Switching dairy animals – particularly lactating cows – from one batch of silage to the next can be disruptive to dry matter intake (DMI) , rumen function, and milk production.
Ben Jensen, Forage Treatment and Calf and Heifer Specialist for Hubbard Feeds, offers the following advice to ease cows from batch to batch:
- Minimize change – Feather new-crop silage into the previous batch over the course of 7-14 days if possible. And when transitions between batches of silage are being made, avoid other significant management changes like pen moves and vaccinations.
- Toss bad feed – The beginning and end of every batch of feed is the most likely place for spoilage. Discard spoiled feed to avoid introducing molds, yeasts, and mycotoxins to the ration. Even at an inclusion rate as low as 5%, damaged feed can negatively impact DMI.
- Carry over old crop – If possible, manage silage inventories so the new crop has at least 3 months to ferment. Like fine wine, the new crop will improve with age in terms of starch digestibility, which will help smooth the transition when it is introduced to the ration.
- Test, test, test – Test silage often for dry matter, protein, NDFD30 (30-hour fiber digestibility), starch (IVSD7 for starch digestibility, and starch as % of dry matter), and organic acids (lactic, acetic, propionic, and butyric). Comparing old- and new-crop results will help paint a picture of the degree of change when switching feeds.
- Manage risk proactively – New technology and availability of information can help you anticipate variation and avoid issues. Local forage labs can provide baseline data for new-crop forages in your area. Precise mycotoxin analysis can assess the risk from over 50 different mycotoxin strains. And testing the whole TMR in an in vitrofermentation model can reveal how the ration digests within the cow, rather than evaluating each ingredient individually.
- Moderate the rumen – Feeding protective yeast additives and direct-fed microbials can help stabilize the rumen, preventing subacute rumen acidosis through feed changes.
Jensen advised keeping ongoing track of silage inventories, and allocating more acreage if possible, to create more carryover inventory and longer fermentation times. “The extra feed required for carryover inventory requires more harvested acres initially,” he advised. “But subsequent years will revert to typical acres, and there will always be fully fermented feed ready.”
