Publication Date
1997
Description
Nutritive value and intake of legumes is generally considered superior to grasses when ensiled at similar digestibility. The objectives of this experiment were to determine the optimum combination of annual ryegrass (Lolium multiflorum) and alfalfa (Medicago sativa) silages to maximize growth rate of steers fed silage, determine chemical components which influenced performance, and to determine if steers selected the optimum mixture when given a choice. Both silages contained similar concentrations of dry matter, acid detergent fibre and organic acids, but alfalfa silage had higher concentrations of nitrogen (N), soluble N and ammonia N. Annual ryegrass contained more neutral detergent fibre. In a 12-wk growth trial, voluntary intake by steers was not influenced when the proportion of the two silages was changed from 0 to 1 in 0.25 increments. However, rate of gain increased linearly (P<0.001) as the proportion of ryegrass silage was increased. When conditioned to either of the two silages, steers showed a significant preference for ryegrass over alfalfa (P<0.5). However, when conditioned to a mixture of both silages no preference was elicited. The results suggested that extensive solubilization and deamination of protein in alfalfa silage nullified the expected intake and performance advantage to feeding a legume.
Citation
Charmley, E, "Intake, Growth and Feed Preference by Steers Fed Combinations of Alfalfa and Annual Ryegrass Silage" (2024). IGC Proceedings (1993-2023). 17.
https://uknowledge.uky.edu/igc/1997/session14/17
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Intake, Growth and Feed Preference by Steers Fed Combinations of Alfalfa and Annual Ryegrass Silage
Nutritive value and intake of legumes is generally considered superior to grasses when ensiled at similar digestibility. The objectives of this experiment were to determine the optimum combination of annual ryegrass (Lolium multiflorum) and alfalfa (Medicago sativa) silages to maximize growth rate of steers fed silage, determine chemical components which influenced performance, and to determine if steers selected the optimum mixture when given a choice. Both silages contained similar concentrations of dry matter, acid detergent fibre and organic acids, but alfalfa silage had higher concentrations of nitrogen (N), soluble N and ammonia N. Annual ryegrass contained more neutral detergent fibre. In a 12-wk growth trial, voluntary intake by steers was not influenced when the proportion of the two silages was changed from 0 to 1 in 0.25 increments. However, rate of gain increased linearly (P<0.001) as the proportion of ryegrass silage was increased. When conditioned to either of the two silages, steers showed a significant preference for ryegrass over alfalfa (P<0.5). However, when conditioned to a mixture of both silages no preference was elicited. The results suggested that extensive solubilization and deamination of protein in alfalfa silage nullified the expected intake and performance advantage to feeding a legume.
