Core Ideas Grazing of vegetative swards results in forage removal trends contradictory to established paradigms. Neutral detergent fiber, and water soluble carbohydrates did not impact forage removal in ways established by studies done on grass with varying maturity. Conclude that species differences rather than cultivars drive forage removal in dairy cattle. Identification of forage grasses that are more readily consumed than others during grazing is vital to determining traits that can be used by plant breeders to increase animal intake and digestibility. Producers can benefit from the identification of what species and cultivars are more readily consumed; thus increasing animal production. The objectives were to: (i) determine forage removal by dairy cattle of several species and cultivars of cool‐season forage grasses: orchardgrass (Dactylis glomerata L.; eight cultivars), tall fescue [Schedonorus arundinaceus (Schreb.) Dumort; five cultivars], perennial ryegrass (Lolium perenne L.; five cultivars), and festulolium [ × Festulolium braunii (K. Richt.) A. Camus; six cultivars]; and (ii) determine if forage nutritive value is correlated with forage removal by animals on vegetative pasture. Forage removal for species varied among seasons; orchardgrass and festulolium were consumed more in spring, while orchardgrass and tall fescue were consumed more in the summer, and species did not affect removal in the fall. Forage removal varied among cultivars. However, when comparing forage removal against neutral detergent fiber (NDF), acid detergent fiber (ADF), crude protein (CP), in vitro true digestibility (IVTD), water soluble carbohydrates (WSC), pre‐grazing herbage mass, sward height, and dry matter concentration, correlations did not adhere to the paradigm of fiber fraction being negatively correlated and nutrient components being positively correlated to forage removal. This indicated that other factors impact forage removal when animals graze completely vegetative swards.
Forage production in the southeastern United States relies heavily on cool-season grasses in winter and spring. The most prolific species is annual ryegrass (Lolium multiflorum Lam.), a winter annual. Historically, secondary seed dormancy of ryegrass inhibits germination at soil temperatures in excess of 21 • C. Normal planting occurs in early-mid fall (mid-October). However, earlier planting (Aug. or Sept.) could expand the grazing period. This work sought use of recurrent phenotypic selection (RPS) to breed an annual ryegrass cultivar that could germinate at high temperatures and survive high temperatures post-germination. All selections were conducted in a growth chamber at 40:30 • C (12:12 h, light/darkness). Germinated seedlings were subjected to 2-3 wk of 40:30 • C conditions post-germination. Selected individuals (Cycle 1) and the base germplasm (Cycle 0) were transplanted to the field in fall 2015, and harvested for seed in spring 2016. Germination tests were conducted to compare mean cumulative germination, velocity of germination within 8 d (VOG 8 ), and realized heritability (h 2 ) at 40:30 • C. Selection was repeated twice to reach Cycle 3. Data from the 2018 germination tests indicated that germination of Cycle 3 seed (45.8%) was significantly greater (P < .001) within 14 d than that of all previous cycles. Cycle 3 VOG 8 was 8 times that of Cycle 0. Total additive gene action was estimated by a calculated realized heritability of h 2 = .41. These data indicate improved germination under high temperatures was achieved in nearly half the population. This will potentially allow for late-summer planting and greater grazing time. INTRODUCTIONAbiotic stresses are one of the most prolific problems associated with the widespread cultivation and development of new crops. These refer to any event and/or phenomenon associated with nonliving factors. The major abiotic stress factors most commonly associated with crop damage and loss are drought, flooding, and temperature extremes (Agrios, 2005; Abbreviations: RPS, recurrent phenotypic selection; VOG 8 , velocity of germination within the first 8 days.
Winter annual forages differ in their comparative forage mass and nutritive value 2. Cereal rye and triticale had the greatest forage mass, but poorest nutritive value 3. Barley had low forage mass, but greater crude protein and lesser fiber 4. Hairy vetch production was poor
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