I. Maize Nutritional characteristics grown in drought conditions
Under drought stressed conditions we observed:
- Lower yields
- Dry Matter (DM) content variation: In field and between fields and so in the silo
- Energy content: Feed value is approximatively 80%, but varies between 70% and 100%
- Low level of starch: can be lower than 10% DM basis
- High levels of sugar: Up to 20% DM basis; sugar is fermented rapidly in the rumen and the acidosis risk increases.
- More ADF and NDF content: decrease in total forage digestibility, but NDF digestibility can be increased. Due to possible higher NDF digestibility, the passage rate in the rumen can be more rapid.
- Higher crude protein content (10%): but more NPN (Non protein nitrogen), ammonia affects liver negatively and increase milk urea.
- High levels of Nitrates.
Figure 1: Maize silage analysis (1,386 samples, 1º. Jul – 7 Aug, 2012 (Dairyland Labs). The year 2012 was a drought year in the US.
Solutions and recommendations:
- Adapt your diet to the maize silage characteristics and consult your nutritionist. Adjust the energy balance as well as energy and nitrogen availability in the rumen. Fast energy needs also fast protein. Don’t feed additional NPN. Check rumen filling, feed intake and subclinical acidosis signs.
- Analyze silage on a regular basis to adapt adequately your diet.
- Take care with high DM variation (from 25% up to 45%).
- Analyze the kernel processing of the silage to adapt the feeding strategy.