Seasonal Forage Research Articles

Ungulate herbivory overrides rainfall impacts on herbaceous regrowth and residual biomass in a key resource area

Key grazing lands that provide dry season forage to both resident and migrating ungulates may experience heavy grazing impacts during the dry season, thereby jeopardizing future forage productivity. In this study a herbivore exclosure experiment was used to quantify the effects of grazing by large ungulates on herbaceous regrowth and residual aboveground biomass in a fragmented key resource area; the fringe zone around Lake Naivasha, Kenya. Top-down control mechanisms were prevalent in both the dry and wet seasons suggesting the existence of a high resident herbivore density. Intense grazing significantly reduced residual biomass that in turn reduced plant regrowth. An increased frequency of defoliation reduced regrowth during the dry season demonstrating the negative effect resulting from high herbivore densities during the dry season. This study indicates that grazing exerts a higher control on regrowth than rainfall as heavily grazed residual biomass did not recover during the following wet season.

Conditional daily and seasonal movement strategies of male Columbia black-tailed deer (Odocoileus hemionus columbianus)

Animals move to maximize fitness via resource acquisition, predator avoidance, thermoregulation, or mate access. Variations in movement strategies among and within populations often reflect habitat- or demographic-specific variations in fitness trade-offs. To examine these conditional movement strategies, we modeled seasonal and diel movement patterns of radio-collared adult male Columbia black-tailed deer (Odocoileus hemionus columbianus (Richardson, 1829)) on a temperate, predator-free island. Linear 10 h displacement and home-range areas reached annual maxima during autumn and minima during late winter, corresponding with known dates for breeding season and lowest quality forage, respectively. For all males in all years, initiation of increased movements began during spring and again, abruptly, in late September, immediately prior to peak breeding season. Larger antlered males continued increased movements longer into December, suggesting increased breeding effort relative to smaller antlered males. Time of day predicted movements during all seasons; however, we observed no strong evidence of the crepuscular or nocturnal movement bias typically noted in deer, likely relating to the lack of predators in our study area. In this way, male black-tailed deer adopted conditional, seasonally specific movement strategies to balance fitness trade-offs in resource acquisition, thermoregulation, and mate access.

Elk (Cervus elaphus) Seasonal Habitat Selection in a Heterogeneous Forest Structure

Seasonal habitat selection by the reintroduced Burwash elk population, approximately 30 km south of Sudbury, Ontario, has been analysed in order to assist in the development of future management. Twenty-five adult females were radio-collared and tracked 1–3 times a week for 3 years. The most prominent patterns included selection of intolerant hardwood forests (trembling aspen, white birch, and balsam poplar) during all seasons, while Great Lakes-St. Lawrence pines (white and red pine dominated stands) were used less than expected based on availability for all seasons. The selection patterns are likely associated with seasonal climatic conditions and forage preferences. Because the selection behaviours displayed here varied greatly from other elk habitat studies, it is suggested that managers consider the importance of population-specific habitat studies before developing related strategies.

Complementary forages – integration at a whole-farm level

A high proportion of the Australian and New Zealand dairy industry is based on a relatively simple, low input and low cost pasture feedbase. These factors enable this type of production system to remain internationally competitive. However, a key limitation of pasture-based dairy systems is periodic imbalances between herd intake requirements and pasture DM production, caused by strong seasonality and high inter-annual variation in feed supply. This disparity can be moderated to a certain degree through the strategic management of the herd through altering calving dates and stocking rates, and the feedbase by conserving excess forage and irrigating to flatten seasonal forage availability. Australasian dairy systems are experiencing emerging market and environmental challenges, which includes increased competition for land and water resources, decreasing terms of trade, a changing and variable climate, an increasing environmental focus that requires improved nutrient and water-use efficiency and lower greenhouse gas emissions. The integration of complementary forages has long been viewed as a means to manipulate the home-grown feed supply, to improve the nutritive value and DM intake of the diet, and to increase the efficiency of inputs utilised. Only recently has integrating complementary forages at the whole-farm system level received the significant attention and investment required to examine their potential benefit. Recent whole-of-farm research undertaken in both Australia and New Zealand has highlighted the importance of understanding the challenges of the current feedbase and the level of complementarity between forage types required to improve profit, manage risk and/or alleviate/mitigate against adverse outcomes. This paper reviews the most recent systems-level research into complementary forages, discusses approaches to modelling their integration at the whole-farm level and highlights the potential of complementary forages to address the major challenges currently facing pasture-based dairy systems.

Dry season forages for improving dairy production in smallholder systems in Uganda

Economically feasible strategies for year-round feed supply to dairy cattle are needed to improve feed resource availability, milk yield and household income for the smallholder dairy farming systems that predominate in the rural Eastern and Central African region. Currently, Napier grass ( Pennisetum purpureum ) is the major forage in zero-grazing production systems, but dry-season production is often constrained. Our results from 24 farms show that sowing forage legumes, including Centrosema molle (formerly C. pubescens ) and Clitoria ternatea, with Napier grass and Brachiaria hybrid cv. Mulato improved both yield of forage and protein concentration. Sowing of 0.5 ha Napier-Centro plus 0.5 ha of Mulato-Clitoria increased milk yield by 80% and household income by 52% over 0.5 ha Napier grass monoculture. Possible income foregone from the crops which could have been grown on the additional 0.5 ha must be considered in assessing the economic viability of the system.

Effects of year-round stocking methods and stocking rates on seasonal forage response and cow-calf weight gain in the gulf coast region of the United States

<h2>ABSTRACT</h2> The present research is the second phase (2 yr) of a multiyear cow-calf study employing fixed stocking rates and examining the effect of stocking method, i.e., continuous and rotational, and stocking rate on beef cattle production. Two sets of 4 adjacent pastures, each containing a mixed warm-season, perennial grass sod [common bermudagrass, Cynodon dactylon (L.) Pers.; dallisgrass, Paspalum dilatatum Poir.], were overseeded to ‘Marshall' annual ryegrass (Lolium multiflorum) in the autumn of 2 consecutive years. Within each set of 4 pastures, one of the following grazing treatments was randomly assigned each pasture: rotationally stocked (8 paddocks) at a low, medium, or high stocking rate and continuously stocked at a moderate stocking rate. Low, medium, and high stocking rates were 1.25, 2, and 2.75 cows/ha. Brangus cows and their suckling calves were stocked on treatment pastures in March 2004. Stocking treatment affected prebreeding cow BW (P < 0.01) and tended to affect precalving (P = 0.13), postbreeding (P = 0.07), weaning (P = 0.11), and subsequent precalving cow BW (P = 0.08). Stocking-method treatments were similar in forage allowance in the early- and late-spring periods (P = 0.67 and P=0.65, respectively), but in the summer period, rotationally stocking at a medium stocking rate was greater (P < 0.01) than continuously stocking at a moderate stocking rate. There was a consistent trend across seasons for the percent CP in the simulated bite sample DM to be greater (P < 0.1) for the continuously stocking at a moderate stocking rate compared with the rotationally stocking at a medium stocking rate stocking methods. Based upon cow BW outcomes in this research, stocking rate is the most important consideration in design of a grazing program.

Agronomic Assessment of Perennial Wheat and Perennial Rye as Cereal Crops

Perennial wheat (Triticum aestivum L. × Thinopyrum spp.) and perennial rye (Secale cereale L. × S. montanum) are novel hybrid species under development as alternatives to annual cereal crops. We conducted a 2‐yr field study with a split plot design to evaluate agronomic performance, including yield, phenology, and biomass production, of perennial accessions of wheat and rye, along with annual analogs. This is one of the first studies to rigorously compare agronomic performance of 2‐yr‐old plants to 1‐yr‐old plants in perennial cereals. Perennial wheat produced 1.0 to 1.6 Mg ha−1 grain yield, 50% of annual wheat (2.7 Mg ha−1), while perennial rye produced 1.3 Mg ha−1, 73% of annual rye (1.8 Mg ha−1). Modest yields from perennials relative to annuals reflected lower harvest index, lower yield per tiller, and less kernel mass. One‐year‐old and 2‐yr‐old perennial plants had similar seed yields, yield components, and biomass production, indicating that plant age had little effect on these parameters and older plants maintained yield potential. In contrast, phenology did vary with plant age, and showed a shift toward earlier spring growth and later flowering dates in older perennial plants. This illustrates an expanded vegetative period for regrowing plants of these perennial cereals. There appears to be potential for producing an early season forage crop from these cereals, although biomass yields were not high at this site and regrowth was not always reliable. Overall, performance of perennial rye was consistent with a viable new cereal crop. On the other hand, perennial wheat requires further selection for allocation of biomass to grain and vigorous regrowth.

Switchgrass silage for methane production as affected by date of harvest

Bélanger, G., Savoie, P., Parent, G., Claessens, A., Bertrand, A., Tremblay, G. F., Massé, D., Gilbert, Y. and Babineau, D. 2012. Switchgrass silage for methane production as affected by date of harvest. Can. J. Plant Sci. 92: 1187–1197. Switchgrass (Panicum virgatum L.) is a warm-season grass recognized as a potential biomass crop for energy production in North America, but little information exists on the effect of harvest date on forage and silage characteristics of switchgrass grown in eastern Canada. Our objectives were to determine how harvest date affects several forage and silage characteristics of switchgrass and to relate these to specific methane yield from anaerobically digested switchgrass silage. Switchgrass, seeded in 2002 and 2006, was harvested and ensiled as a one-cut system on three dates in 2007: late July, early September, and early October. The regrowth from the late July harvest was also harvested in early October as a two-cut system. Silage quality parameters [pH, and concentrations of N, N-NH3, total amino acids (TAA), and volatile fatty acids (VFA)] indicated adequate fermentation of all silage samples. In a one-cut system, delaying harvest from late July to early September increased forage dry matter (DM) yield from 9.0 to 11.5 Mg ha−1, forage soluble carbohydrate (SC) concentration from 51 to 85 g kg−1 DM, and silage SC concentration from 13 to 25 g kg−1 DM; delaying harvest from late July to early October decreased forage in vitro true digestibility (IVTD) from 720 to 582 g kg−1 DM, forage in vitro digestibility of the neutral detergent fibre (dNDF) from 590 to 409 g kg−1 DM, and silage acetate concentration from 7.7 to 2.6 g kg−1 DM. The regrowth had higher IVTD and dNDF, lower acid detergent fibre concentration, and higher silage lactate and acetate concentrations than a single harvest taken in early September or early October. The two-cut system and the single harvest in early September produced the highest seasonal forage DM yields (11.5 and 11.9 Mg ha−1). High specific methane yield was (i) correlated with low forage fibre concentration and high DM digestibility and (ii) more correlated to silage concentrations of lactate and acetate than to silage SC concentration.

Quality of the forage apparently consumed by beef calves in natural grassland under fertilization and oversown with cool season forage species

The objective of this study was to evaluate the chemical composition of the forage apparently consumed by steers in a natural grassland on region of Campanha, in Rio Grande do Sul, Brazil, subjected or not to different inputs: NP - natural pasture without inputs; FNP - fertilized natural pasture and INP - improved natural grassland with fertilization and over-seeded with cultivated winter species. Three Angus steers testers and a variable number of regulator animals per experimental unit were utilized in order to maintain 13 kg of DM/100 kg of live weight (LW) as forage allowance. One time at each season, hand plucking samples were performed along the daily grazing time simulating forage harvested by the animals. The collected samples after drying and grind were submitted to chemical analysis to determine the forage quality. Except in winter and spring, the values of neutral detergent fiber were higher than the critical value of 550 g/kg of DM, which could limit forage intake, demonstrating that the values of forage on offer provided (15.6; 13.7; 13.5; 15.8 kg of DM/100 kg of LW/day in summer, autumn, winter and spring, respectively) were not restrictive to intake. The oversowing of winter cultivated species or fertilization positively alter the degradable fiber content. The seasons had marked influence on the chemical composition of forage apparently consumed; positively increasing some fractions of forage chemical composition in the seasons in which native or cultivated winter species increased their participation. The forage chemical composition is the determining factor in animal performance in natural pasture.

Temperate Silvopasture Tree Establishment and Growth as Influenced by Forage Species and Cultural Management Practices

Tall fescue (Lolium arundinaceum (Schreb.) Darbysh.) is known to inhibit tree growth. Competition for moisture and nutrients, and possibly allelopathy are suspected. This study examined if tall fescue inhibits tree growth more than two other cool-season forages, if tree growth differences are attributed to forage yield or tall fescue’s endophyte, and if irrigation and fertilizer can alleviate forage inhibition of tree growth. Four silvopasture tree species were planted into sods of three cool season forage species and grown four years with and without irrigation and fertilizer. Differences in tree growth did not correspond with forage dry matter yield or tall fescue endophyte status. Black walnut and red oak height and diameter growth and pitch x loblolly pine diameter growth were greater in Kentucky bluegrass and orchardgrass compared to the forage tall fescues [Ky-31 (E+), Ky-31 (E-), and Max-Q]. Irrigation and/or fertilizer did not alleviate forage competition on two tree species.

The food habits of goats on rangelands with different amounts of fourwing saltbush (Atriplex canescens) cover

Esophageally fistulated goats were released in a microphyll desert scrub habitat with 14.6% or 46.2% aerial cover of Atriplex canescens (induced by removal of all shrubs except A. canescens, with livestock grazing exclusion for 10 years) to determine the seasonal forage species selected by the goats. The shrub removal strongly influenced the goats’ feeding habits. The goats grazing the Atriplex-dominated site consumed 4.5 times more A. canescens than the goats on the untreated (control) pasture during all seasons. Shrubs were used heavily during all seasons by goats in both pastures, with higher percentages (75.5–82.8%) in the diets of goats grazing the control pasture than in the diets of goats grazing the Atriplex-dominated area (62.5–68.5%). No differences were found between seasons. The goats in the Atriplex-dominated pasture ate more grass than the goats grazing the control area and used more perennial graminoids during the summer (15.0%) and spring (18.3%) than the goats on the control area (6.0–7.0%). Forbs were an important component of diets. It was concluded that the successful revegetation of the treated pasture affected the goats’ feeding strategy, with an increase in the use of A. canescens, forbs and grasses in all seasons.

Transgenic Expression of MsHsp23 Confers Enhanced Tolerance to Abiotic Stresses in Tall Fescue.

Tall fescue (Festuca arundinacea Schreb.) is an important cool season forage plant that is not well suited to extreme heat, salts, or heavy metals. To develop transgenic tall fescue plants with enhanced tolerance to abiotic stress, we introduced an alfalfa Hsp23 gene expression vector construct through Agrobacterium-mediated transformation. Integration and expression of the transgene were confirmed by polymerase chain reaction, northern blot, and western blot analyses. Under normal growth conditions, there was no significant difference in the growth of the transgenic plants and the non-transgenic controls. However, when exposed to various stresses such as salt or arsenic, transgenic plants showed a significantly lower accumulation of hydrogen peroxide and thiobarbituric acid reactive substances than control plants. The reduced accumulation of thiobarbituric acid reactive substances indicates that the transgenic plants possessed a more efficient reactive oxygen species-scavenging system. We speculate that the high levels of MsHsp23 proteins in the transgenic plants protect leaves from oxidative damage through chaperon and antioxidant activities. These results suggest that MsHsp23 confers abiotic stress tolerance in transgenic tall fescue and may be useful in developing stress tolerance in other crops.

Are warbles and bots related to reproductive status in West Greenland caribou?

In March-April 2008-09, using CARMA protocols, 81 cows and 16 calves were collected in West Greenland from two caribou populations; Akia-Maniitsoq (AM) and Kangerlussuaq-Sisimiut (KS). In both populations, warble larvae numbers were highest in calves and higher in non-pregnant than pregnant cows. Nose bots showed no relationship with pregnancy or lactation; KS calves had higher nose bot loads than cows, a pattern not observed in AM. Pregnant cows had more rump fat than non-pregnant cows. KS cows lacking rump fat entirely had the highest warble burdens. We observed lactating pregnant cows with moderate larval burdens. Projected energy cost of the heaviest observed combined larvae burdens was equivalent to 2-5 days basal metabolic rate (BMR) for a cow, and 7-12 days BMR for a calf. Foregone fattening in adult cows with average burdens was 0.2 to 0.5 kg, but almost doubled with the heaviest infestations to 0.4 and 0.8 kg. Average burdens in calves resulted in forgone fattening of about 0.5 kg, with peak costs equivalent to 0.7 and 1.1 kg fat for AM and KS calves respectively. Although modest, these projected energy costs of hosting larvae for cows support the negative relationship between rump fat and larvae burden. For calves, hosting high burdens of warble larvae could affect winter survival, specifically those weaned normally in October or in early winter. Harmful effects of oestrid larvae burdens may remain subtle but clearly cumulative in relation to seasonal forage availability and incidence of other parasites.

Fall Harvesting of Alfalfa in North Dakota Impacts Plant Density, Yield, and Nutritive Value

Alfalfa (Medicago sativa L.) is often not harvested in North Dakota during the fall because producers fear the risk of winter-kill and stand reduction. The objective of this study was to determine the impact of a fall harvest on plant density, forage yield, and nutritive value of alfalfa. Two replicated experiments were planted and evaluated in Fargo, ND. Experiment 1 was conducted from 2004 to 2008 and Experiment 2 from 2007 to 2011. Treatments in the two experiments were either a 3-cut system with no fall harvest or a 4-cut system with a fall harvest. Analysis was conducted across experiments and years. In certain years, plant density was significantly reduced when alfalfa was harvested in the fall. The 4-cut system, which included a fall harvest, had significantly greater seasonal forage yield. The total seasonal forage yield for the 4-cut system was approximately 1.04 to 3.88 Mg/ha greater than that of the 3-cut system. However, including a fall harvest decreased forage yield in the first cut the following season. In general, a fall harvest of alfalfa increases seasonal forage yield without reducing stand persistence and overall forage nutritive value.

Seasonal Patterns of Forage Availability in the Fescue Grasslands Under Contrasting Grazing Histories

Grazing by large herbivores has been shown to condition vegetation in a manner that improves grassland quality for subsequent herbivory. Fescue grasslands evolved with disturbance from fire and winter grazing by bison but are now grazed primarily by cattle during summer. We examined the effect of long-term summer grazing on the seasonal forage production and quality of fescue grasslands in an examination of the hypothesis that long-term grazing had conditioned fescue grasslands to benefit livestock. This hypothesis was examined by comparing, between grazed and ungrazed plots, the biomass and composition of herbage components, concentrations of nitrogen (N) and acid detergent fiber (ADF) therein, and the ability of major plant types to maintain their biomass and quality throughout the growing season. The study was conducted in southern Alberta at five sites that had long-term exclosures (20+ yr) on grasslands that had been moderately grazed. Grazing had no effect on the N concentration of associated grasses, but grasses had lower N concentration than forbs. Concentrations of ADF followed a reciprocal trend to N. Grazing increased the mass of forbs from about 10% to 20% as a proportion of total biomass, which in turn, was not affected by grazing history. However, this grazing-induced shift to a higher quality vegetation type was not sufficient to affect total mass of N or total digestible nutrients at the community level. Rather than changes in current growth and quality, the predominant effect of summer grazing was in reducing litter mass, which also had the potential for affecting forage production and selection by herbivores. Finally, grazing reduced the relative contribution of rough fescue to total biomass by about 30%, and despite no significant effect on the potential to support summer grazing, this change could reduce the quality of these grasslands for winter grazing. El Pastoreo por grandes herbívoros ha demostrado que mejora la vegetación incrementando la calidad de los pastizales para un pastoreo subsecuente. Los pastizales de Festucas evolucionaron con perturbaciones de fuego y pastoreo por el búfalo durante el invierno, pero ahora son pastoreados principalmente durante el verano por ganado doméstico. Examinamos el efecto a largo plazo del pastoreo de verano sobre la producción de forraje estacional y la calidad de los pastizales de Festuca, y probamos la hipótesis de que el pastoreo a largo plazo ha acondicionado los pastizales de Festuca en beneficio del ganado doméstico. Esta hipótesis se examinó por comparación entre parcelas pastoreadas y no pastoreadas, la biomasa y la composición de componentes del forraje, las concentraciones de nitrógeno (N) y fibra detergente ácido (ADF) y en la capacidad de la mayoría de tipos de plantas para mantener su biomasa y calidad a lo largo de la temporada de crecimiento. El estudio se realizó en el sur de Alberta en cinco sitios que tenían exclusiones a largo plazo (más de 20 años) en pastizales ha habían sido pastoreado moderadamente. El pastoreo no tuvo ningún efecto en la concentración de N de los pastos asociados, pero las gramíneas tenían una menor concentración de N que las herbáceas. Las concentraciones de ADF siguieron una tendencia recíproca al N. El pastoreo aumentó la masa de herbáceas de alrededor del 10% al 20% como proporción de la biomasa total, que a su vez, no se afectó por la historia de pastoreo. Sin embargo, este cambio inducido por el pastoreo a un tipo de vegetación de mejor calidad, no fue suficiente para afectar la masa total de N o TDN a nivel de la comunidad. En lugar de los cambios en el crecimiento real y en la calidad, el efecto predominante de pastoreo de verano fue en la reducción de la masa del mantillo, que también tenía el potencial de afectar la producción de forraje y selección por herbívoros. Finalmente, el pastoreo redujo la contribución relativa de Festuca aproximadamente un 30%, de la biomasa total a pesar de no mostrar ningún efecto significativo sobre el potencial de apoyar el pastoreo de verano, este cambio podría reducir la calidad de estos pastizales para el pastoreo durante el invierno.

Limitations and potentials of dual-purpose cow herds in Central Coastal Veracruz, Mexico

Feed chemical and kinetic composition and animal performance information was used to evaluate productivity limitations and potentials of dual-purpose member herds of the Genesis farmer organization of central coastal Veracruz, Mexico. The Cornell Net Carbohydrate and Protein System model (Version 6.0) was systematically applied to specific groups of cows in structured simulations to establish probable input–output relationships for typical management, and to estimate probable outcomes from alternative management based on forage-based dietary improvements. Key herd vulnerabilities were pinpointed: chronic energy deficits among dry cows of all ages in late gestation and impeded growth for immature cows. Regardless of the forage season of calving, most cows, if not all, incur energy deficits in the final trimester of gestation; thus reducing the pool of tissue energy and constraining milking performance. Under typical management, cows are smaller and underweight for their age, which limits feed intake capacity, milk production and the probability of early postpartum return to ovarian cyclicity. The substitution of good-quality harvested forage for grazing increased predicted yields by about one-third over typical scenarios for underweight cows. When diets from first parturition properly supported growth and tissue repletion, milk production in second and third lactations was predicted to improve about 60%. Judiciously supplemented diets based on good quality grass and legume forages from first calving were predicted to further increase productivity by about 80% across a three-lactation cow lifetime. These dual-purpose herd owners have large incentives to increase sales income by implementing nutritional strategies like those considered in this study.

Contrasting timing of parturition of chital Axis axis and gaur Bos gaurus in tropical South India – the role of body mass and seasonal forage quality

Seasonal variation in forage availability and quality is understood to affect the annual timing of parturition in large herbivores. In India–where seasonal monsoonal rains define variation in forage availability and quality–chital Axis axis exhibit stronger seasonality in parturition than the larger gaur Bos gaurus. We hypothesized that this difference can be explained by forage requirements determined by body mass. We developed a model to simulate changes in leaf biomass and nitrogen content based on plant available moisture and nutrients, and calibrated our model with field data. Our results show that the minimum forage nitrogen content required by lactating gaur was available throughout the year, but that required by lactating chital was available for less than 40% of the year, i.e. during the early wet season, which coincides with the annual peak period of chital births. The three to four month spread of chital births, which begins in the dry season, implies that the period of highest quality is also important for females to replenish maternal reserves for future reproduction and help maximize the growth rate of neonates. This spread also indicates low synchrony of chital births and suggests that predator swamping was less important in influencing their timing of parturition. As monsoonal rain exhibits annual temporal variation, we analyzed our model under different rainfall patterns while keeping the total annual rainfall constant. We found that the difference between the durations of how long forage quality is available to satisfy the minimum requirements of lactating gaur and lactating chital is similar for all simulated patterns. This insensitivity to variable rainfall patterns lends support to our hypothesis that forage requirements determined by body mass is one plausible explanation for the variation in parturition strategies among large herbivores species.

Strategies for Cost-Effective Supplementation of Beef Cattle

Forage should provide the majority of the nutrition for the beef herd. Seasonal forage growth and changes in forage quality challenge most cattle managers to provide adequate nutrition at reasonable costs. This revised 6-page fact sheet gives several alternatives to consider in your cow-calf production system. Written by Matt Hersom and W.E. Kunkle, and published by the UF Department of Animal Science, October 2011. SS-ANS-14/AN085: Strategies for Cost-Effective Supplementation of Beef Cattle (ufl.edu)

Growth and Nutritive Value of Grass Pea in Oklahoma

The cool‐season pulse grass pea (GP, Lathyrus sativus L.) has the potential to provide late‐spring forage in the southern Great Plains (SGP), but genetic materials for development of new cultivars is limited. Our objective was to evaluate seasonal forage production and grain yield of 10 new Mediterranean‐origin GP lines, in central Oklahoma. Replicate (n = 3) plots (3 by 10 m) were disked, fertilized (60 kg ha−1 P2O5), and sown (60 kg seed ha−1) in 60 cm rows with GP lines 190, 288, 289, 290, 299, 387, 390, 736, B22, B111, and AC‐Greenfix (control) that were treated with inoculum (Rhizobium leguminosarum) during early March in 2007, 2008, and 2009. Whole plant samples were collected 59, 73, 94, and 115 d after planting. Biomass collected on Day 115 was separated into seed and nonseed biomass. Biomass accumulation, N concentration and nongrain digestibility showed significant (P ≤ 0.05) line, year, and sampling date effects. Grain biomass, N concentration and digestibility also showed significant line and year effects. AC‐Greenfix produced the most nongrain biomass each year [2499 kg ha−1 for AC‐Greenfix vs. an average of 1899 (±145) kg ha−1 for the other 10 lines] and sampling date. Line × year interactions for grain biomass was statistically significant, with 2008 being the most productive year for all lines. Additional development is needed for these new Mediterranean GP lines to perform with the same consistency as AC‐Greenfix in the SGP.

Performance and Grazing Pattern of West African Dwarf Sheep to seasonally Variable Forage Supply and Quality

Sixty (60) West African Dwarf sheep managed semi intensively and grazing on natural pastures were used in a study to determine the performance and grazing pattern to seasonal forage supply and quality. The animals were allowed to graze for about 6 hours daily for four months each in the dry and wet seasons, respectively. Results showed that field grazing time and active grazing time significantly increased (P