Manitoba Agriculture, Food and Rural Initiatives

Research Abstracts for August 1998

Nutrition Update
Volume 9 No.2, August 1998

G.W. Mathison et. al. 1997. Effects of tempering and degree of processing of barley grain on the performance of bulls in the feedlot. Can. J. Anim. Sci. 77:421.

An experiment with 216 bull calves (ave. wt ' 288 kg) was conducted in which tempered and dry barley grains were lightly rolled (most of kernels cracked, few broken), medium rolled, or crushed (almost all kernels broken) and included in a feedlot diet containing 90% concentrate and 10% barley silage on a dry matter basis. In the tempering process 6% water was added to the control barley, which initially contained 13% moisture, and the damp grain was allowed to stand overnight at room temperature before rolling. Tempering had no influence on rate or efficiency of gain of the bulls during the 134 day trial or on carcass characteristics. Cattle fed slightly rolled, medium rolled, and crushed barley (kernel thicknesses of 2.7, 2.56 and 2.31 mm) gained 1.55, 1.57 and 1.61 kg/day, respectively, with no difference detected between treatments. Corresponding DM intakes were 8.04 , 7.79 and 7.54 kg/day. Dry matter intake to gain ratios were 5.2, 4.96 and 4.68. Carcasses of bulls fed crushed barley had more grade fat than bulls fed slightly rolled barley.

It was concluded that there was no advantage in tempering barley which initially contained 13% moisture. There is now sufficient evidence to recommend that for maximal feed efficiency all barley kernels should be broken before feeding to cattle. A standardized procedure consisting of measurement of whole barley kernels (ideally less than 3% by weight) and the percentage of material passing through either a 1.4 mm or 2.0 mm sieve (ideally less than 3 and 10% by weight, respectively) is recommended for use in describing the degree of processing of dry-rolled barley grain.

B.S. Dalke et. al. 1997. Wheat middlings in high-concentrate diets: feedlot performance, carcass characteristics, nutrient digestibilities, passage rates, and ruminal metabolism in finishing steers. J. Anim. Sci. 75:2561.

Although wheat middlings (WM) are used commonly as a feed source for livestock, very little information is available concerning their nutritive value in high-concentrate diets. There can be considerable load-to-load variation in nutrient content. The WM used in this experiment were from a single source and had the following composition (%, DM basis): 19 CP, 44.3 NDF, 10.7 ADF, 23.2 starch, .14 calcium, 1.2 phosphorus, and 1.0 potassium. One hundred and twenty medium frame calves, weighing 365 kg, were assigned to one of six treatments of 90% concentrate diets: control (0%); 5, 10 or 15% pelleted WM replacing dry-rolled corn (DRC); and 5 or 10% pelleted WM replacing chopped alfalfa hay (ALF) components of the diet.

WM can replace only up to 5% of DRC without reducing feed conversion efficiency and diet digestibilities, but could completely (100%) or partially (50%) replace the chopped alfalfa hay component with no adverse effect on feedlot performance.

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