The cow days of summer

dairy cattle

We are in the midst of the period of the year often referred to as the “dog days of summer.” This period is characterized by high heat and humidity, along with the associated thunderstorms. Although this time frame has historically been associated with Hellenistic astrology related to the heliacal rising of the star system Sirius, we just associate it with the hottest and most sultry days of summer, typically experienced in July. 

Historically, it has become proverbial among farmers that a dry growing season through the dog days is preferable to the trouble of a wet one.

“Dog days bright and clear

Indicate a good year;

But when accompanied by rain,

We hope for better times in vain.”

This quote is attributed to being written in 1883 by Henry Dunwoody who worked for the Army Weather Bureau. 

When “dog days” arrive, it a good time to reflect on management aspects on the dairy farm to deal with some possible immediate needs and some short-term needs during the next several weeks and months. Three aspects will be the focus here: 

Keeping cows comfortable

We are always encouraged to prepare for the comfort of our cows before summer starts, but now is a good time to review how the cows are handling the heat and humidity. 

As “dog days” arrived, did milk production take a hit? Has there been an uptick in mastitis cases? Have you been experiencing more problems with the health and production of fresh cows? Have conceptions rates dropped? Observe the cows for comfort and feed intake. You still have time to make some changes in heat stress mitigation with ventilation and cooling in the housing and holding pens and providing a more comfortable lying surface to pay huge dividends. 

Assess forage needs

By now, the small grain forage has been harvested and hopefully, you have harvested at least 2 cuttings of your perennial forages. How were the yields in contributing to your yearly forage needs? If it appears that you may be short in forage supply, you should consider planting some summer annuals (see article at:

You also may need to plan on planting some small grains or establish new alfalfa stands in August. Also, look around the neighborhood for some opportunities to purchase standing corn for harvesting as additional silage. If you need straw for bedding and including in rations, Now is the time to purchase it. Straw has already been harvested in many areas of the state, but some of the northern areas are yet to harvest. 

Prepare for corn silage harvest. In some areas of the state, corn will begin being harvested for silage within the next month. Make sure you have all of the supplies you need, including inoculants and other additives and plastics, and that all equipment is well maintained. Check the storage structures for any repair needed. 

Now is the time to plan on how you are going to transition from the 2020 crop in storage to the 2021 crop. If possible, it is best to permit the silage to ferment for two to four weeks before beginning to feed it. This approach will reduce the risk of a drop in milk production during the forage transition. 

So as you reflect on the misery of “dog days,” as dairy farmers this translates to “cow days” in that we need to be assessing the heat stress on our cows and the forage supply for the next 12 months. These are really critical days that we need to be focusing on the lactating and dry cows. The heat stress can have major impacts on the milk yield in the current and next lactation relative to heat stress in dry cows. The heat stress and nutritional status of cows at present can have long term impacts on reproductive efficiency of the herd and the farm’s profitability. 

So as you sip on the glass of iced tea or lemonade, you are encouraged to reflect on how you can best manage through these “cow days of summer.”


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