Scientists studied 60 dairy cows right after they gave birth to see how different types of food affected their milk production. They tested four different diets that varied in starch (a type of carbohydrate) and added fats. The cows that ate higher-starch diets produced more milk and lactose (milk sugar), while cows that got added fats produced richer milk but ate less food overall. Interestingly, what the cows ate in their first three weeks after birth affected their milk production even weeks later. This research helps farmers understand the best way to feed new dairy cows to get the most milk.

The Quick Take

  • What they studied: How different combinations of starch levels and added fats in cow feed affect milk production and cow health during the first few weeks after giving birth
  • Who participated: 60 adult dairy cows (Holstein breed) that had given birth before, divided into four groups receiving different diets for the first 23 days after birth
  • Key finding: Cows fed higher-starch diets produced significantly more milk and milk sugar compared to other groups. Adding fats to the diet made the milk richer but caused cows to eat less food overall
  • What it means for you: If you’re a dairy farmer, feeding new mothers higher-starch diets in their first weeks may boost milk production. However, the best diet depends on your specific goals—more milk volume versus milk quality and cow body condition. Talk to a veterinarian or nutritionist before making changes.

The Research Details

Researchers divided 60 dairy cows into four equal groups using a randomized design, meaning each cow was randomly assigned to a treatment group. This helps ensure fair comparisons. The four groups received different combinations: some got lower starch with no added fats, some got higher starch with no added fats, some got lower starch with added fats, and some got higher starch with added fats. The cows ate these special diets for 23 days right after giving birth (called the ‘fresh period’). After that, all cows ate the same standard diet for three more weeks so researchers could see if the early diet had lasting effects.

The researchers measured how much food each cow ate, how much milk they produced, the composition of the milk (fat, protein, and lactose content), and various blood markers that show how well the cow’s body is handling the stress of producing milk. Blood markers included BHB (a sign of energy stress) and NEFA (a sign of fat breakdown).

This type of study design is considered strong because it randomly assigns animals to groups and carefully controls what they eat, reducing the chance that other factors are causing the differences they observe.

The early weeks after a cow gives birth are critical for her health and milk production. During this time, cows often struggle to eat enough food to support milk production, which stresses their bodies. Understanding the best diet during this vulnerable period could help farmers keep cows healthier and more productive. Additionally, studying how early diet affects later performance helps farmers plan long-term feeding strategies.

This study is a well-designed controlled experiment with a reasonable sample size (60 cows) and careful measurement of multiple outcomes. The random assignment to groups strengthens confidence in the results. However, the study only included one breed of cow (Holstein) and was conducted in a specific setting, so results may not apply to all dairy operations or other cow breeds. The study was published in a respected peer-reviewed journal, which means other experts reviewed it before publication.

What the Results Show

During the first 23 days after birth, cows fed the highest-starch diet produced the most milk and milk sugar (lactose) compared to all other groups. Specifically, the high-starch group produced about 3-4 more pounds of milk daily compared to the low-starch group without added fats. The high-starch diet also improved the amount of milk that could be sold (measured as ’energy-corrected milk’), suggesting the milk was more valuable.

When researchers added fats to the diet, something interesting happened: the milk became richer in fat content, but the cows ate less food overall. Cows receiving added fats also showed signs of greater body stress (higher blood markers indicating fat breakdown) and lower blood sugar and insulin levels, suggesting their bodies were working harder to produce milk.

Cows on the high-starch diet had lower levels of BHB in their blood, which is good because high BHB indicates the cow’s body is under metabolic stress. This suggests the high-starch diet helped cows feel better during this demanding period.

Surprisingly, the diet cows ate in their first three weeks affected their milk production even after they switched to a standard diet. Cows that had eaten the high-starch diet continued to produce slightly more milk and milk sugar in the following weeks, showing that early nutrition has lasting effects.

Cows receiving added fats lost more body weight and body condition score (a measure of how thin or fat the cow is), which could be a concern for long-term cow health. The added fats increased the ratio of milk produced per pound of food eaten, meaning the milk was more concentrated in nutrients, but this came at the cost of the cow’s own body reserves. Cows on added-fat diets also had lower insulin and glucose (blood sugar) levels, indicating their metabolism was shifted toward breaking down body fat for energy rather than using dietary energy.

This research builds on previous studies showing that early-lactation nutrition is critical for dairy cow performance. The finding that high-starch diets improve milk production aligns with some earlier research, but this study provides new information about how starch and added fats interact together. The discovery that early diet has carryover effects into later lactation is particularly valuable and suggests farmers should prioritize fresh-period nutrition more than they might currently.

The study only included one breed of dairy cow (Holstein), so results may not apply to other breeds. All cows were in a research setting with controlled conditions, which may differ from typical farm environments. The study lasted only about six weeks total, so we don’t know if these effects continue longer. The researchers didn’t measure some factors that might be important, like how the different diets affected cow comfort or behavior. Additionally, the study was conducted at one location, so results might vary in different climates or management systems.

The Bottom Line

For dairy farmers: Consider feeding higher-starch diets during the first three weeks after cows give birth if your goal is maximizing milk production (moderate confidence). If you’re concerned about milk quality or cow body condition, the benefits of added fats may be worth the trade-off of slightly lower milk volume (moderate confidence). Consult with a dairy nutritionist to determine what’s best for your specific herd and goals. These recommendations apply specifically to Holstein dairy cows in similar management systems.

Dairy farmers and farm managers should care about this research, especially those managing Holstein dairy cows. Veterinarians and dairy nutritionists can use this information to make better feeding recommendations. This research is less relevant to people who don’t work with dairy cattle, though it may interest those interested in animal agriculture or food production.

Changes in milk production should be noticeable within the first week of feeding a new diet, with full effects visible by the end of the three-week fresh period. The carryover effects (benefits that continue after switching diets) appeared to last at least three more weeks based on this study, though longer-term effects are unknown.

Want to Apply This Research?

  • If you manage dairy cows, track daily milk production (in pounds), milk composition (fat and protein percentages), and cow body condition score (on a 1-5 scale) for each cow during the first 30 days after birth. Compare these metrics between cows on different diets to see which diet works best for your herd.
  • Implement a specific fresh-period feeding protocol: feed a high-starch diet (around 28% starch) for the first 23 days after cows give birth, then transition to your standard lactation diet. Monitor individual cow response and adjust based on milk production and body condition changes.
  • Create a simple spreadsheet tracking each cow’s milk yield, milk composition, and body condition score weekly during the fresh period and for 4-6 weeks after. Compare results between cows on different diets. Also monitor blood work if available (BHB and NEFA levels) to assess metabolic health. Review this data monthly with your veterinarian or nutritionist to optimize feeding strategies.

This research applies specifically to Holstein dairy cows and may not apply to other breeds or species. These findings are based on a controlled research study and should not replace professional veterinary or nutritional advice. Before making significant changes to your dairy herd’s diet, consult with a veterinarian or dairy nutritionist who understands your specific operation. Individual cow responses may vary, and what works best depends on your farm’s goals, resources, and management system. This information is for educational purposes and does not constitute medical or veterinary advice for your animals.