Chemical Preservation of Alfalfa Hay for Dairy Cows

Abstract

Alfalfa hay from a common field was baled at an average moisture content of 19% (dry control), at 28% with the addition of a chemical preservative, and at 29% with no preservative (wet control). The preservative consisted of 70% propionic acid and 30% formalin. Heating in storage and molding were prevented by the chemical treatment. After 4 mo of storage, the hay baled at 29% moisture content without a preservative had higher acid detergent fiber and lignified nitrogen content than hay baled dry or with a preservative. Yield and composition of milk from 16 lactating Holstein cows fed the dry control and the treated hays in a switchback trial were similar. The digestibility of dry matter, total protein, neutral detergent fiber, and organic matter were also similar. Molar percentages of rumen volatile fatty acids were similar in the two groups. Applied at 1% of the hay as baled, the preservative was effective in maintaining hay quality equal to that of hay baled at 19% moisture content. acids react to form indigestible compounds (6, 10, 13). Van Soest (12) noted that the extent of browning in heated forages was correlated positively with the nitrogen in acid detergent fiber (ADF) which had low in vivo digestibility. Goering and Gordon (5) observed that the effective heating period, temperature, and moisture content were related to the amount of browning in forages. Moreover, utilization of protein in heated alfalfa by dairy cows has been decreased (2).