There are several reasons why fall is my favorite time of the year. Dropping temperatures, cooler mornings, turning leaves, and perhaps most importantly, football. To be sure, the September games can feel like a sauna, but knowing that true fall weather is on the way is enough to push through the last that summer has to offer.

Fall is a tricky and sometimes unpredictable season for milk production. It is highly dependent on your geography to determine your anticipation for fall milk production results. In the early years of my nutrition career in hot and humid central Texas, a fall rebound in milk production was fully expected. As I moved into the High Plains region a few years later, fall was not nearly as highly regarded as an opportunity to make nice improvements in milk production as the temperatures dropped. This was curious to me at the time, but with a better understanding of a few things about corn silage chemistry, a now common management practice and a shift to more solids-based milk pricing has changed the way I look at fall milk production expectations now.

In this comparison of two very different geographies (though in the same great state of Texas), it must be stated that the summer heat and humidity stress in central Texas was much more impactful on the cows. Cows in the High Plains do not experience the same dry matter intake reductions as those further south. Humidity and higher nighttime lows probably account for most of this difference. Thus, the High Plains cows don’t have as much lost ground to recover, body condition to build back and so forth as those in the hotter, more humid regions. Many strides have been made to cool cows better across the humid South, and the cows are better for it.

Understanding starch digestibility

Back to the corn silage part of this discussion. In the days when I first started learning how to feed cows in places like eastern New Mexico and the Texas Panhandle, we didn’t understand some of the finer details of starch digestibility potential and rates as we do now. Also, these were days before kernel processing (KP) was the norm. So, looking back, we know that part of the fall milk blues further north was largely due to poor starch digestion dynamics in new crop corn silages with no or poor KP.

In recent times, we have better lab analysis to help us predict starch dynamics and make ration adjustments when necessary to support higher levels of milk production. Don’t forget that not only is starch a significant contributor to the energy available for cows to produce high levels of milk, but the fermentation of this key carbohydrate in the rumen also drives metabolizable protein supply to support overall milk flow and milk protein content. It is a big deal that cannot be overstated.

I mentioned earlier a core management practice that has become a standard operating practice since those previous years. Knowing that the starch availability we desire takes time to accomplish, waiting a few months to open new crop silage is a must where possible. Drought can wreck this plan for sure, but planning for three to four months of time in the pit before opening and feeding should be standard. This is a key management and tracking practice that is critical for success. If you have to open and feed silage sooner, there are ways to mitigate the negatives, but this should not be the goal.

Back to the geography comparison, the southern region that experienced better gains in milk during the fall had harvested corn silage in early July and by the time football season was in full swing, that feed had been in the pit for 60 to 90 days. In the High Plains, it was nearly Christmas before some of that corn silage had the same time in the pit.

Take a clear picture

Another significant change in the way we consider milk production that has a meaningful impact on how we feel about production results is the shift to thinking about solids corrected milk. This may be energy corrected (ECM), fat corrected (FCM), or simply the pounds of solids produced and the income from each. As the temperatures drop and the days get shorter, cows tend to reduce milk flow but improve the fat and protein on a percentage basis. So yes, milk flow might go down, but solids produced and the income from the milk might overcome that loss in pounds shipped.

As cows eat more in cooler weather, if we don’t use solids corrected milk for milk-to-feed conversion calculations, efficiency looks bad in the fall. Using ECM or FCM in a ratio to intake will offer a much better picture of how the herd is doing. In the old days, we knew this was happening but somehow didn’t let it make us feel better about overall production. Perhaps that is because the understanding of how milk price and milk income is calculated is much better now than it was.

Having said all of that, the fall season is still a tricky one for a dairy. I always wonder if that is because our dairy cows’ cousins that may have antlers instead of horns and live in the mountains don’t do much lactating in the fall. By then, the previous calf crops have been mostly kicked off and the focus has turned to rebreeding and consuming extra feed to survive the coming winter. I notice the days getting shorter in the fall, but I think the cows notice it even more keenly.

Work hard in the next few weeks to put up a good corn silage crop if that fits your geography. And no matter where you milk cows, when you open the new pit, work with your nutritionist to get samples to the lab to be sure there is a good understanding of how this year’s starch will feed. Every year, there is a little learning curve to be expected. Send samples, watch the cows, and enjoy a few football games along the way. I hope your teams always win — unless they are playing my teams.

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(c) Hoard's Dairyman Intel 2023
September 11, 2023

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