Increased Concentration of Sodium Chloride on Milk Production of Cows Fed Low Fiber Diets

Fifteen lactating Holstein cows fed a low-fiber diet were used to investigate effects of feeding high concentrations of sodium chloride on milk production and feed efficiency. Cows were fed a normal fiber diet (acid detergent fiber = 26.4%) the first 28 to 34 d following calving and then were adjusted to a low-fiber diet (acid detergent fiber = 10.3%) over the next 28 d. Following adjustment, a reversal trial had two 28-d periods. In period 1, cows in group 1 received 6.0% sodium chloride added to the concentrate dry matter, whereas group 2 received 1.2% sodium chloride (control) added to the concentrate; these treatments then were reversed. Daily hay (kg), grain (kg), organic matter (kg), and water (L) intakes averaged 2.0, 13.6, 14.5, 74.9 and 2.1, 13.6, 13.5, 91.3 for low fiber control and low fiber plus 6.0% sodium chloride. Consumption decreased with 6.0% sodium chloride supplementation, and water intake increased 22%. High sodium chloride did not change milk yield or composition. Ratio of ruminal acetate to propionate increased from 2.69 to 3.13, and fecal starch increased from 15.6 to 20.1% with 6.0% sodium chloride. Increased concentrations of sodium chloride did not change most blood measures, although potassium increased and acetate and propionate concentrations declined. Arteriovenous differences of glucose, acetate, and proprionate across the mammary gland were not affected. Feeding 6.0% versus 1.2% sodium chloride did not enhance production and feed efficiency in cows fed a low fiber diet.