Ca requirements were also altered. (IThis manuscript (93-5-48) is published with the approval of the director of the Kentucky Agricultural Experimental Station.
Journal of Dairy Science, 2006
High-producing dairy cows are commonly fed diets containing a high proportion of rapidly degradable starch, which can cause subacute acidosis and reduce dry matter (DM) intake. Because of the properties of nonmetabolizable cations and anions, increasing the dietary cation-anion difference (DCAD = Na + K − Cl − S in mEq/kg of DM) may prevent a drop in DM intake. To test this hypothesis, 48 Holstein cows were blocked into 2 groups of 24 and assigned to two 3 × 3 Latin squares in a split-plot design. Each group received one level of concentrate at either 20% or 40% on a dry matter (DM) basis. The diet containing 20% concentrate was formulated to supply 4% rapidly degradable starch, whereas the diet containing 40% concentrate supplied 22% rapidly degradable starch. Diets in each square were formulated to provide a DCAD of 0, 150, or 300 mEq/kg of DM. The 3 values were obtained by manipulating Na and Cl contents. Intake, 4% fat-corrected milk yield, and milk fat percentage, as well as blood nonesterified fatty acids and β-hydroxybutyrate increased with DCAD, but only on the diet providing 40% concentrate. The yield of trans-10 C 18:1 and odd-chain fatty acids decreased with increasing DCAD, whereas trans-11 C 18:1 increased. Again, this occurred only with the diet providing 40% concentrate. Blood pH and HCO 3 concentration increased along with DCAD, irrespective of the concentrate level. A positive DCAD led to increasing DM intake and fat-corrected milk yield in dairy cows fed highly degradable diets. The mechanism involved may be a localized rumen buffering effect, together with the ability of positive DCAD to maintain blood acid-base status in cows faced with a massive acid input.
Effect of prepartum dietary calcium on intake and serum and urinary mineral concentrations of cows
Journal of dairy science, 2006
Nine multiparous and 12 primiparous cows were fed diets containing an anionic salt supplement and moderate Ca (0.99%) or high Ca (1.50%) concentrations for 21 d prepartum to determine the effects of dietary Ca concentration on serum and urine electrolytes and on postpartum intake and milk yield. Blood samples were collected during 21 to 1 d prepartum, 0 to 2 d postpartum, and 3 to 21 d postpartum. Dietary cation-anion difference (DCAD) for prepartum diets was approximately -6 mEq/100 g of dry matter (Na + K - Cl - S). Immediately postpartum, cows were fed diets with positive DCAD with greater than 1.00% Ca concentration. Mean serum Ca concentrations 21 to 1 d prepartum, 0 to 2 d postpartum, and 3 to 21 d postpartum were 9.62, 8.41, and 9.38 mg/dL. There were no treatment effects on serum Ca concentration. Mean serum Ca concentration was higher for primiparous than multiparous cows (9.34 vs. 8.93 mg/dL) for the trial and at calving (8.77 vs. 8.13 mg/dL). Mean serum HCO(3)(-) and urin...