RE:RE:Animal Feed Supplement
Snippet from a study on milk production. Harrison et Al.
Potassium (K) is the principal intracellular cation of most body tissues. Potassium ions participate in many essential biological processes such as the maintenance of osmotic potential within cells, nerve impulse transmission, enzyme reactions in cellular metabolism, the maintenance of normal kidney function, and cardiac, skeletal and smooth muscle function. Because milk is an intracellular fluid, milk contains a large amount of K. Published research suggests that the early lactation dairy cow is in negative K balance (Bannink et al., 1999; Nennich et al., 2006; Silanikove et al., 1997). Potassium retention and excretion, along with the effect of K on milk production, were evaluated using a combination of data from various total collection metabolism trials (Nennich et al., 2005 and 2006). Potassium retention in this data set was positive for over 85% of cows in the calibration dataset; however, in a set of early lactation cows, K retention was negative for all cows. Early lactation cows (less than 75 days in milk) had an average K retention of 66 g/d (Figure 1). Excretion of K appears to be directly related to K intake. Figure 2 shows the relationship of K intake and K excretion. Potassium metabolism of cows in the early lactation dataset varied from cows in the calibration dataset. Early lactation cows tended to excrete greater amounts of K even though K intakes were similar to cows in the calibration dataset (Figure 2). Due to the greater K excretion and the greater secretion of K in milk, early lactation cows were in a negative K balance. Silanikove et al. (1997) found that cows in early lactation are often in a negative K balance and suggested that increased amounts of K in the diet may be beneficial to milk production.
The early production can be juxtaposed against another study which showed no difference with dietary potassium in later milk production.
I have no idea what the dairy calving cycles are in Brazil.