Abstract

Increased intensification of dairy production has contributed to a decrease in the sodium (Na) status of soils throughout New Zealand. This decline has the potential to detrimentally affect animal health and production. A trial was established to determine whether milk production responses would be obtained to sodium supplementation of cows receiving about 0.1% (0.06-0.14%) Na in pasture. The cows were in mid-lactation and were randomly allocated to either the control group or a group receiving 14 g Na/cow/day. Supplementation with 14 g Na did not increase milk yield or affect milk composition and there was no interaction with stocking rate. Serum Ca, Mg, Na, and Cl concentration were not affected by treatment, but serum K concentration decreased with Na supplementation. In summary: 0.1% Na in the diet is sufficient for mid-lactation dairy cows producing 10-12 litres milk/cow/day (0.9 kg milksolids/cow/day) and a milk production benefit will not be achieved through Na supplementation.

KA, MacDonald, JA Lile, JAS Lancaster, M Coulter, and MB O'Connor

Proceedings of the New Zealand Society of Animal Production, Volume 62, Palmerston North, 236-239, 2002