The deposition and redistribution of 14C was followed during the growth of individual alfalfa plants. 14CO2 was administered at 5 weekly intervals (plants were sampled 2 days after each addition of 14CO2). The plants were then defoliated, and the redistribution of 14C was followed during the subsequent growth.During the 1st week of 14CO2 uptake, only 17% of the 14C in the ]plant was translocated to crown and roots. By the 5th week, 36% of the 14C in the plant was in crown and roots. It was not until the 3rd week that 14C started to accumulate (exponentially) in the “starch” fraction. This coincided with the time that large roots (> 1 mm in diameter) started to increase in dry weight.After defoliation, 14C changes in the plant best fit a sigmoid curve. The greatest changes occurring between 3 and 15 days after defoliation. During the 28 days of regrowth, 45% of the 14C was lost (respiration, leaching, and sloughing) from the plant, 19% had moved into top growth and large roots had lost 70% of their original 14C content.

The potential effects of adverse constituents in crownvetch (Coronilla varia L.) forage on animal response were assessed using the weanling meadow vole (Microtus pennsylvanicus) as the test animal. ‘Chemung, ’ ‘Emerald,’ and ‘Penngift’ crownvetch were harvested at the early‐bud and late seed‐set stages during two growing seasons. Crownvetch forage extracted with ethanol and unextracted forage were incorporated into diets supplemented with adequate levels of protein, carbohydrate, vitamins, and minerals and fed to weanling meadow voles. Of 72 voles fed unextracted crownvetch diets, 46 died within 6 days, and most of the remaining voles lost weight. Deaths and weight losses were greatest on the mature crownvetch diets, with more deaths occurring from the 1969‐harvested forage than from that of 1971. The deleterious substance was apparently removed by ethanol extraction of the forage as shown by the death of voles fed control diets to which the ethanol extract was added. Weight gains and dry matter consumption of voles fed diets prepared with ethanol‐extracted forage were equivalent to those of the voles fed control diets containing purified cellulose.

Quantitative in vitro methods using commercial cellulase (CEL), pectinase (PECT), and hemicellulase (HCEL) preparations were developed to simplify prediction of digestibility of cool-and warm-season forage grasses. Samples of orchardgrass (Dactylis glomerata L. var. Pennlate), tall fescue (Festuca arundinacea Schreb. var. KY 31) (cool-season grasses), big bluestem (Andropogon gerardi Vitman var. NY 1145), and switchgrass (Panicum virgatum L. var. KY 1625) (warm-season grasses) were taken at advancing stages of maturity. Isolated cell-wall material (CWM) was prepared by repetitively extracting lyophilized, ground tissue with aqueous and organic solvents. Relative solubilities of CWM digested individually with CEL, HCEL, or PECT were 100:30:40, respectively. When enzyme preparations were used sequentially, the influence of CEL, HCEL, and PECT on CWM solubility depended on the order in which the enzyme preparations occurred in the sequence. The fraction of CWM solubilized with CEL was similar to that obtained when CWM was digested with CEL, HCEL, and PECT simultaneously. Solubilities of cell-wall material in unfractionated tissues digested with CEL were comparable to those of corresponding CWM digested with CEL; thus, the laborious steps required for isolation of cell-wall material can be avoided.

Crownvetch (Coronilla varia L.) has not been widely used for forage, partly because its forage quality has been reported as poor. Studies were undertaken to determine the effects of different environments and clipping schedules on composition and in vitro digestibility of crownvetch stems and leaves. First growth was sampled from flower bud to seedpod growth stage, and regrowth was sampled in July and September. Identical cutting schedules were used at four field locations in West Virginia for 2 years. Also, in growth chambers, controlled day‐night temperature combinations of 16‐2, 16‐10, 16‐18 C; 21‐2, 21‐10, 21‐18 C; and 38‐2, 38‐10, and 38‐18 C were used to determine temperature effects on herbage comosition. Acid detergent fiber and permanganate lignin levels in crownvetch were influenced differently by environment than were their deposition rates. High leaf ADF and lignin levels were attributed to high light intensities within the crownvetch canopy. Stem ADF averaged 18% higher and leaf ADF 36% higher in first regrowth than in second regrowth. Leaf lignin averaged 67%, higher in fist regrowth than in second regrowth. Leaf lignin levels of crownvetch under controlled temperatures and low light intensities were one‐fourth to one‐half of that in field samples. Maturity effects on ADF and lignin levels were significantly greater at the two locations with higher elevations. The ADF and lignin deposition rates in late spring 1970 averaged three times those in 1969 and were associated with higher rainfall. Cutin level of leaves was 65% higher than that of stems, and maximum levels were obtained either at early or full bloom stage. In vitro digestibility of crownvetch stems decreased 0.81 percentage points per day from flower bud to early bloom, and thereafter at lower rates. Digestibility of crownvetch stems and leaves of first regrowth (58, 74%) was lower than that of second regrowth (66, 78%). The ADF and lignin levels of stems, but not of leaves, were largely independent of crop yield and were inversely related to digestibility. Prediction of nutritive value of firstcrop crownvetch is far more difficult than of other commonly used legumes