Methodological aspects in ruminal digestion studies. I. Effect of feeding frequency

Abstract

Two experiments were conducted to compare different feeding frequencies with regard to dry matter (DM) intake, rumen contents, apparent ruminal retention time of the neutral detergent fiber (rNDF) and 48-h in situ DM digestibility (ISDMD). In experiment 1 three rumen-fistulated steers were fed a ration of brachiaria (Brachiaria decumbens) hay, freshly cut pigeon pea (Cajanus cajan) forage and ground sorghum; six treatments were applied in an unbalanced design: a) Hourly feeding, b) Feeding every 3 h, c) Feeding every 6 h, d) Feeding every 12 h, e) Feeding every 3 h from 6:00 AM to 9:00 PM at which time the rest of the daily ration was given, and f) Feeding every 3 h from 6:00 AM to 6:00 PM when the rest of the daily ration was offered. In experiment 2, six animals were used to compare hourly feeding vs. feeding every 6 h in a switchback design. The ration consisted of sugarcane tops, pigeon pea forage and ground corn ears. Means for net DM intake (kg/100 kg LW/ day), rumen contents (kg DM/100 kg LW), rNDF (h), brachiaria ISDMD (%) and pigeon pea forage ISDMD (%) for experiment 1 were: 1.93, 1.76, 23.8, 66.0 and 63.1, respectively, with no significant differences. In experiment 2, the means for DM intake, rumen contents, rNDF and pigeon pea ISDMD were: 1.76, 1.79, 37.6 and 53.4, respectively, again with no significant treatment differences. It was concluded that feeding frequency is not a factor of importance in the methodology for rumen digestion studies.