In the US farmers often market pastured poultry eggs for a premium price, claiming animal and human health benefits. We examined how moving pastured hens to forage legumes or mixed grasses influenced hen (Gallus gallus L.) egg omega-3 fatty acids and concentrations of vitamins A and E. We also compared the eggs of the pastured hens to those of hens fed a commercial diet in cages. We used a cross-over design to compare pasture species: 75 sister hens were assigned to one of three pasture treatment groups: (1) alfalfa (Medicago sativa L.), (2) red and white clover (Trifolium pretense L. and Trifolium repens L.) or (3) mixed cool season grasses. Groups were rotated to all three pasture treatments, each for 2 weeks and supplemented with 70 g commercial hen mash bird -1 day -1 . Pasture botanical composition, forage mass, leaf to total ratio and plant fatty acid composition were compared among pasture treatments. Eggs of the pastured hens were compared to eggs of 50 sister hens that were fed only commercial hen mash in cages for the entire 6 weeks. Forage parameters varied somewhat, but did not explain plant linolenic acid variation. Seventeen of the 18 quantified egg fatty acids, and vitamin A concentrations did not (P < 0.05) differ among the three pasture treatment groups. Eggs of the hens that foraged grasses had 23% more (P < 0.0001) vitamin E than eggs of hens that foraged clover. Compared to eggs of the caged hens, pastured hens' eggs had twice as much vitamin E and long-chain omega-3 fats, 2.5-fold more total omega-3 fatty acids, and less than half the ratio of omega-6:omega-3 fatty acids (P < 0.0001). Vitamin A concentration was 38% higher (P < 0.05) in the pastured hens' eggs than in the caged hens' eggs, but total vitamin A per egg did not differ. At the end of the experiment, pastured hens weighed 14% less and averaged 15% lower hen-day egg production than caged birds (P < 0.0001). Results suggest that grass pastures may enhance vitamin E in eggs of pastured hens more than clover, and pastured hens supplemented with commercial mash will produce eggs with significantly more vitamin E and total omega-3 fatty acids compared to eggs from caged hens fed only commercial hen mash. Pastured hens may have lower body weight and egg production than caged hens, unless they are supplemented adequately to meet their dietary energy and crude protein needs.Key words: omega-3 fat, pastured poultry, vitamin A, vitamin E, poultry eggs, pasture, legumes Recent research indicates that livestock products from animals that forage grasslands have a higher concentration of omega-3 fatty acids and fat-soluble vitamins than livestock products from animals that are fed grain and stored feed diets 2-5 .The chicken has a short digestive tract and can rapidly assimilate dietary nutrients. Fat-soluble vitamins in the diet are readily transferred to the liver and then the egg yolk. Naber 6 classified nutrients in the egg by responsiveness to dietary change and determined that all the fat-soluble vitamins, including A and E, and the unsatu...

Formulating grass-legume mixtures requires knowledge of how the proportion of species in a seed mixture (i.e., species evenness) affects productivity and weed abundance. We hypothesized that mixtures with more equal proportions of species in the seed mixture (i.e., greater species evenness) would have greater productivity and fewer weeds than mixtures dominated by one or two species or monocultures. Two experiments with 15 mixtures and monocultures of orchardgrass (Dactylis glomerata L.), quackgrass (Elytrigia repens L.), alfalfa (Medicago sativa L.), and white clover (Trifolium repens L.) (Exp. 1) or 15 mixtures and monocultures of meadow fescue [Schedonorus pratensis (Huds.) P. Beauv.], reed canarygrass (Phalaris arundinacea L.), red clover (T. pratense L.), and kura clover (T. ambiguum L.) (Exp. 2) were sown in autumn 2008 at four locations in Pennsylvania and Wisconsin. In each experiment, there were four monocultures, four mixtures dominated by one species, six mixtures dominated by pairs of species, and one equal mixture. Mixtures and monocultures were harvested four to five times each year from 2009 to 2011. Mixtures often had more biomass than the average of legume or N-fertilized grass monocultures. Mixtures with more equal proportions of species in the seed mixture, however, did not have more biomass or fewer weeds than other mixtures. Rather, differences in yield were related to the dominant species in the mixture. Optimal legume percentages (30-40%) in the harvested biomass were achieved with a wide range of grass and legume seed proportions, which suggested that farmers have wide flexibility in formulating seed mixtures for pastures.

Alfalfa (Medicago sativa L.) seeding rates greatly affect the number of surviving plants after 1 yr. The objective of this research was to determine what effect seeding rate has on alfalfa stand density two or more years after seeding. Different alfalfa cultivars were spring‐seeded at rates ranging from 3 to 27 kg ha−1 pure live seed into tilled seedbeds in Missouri and Pennsylvania to provide eight location‐years of data. After the seeding year, herbage was removed four or five times each year. Stand densities were determined one to three and five to eight months after planting (MAP) and annually in the spring thereafter for up to 7 yr after planting. Increasing seeding rates resulted in near linear increases in plant densities from 100 to 800 plants m−2 within 3 MAP. Higher plant densities experienced eight times higher plant deaths the first year after planting compared with lower plant densities. At all eight location‐years of this research, the period 24 to 36 MAP had the least amount of plant deaths regardless of seeding rate. Higher plant densities associated with seeding rates greater than 17 kg ha−1 did not persist beyond 6 MAP. Seeding rates of 10 and 17 kg ha−1 had similar plant densities by 24 MAP in 75% of the location‐years although further reductions in seeding rate reduced plant density for up to 4 yr after planting. Seeding rates greater or slightly less than those recommended have little to no effect on the life expectancy of an alfalfa stand.

Maintaining a diversity of plant species in pastures may reduce weed invasion. Knowledge of how the proportion of species in a mixture (i.e., species evenness) aff ects weed invasion would be useful in formulating seed mixtures. We hypothesized that forage mixtures with greater species evenness would reduce weed invasion at establishment better than mixtures dominated by a few species (low species evenness) or monocultures. Fift een mixtures and monocultures of orchardgrass (Dactylis glomerata L.), quackgrass (Elytrigia repens L.), alfalfa (Medicago sativa L.), and white clover (Trifolium repens L.) were sown in autumn 2008 at four locations in Pennsylvania and Wisconsin. Th ere were four monocultures, four mixtures dominated by one species (evenness = 0.64), six mixtures dominated by pairs of species (evenness = 0.88), and one equal mixture (evenness = 1). We measured the amount of naturally occurring weeds in harvested herbage at each location in 2009. At two locations, we added seed of plumeless thistle (Carduus acanthoides L.) and canola (Brassica napus L.; a surrogate weed) to each treatment during autumn of 2008 and measured their establishment and dry mass during 2009. Grass-legume mixtures resisted weed invasion better than monocultures. Within mixtures, however, species evenness did not infl uence weed invasion. Species evenness did not aff ect resource use (light interception or soil inorganic N levels). Individual forage species had a strong eff ect because weed proportions decreased curvilinearly as orchardgrass proportion of the seed mixture increased. Selecting appropriate species to use in mixtures is more important than the evenness of the species in the mixture.

Many studies have looked at the economically optimum N application rate (cost of N vs. increased yield) for cool‐season forage grasses, but few of these studies have also addressed the effect of N fertilization on livestock or environmental health. The objective of this study was to determine the N application rate to cool‐season grass species that optimizes economic return without elevating herbage or soil NO3–N levels. Four N rates were applied in split applications to established stands of orchardgrass (Dactylis glomerata L.), smooth bromegrass (Bromus inermis Leyss.), tall fescue (Festuca arundinacea Schreb.), and timothy (Phleum pratense L.) near State College, PA, on a Murrill silt loam (fine‐loamy, mixed, mesic Typic Hapludults) soil. Harvest treatments of three and four times per year were imposed on each Grass × N treatment. Economically optimum N rates (EONR) were 284, 368, and 299 kg N ha−1 or 26, 32, and 29 kg N Mg−1 of forage harvested for orchardgrass, tall fescue, and timothy, respectively. Smooth bromegrass did not reach an economic plateau at the highest (402 kg ha−1) N rate. At EONR, NO3–N concentration exceeded 1000 mg kg−1 in forage from early season harvests when four harvests per year were taken but not when three harvests per year were taken. Soil NO3–N concentration generally was not elevated above background levels when EONR was applied to orchardgrass or tall fescue. Our results, in conjunction with results from New York, indicate that the EONR for the cool‐season grasses and harvest systems evaluated is 5 to 10 kg N Mg−1 of dry forage greater than current recommendations in New York and Pennsylvania. However, continued research is needed in a wider range of climates and soil types using various N sources.

ABSTRACT

Pastures in the northeastern United States are oft en planted to mixtures of grasses and legumes. We evaluated several commercial seed mixtures to determine if the number of species in mixture aff ected yield and botanical composition in central Pennsylvania. Th ree replicate plots of 25 mixtures, fi ve each of two, three, four, fi ve, and six species of grasses and legumes were planted in August 2007 near State College, PA. Plots were grazed by beef cows for 3 yr. Dry matter (DM) yield was determined at each of the six harvests in each year. Botanical composition was measured at the fi rst, third, and last harvest each year. Annual DM yield was positively related to the number of species planted (r 2 = 0.15, 0.18, and 0.26 for 2008, 2009, and 2010, respectively). Mixtures within groups of similar species richness, however, varied in yield. Kentucky bluegrass (Poa pratensis L.), birdsfoot trefoil (Lotus corniculatus L.), and timothy (Phleum pratense L.) did not establish or persist well in mixture with taller grasses [e.g., orchardgrass (Dactylis glomerata L.)]. Th e short-lived species festulolium (X Festulolium Asch. & Graebn.) and red clover (Trifolium pratense L.) contributed signifi cantly to production during the fi rst year and were replaced by longer-lived species such as orchardgrass and white clover (T. repens L.). Forage nutritive value was related to the botanical composition but not the number of species in mixture. Results suggest that a strategy of planting mixtures with a combination of fast-and slow-establishing species can be eff ective for multispecies pastures in central Pennsylvania.M. Sanderson, USDA-ARS Northern Great Plains Research Lab.,

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