Abstract

Four trials in early to mid lactation investigated the effect of supplementation with sodium bicarbonate on milk production from cows grazing pasture. In Trial 1, 3 groups of 14 cows received 0, 100 g or 200 g NaHCO3/cow/day for 28 days. Trial 2 assessed whether any effects of sodium carbonate were due to sodium by comparing no supplement, 200 g NaHCO3/cow/day and 140 g NaC1 with three groups of 20 cows for 28 days. In both trials treatments were administered by drenching at each milking. Trial 3 assessed the importance of method of administration. Treatments of no supplement, 100 g NaHCO3/cow/day by drenching at the morning milking, or 100 g NaHCO3/cow/day in the drinking water were administered to 3 groups of 20 cows, during three 21 day periods according to a latin square design. Trial 4 compared rates of 0, 50, and 100 g NaHCO3 via drinking water with 3 groups of 18 cows for 21 days. In Trial 1 milk yield and protein yield were significantly reduced (P<0.10) by drenching 200g NaHCO3/day, compared to the control cows (14.,7 vs 15.3 kg milk/cow/day). The lower dose rate did not affect milk yield or composition. In Trials 2 and 4, none of the treatments significantly affected milk solid yields. Milk, protein and lactose yields from cows on the trough treatment were higher than those for control and drenched cows in Trial 3. Plasma magnesium was lower in drenched cows than in control or trough treatment cows.

TC, Reid, and RMW Sumner

Proceedings of the New Zealand Society of Animal Production, Volume 51, , 383-388, 1991