Showing papers in "Journal of Animal Science in 1970"

An in vitro technique for estimating digestibility of treated and untreated wood.

Abstract: N the United States, about 50 million tons I of wood and bark residues, containing up to 75% carbohydrate are available annually as a potential energy source for ruminants. Except for modest digestibility of a few hard­ wood species, however, the carbohydrates of whole-wood residues are essentially unavail­ able to the ruminant animal. The close molecular association between the major con­ stituents of wood-cellulose,hemicellulose, and lignin-appearsto limit bacterial and enzymatic access to the carbohydrates of the cellwall. Success in using wood residue carbohy­ drates as an energy source thus requires the development of an effective and practical means for enhancing the accessibility of the cell wall constituents to the action of rumen microorganisms. Of prime importance to this type of undertaking is a rapid, accurate, and inexpensive in vitro technique for assaying the large numbers of samples that will be generated. The in vitro procedure of Tilley and Terry (1963) or one of its modifications has been used extensively and is one of the better laboratory methods for evaluating the nutri­ tive quality of forages (Barnes, 1967; Oh, Baumgardt and Scholl, 1966; Van Soest, Wine and Moore, 1966). When used to esti­ mate the digestibilities of modified woods and other high-cellulosic substrates, however, it yielded low and quite variable coefficients of digestibility. The purpose here was to adapt the first stage of the Tilley and Terry technique to as­ say treated and untreated woods. Through critical investigation, each operational step was optimized. The resultant modified proce­ dure lends itself with acceptable precision to routine processing of multiple samples. Ex­ amined during optimization were the follow­

Taste Responses in Ruminants. IV. Reactions of Pygmy Goats, Normal Goats, Sheep and Cattle to Acetic Acid and Quinine Hydrochloride

Abstract: B EHAVIORAL taste thresholds are often used to compare gustatory chemoreception among species. However, such thresholds may vary depending upon a number of environmental and intraorganic factors. In order to obtain reasonably precise species-comparisons, it is necessary that as many as possible of the influencing factors be controlled. The purpose of the studies reported in this paper was to compare the taste responses of four species of ruminants to acetic acid (HAc) and quinine hydrochloride (QHC1) when some of the more important factors (age, diet and testing procedure) influencing taste responses were controlled.