Optimizing Dairy Cow Nutrition to Manage Milk Fat Reduction in the Summer

Milk fat depression during the summer months poses a considerable challenge for dairy farmers, impacting both the quality of milk and overall profitability. As temperatures rise, cows often experience stress that can lead to a decline in milk fat content. Understanding the factors contributing to this phenomenon and implementing effective management strategies is crucial for maintaining the nutritional health and productivity of dairy cows during the warmer months.

Milk Fat Synthesis in the Udder

The mammary gland produces milk fat with raw materials coming from the ration, either through feed converted into acetate or butyrate, or different fat sources added into the ration. These are then circulated through the blood where ultimately, they are taken up by the alveoli in the udder. It’s very important to maximize the required precursors and minimize potential isomers such as trans-10 and cis-12 conjugated linoleic acid (CLA) in the rumen that inhibit fat synthesis in the udder.

Although several factors influence milk fat depression in dairy cows and buffaloes, some can be influenced by management and nutrition.

Feed Intake in the Summer Season

Elevated temperatures negatively affect cows’ feed intake, leading to a reduction in the consumption of essential nutrients through roughages and concentrates. Heat-stressed cows prioritize nutrients for maintenance over milk and component production, impacting the synthesis of milk and milk components.

Best Practices

• Feeding times during the cooler parts of the day and in cooler areas of the farm to encourage higher feed intake. This not only supports milk production but also aligns with the natural feeding behavior of cows, which tend to eat more during cooler periods.
• Provide more water to increase feed intake.
• Increase nutrient density in the concentrate

Forage Quality Challenges in the Summer Season

Fodder available in summer often faces quality challenges, including changes in dry matter levels, nutrient composition, and reduced fiber digestibility. The decline in forage quality can affect the rumen environment, disrupting the microbial fermentation processes crucial for milk fat synthesis.

 Best Practices

• Monitor moisture level in forage sources; as the level of moisture.
• Provide fresh, palatable forages rich in nutrients that support the cow’s overall health and contribute to stable milk fat production.
• Clean out unfed forages left behind before the next feeding.
• Work with the feed mill to select the right concentrate feed to balance the nutrients available from green and dry fodder.

Concentrate vs Roughage Ratio in the Summer Season

During the summer when the cows have depressed feed intake, the cows can have an imbalance in the amount of concentrate versus fodder. In general, Indian cows or buffaloes are consuming all the concentrate feed as it is fed separately; however, they will not be able to eat all the forages offered. A more concentrated portion compared to roughage can lead to rumen acidosis resulting in lower milk production and fat.

Best Practices

• Practice Total Mixed Ration or Partially Mixed Ration
• Provide a smaller portion of concentrate per feeding if fed separately.
• Provide concentrate just or after roughage feeding to reduce the negative effects of a higher portion of concentrate.

Rumen Microbial Activity in the Summer Season

Heat-stressed cows may exhibit a shift in microbial populations, which leads to increased production of intermediates that inhibit milk fat synthesis in the udder. This can also negatively affect ruminal health.

Best Practices

• Provide adequate amounts of fodder as part of a balanced ration.
• Monitor the intakes of individual animals with a goal of each cow eating a consistent amount every day.
• Feed suitable additives to maintain microbial activities.

Role of HMTBa to Improve Milk Production & Milk Components

A great portion (60%) of HMTBa (hydroxy analogue of methionine at MFP® Feed Additive) works to make the rumen function more effective and the remaining (40%) gets converted to et al 2002). HMTBa increases the diversity and mass of the ruminal microbial community (Pitta et al., 2020), produces more microbial crude protein (Lee et al., 2015), and reduces the level of intermediate metabolites (such as Trans 10 Cis 12 CLA) in the udder helps cows to produce more milk fat (Baldin et al., 2018, 2019, 2022).

Effectively managing milk fat depression in cows during summer stress requires a multifaceted approach that addresses the interconnected factors influencing nutritional health. By focusing on nutritional adjustments, feeding times, and implementing proactive monitoring strategies, dairy farmers can navigate the challenges of summer, and ensure the well-being and productivity of their farms. A holistic approach in association with experts from feed mills, dairy farm consultants, and industry experts is key to sustaining milk quality and profitability in the face of heat stress.

1. Baldin, M., G.I. Zanton and K.J. Harvatine. 2018. J. Dairy Sci. 101:376-385.
2. Baldin, M., H.A. Tucker, and K.J. Harvatine. 2019 J. Dairy Sci. 102:6157-6166
3. Baldin, M., D. Garica, G. I. Zanton, F. Hao, A. D. Patterson, and K. J. Harvatine. 2022. J. Dairy Sci. 105:7446-7461.
4. Koenig, K.M, M. Rode, C. D. Knight, and M. Va´zquez-An˜o´n 2002 J. Dairy Sci. 85:930–938
5. Lee C, J. Oh, A. N. Hristov, K. Harvatine, M. Vazquez-Anon and G. I. Zanton. 2015 J. Dairy Sci. 98 :1234–1247
6. Pitta, D.W., N. Indugu, B. Vecchiarelli, M. Hennessy, M. Baldin and K.J. Harvatine. 2020. J. Dairy Sci. 103:2718-2730.

Gnanasekar Rangasamy, M.V.Sc  

Dr. GS is the species solutions manager for dairy supporting the Asia team and customers. In this role, he is responsible for planning and executing the go-to-market strategy for the dairy business in the Asia region, with a strong focus on India. He also works with customers to improve milk and component production and support their financial goals.

Hannah Tucker, Ph.D., PAS 

Dr. Tucker was raised in the dairy industry and now works with the NOVUS Sales Team in North America to determine the best way to support customer goals and address production challenges. She also collaborates with the NOVUS R&D Team to design university and field trials and translate the results to further the understanding of the intelligent nutrition company’s solutions.  Read more about Dr. Tucker...