Evaluation of potato meal as a feedstuff for lactating dairy cows.

Potato meal was ensiled with a grass-legume forage at 7.5% of fresh weight and substituted for ground corn in concentrate mixtures at 0, 15, and 30% fresh weight. Production, digestion, and nitrogen balance trials were conducted on 12 lactating Holstein cows fed individually for ad libitum intake. Potato meal was consumed readily in the quantities offered. Mean daily milk production for cows receiving the hay-crop silage ensiled with potato meal was 28.6 compared with 26.3 kg for cows consuming untreated silage. Molar percentages of acetate in rumen were lower and propionate higher for cows receiving hay-crop silage ensiled with potato meal. Digestibility coefficients for dry matter, organic matter, acid detergent fiber, neutral detergent fiber, crude protein, and gross energy all tended to be lower for the silage with added potato meal. Nitrogen balance was higher for cows consuming silage with potato meal. When potato meal was added to concentrate mixes replacing corn at 0, 15, and 30%, milk production was 27.5, 26.8, and 28.0 kg/day. Potato meal can be used advantageously as a silage additive and can be included in concentrate mixtures up to 30% of the fresh weight.