Technical note: utilization of sainfoin by grazing steers and a method for predicting daily gain from small-plot...

Area of Science:

• Agronomy
• Animal Science
• Forage Production

Background:

• Sainfoin (Onobrychis viciaefolia Scop.) is a legume adapted to calcareous soils, offering bloat-free early-season forage.
• Limited data exists on ruminant performance when grazing sainfoin, necessitating further research.

Purpose of the Study:

• To evaluate the impact of plant growth stage and grazing intensity on potential animal production from sainfoin.
• To predict animal performance using energy intake as a multiple of maintenance.

Main Methods:

• Nitrogen-fertilized sainfoin was grown under irrigation and subjected to light, medium, and heavy grazing pressures at bud, flower, and seed shatter stages.
• Grazing pressures aimed to remove 50%, 75%, and 90% of standing plant height, corresponding to 52%, 69%, and 87% herbage removal.
• Steer dry matter intake and predicted live weight gain were measured.

Main Results:

• Dry matter intake as a percentage of body weight decreased with increasing grazing pressure (3.9% for light, 2.8% for medium, 1.7% for heavy).
• Predicted live weight gain was highest under light grazing (.86 kg/d) and lowest under heavy grazing (.03 kg/d).
• Sainfoin growth stage influenced intake and gain, with bud stage generally showing better outcomes under appropriate grazing.

Conclusions:

• Management of grazing pressure is critical for optimizing animal production from sainfoin pastures.
• The multiple of maintenance method shows promise for assessing treatments in small-plot grazing trials.
• Further research should explore optimal grazing strategies for sainfoin to maximize its potential as a livestock forage.