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Forage Quality, Mineral Constituents, and Performance of Beef Yearlings Grazing Two Crested Wheatgrasses
Author(s) -
Vogel K. P.,
Gabrielsen B. C.,
Ward J. K.,
Anderson B. E.,
Mayland H. F.,
Masters R. A.
Publication year - 1993
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1993.00021962008500030012x
Subject(s) - grazing , hectare , forage , agropyron cristatum , zoology , agronomy , biology , beef cattle , ecology , agriculture
In the central Great Plains, crested wheatgrasses [ Agropyron cristatum (L.) Gaetner and A. desertorium (Fischer ex Link) Schultes] are best utilized for early spring and late fall grazing. The principal objective of this study was to determine if beef ( Bos taurus L.) yearlings grazing ‘Ruff’ ( A. cristatum ) during the spring grazing season had higher average daily gains and gains per hectare than cattle grazing ‘Nordan’ ( A. desertorum ). These cultivars were evaluated in grazing trials (four replications) in eastern Nebraska in 1985, 1986, and 1987. The 0.8‐ha pastures were seeded in the fall of 1983 on a Typic Argiudoll soil and were fertilized annually with 68 to 90 kg N ha −1 . Grazing was for 6 wk each spring by yearling steers with a beginning average weight of 250 kg. Averaged over 3 yr, Ruff produced higher gains per hectare than Nordan (272 vs 245 kg ha −1 ) probably because it produced more herbage because of its better persistence. At the end of the trial, the averge basal cover of Ruff and Nordan were 21 and 6%, respectively. Three‐year mean average daily gains were Ruff = 1.28 vs. Nordan = 1.34 kg d −1 , which were unexpected, because Ruff generally had higher forage quality as measured by an array of parameters. Ruff forage had a higher, less desirable grass tetany ratio [K/(Mg+Ca)] than Nordan (2.6 vs. 2.3) averaged over 3 yr. Cattle grazing Ruff had lower blood serum Mg levels than rattle grazing Nordan (15.4 vs. 16.2 mg −1 , both of which were below the hypomagnesemia threshold of 18 mg L −1 . This condition may have reduced intake and animal gains. These results indicate the need for evaluating pasture and range grass cultivars under grazing conditions.