Project status: 100%
Problem/Task Statement:
To prevent the common metabolic disorder parturient paresis in dairy cows, the so-called DCAB concept (anion-cation feeding) has recently been successfully implemented. The DCAB concept focuses on balancing the anions chloride and sulfate and the cations potassium and sodium in the feed ration, expressed in meq/kg DM. While a positive cation/anion ratio of +100 to +200 meq/kg DM is targeted and usually achieved during lactation, an anion surplus of approximately -100 to -150 meq/kg DM should be aimed for in the last 2-3 weeks before calving. This negative cation/anion balance can only be achieved by adding acidic salts (Mg, NH4, Ca sulfate, Ca chloride) to the dry cow ration. The effect on the acid-base balance manifests itself in the development of metabolic acidosis, which leads to a decrease in urine and blood pH values.
This results in a generally positive effect on mineral balance. Adult cattle usually overcome this temporary acidotic state without complications. In contrast, the acid-base balance of newborn calves is particularly fragile. Various external factors such as diarrhea, respiratory problems, and dietary errors can quickly lead to serious health issues. In animals already compromised by the DCAB (Dual Acid-Base Balance) concept, the blood's buffering capacity is especially stressed and rapidly depleted. This project will investigate the effects of the DCAB concept on vital parameters and acid-base balance in dairy cows and calves.
Results:
Hypocalcemic parturient paresis is, in most cases, a feeding-induced and therefore often (at least theoretically) preventable condition. Precise ration calculations, regular monitoring of feed intake, optimal body condition management, and especially the correct use of mineral supplements, particularly during the dry period, are essential prerequisites for preventing parturient paresis. The use of acidic salts is one of several, sometimes very effective, methods for preventing parturient paresis. Other options include oral administration of calcium salts in gel or bolus form, or a single injection of vitamin D3.
The actual main cause of the disease, namely an incorrect mineral supply due to excessive calcium and potassium intake (and insufficient phosphorus and magnesium intake in other forms of paresis) before calving, is unfortunately all too often forgotten by the representatives and users of the individual prophylaxis methods.
The following points must be observed as a basic requirement for the successful use of an anion-rich ration: chemical analysis of the ion content (Na, K, Cl, S), avoidance of cation-rich ration components, calculation of the DCAD and substitution with acidic salts, whereby the cation/anion ratio of the dry steric ration before the addition of the acidic salts should not exceed 180 meq/kg T, as otherwise the amount of acidic salts to be used will be too high (depression of feed intake), regular monitoring of the urinary pH value (better: NSBA) and feed intake.
The determination of urinary NSBA, which proved to be a significantly more sensitive method than measuring urinary pH for assessing acidification, is not routinely offered in practice.
When acidic salts are used, acidotic neonates are to be expected, which is why management and hygiene in calf rearing are of particular importance in these operations.
