A NOTE ON THE EFFECT OF SODIUM FERTILIZATION OF PASTURE ON THE PERFORMANCE OF LACTATING DAIRY-COWS

Sixty-four lactating cows were allocated among five treatment groups. Four of the treatments involved varying the level of sodium fertilisat ion of pasture: 0, 19, 38 and 56 kg Na/ha. Na was applied as salt (NaC l) in conjunction with a compound fertiliser. The fifth treatment invo lved 16 cows grazing the same pasture as the cows on the 0-Na treatmen t and offered a daily allowance (1 kg/head) of a concentrate containin g 23 g Na per kg dry matter (DM). All other cows involved in the study received the same daily allowance of a concentrate containing 0.5 g N a/kg DM, Na fertilisation increased the mean Na content of the herbage from 2.4 to 3.6 g/kg DM, and occasionally increased DM digestibility coefficients. Herbage intake, milk yield, butterfat concentration and live weight were not significantly affected either by Na fertilisation or Na supplementation via the concentrate supplement.