Alfalfa (Medicago sativa L.), known as the queen of forages, is a versatile and valuable forage crop that holds significant importance in agriculture due to its myriad benefits for livestock. Ruminants benefit from alfalfa's digestible fiber and protein, contributing to improved feed efficiency and milk production. However, alfalfa protein is rapidly and extensively degraded in rumen, and it is a challenge to maximize the efficiency of the forage crude protein utilized as metabolizable protein by ruminant livestock. In this study, the phenotypic data of 14 traits related to forage digestibility were collected from 200 alfalfa accessions planted at three different locations for 2 years. The performance of these accessions showed dramatic variations by location, indicating that environmental factors play important roles in alfalfa digestibility. Twenty-two significant genetic markers associated with 12 traits related to forage digestibility were identified by genome-wide association study. Among them, seven markers were associated with more than one trait, although the significant markers varied by year and location. Putative candidate genes associated with these loci were also identified. The digestibility-related markers and associated genes identified in this study will help to better understand the genetic basis of forage digestibility and its interaction with environments. After validation, the closely linked markers and associated genes can be used for marker-assisted selection of alfalfa with improved forage quality.

Yield is one of the most important agronomic traits in alfalfa breeding; however, this is a complex trait affected by genetic and environmental factors. In this study, we used multi-environment trials to test yield-related traits in a diverse panel composed of 200 alfalfa accessions and varieties. Phenotypic data of maturity (MSC), dry matter, plant height (PH), yield (Yi), and fall dormancy (FD) were collected in three locations: Idaho, Oregon, and Washington from 2018 to 2020. Single-trial and stagewise analyses within each environment were used to obtain estimated means by genotype by trait by environment. Genome-wide association studies identified a total of 84 non-redundant markers associated with the traits analyzed. Of those, 55 markers were located at 44 different loci. Ten significant SNPs at the same locus were associated with FD and they were linked to a gene annotated as a nuclear fusion defective 4-like (NFD4) protein. SNPs linked to transcription factors such as Cysteine3Histidine (C3H), Hap3/NF-YB family, and serine/threonine-protein phosphatase 7 proteins were associated with MSC, PH, and Yi, respectively. Our results provide insight into the genetic factors that influence alfalfa maturity, yield, and dormancy, which is helpful to speed up the genetic gain of alfalfa yield improvement.

The objective of this study was to determine the effect of drought stress on the in situ ruminal starch degradation kinetic parameters of corn for silage. Five commercial corn hybrids for silage were utilized. The experiment was designed as a split-plot within a randomized complete block design with 4 blocks. Eight plots were blocked and randomly subjected to a watered (W) or non-watered (NW) treatment. Within each block, plots were split into 5 sub-plots, to which 1 of the 5 corn hybrids were randomly assigned. Before planting, all plots were irrigated with 150 mm of water to ensure a consistent emergence of corn seedlings. After this pre-planting irrigation, NW plots were not irrigated ever again. After planting, W plots were irrigated with 75 mm of water when the crop showed 2 visible leaves, 6 visible leaves, and pre-tasseling and with 45 mm every week, thereafter, for a total of 8 weeks (360 mm post-tasseling). Three ears from each subplot were collected when corn crops were between the 1/4 and 3/4 milk-line stage of maturity. Kernels were shelled by hand and dried. The in situ ruminal starch degradability was determined on ground (4-mm) grain samples placed in Dacron porous bags. All bags were immersed within the rumen of 3 rumen-cannulated cows fed a totally mixed ration containing 32 % corn silage, 3 % alfalfa hay, and 65 % concentrate mix (DM basis). Bags were incubated for 0, 4, 8, 12, 24, and 48 h. Water stress did not affect the fraction of instantly degraded starch (203 mg/g), the fraction of potentially degraded starch (759 mg/g), the fraction of undegraded starch (38 mg/g), or the differential starch degradation rate (0.0669/h). Corn hybrids did not affect any of these degradation kinetic parameters and no interactions existed between irrigation treatment and corn hybrid. In conclusion, drought stress had no effect on the in situ ruminal starch degradability of corn for silage.

The objective of this study was to determine the effect of drought stress on neutral detergent fiber (NDF) and lignin (LIG) concentrations and on in vitro dry matter digestibility (IVDMD) and in vitro neutral detergent fiber digestibility (IVNDFD) of leaf blades and stem internodes of corn for silage. Eight plots were blocked (i.e., 4 blocks) and randomly subjected to a watered (W) or non-watered (NW) treatment. Within each block, plots were split into 7 sub-plots, to which 1 of 7 corn hybrids were randomly assigned. Before planting, all plots were irrigated with 150 mm of water to ensure a consistent emergence of corn seedlings. After this pre-planting irrigation, NW plots were not irrigated ever again. After planting, W plots were irrigated with 225 and 360 mm of water pre-tasseling and post-tasseling, respectively. Stem internodes and leaf blades from the second phytomer below (LOWER) and the second phytomer above (UPPER) the ear insertion were collected to determine tissue composition and digestibility. Drought stress increased the concentration of NDF in both leaf blades (628 vs. 613 mg NDF/g DM) and stem internodes (625 vs. 572 mg NDF/g DM). Drought stress decreased IVDMD in stem internodes (0.575 vs. 0.525 IVDMD) but had no effect on IVDMD of leaf blades (0.561 IVDMD). Similarly, drought stress decreased IVNDFD in stem internodes (0.422 vs. 0.391 IVNDFD) but had no effect on IVNDFD of leaf blades (0.536 IVNDFD). Drought stress increased the concentration of lignin in the cell wall of leaf blades (161 vs. 141 mg/g CW) but had no effect on stem internodes (266 mg/g CW). Under the conditions of this study, water supply had a minimal effect on lignin concentration in the cell wall and did not increase the in vitro digestibility of fiber in corn for silage. The latter observation is contrary to the general industry belief that water stress increases fiber digestibility in forages.

Autotetraploid alfalfa is a major hay crop planted all over the world due to its adaptation in different environments and high quality for animal feed. However, the genetic basis of alfalfa quality is not fully understood. In this study, a diverse panel of 200 alfalfa accessions were planted in field trials using augmented experimental design at three locations in 2018 and 2019. Thirty-four quality traits were evaluated by Near Infrared Reflectance Spectroscopy (NIRS). The plants were genotyped using a genotyping by sequencing (GBS) approach and over 46,000 single nucleotide polymorphisms (SNPs) were obtained after variant calling and filtering. Genome-wide association studies (GWAS) identified 28 SNP markers associated with 16 quality traits. Among them, most of the markers were associated with fiber digestibility and protein content. Phenotypic variations were analyzed from three locations and different sets of markers were identified by GWAS when using phenotypic data from different locations, indicating that alfalfa quality traits were also affected by environmental factors. Among different sets of markers identified by location, two markers were associated with nine traits of fiber digestibility. One marker associated with lignin content was identified consistently in multiple environments. Putative candidate genes underlying fiber-related loci were identified and they are involved in the lignin and cell wall biosynthesis. The DNA markers and associated genes identified in this study will be useful for the genetic improvement of forage quality in alfalfa after the validation of the markers.

Once a good stand of alfalfa has been established, continued production and stand life depends on good management practices, which include maintaining soil nutrients, applying manure judiciously, and irrigating properly. The following article is a section from the revised (2015) Alfalfa Management Guide , which is available for purchase here: www.societystore.org . Earn 1 CEU in Nutrient Management by reading this article and completing the quiz at www.certifiedcropadviser.org/certifications/self‐study/771 .

Sagebrush (Artemisia spp.) habitat in the Intermountain West is one of the most endangered ecosystems in North America due, in part, to fire, climate change, and anthropogenic disturbances. However, restoration efforts rarely consider the dietary quality of sagebrush that is conserved or restored despite growing evidence that it is an influential parameter explaining habitat use by many important wild and domestic herbivores. The objective of this study was to evaluate the capacity of near-infrared reflectance spectroscopy (NIRS) to measure and monitor the dietary quality of sagebrush. Leaf samples were collected from two sagebrush species over two seasons and three sites in Idaho, USA. We developed calibration equations for crude protein (CP), dry matter digestibility (DMD), 1,8-cineole (cineole), and total polyphenolics. The coefficient of determination (r2) and ratio of performance to deviation (RPD) were 0.93 and 3.5 for CP, 0.83 and 1.8 for DMD, 0.64 and 1.5 for cineole, and 0.64 and 1.6 for total polyphenolics. These results indicate that NIRS may offer a rapid, noninvasive, diagnostic tool for assessing dietary quality of sagebrush, but future research should explore the potential for development of improved prediction equations and in situ analysis of sagebrush dietary quality with field spectroscopy.

ABSTRACTOrchardgrass (Dactylis glomerata L.) is a major component of many pastures in temperate North America. Early and profuse flowering in pastures is problematic, because livestock refuse to consume flowering stems, prompting many graziers to simply avoid using this species. The objective of this research was to determine the impact of reduced flowering on the quality of harvested forage under two harvest managements of orchardgrass. Six cultivars, three normal cultivars and three sparse‐flowering cultivars (mean panicle density of 141 vs. 61 panicles m⁻2, respectively), were evaluated in field experiments at 21 locations in North America under a 3‐cut harvest management. These cultivars were also evaluated at seven locations under a 5‐cut harvest management. Sparse‐flowering cultivars averaged 9% greater crude protein (CP), 3% lower neutral detergent fiber (NDF), 2% greater NDF digestibility, and 2% greater in vitro dry matter digestibility (IVDMD) than normal cultivars. For the two digestibility measures, differential panicle density between the cultivar groups explained a significant portion of variability, indicating that the increase in forage quality was proportional to the decrease in panicle density below a threshold of about 50 panicles m⁻2. Lastly, differences in regrowth forage quality between cultivar groups were smaller, less consistent, and of lesser statistical significance than for first harvest. While selection for sparse flowering in orchardgrass resulted in significant cause‐and‐effect increases in first‐harvest forage quality, these effects were too small to offset the reduced forage yield associated with the sparse‐flowering trait.

stacking became commonplace, larger and denser bales were desired, and they could weigh 80 to 120 lbs per 2-string bale. Three-string bales became more popular for transporting because they were more dense and stable than 2-string bales. During the same time, commercial dairies wanted premium hay with high leaf attachment. The 3x3, 3x4, and 4x4 (ft) large rectangularended bales with 8-ft length have densities of 14 to 16 lbs/ft 3 , which is nearly double the density of the old 2-string bales. In the last 25 years, there may be more hay fires than in the past because high moisture is retained longer in the more dense and massive types of bales.

Alfalfa is a key economic crop in all 11 Western states. In this paper we examine historical factors and key recent ‘megatrends’ which will likely impact alfalfa in the future. Acreage, yield, and production has mostly been static over the past 20 years, but the importance of alfalfa and other forages is thought to be increasing, given high world demand and increases in Western dairy herds. Key trends include a rise in emphasis on forage quality and testing, the advent of genetically engineered alfalfa, emerging pests such as aphid infestations and stem nematode. The economic and environmental health of the Western dairy sector is certainly of concern. Water restrictions, cost of production, availability, and quality are undoubtedly the most important limiting factor for alfalfa for the future, as well as a need to increase yields and improve consistency of forage quality testing. Researchable issues include development of salt resistance and drought tolerance, irrigation management approaches, improved IPM techniques, and forage quality evaluation. The lack of grower and USDA support for research is noted as a key limiting factor for the future of forage crops.

ABSTRACTOrchardgrass (Dactylis glomerata L.) is a major component of many pastures in temperate North America. Early and profuse flowering in pastures is problematic due to livestock refusal to consume flowering stems. The objective of this research was to determine the stability and agronomic impact of recently developed sparse‐flowering orchardgrass populations across temperate North America. Six cultivars, three sparse flowering and three normal flowering, were grown at 21 locations in temperate North America and evaluated for panicle density, heading date, and forage yield. Sparse‐flowering cultivars had 57% fewer panicles than normal‐flowering cultivars, but this effect was highly dependent on mean winter temperature, with normal‐flowering cultivars showing twice as much temperature sensitivity compared to sparse‐flowering cultivars. Forage yield of sparse‐flowering cultivars was reduced by approximately 24 to 32% for first harvest and 2 to 9% for regrowth harvests compared to normal‐flowering cultivars and this reduction in forage yield was independent of mean winter temperature. The forage yield reduction associated with sparse flowering is most likely due to a combination of physiological load (loss of stems) and opportunity cost (lack of selection pressure for yield), suggesting an opportunity to improve forage yield potential of this sparse‐flowering germplasm pool.

Interseeding legumes into grass-dominated stands can benefit pasture and hay producers by increasing the yield and quality of forage they produce and reducing their need for inputs of nitrogen fertilizer. The challenge is to get the legumes established given the competition from existing vegetation. This study confirmed that suppressing the grasses with glyphosate prior to seeding results in the most consistent legume establishment. Close mowing to simulate heavy grazing generally did not result in improved establishment. Of the 5 legumes evaluated, alfalfa established the best in the glyphosate treatment in Colorado, increasing yield by over a ton per acre. In Idaho, establishment was more variable with red clover establishing well regardless of suppression treatment. No legumes established at the Oregon site due to heavy rodent activity. This study highlighted the importance of suppressing the existing grasses and choosing a vigorous legume species for interseeding to reduce the risk of seeding failure.