An open-circuit indirect respiration calorimetry system for the collection of long-term metabolic heat production data for medium and small animals is described. The system is designed for use with small ruminants, but it has the capacity for measuring heat production in nonruminant species up to 150 kg. The system consists of an internal climatic control system, air flow control and volume measuring system, and gas analyzers for O2, CO2 and CH4. Carbon dioxide recovery checks of the four chambers produced recovery values ranging from 96.73 to 100.89%. The actual mean fasting heat production measured for 12 wether sheep was 63.13 kcal/kg.75 +/- .83. The total estimated cost of four chambers and the associated instrumentation was less than $17,000 in 1984.

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The nutritive value of reed canarygrass (Phalaris arundinacea L.) was studied in two experiments. In the first year, effects of stage of growth at harvest and method of preservation on digestibility and nutritive value were studied using cattle. In the following year, effects of degree of maturity at harvest and level of feed intake on digestibility and nutritive value were investigated. Maximum ad libitum intake of each forage was determined with both cattle and sheep. First‐cutting reed canarygrass was harvested the first week of June and conserved as hay. In the first year, it also was stored as haylage in a conventional tower silo. Twelve to 15 days later, a more mature first‐cutting was harvested as hay. Forty days after each first‐cutting, an aftermath (second year only) was harvested and conserved as hay. For uniformity, all hay was artificially dried with heat at a mean temperature of about 44 C. On a percentage basis, a delay in harvest of 12 to 15 days after the first week in June was accompanied by mean losses of 8% TDN, 15% net energy, and 34% digestible protein concentrations in the hay. A concurrent 20 and 24% loss in maximum dry matter intake was observed in cattle and sheep, respectively. Level of feed intake significantly affected nutritive value expressed as net energy per unit dry matter. Aftermaths and haylage generally were intermediate between the two first‐cutting hays in digestibility, nutritive value, and maximum intake.