Why Feeding New Crop Corn Silage Results in Depressed Milk Production
Each fall dairy nutritionists wrestle with feeding new crop corn silage because cows go down in milk production when the new forage is introduced into the diet. The following is a list of ideas to minimize corn silage transition milk production changes:
- The old and new silages need to be well characterized for nutritional and digestion value. Starch content and NDF digestibility are two key measures required during the ration formulation. These values help the nutritionist determine if more or less supplemental energy should be added to the ration. The dry matter content of the silage is another essential measurement as that value predicts how available starch will be to the rumen in non-processed corn silages.
- The old and new silages need to have an assessment of kernel physical damage if the corn silage was processed during harvest as that value predicts how available starch will be to the rumen. Analysis of samples for degree of kernel processing using laboratory techniques offered by leading forage testing laboratories can accurately assess the degree of kernel damage.
- The old and new silages need to be assessed for particle length comparisons, making sure the physical effective NDF contribution from corn silage is accounted for during ration formulation and this assessment is done in conjunction with the kernel processing determination at leading forage testing laboratories.
- Make sure the new silage has fermented long enough to maximize feed value. Often dairymen assume that because corn forage has fermented into silage after one week, that it must be ready to feed. Microbial and hydrolysis activity at low pH is still occurring after completion of fermentation, meaning that the feed value of the silage won't be maximized until 45-60 days after ensiling the crop. A good management practice is to ensile transition corn silage such as bagged silos so that after a main bunker of last year's corn silage is emptied, the new bunker won't be opened until the transition corn silage is fed.
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