Chemical changes in esophageal fistula samples caused by salivary contamination and sample preparation.

Abstract

A chemical comparison of hand-squeezed and non-squeezed esophageal samples with standard hand-clipped samples was made, using four esophageal fistulated steers in each of five trials. Prairie sandreed (Calamovilfa longifolia) and blue grama (Bouteloua gracilis) were clipped and hand-fed at varying stages of maturity. Chemical analyses included ash, calcium, phosphorus, chloride, crude fiber, lignin, crude protein, water soluble carbohydrates, total sugars and total fructose. Salivary contamination and mastication resulted in an increase in the ash, phosphorus and chloride content and a decrease in calcium content of esophageal samples, as compared to the forage which was fed. Crude protein, water soluble carbohydrates, total sugars and total fructose were lower in both squeezed and non-squeezed esophageal samples than in samples of that fed. This change was attributed to salivary contamination and preparation of esophageal samples. In most cases crude fiber, and in all cases, lignin, were not greatly affected. The results of this study indicated that acid-detergent crude fiber and lignin of certain forages can be adequately sampled with esophageal fistulated cattle. However, changes occur in the mineral, water soluble carbohydrate and crude protein content of forages which are sampled with this technique. Squeezed esophageal samples have a lower mineral content than non-squeezed samples. Squeezed and non-squeezed esophageal samples have similar water soluble carbohydrates and crude protein contents.