EFFECTS OF INITIAL HARVEST DATE ON DRY MATTER YIELD, IN VITRO DRY MATTER DIGESTIBILITY AND PROTEIN IN TIMOTHY, TALL FESCUE, REED CANARYGRASS AND KENTUCKY BLUEGRASS

1983 ◽  
Vol 63 (3) ◽  
pp. 675-685 ◽  
Author(s):  
W. MASON ◽  
L. LACHANCE

Timothy, tall fescue, reed canarygrass and Kentucky bluegrass plots were harvested at weekly intervals from the vegetative stage through to seed maturity for 3 yr in order to evaluate the effect of harvest and species on nutrient production. The forage of the early harvest regimes was cut after 5 wk of regrowth and all plots were harvested in the fall. In vitro dry matter digestibility (IVDMD) values ranged from above 80% down to 45%, with an average rate of decrease during June of 0.74, 0.84, 0.85 and 0.45% per day in timothy, tall fescue, reed canarygrass and Kentucky bluegrass, respectively. Similarly, crude protein (CP) in first-cut forage ranged from 28% to 6% and had respective decreases of 0.47, 0.40, 0.39 and 0.28%/day. Regrowth forage in the midsummer and fall harvests averaged from 63 to 59% IVDMD and from 16 to 20% CP, respectively. With the exception of reed canarygrass, delaying the initial cut resulted in continued increases in total annual dry matter (DM) yield, significant increases in total IVDMD yield until flowering, and decreases in total CP yield from stem elongation onwards. Reed canarygrass reached its optimum CP yield at early heading and had significant increases in IVDMD yield until the flowering stage. Harvesting all forages at the stem elongation stage substantially reduced the yield of DM, IVDMD and CP. Although most of the DM was obtained in the initial harvest, almost half of the total CP was obtained in the final harvest.Key words: Timothy, tall fescue, reed canarygrass, Kentucky bluegrass, growth cycle, forage quality

1975 ◽  
Vol 26 (1) ◽  
pp. 127 ◽  
Author(s):  
JR Wilson ◽  
TT Ng

Plants of Panicum maximum var. trichoglume grown in soil in pots under a controlled environment were subjected to water stress and the effect on forage quality was assessed. Stress was applied as a series of drying and re-wetting cycles, and harvests of total laminae, stem, root, and also specific laminae, were taken 5, 10, 17, 27 and 57 days after the commencement of stress treatment. When compared with control plants of similar chronological age, the dry matter digestibility (estimated by an in vitro technique) of the stressed plants was lower in leaves 4, 6 and 8, similar in total green laminae and in leaves 10 and 12, and higher in stem and dead laminae. The cell wall content of various tissues of the stressed plants was lower than that of the controls. Water stress delayed stem elongation and flowering. It is postulated that stress also delayed the normal ontogenetical changes of the leaves. If comparison was made on a physiological age basis then stress markedly lowered the dry matter digestibility but had little effect on the cell wall content. The broader implication of delayed ontogeny is briefly discussed. The decrease in dry matter digestibility in stressed plants was not associated with changes in the proportions of cellulose, hemicellulose or lignin, but reflected a decline in digestibility of cell wall material.


1960 ◽  
Vol 40 (1) ◽  
pp. 123-129 ◽  
Author(s):  
K. W. Clark ◽  
G. O. Mott

An artificial rumen technique was evaluated as a method of determining the dry matter digestion of forages. The digestibility estimates obtained in the spring were significantly correlated (r = 0.77xx) with estimates obtained on these forages from a conventional digestion trial, whereas in the fall the coefficients were low and no longer significantly correlated (r = 0.49) with the conventional trial data.A medium maturing timothy polycross nursery was harvested at 10-day intervals throughout the first growth cycle. With the exception of the April 14th stage there were no significant differences in digestibility between the clones harvested in the early-leaf stage. Significant differences between selections were obtained in digestibility at later stages of maturity which may be a function of the leaf-stem ratio, the amount of leaf firing and thickness of the culms as well as changes in chemical composition. The per cent fructose content of this timothy herbage was significantly correlated (r = 0.78xx) with the dry matter digestibility only at the first stage of cutting.Changes in dry matter digestion using this artificial rumen technique were observed, with digestion estimates being higher during the spring and summer than during fall and winter.The method of drying herbage for these in vitro digestion experiments was studied with the conclusion that there was a significant difference in favour of freeze-drying. The dry matter digestion coefficients of the freeze-dried herbage were comparable to those expected for herbage of such quality digested in vivo.The use of an artificial rumen technique for estimating digestibility of clonal material shows promise for the plant breeder, providing certain precautions are taken. All lines to be screened should be included in a single trial to ensure maximum control of variables associated with technique. Samples should be uniformly processed, preferably freeze-dried, and digested with a single sample of rumen fluid.


1963 ◽  
Vol 43 (1) ◽  
pp. 79-87 ◽  
Author(s):  
G. I. Pritchard ◽  
L. P. Folkins ◽  
W. J. Pigden

The in vitro dry matter digestibility (IVD) of timothy, orchard, brome, reed canary, tall fescue and mountain rye grasses decreased at the rate of approximately 0.5 per cent per day throughout the growing season. The most rapid decline in IVD began with head emergence. The earliest maturing grasses tended to be higher in IVD than the other grasses at the flowering stage. The decline in IVD as the season progressed was observed in all portions of the plant, the rate of decline for the heads and stems being greater than for the leaves. The upper segments of the stems tended to have a lower IVD than the basal segments.


Author(s):  
Janet H. Woodward ◽  
D. E. Akin

Silicon (Si) is distributed throughout plant tissues, but its role in forages has not been clarified. Although Si has been suggested as an antiquality factor which limits the digestibility of structural carbohydrates, other research indicates that its presence in plants does not affect digestibility. We employed x-ray microanalysis to evaluate Si as an antiquality factor at specific sites of two cultivars of bermuda grass (Cynodon dactvlon (L.) Pers.). “Coastal” and “Tifton-78” were chosen for this study because previous work in our lab has shown that, although these two grasses are similar ultrastructurally, they differ in in vitro dry matter digestibility and in percent composition of Si.Two millimeter leaf sections of Tifton-7 8 (Tift-7 8) and Coastal (CBG) were incubated for 72 hr in 2.5% (w/v) cellulase in 0.05 M sodium acetate buffer, pH 5.0. For controls, sections were incubated in the sodium acetate buffer or were not treated.


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