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The Fall Slump (in milk production)… is it avoidable?

By: Kevin Caspersen, Key Account Manager, Chr. Hansen




I love fall, it is definitely my favorite season for many reasons: cooler weather, harvest, no bugs, hunting season and all things pumpkin spice! Ok, just kidding about the pumpkin spice thing, I actually dislike pumpkin spice immensely, especially pumpkin spiced beer (which should be illegal to brew in my opinion).


In spite of being my favorite season of the year, USDA statistics, from the top 24 milk producing states, show that year-after-year, the period from September through November shows the lowest U.S. milk production. This statistic reinforces the fact that many dairy producers across the country experience the dreaded fall slump! This seasonal slump happens even though we have cooler weather, less stress from flies, more stable feed, etc. I wish I had a quick and easy answer to this problem but it is multi-faceted, and sometimes, complicated. The fall milk slump is typically the time frame from September to late November when cows just don’t seem to milk like we think they should; usually milk components are higher than normal and efficiency is lower.


We have defined what the fall milk slump is so, what causes it and what are some strategies to mitigate its effects? First, even with modern barns and up-to-date management, cows still have a very natural biological process that they go through every year. It is theorized that the effects of evolution still have an effect on how our modern cows react to the changes of the seasons and are most likely due to changes in photoperiod (the amount of light each day that a cow receives). Over the millennia, fall has typically been a time for animals to get ready for winter and restore body fat supplies, winter is a time for survival and growth of the calf in utero, spring is for calving. During fall, cows are preparing for winter by putting on body fat and are utilizing energy that would typically go towards milk production, thus reducing the amount of milk they are producing.


Also, some summers can be more difficult for cattle to recover from. Long hot summers and spending lots of time on their feet have possibly caused a loss of body condition that needs to be replenished going into fall. Photoperiod plays a large role in the reduction of milk production during this fall slump time. Dr. Geoff Dahl has looked extensively at the role that light has on milk production. Dairy cows that receive 16-18 hours of light produce more milk than cows that receive less than 16 hours of light. During fall, daylight is reduced and, while we do use artificial lighting, there is a biological process that these animals go through and sometimes milk production drops because of the natural rhythm of the season.


The slump in milk production during the fall can also be caused by the introduction of new crop corn silage. We know from several years of good data that starch digestibility increases over time, and starch digestibility is lowest right after harvest and then slowly increases over time. Starch digestibility will have a huge effect on milk production and so, during corn silage harvest, one management practice that we can influence is kernel processing scores (KPS) coming out of the chopper. Make sure you are watching the KPS coming out of the chopper during harvest. Several of the reputable forage testing labs have KPS scoring analysis available and there are also quick and easy ways to evaluate KPS scores on fresh corn silage. Please feel free to reach out to your local Chr. Hansen representative to learn how to utilize these opportunities.


Building corn silage inventory is a great way to minimize the effects of having to go directly into new corn silage. Having 3-4 months or more of corn silage inventory before having to feed new silage is ideal, although we understand this isn’t possible in all circumstances. If you need to feed newly fermented corn silage, I highly recommend applying a science-based, research-proven inoculant at chopping, like SILOSOLVE® FC which provides a very, very quick fermentation and excellent stability during feed-out, as well. Feeding newly fermented corn silage can also create some unhealthy rumen issues that could cause a dip in milk production. During times of feed changes, we need to get cows back to normal as soon as possible and keep them normal. A combination of live cell yeast, like our BIOMATE® YC-20 and feeding an effective probiotic, like BOVAMINE® Dairy Plus can go a long way in helping mitigate some of the issues that cause the dreaded fall slump.


Unfortunately, even with these technologies and management practices, we must remember that cows are cows and have been for thousands of years. We might not be able to completely change mother nature, but we can try to minimize the effects by implementing some new and different strategies.