Relative Acidifying Activity of Anionic Salts Commonly Used to Prevent Milk Fever

Abstract

High cation diets can cause milk fever in dairy cows as they induce a metabolic alkalosis reducing the ability of the cow to maintain calcium homeostasis at the onset of lactation. Adding anions to the diet can offset the effect of the high cation forages by inducing a mild metabolic acidosis, restoring the ability to maintain calcium homeostasis. The difference in mEq of dietary cations and anions (DCAD) is most often expressed as (Na(+) + K+) - (Cl- + S(--)). This equation implies that a mEq of chloride and a mEq of sulfate are equipotent in their ability to alter acid-base balance of the cow. Using blood and urine pH to monitor effects on acid-base balance, experiments were conducted to test the relative acidifying activity of various sulfate and chloride anion sources in nonpregnant, nonlactating Jersey cows. Across all experiments, chloride proved to have about 1.6 times the acidifying activity of sulfate. Calcium and magnesium, ignored by the common DCAD equation, had a small but significant alkalinizing effect when accompanying chloride or sulfate. The ranking of the anion sources tested at a dose of 2 Eq/d, from most to least potent urine acidifier, was hydrochloric acid, ammonium chloride, calcium chloride, calcium sulfate, magnesium sulfate, and sulfur. These data should allow more accurate prediction of the response of late gestation cows to dietary cation-anion manipulation.

The effect of MgSO4 addition and the increasing doses of calcium and phosphorus during ending drying period on the occurrence of hypocalcaemia and hypophosphataemia in dairy cows

“…The decrease of urine pH after application of sulphate was observed in studies of Goff et al (2004), Peterson et al (2005) and Chan et al (2006). Chiappi (2003) suggested, that application of the high amount of calcium (100 g of Ca) could limit anions acidifying effect.…”

“…with the large amount of dietary Ca and have a negative effect on the process of ovulation. Goff et al (2004) suggested that hydrated magnesium sulphate could be used not only as acidifying agent, but also as a source of magnesium. Among the anion salts, this compound has the least effect in decreasing appetite in cows (Goff 2006).…”

Nutrition and Health of Dairy Animals

“…Equation D can serve the same purpose (Goff et al, 1991). The last equation J, (Na + K) − (Cl + 0,6S), was the most recently proposed by Goff et al (2004).…”

Strategic nutritional management for organic livestock and poultry farming-A review

“…(ii) Milk fever: The feeding of a diet high in cations especially in K and Na in dry period tends to increase incidence of milk fever (Goff et al,2004). Whereas, feeding cows with diet relatively high in anion, primarily Cl and SO 4 may help to prevent milk fever.…”