The maximum recommended inclusion rate of wheat forage in ruminant diets is 40% of the forage intake. Wheat forage is preferable to barley forage, as the latter forms a tough grain coat once the crop exceeds 35% DM, resulting in poor digestibility (Ewing, 1997). Some wheat forage cultivars may have a higher nutritive value than triticale (Cash et al., 2009).
Because wheat forage contains high concentrations of nitrogen, non-protein N, digestible dry matter and water, beef cattle and sheep require an adaptation period before positive body weight gains are seen. A daily gain lower than average during the first 14 days of wheat pasture grazing by stocker calves and lambs is most likely the result of less DMI by non-adapted animals and is not due to diet digestibility or N metabolism (Phillips et al., 2008).
Consumption of small amounts of low quality roughage by growing cattle on wheat pasture did not alter wheat forage intake or utilization (Mader et al., 1986). Quebracho condensed tannins have been proposed as a potential supplement for stocker cattle-wheat systems, as it can decrease the impact of frothy bloat and increase body weight gains (Min et al., 2006).
At pasture, in vivo digestibility in young crossbred sheep grazing dual-purpose wheat crops was high (84-85%). Total intake was between 3.7 and 4.0% of live weight (Dove et al., 2009). Dual-purpose wheat planted in the autumn can be grazed within about five weeks and support about 10 sheep/ha without impairing the wheat as a grain crop (Göhl, 1982).
Providing supplementary DM to lambs grazing fresh wheat forage does not increase lamb performance (Phillips et al., 1995). In young sheep grazing wheat pasture, there were marked live-weight gain responses (30-50%) to mineral supplements based on NaCl, CaCO3 and MgO (Dove et al., 2009).
No significant differences were found in preferences of sheep for six different wheat cultivars (Dove et al., 2009).
Wheat forage can be ensiled with a DM content either low (35%) or high (50-60%). When ensiled at high DM, urea treatment at 20-30 kg per tonne of fresh forage increases its protein content (Ewing, 1997). The digestibility of ensiled wheat forage is significantly reduced (up to -2.3%) compared to fresh forage, depending on forage maturity. When an application of urea of more than 40 kg/t DM at harvest was made, there were no differences in digestibility between urea-treated forage and fresh forage. Treatment of whole-crop wheat forage with urea at harvest can be an effective method of preserving its nutritive value (Hill et al., 1999). Wheat forage preservation and digestibility can be improved with silage additives. For instance, a mixture of amylase and sulphur salts was shown to increase digestibility of DM and fibre of wheat silage-based diets fed to Holstein heifers (Froetschel et al., 1991).
Although differences in average daily gain of beef calves were not noted, increased maturity at harvest and preservation as silage caused differences in DMI and digestibility of DM and NDF when included at 40% of the diet, when compared to a similar diet based on wheat hay (Beck et al., 2009).
The energy values of several whole crop silages, made from barley, wheat and triticale, harvested at the milk-dough stage with 30-35% DM, were lower or close to those of grass silages (Emile et al., 2007).
Wheat and legume silages
The energy value and particularly the nitrogen value of silages made from cereal forage and legume mixtures were higher than those of silages made from cereal forages alone, and comparable or better than those of grass silages (Baumont et al., 2009). For instance, the intake of dairy cows was improved by 1.9 kg DM and the milk production by 1.8 kg with silage made from a mixture of triticale, oat, pea and vetch compared to pure triticale silage (Emile et al., 2008). However, the replacement of 50% maize silage by a cereal/legume silage in the diet of dairy cows depressed intake and production by 7 and 6% respectively (Brunschwig et al., 2008).