Right now, it might feel like colostrum is in no short supply. Cows are calving, freezers are full and you might think you’re sitting pretty when it comes to inventory for the remainder of the year. But as the days get shorter and temperatures begin to cool, many operations will start to experience a perplexing challenge when it comes to feeding calves – lower colostrum yields.

“Many farms experience a common issue that leaves farmers and calf managers scratching their heads: declines in colostrum production during the fall and winter months,” says Katelyn Goldsmith, dairy outreach specialist at the University of Wisconsin-Madison. “This problem can make it difficult to quickly feed calves high-quality colostrum in adequate quantities.”

While this seasonal slump is common, it doesn’t have to catch you off guard. With the right planning and management, you can stay ahead of the dip and maintain control over your colostrum supply.

Why Does it Happen?

While there’s no sure answer as to why colostrum production takes a dip during the fall and winter, research points to two key factors: shorter daylight hours and lower temperature-humidity index (THI).

As days shorten after June, cows receive less light, and cooler, drier conditions set in. Both have been linked to lower colostrum yield. Goldsmith notes that in one Texas study, average colostrum production fell from 14.5 lb. in June to just 5.5 lb. in December. Older cows were especially affected.

Similar seasonal declines have been observed in studies across New York, Michigan and Europe. While genetics, nutrition and lactation history play a significant role, the consistent pattern suggests that reduced light and lower THI are major drivers of the slump.

How to Prepare

To minimize the impact of seasonal dips, Goldsmith recommends focusing on what you can control. She provides the following strategies to help you get ahead of the slump:

• Pay Attention to Dry Period Length: Ensuring cows have an adequate dry period length is crucial. Cows with short dry periods tend to produce lower yields of colostrum. Goldsmith notes a 45- to- 60-day dry period is considered ideal.
  
• Minimize Environmental Stress: Dry cows should have consistent and adequate access to feed and water, especially during the summer months. Limited or restricted feed and water access can reduce dry matter intakes, negatively affecting colostrum production.
  

• Encourage Colostrum Let Down: During milking, maintain a calm and low-stress environment. Ensure cows are properly prepped prior to attaching milking units and that they are completely milked out before unit removal.

  “Colostrum quality decreases when harvest is delayed,” she adds. “For best quality, harvesting colostrum less than 8 hours post-calving is recommended.”
  

• Consider Oxytocin for First-lactation Cows: Administering oxytocin has been shown to promote colostrum let down and increase yield in first-lactation cows. Recent research found first-lactation cows produced 3.5 lb. more colostrum when administered an appropriate dose of oxytocin compared to untreated cows. If considering this route, farmers should discuss with their veterinarian whether or not using oxytocin fits with their operation.
  
• Assess Feed Additives: Recent studies have found feed additives such as choline or calcidiol in dry cow diets have improved colostrum yields. When evaluating feed additives, ensure they are research-backed products that have been assessed for their impact on colostrum production.

Managing Supply When Yields Are Low

Even with the best preparation, there may be times when colostrum is in short supply. That’s where smart inventory management comes in.

“A well-stocked colostrum bank can be a lifesaver during periods of low production,” Goldsmith says. “Use a tool such as a Brix refractometer to assess colostrum quality and store it accordingly.”

And when stored colostrum isn’t available, be ready with a replacer. Goldsmith recommends selecting a replacer — not supplement — that will provide newborn calves with 300 grams of immunoglobulin G (IgG).

“Since providing extra daylight is not possible for many farms, the potential adverse effects of the colostrum shortage must be addressed through well-planned banking of high-quality colostrum and the use of colostrum replacement strategies when necessary,” Goldsmith says.

And as always, be sure to follow proper storage practices.

“Colostrum should be refrigerated for no more than one day or frozen for up to a year to maintain quality,” she says. “Properly label colostrum and store it in a clean environment to prevent contamination.”

Stay Ahead of the Slump

Seasonal drops in colostrum can be frustrating but it helps to know why they happen and how to prepare. Shorter days and cooler temps can lower yields in fall and winter, but good management can make a difference. Focus on a proper dry period, build a strong colostrum bank and keep quality replacers ready to protect calves when inventories get low. With planning, you can keep freezers stocked with high-quality colostrum to ensure calves stay well nourished.

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