The effects of grain treatment, grain feed level and grass silage feed value on the performance of and meat quality from, finishing beef cattle

Abstract

A completely randomised design study involving 132 continental crossbred beef steers was undertaken to evaluate the effects of method of grain treatment and feed level, and grass silage feed value on animal performance, carcass characteristics and meat quality of beef cattle. Winter wheat was harvested and the grain was stored either ensiled crimped and treated with 4.5 l/t of a proprietary acid-based additive (crimped), ensiled whole and treated with 20 kg feed-grade urea per t (urea) or stored conventionally in an open bin treated with 3 l propionic acid per t. Two grass silages, of contrasting feed value (L and H) were ensiled. For the conventional, crimped and urea treatments, grain dry matter (DM) concentrations were 802, 658 and 640 g/kg, respectively. For the L-and H-feed value silages, DM concentrations were 192 and 240 g/kg and D values were 671 and 730 g/kg DM, respectively. The silages were offered as the sole forage supplemented with either conventional, crimped or urea-treated grain-based concentrate at either 3.5 or 6.0 kg DM per steer per day. The grain supplement consisted of 850 and 150 g/kg DM of grain and citrus pulp, respectively. For the conventional, urea and crimped treatments, DM intakes were 8.85, 9.43 and 9.04 kg/day (standard error (s.e.) 5 0.129); estimated carcass gains were 0.60, 0.55 and 0.61 kg/day (s.e. 5 0.020), respectively. For the low-and high-feed value grass silages, estimated carcass gains were 0.56 and 0.61 kg/day (s.e. 5 0.014), respectively. For the low and high grain feed levels, estimated carcass gains were 0.56 and 0.61 kg/day, respectively. Grain treatment, grain feed level or silage feed value did not alter (P . 0.05) meat quality, lean colour or fat colour. There were significant silage feed value 3 grain feed level interactions (P , 0.05) for final live weight (LW) and daily live-weight gain (DLWG). Increasing grain feed level increased final LW and DLWG when offered with the low-feed value silage, however, grain feed level had no effect on final LW or DLWG when offered with the high-feed value silage. It is concluded that urea treatment of grain increased silage intake and feed conversion ratio (kg DM intake per kg carcass) and tended to decrease carcass gain. Crimping provides a biologically equally effective method to store grain as conventional methods. Improving grass silage feed value had a greater impact on animal performance than increasing grain feed level by 2.4 kg DM per day.

Effects of replacing grass silage with maize silages differing in inclusion level and maturity on the performance, meat quality and concentrate-sparing effect of beef cattle

“…This response is considerably higher than the response of 21 to 27 g carcass gain per 1 kg increase in concentrate DM intake reported by Keane et al (2006) and Keady et al (2007 and2008b), but is similar to the response reported by Steen et al (2002). The higher response in the current study was probably because of the lower substitution rate (0.53 kg/kg for silage DM by concentrate), which reflects the low intake characteristics of the grass silage.…”

“…The higher level of performance achieved in response to increased concentrate feeding resulted in an improvement in the efficiency of feed utilization (carcass gain relative to ME intake) similar to the results of previous authors (Steen and Kilpatrick, 2000;Steen et al, 2002) using similar feed value grass silages as in the present study. The 'paler' fat colour associated with increased level of concentrate feeding, contrary to previous studies at this centre (Keady et al, 2007 and2008b), is probably due to reduced intake of carotenoids, as cereal-based diets have a lower concentration of carotenoids than grass-based diets (Dunne et al, 2009). Furthermore, the animals offered the high-concentrate diet accreted more adipose tissue and that may have diluted the carotenoids present.…”

“…In the current study, the carcasses were suspended from the aitch bone (tenderstretch), and Lively et al (2006) concluded that differences between breeds that existed when carcasses were suspended by the Achilles tendon were greatly reduced relative to carcasses suspended tenderstretched. Previous studies at this centre (Lively et al, 2005 and2008;Keady et al, 2007 and2008b) have not revealed an effect of concentrate feed level on meat tenderness.…”

“…Although the optimum stage of maturity to harvest grass silage for feeding to finishing beef cattle and lactating dairy cows is at the leafy immature stage (Gordon, 1980;Keady et al, 1999Keady et al, , 2003Keady et al, , 2008aKeady et al, and 2008b, for maize silage the intention is to increase starch concentration and consequently harvest as a mature crop. Previous studies have shown that the optimum stage of maturity, for milk output of dairy cows, to harvest maize for ensiling is at a DM concentration of ,300 g/kg (Phipps et al, 2000;Keady, 2005;Keady et al, 2008a).…”

Effects of silage from maize crops differing in maturity at harvest, grass silage feed value and concentrate feed level on performance of finishing lambs

“…Although the lipid and protein concentrations of carcass gain were not determined in the current study, increasing silage feed value improved the efficiency of ME utilisation for carcass gain. Similarly, Steen et al (2002) and Keady et al (2008a) reported that increasing the feed value of grass silage improved the efficiency of feed utilisation by finishing beef cattle.…”