Using 80 Holstein heifer calves, this study investigated the effects of supplementing 2 levels of pasteurized whole milk with or without a pasteurized all-milk balancer product (Land O’Lakes Pasteurized Milk Balancer), on the growth of dairy calves. Two locations were used in this trial, NCSU Lake Wheeler Dairy (Raleigh, NC) and NCDA Piedmont Research Station (Salisbury, NC), with 40 calves fed according to the protocol at each site. All calves were removed from their dams after birth (d 0), fed 3.8L pasteurized colostrum, and received their respective treatment from d 1 until weaning at d 56. All calves were fed pasteurized whole milk from d 1 through d 56. There were 4 dietary treatments (n = 20 calves per treatment). Calves on treatment 1 and 2 were fed 3.8 L milk divided into 2 equal feedings from d 1 through d 56. Calves on treatment 3 and 4 were fed 3.8 L milk divided into 2 equal feedings from d 1 through d 14, 5.7L milk divided into 2 equal feedings from d 15 through d 42, and 2.85L milk fed once daily from d 43 through d 56. Treatments 2 and 4 included pasteurized all-milk balancer fed at a rate of 0.23kg per 3.8L of pasteurized whole milk. Calves were weighed and measured for wither height (WH), hip height (HH), and hip width (HW) every 7 d from birth until weaning at d 56. Average daily gain (ADG) and feed efficiency (FE) were calculated from d 0 through d 56. Feed efficiency is the ratio of ADG to dry matter intake (DMI), which included the total of milk dry matter (DM), milk balancer DM, and calf starter DM consumed. Calves fed treatment 4 had greater body weight (BW) and ADG through 56 d of age.

Robert D. Tompkins, William C. Stringer and William C. Bridges Jr.

SUMMARY Fifty-four Hereford steers and heifers, equal- ly divided into three groups, were grazed on fescue grass for 180 days. One group was slaughtered after the grazing period and the two remaining groups were fed a high concentrate diet for 56 and 112 days. Longissimus and semitendinosus muscle characteristics of these animals were determined. Carcass quality grades improved with grain feeding. Sarcomeres were longer and fiber diameters were generally less for semitendinosus than for longissimus mus- cles. Percent moisture declined and ether ex- tractable constituents increased in both muscles as period of grain feeding was increased. Per- cent protein did not change with grain feeding but was higher for longissimus than for semi- tendinosus. Collagen content did not change in semitendinosus but declined in longissimus as determined from histological sections. Amount of reticulin did not differ among muscles or due to feeding treatment. Elastin was greater in semitendinosus than in longissimus. Tenderness of both muscles improved with grain feeding but declined for both muscles as internal temperatures were increased from 63 to 68 to 73C.

Persistence of endophyte-free (E-) tail fescue (Festuca arundinacea Schreb.) is erratic. Little information exists as to how fast endophyte (Neotyphodium coenophialum)-infected (E+) tall fescue might encroach on E- tall fescue and whether specific conditions might influence the speed of encroachment. Plots of E+ and E- tall fescue genotypes 7 and 17 were established using a modified Nelder's design to compare performance of the E+ forms of the plants in pure and mixed communities at different population densities. The plots were planted at the USDA Southern Piedmont Conservation Research Laboratory in Watkinsville, Georgia, and the University of Georgia Plant Sciences Farm in Bogart, Georgia. Plants were grown over a 5 year period and dry matter yield monitored 1, 3, and 5 years after establishment. Relative crowding coefficients were calculated for each to establish trends of encroachment of the E+ on the E- plants in the mixed communities. Generally, dry matter yields of E+ tall fescue were greater than E- tall fescue regardless of whether they were grown in pure or mixed communities. As time progressed, the difference in dry matter yield between E- and E- tall fescue grown in mixed communities was greater than that of the pure communities. Relative crowding coefficients increased as time progressed. Relative crowding coefficients at the Walkinsville location were greater after 5 years than those at the Plant Sciences Farm. Therefore, site specific conditions exist which affect the competitiveness of E- tall fescue and degree of encroachment by E+ tall fescue. Research is needed to identify which biotic, abiotic and management variables exacerbate encroachment of E+ tall fescue to better define the conditions which best suit E- tall fescue. (C) 1998 Annals of Botany Company.

Interseeding legumes into grass sods increases herbage quality, Interseeding alfalfa (Medicago sativa L.) into bermudagrass [Cynodon dactylon (L.) Pers.] has given yields comparable to grass fertilized with high rates of N. Our objective was to compare forage quality attributes of N-fertilized bermudagrass with alfalfa-bermudagrass mixtures. N rates of 0, 112, 224, and 448 kg ha(-1) were applied to bermudagrass monoculture and to alfalfa interseeded into bermudagrass at 20-, 40-, and 60-cm row spacings. Experiments were conducted on a Cecil sandy clay loam (clayey, kaolinitic, thermic Typic Kanhapludult) and a Norfolk sandy loam (fine-loamy, siliceous, thermic Typic Kandiudult) site. Hand-harvested herbage samples were separated into botanical components. Crude protein, acid-detergent fiber and neutral-detergent fiber were measured using a combination of wet-lab and near infrared reflectance spectroscopy (NIRS) procedures. Nitrogen increased the crude protein in bermudagrass monoculture by 11 to 61 g kg(-1). The crude protein response of bermudagrass in mixtures to N was slight to nonsignificant. Increasing row spacing of alfalfa reduced grass crude protein by 9 to 23 g kg(-1) and had no effect on alfalfa crude protein, Fiber fractions decreased slightly in grass with added N, but fiber in alfalfa was not influenced by any treatment. Yield of crude protein increased with N, particularly in bermudagrass monoculture, but interseeding alfalfa without N produced crude protein yields that usually exceeded those of bermudagrass monoculture at the 448 kg ha(-1) N rate, Interseeded alfalfa, even at wide row spacings, appears to produce enough biological N to replace 448 kg fertilizer N ha(-1) or more in the production of herbage protein in bermudagrass.

Assessing livestock preference for entries of forage breeding programs is important because livestock defoliate plants discriminantly, and thus influence plant competition and survival. We compared seven non‐destructive methods for evaluating tall fescue (Festuca arundinacea Schreb.) defoliation. Cross‐section, height, and spread measurements from a grid; hemisphere, cube, and cylinder formulae applied to height and diameter; and settling plate measurements were regressed against non‐subjective determinations using a plane table. The hemisphere equation applied to height and diameter assessed defoliation best. Coefficients of determination ranged from 0.07 to 0.85 for the plate method and hemisphere formula respectively. Our results reflect vegetative plants. Other methods may be better for taller plants.

The purpose of this trial was to determine the mineral concentration of various weeds that could potentially be part of the grazing animal's diet. Mineral content of plant species from three ungrazed and unimproved upland range communities (old field, young pine, and established hardwood) were evaluated at three locations in Pennsylvania. Vegetation samples were obtained in the spring, summer, and fall from each of the nine community-location combinations. A total of 31 species were analyzed for Mg, P, Ca, K, and Cu concentrations. Mineral values were compared to published dietary recommendations for beef and sheep and to mean compositions of corn silage, grass hay, and legume hay also sampled in Pennsylvania. Practically all sampled weeds met or exceeded beef and sheep dietary recommendations for Mg and Ca concentrations, with a lesser proportion of weed species meeting or exceeding P dietary recommendations. Several weed species sampled had an undesirably high Ca:P ratio, but the K:(Ca + Mg) ratio indicated that weeds were not generally tetanigenic. These results suggested that plant species growing in unmanaged communities can contribute macrominerals (particularly Mg and Ca) and microminerals (Cu) in sufficient amounts to negate or reduce the incidence of hypomagnesemia and other metabolic diseases. The community and geographic location in which sampled plants grew were generally not important in detennining mineral concentrations. Season tended to be more important than location, but also had minor effects on Mg, P, Ca, K, and Cu concentrations.

Widespread infection of tall fescue (Festuca arundinacea Schreber) by the endophytic fungus (Acremonium coenophudum Morgan‐Jones and Gams) is responsible for poor performance of grazing animals. Because infection results in changes in phenotypic means for numerous traits, changes in phenotypic variances could also be a result of infection. Phenotypic variances for forage and seed production were investigated in studies of polycross families from endophyte‐infected (El) and endophyte‐free (EF) clones of 20 tall fescue genotypes. No significant phenotypic variance for forage production was detected among El families during the study. In 1989, phenotypic variances for EF were greater than El for both harvests, suggesting that the endophyte can mask plant genotypic variance. Significant phenotypic variances were observed for all seed production traits in both El and EF. Phenotypic variances for total seed weight and seed numbers in 1990 were greater for El than for EF. Estimates of genetic variance for these traits were not greater than twice the standard error in the EF state but were greater than twice the standard error in the El state. The resulting heritability estimates reflected this difference. Endophyte presence could result in overestimates of plant genotypic variance for these traits. Breeding strategies should consider presence or absence of endophyte and the possible effects on variances.

Interseeding perennial legumes into bermudagrass [Cynodon dactylon (L.) Pers.] sods should increase forage quality. Preliminary research revealed that alfalfa (Medicago sativa L.) interseeded into bermudagrass (BG) rapidly reduced BG vigor, possibly because of shading by alfalfa. Grass-legume pastures should contain balanced mixtures for quality maintenance and bloat prevention. It may be possible to manipulate botanical composition with N and row spacing. The objective of this research was to examine effects of these factors on botanical composition and yield of alfalfa-BG swards. We interseeded alfalfa into 'Tifton 44' BG in 20-, 40-, and 60-cm row spacings, and included a non-interseeded check treatment. Experiments were on Norfolk sandy loam (fine-loamy, siliceous, thermic Typic Kandiudult) and Cecil sandy clay loam (clayey, kaolinitic, thermic Typic Kanhapludult) sites. Nitrogen was applied at 0, 112, 224, and 448 kg ha-1 yr-1. Yield of BG increased by a factor of 2.06 with 448 kg ha-1 of N, compared with 0 N. Alfalfa increased total yields over BG alone, at all but the highest rates of N. Nitrogen increased yields of interseeded plots an average of 11%. Yield increases from N did not result from increased grass percentage. Increasing row spacing decreased yields of interseeded mixtures, but increasing N rate sometimes compensated slightly for wide rows. Nitrogen had no effect or decreased grass percentage, whereas wide row spacing usually increased the grass component. It appears that alfalfa utilized a significant portion of applied N, and that N will not aid in retaining BG in mixtures. Increasing row spacing will aid in retaining grass in mixture, probably through reduced shading of grass.

Tall fescue (Festuca arundinacea Schreb.) is a common pasture grass adapted to a wide range of environmental conditions. An endophyte, Acremoninm coenophialum Morgan‐Jones & Gams, growing in association with tall fescue is known to produce ergopeptine alkaloids that are thought to be detrimental to animal health. Endophyteinfection changes how tall fescue plants grow and may be involved in the adaptability of tall fescue to environmental extremes. The objective of this study was to determine whether plant‐endophyte associations that had previously tested as high and low ergopeptine alkaloid producers varied in competitive ability when their endophytes were removed. Two identical field studies were conducted on a Cecil sandy clay loam and a Pacolet sandy clay loam soil (both clayey, kaolinitic, thermic Typic Hapluduits) in 1987 and 1988, respectively. In each study, a modified Nelder's design was used to test the competitiveness between infected and noninfected forms of two tall fescue genotypes. Endophyte‐infected plants were larger and, generally, more competitive in mixtures with noninfected plants. When infected with endophyte, the high ergopeptine alkaloid‐ producing genotype of tall fescue had similar or reduced competitiveness than the low‐alkaloid genotype when compared with their noninfected forms. We conclude that if ergopeptine alkaloids can be genetically removed from tall fescue‐endophyte associations, the competitiveness of the plant would be unaffected in nongrazed conditions. Reduction or elimination of ergopeptine alkaloids would help improve animal health when consuming endophyte‐infected tall fescue forage.

A symbiotic relationship exists between the endophytic fungus, Acremonium coenophlalum Morgan‐Jones and Gains and tall fescue (Festuca arundinacea Schreb.). The response of the host planto the endophyte has been studied by comparing infected or noninfected populations in the field or by an individual plant genotype in the greenhouse. The lack of a more thorough investigation of tall fescue genotypes with and without their endophytes suggests that known responses of tall fescue plants to endophyte infection are limited to the restricted conditions by which they were tested. The objectives of this study were to determine variability in responses of tall fescue genotypes to endophyte infection for select growth characteristics, plant morphology, and chemical components. Five genotypes of tall fescue were grown in both endophyte‐infected (EI) and noninfected (NI) forms in the greenhouse under different clipping treatments. Tiller and dry matter production, crown depth, and total nonstructural carbohydrates (TNC) were measured. In addition, leaf area per plant (LAP), specific leaf weight (SLW), and ergovaline duction were measured on two diverse plant genotypes. Forage yield, tiller number, and TNC varied for EI and NI treatments among plant genotypes. Dry matter production per tiller was greater and crown depth was approximately 1‐cm lower in EI plants than NI plants. Leaf area was greater in EI plants but SLW was higher in EI Genotype 7 (3.94 vs. 3.65 mg cm−2) and lower in El Genotype 17 (4.25 vs. 4.91 mg cm‐2) compared to their NI forms. Ergovaline production was constant regardless of leaf area in Genotype 7, but increased linearly with leaf area in Genotype 17. We conclude that endophytes increased phenotypic variation in this study and thus may increase the ability of mixed EI and NI populations to adapt to diverse environments.

Relative seed yields should be an important measure of the effects of the endophytic fungus Acremonium coenophialum Morgan‐Jones & Gams on relative fitness in tall fescue (Festuca arundinacea Schreb.). Two field experiments were conducted on Cecil sandy‐loam soils (clayey, kaolinitic, thermic Typic Kanhapuldults) to investigate the effects of endophyte infection on seed production and associated traits. The studies used endophyte‐infected and uninfected clones of the same plant genotypes. In Exp. I and II, endophyte infection resulted in 79 and 32% more total seed by weight, 60 and 33% more seeds per plant, 20 and 34% more panicles per plant, and 32 and 4% more seeds per panicle, respectively. The 300‐seed wt. was greater for infected plants in Exp. I but not in Exp. II. Plant genotype ✕ fungal status interactions occurred for all traits except for seeds per plant and seeds per panicle in Exp. II. These interactions occurred largely because the effect of the endophyte varied from no or small increases to significant increases in trait expression for different plant genotypes. The results indicate that endophyte‐infected tall fescue plants have much higher relative fitness for seed production than uninfected plants. Populations with low fungal incidence could rapidly shift toward high levels of infestation during seed increase or in pastures when seed production is allowed, leading to establishment of volunteer plants.

Alkaloids, along with specific environmental conditions, have been associated with both detrimental and beneficial aspects of endophyte (Acremonium coenophialum Morgan-Jones et Gams) infected tall fescue (Festuca arundinacea Schreb.) associations. Benefits to the plant accrue through reduced herbivory, whereas detriment to the animal occurs as altered grazing behaviour and reduced productivity. A controlled environment study was conducted to examine pyrrolizidine and ergopeptine alkaloid concentration of four tall fescue accessions as influenced by endophyte status and water regime. Endophyte-free plants were devoid of ergopeptine alkaloid and contained little, if any, pyrrolizidine alkaloid. Leaf blade tissue of endophyte-infected isolines contained a range of both ergopeptine (256 to 1633 ng g−1) and pyrrolizidine (92 to 450 μg g−1) alkaloid concentrations. Water deficit generally increased alkaloid concentration. Alkaloid yield, based upon concentration and tissue d. wt, showed that significant increase in ergopeptine and pyrrolizidine alkaloid in leaf tissue was associated with water deficit and was due to actual increased synthesis and not simply decreased phytomass. Leaf and pseudostem (leaf sheath and stem base) tissue alkaloid concentrations indicated different accumulation patterns for ergopeptine and pyrrolizidine alkaloids. Ergopeptine alkaloid yield increased in water-stressed pseudostem, whereas pyrrolizidine alkaloid yield decreased in some, but not all accessions. The range of host genotype/endophyte biotype response offers the possibility to select associations which produce few deleterious effects in animals yet maintain high forage productivity and persistence.

Superior growth and persistence has been reported in endophyte-infected grasses; however, findings may have been confounded by experiment conditions including plant genotype. A controUed-environment study was designed to address some growth characteristics of four tall fescue (Festuca arundinacea Schreb.) accessions as influenced by endophyte (Acremonium coenophiahim Morgan-Jones et Gams) and water regime. Endophyte-infected plants were collected, vegetatively propagated and some treated with propiconazole (11 kg a.i. ha−1) to develop non-infected isolines of each accession. The phenotypically diverse accessions, each represented by infected and non-infected isolines, were grown with adequate (−0–03 MPa), or a series of deficit (<−1·5 MPa) and recovery water regimes, replicated three times. Plant growth characteristics were measured during (leaf elongation and tillering) and upon conclusion (phytomass production, tillering, and leaf area) of the study. Leaf elongation, as a function of leaf length, was significantly different among accessions, and generally decreased with water deficit although some non-infected isolines were not affected. Water deficit depressed tiller production in virtually all accessions while endophyte effects depended upon accession. Leaf blade yield was not significantly influenced by endophyte status or interaction of endophyte, with water regime and accession; however, pseudostem (stem base and leaf sheath), root and dead leaf yields were affected in some cases. Non-structural carbohydrate concentration in all plant parts except roots, was decreased by water deficit, whereas root non-structural carbohydrate concentration tended to increase with water deficit. Non-structural carbohydrates of all plant parts was not influenced by endophyte status. Tall fescue-endophyte association responses vary due to genotype, therefore a simple generalization of endophyte impact upon tall fescue productivity and persistence is not possible based upon the results of this study

Rapid, nondestructive methods of estimating herbage mass (HM) are vital to experiments involving frequent collection of data, especially where physical sampling may alter growth. Herbage mass estimation techniques are based on double-sampling, in which clipped HM and corresponding nondestructive sward measurements are used in regression analysis to obtain prediction equations. Our objective was to evaluate the precision and accuracy of sward height (SH), ground cover (GC), and disk height (DH) as predictors of HM in alfalfa ( Medicago sativa L.) at weekly intervals after cutting. Sward height was measured with a sliding crossbar on an upright meter stick. Ground cover was estimated using a 0.18- by 0.22-m grid subdivided into 20 cells. Disk height was measured with 0.96- and 1.76-kg, 0.2-m 2 aluminum disks, allowed to settle on the sward canopy. All nondestructive measures were accompanied by clipping ofthe areas measured. Clipped HM ranged from 12 to 794 g m −2 . Herbage mass prediction equations were developed following stepwise regression of sample HM on SH, DH, GC, days of growth, and derived variables. The most precise HM prediction models were based on SH and DH, accounting for 79 to 94% of variation in HM of calibration samples. Applying prediction equations to a validation data set generated predicted HM values. Sward height and DH models accounted for 59 to 86%, and 80 to 97%, respectively, of the variation in HM of validation samples. Herbage mass of validation samples was predicted with lower standard errors of validation by DH models (19.5–35.9 g m −2 ) than by SH models (60.8–65.6 g m −2 ) on the same stands in the same year. The disk technique provides a rapid, accurate means of nondestructively monitoring growth in alfalfa plots.