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The performance of beef cattle given silages made from perennial ryegrasses of different maturity groups, cut on different dates
Author(s) -
STEEN R. W. J.
Publication year - 1992
Publication title -
grass and forage science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.716
H-Index - 56
eISSN - 1365-2494
pISSN - 0142-5242
DOI - 10.1111/j.1365-2494.1992.tb02268.x
Subject(s) - silage , wilting , zoology , dry matter , perennial plant , biology , agronomy
Two experiments were carried out to examine the interaction between early and late‐heading varieties of ryegrass and date of harvesting of primary growths for silage in terms of the performance of beef cattle. A sward containing equal proportions of three early heading varieties (Cropper, Premo and Frances) (50% ear‐emergence on 18 May) was harvested on 20 May (T1), 28/29 May (T2) and 5/6 June (T3) and a sward containing three late‐heading varieties (Perma, Preference and Parcour) (50% ear‐emergence on 12 June) was harvested on 28/29 May (T4), 5/6 June (T5) and 12/14 June (T6) in 1985 and 1987. In each year the six silages were harvested without wilting and were ensiled in trench silos. In Experiment 1 they were offered ad libitum and unsupplemented to 48 steers (407 kg live weight (LW)) for 101 days and in Experiment 2 they were offered with 2 kg concentrates per head daily to 48 heifers (392 kg LW) for 105 days. In Experiment 1 in vivo digestible organic matter (DOMD) concentrations in dry matter were 717, 671, 643, 709, 672 and 640 (s.e. 8·4) g (kg DM) −1 ; silage DM intakes 7·1, 6·6, 6·6, 7·2, 7·3 and 6·7 (s.e. 0·15) kg d −1 ; LW gains 0·94, 0·74, 0·62, 0·90, 0·82 and 0·57 (s.e. 0·047) kg d −1 ; for T1 to T6 respectively. For Experiment 2, DOMD concentrations were 732, 699, 636, 734, 686 and 663 (s.e. 9·6) g (kg DM) −1 ; silage DM intakes 6·4, 5·7, 6·0, 6·0, 5·5 and 5·0 (s.e. 0·22) kg d −1 ; LW gains 1·12, 0·92, 0·99, 1·14, 0·88 and 0·76 (s.e. 0·078) kg d d −1 ; and carcass gains 0·66, 0·56, 0·51, 0·68, 0·55 and 0·48 (s.e. 0·048) kg d d −1 ; for TI to T6. It is concluded that silages made from early and late‐maturing swards of perennial ryegrass sustained similar levels of performance in beef cattle when they were harvested at equal digestibility, and the digestibility declined at similar rates for the two sward types when harvesting of the primary growths was delayed. Under the conditions of these experiments the same level of animal performance was sustained by silages made from the two swards when the late‐maturing varieties were harvested 7 days after the early varieties. This compares with an interval of 25 days between the early and late‐maturing varieties reaching 50% ear‐emergence.