Herbage and Beef Production from Ryegrass‐Alfalfa and Orchardgrass‐Alfalfa Pastures1,2

Abstract

AbstractMost grass species are not highly compatible with alfalfa, Medicago sativa L., in a mixture, either because they do not persist under certain harvest schedules or they are too competitive and are not readily acceptable to grazing animals. This study compared perennial ryegrass, Lolium perenne L., with orchardgrass, Dactylis glomerata L., each in combination with alfalfa under grazing situations. Dry matter yields, herbage nutritional value, changes in botanical composition, alfalfa persistence, animal acceptance, and average daily weight gains (ADG) of beef cows and calves were recorded. ‘Terhoy’ and ‘Reveille’ perennial ryegrass and ‘Pennlate’ orchardgrass were planted with ‘Saranac‐AR’ alfalfa at 17, 17, 7, and 11 kg.ha−1, respectively. The grass‐alfalfa stands were established on Hagerstown silt loam (fine, mixed, mesic Typic Hapludalf), and on Hublersburg silt loam (clayey, illitic, mesic, Typic Hapludult). A four‐paddock rotational grazing system was used with each mixture, with an average of 12 days grazing paddock−1 and a 36‐day rest period. There were 117 days of grazing in 1978 using four tester beef cows and calves per mixture and 163 days of grazing in 1979 using five tester beef cows and calves per mixture. Additional animals were added as needed to equalize grazing pressure. Herbage yield and quality samples were taken before grazing in each paddock. In 1979, additional herbage samples were taken after animals were removed from a paddock. Annual dry matter yields for 1978 and 1979 were not significantly different for the three mixtures. Mean herbage crude protein concentrations were: alfalfa, 22%; ryegrass, 20%; and orchardgrass, 16%. Reveille‐alfalfa and Terhoy‐alfalfa pastures produced 473 and 320 kg more herbage protein.ha−1.year−1, respectively, than orchardgrass‐alfalfa pastures. Mean in vitro dry matter digestibility was: ryegrass, 77%; alfalfa, 73%; and orchardgrass, 70%. Reveille ryegrass‐alfalfa and Terhoy ryegrass‐alfalfa produced 886 and 331 kg more digestible dry matter.ha‐1.yr‐1, respectively, than orchardgrass‐alfalfa. Orchardgrass contributed 50 and 80% of the dry matter yields in May of 1978 and 1980, respectively, whereas ryegrass contributed 35 to 40% of May dry matter yields each year. After 2 years of grazing, ryegrass pastures contained 53% more alfalfa plants than orchardgrass pastures.Animal preference was ryegrass > alfalfa » orchardgrass. Composition of stubble remaining after grazing averaged 28% ryegrass‐62% alfalfa vs. 74% orchardgrass‐24% alfalfa.The ADG of beef cows and calves were influenced by a) pretrial diet, b) plant maturity, c) a changing environment that influenced botanical and chemical composition of forage components and animal metabolism, d) age of animals, and e) cow‐calf interactions. In 1978, ADG means were not significantly different for cows or calves on the three grass‐alfalfa mixtures. In 1979, the combined ADG of cows and calves on the ryegrass‐alfalfa mixtures averaged 21 % higher than those of cows and calves on orchardgrass‐alfalfa.Ryegrass‐alfalfa mixtures should be widely tested under different soil and weather conditions in the humid U.S.A. to determine areas of adaptation. Where adapted, ryegrass‐alfalfa mixtures offer substantial potential contributions to forage‐animal production systems and economies.