Previous Diet of Deer, Cattle, and Sheep and Ability to Digest Alfalfa Hay

The capacity of rumen microorganisms of deer, cattle, and sheep on different diets to digest alfalfa hay was tested in an artificial rumen system by measuring the production of gas and short chain fatty acids. Inocula were obtained from the rumens of (1) four wild deer on a natural winter browse diet, (2) one captive deer fed a starvation diet of sagebrush, (3) a cow on a hay diet, (4) the same cow on hay and concentrate, and (5) two sheep on hay and concentrate. Production of short chain fatty acids by the inoculum of the deer fed sagebrush was significantly lower than that from all other animals. Except for appreciably smaller percentages of butyrate and iso-valerate plus valerate by the inoculum of the deer fed sagebrush, the composition of short chain fatty acids produced was very similar among all inoculum sources. Production of gas by the inoculum of the deer fed sagebrush was significantly less than that from all other animals. Inocula from the sheep and the cow fed concentrate and hay produced more gas, and those from the deer on browse and the cow on hay produced similar but progressively larger amounts. These results indicate that normal wild deer, like domestic ruminants, have a microflora capable of digesting hay and converting it to volatile fatty acids. However, by the time that starving deer arrive at a hay supply, the rumen microorganisms may be completely dead or contain low energy