Comprehensive analysis of the interactions between harvest schedule and persistence, hay yield, and forage quality is lacking for cool‐season perennial grasses. Our objective was to determine whether harvest schedules typical of those producing a range from poor to excellent hay quality (two, three, or four times of cutting/year) under weed‐free conditions would differentially influence these properties for orchardgrass (Dactylis glomerata L.), tall fescue (Festuca arundinacea Schreb.), reed canarygrass (Phalaris arundinacea L.), and smooth bromegrass (Bromus inermis Leyss.). Three harvest schedules were used during the first 3 production years of this field experiment on Typic Hapludoll soil. In the 4th and 5th years, all plots were harvested three times to determine whether any adverse responses by the grasses to either more or less frequent harvest could be overcome. Smooth bromegrass persisted poorest at the four‐cutting schedule, tall fescue and orchardgrass persisted poorest at the two‐cutting schedule, and reed canarygrass persisted best at all cutting schedules. Smooth bromegrass cut four times recovered substantially after the switch to three‐time harvest. In vitro digestibility and crude protein concentration of reed canarygrass declined most rapidly, while those of orchardgrass or tall fescue declined least rapidly, due to maturation. The grasses did not differ greatly in rate of cell wall concentration increase. We obtained new evidence that crude protein concentration cannot be relied upon for assessment of generalized forage quality. Reed canarygrass consistently yielded more dry matter than did smooth bromegrass, but otherwise frequent year‐to‐year yield variations existed among species and cutting schedules. Our results show the necessity for imposition of several controlled harvest schedules over prolonged periods for accurate measurement of the potential of grasses intended for flexible forage management systems.

Total basic alkaloid concentration of reed canarygrass (Phalaris arundinacea L.) is negatively correlated with palatability (selection when a choice is offered) of the grass to ruminant animals. The significance of these alkaloids to ruminants not offered a choice of pasture forage remained unknown. Our objectives were to determine whether alkaloid concentration and alkaloid type differences among reed canarygrass genotypes affect animal performance, grass intake, and health of grazing sheep and cattle. Replicated pastures representing two primary alkaloid types (gramine vs. tryptamine‐carboline) and two alkaloid concentrations were primarily established from eight clones of reed canarygrass. During 1973 and 1974, these pastures were grazed by lambs and during 1975, by steers. Total alkaloid concentration of the grass was highly negatively associated with average daily gains by lambs and steers (r= —0.91, —0.90, and —0.91 for 1973, 1974, and 1975, respectively). Alkaloid concentration was highly negatively correlated with an estimate of voluntary intake (r = −0.85) by lambs not offered a choice of reed canarygrass genotypes, but alkaloid concentration was not usually overtly associated with voluntary intake by steers. Animals had more diarrhea when grazing high‐alkaloid plants and when grazing tryptamine‐carboline‐containing compared to gramine‐containing plants. This physiological upset may have been a major contributor to reduced animal gains. Breeding or managing reed canarygrass cultivars for lower alkaloid concentration per se, and breeding for tryptamine‐carboline‐free (gramine‐containing) cultivars, should provide pasture that has improved animal performance potential. “Phalaris staggers” or “sudden death” were not incited in sheep or cattle grazing exclusively reed canarygrass that had very high indole alkaloid concentrations. This indicated that these disorders, thought to be caused by indole alkaloids in animals grazing Phalaris species, are very likely not caused by indole alkaloids alone. We have conclusively demonstrated that palatability differences and their associated alkaloid concentration differences among reed canarygrass genotypes have a substantial biological significance for grazing lambs and steers.

We earlier documented that indole alkaloid concentration of vegetatively propagated reed canarygrass (Phalaris arundinacea L.) clones was inversely associated with average daily gains of lambs and steers. Our objectives were to determine whether alkaloid concentration and type in two commercially available cultivars (‘Rise’ and ‘Vantage’) and in a low‐alkaloid, tryptamine‐carboline‐free strain (MN‐76) were associated with performance and health of grazing lambs. These seed sources of reed canarygrass were each planted in three pastures (0.27‐ha/pasture) in a randomized complete block design.Lambs that grazed MN‐76 gained from 51 to 95% more per day than did those that grazed Rise and from 14 to 87% more than did those that grazed Vantage during a 2‐year period. Rise contained a mean of 0.28 to 0.32% dry wt of a mixture of gramine and tryptamines‐carbolines, Vantage contained 0.20 to 0.33% gramine, and MN‐76 contained 0.09 to 0.12% gramine. The three grasses did not differ in most other quality components, but MN‐76 had up to 8% less cell walls and up to 9% more crude protein during the 2 years, as well as up to 28% more Ca during Year 1. The correlation between total indole alkaloid concentration of the grasses and lamb average daily gain was −0.97 in Year 1 and −0.66 in Year 2. Incidence of diarrhea among lambs was 4 to 26 times greater when they grazed Rise compared to Vantage or MN‐76.We conclude that the indole alkaloid concentration threshold in reed canarygrass at or above which lambs will show reduced gain is about 0.20% dry wt, that diarrhea in grazing lambs specifically caused by consumption of reed canarygrass is very likely due to tryptamine‐carboline alkaloids, and that MN‐76 is a biologically significant grass breeding advance.

Forage dry matter intake potential by ruminants is negatively associated with its cell wall constituent (CWC) concentration. The objectives of this study were to estimate genetic variance components and determine combining ability and heritability of CWC percent, and other associated quality traits in reed canarygrass (Phalaris arundinacea L.). Genotypic correlations were computed between paired characters. Twelve heterozygous clones used in two 6 ✕ 6 diallels and progenies from 30 crosses were grown for 2 years at two locations with three replicates arranged in randomized complete blocks. One plot consisted of six plants on 91 cm spacing in a row. Infrared spectroscopy was used to determine CWC, acid detergent fiber (ADF), acid detergent lignin (lignin), silica, crude protein, and in vitro digestible dry matter (IVDDM). Separate predictive equations were necessary for each year, probably due to yearly differences in drying procedures of samples. General (GCA) and specific combining ability (SCA) were estimated least squares analysis for one harvest in 1976, two harvests in 1977, and for the mean of the three harvests.Mean squares for GCA were significant for CWC, ADF, and lignin. Mean squares for SCA were significant for CWC, ADF, lignin, crude protein, and IVDDM. Estimates of variance components due to SCA were nearly twice as large or larger than the variance components due to GCA for CWC, ADF, lignin, crude protein, and IVDDM, indicating the presence of large amounts of nonadditive genetic variance under noncompetitive, spacedplant conditions. Broad‐sense and narrow‐sense heritabilities for CWC were 0.81 and 0.26, respectively.Estimates of genotypic correlations suggested that: (i) CWC was strongly positively correlated with ADF and lignin and strongly negatively correlated with protein and IVDDM; (ii) ADF had the highest correlation with IVDDM and was closely followed by lignin and CWC, which agreed with other reports using laboratory procedures for estimating these traits; (iii) none of the quality components was strongly correlated with spaced‐plant yield of first growth.