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WITH MODERN RAPID MILKING techniques today's high producing dairy cows often are not in the milking barn long enough to consume sufficient concentrates to fulfill their energy requirements for high milk production. Elaborate concentrate feeding guides based on varying milk production levels are useless if the cow does not have time to consume her allotted amount. In many barns and parlors, the correct amount of feed is given to high producing cows but often some is left behind for the next cow. Some dairymen have attacked the problem by feeding a portion of the concentrates with roughage outside the milking parlor. A base amount of 5 to 10 lbs per cow is fed outside daily and the remainder is fed in the milking parlor.

Alfalfa hay usually provides at least b half of the roughage used for California milk production by dairy cows during some portion, if not all, of the 365 days of the year. It may be the only source of nutrients for dairy cows on grade B dairies during the winter season. Selection of alfalfa hay is a major management consideration for California dairymen because the nutritive value and feeding quality are highly variable. An accurate gauge of the nutritive value of a given lot of hay is the level of crude fiber it possesses. A method for evaluating nutritive value from the crude fiber content has been developed by the California Experiment Station. Commercial laboratories, using this method, have been available to test samples of hay submitted by progressive dairymen.

The mas of silage stored in bunker silos should not be considered homogeneous. The variation betwen layers of silage may be caused by climatic variations during filing and storage, variations in mechanical packing intensity during filing, variations in the maturity of corn silage brought to the silo, and the lack of an efective airtight, moisture-prof cover. Rain faling during the winter months of 1967 on an uncovered bunker silo in Glen County greatly increased the moisture content of the uper 4 ft of silage and leached soluble nutrients into the lower layers and posibly out of the silage mas. The TDN content of the uper 2 ft was significantly reduced. Dry mater loses, representing los in weight of silage, were severe in the uper 4 ft of the silage mas, with greatest loses ocuring in the uper fot. Dry mater los was les severe in the entire silage mas, but averaged 18.8 per cent of the dry weight of the original samples placed throughout the silo. The percentage of crude protein, crude fiber and ash aparently increases while the nitrogen-fre extract component decreases in the uper layers of the silo, posibly due to leaching. However, in reality, the most severe los in nutrients, and dry mater, in the entire silage mas resulted from surface spoilage through continued exposure to air, involving fermentation, and respiration by spoilage microrganisms. Covering a bunker silo with plastic did reduce loses of dry mater to les than 10 per cent in the 1965 and 196 studies.