Arm & Hammer Animal and Food Production

Use Improved Nutrition to Enhance Immune Function and Fertility

Dairy cow fertility has improved significantly over the past 10 – 15 years. Recent USDA data show that on most farms, 21-day pregnancy rates are on the rise, with many herds achieving 20% or better on a regular basis. That’s great news because it wasn’t long ago when it was common for pregnancy rates to languish around 12 – 14%.

Not only does this improved reproductive performance mean improved productivity for the herd, it has significant implications for the financial performance for your dairy. Data1,2 show:
• Increasing pregnancy rate from 15% to 25% results in an increase of $40 to $60 per cow, depending on feed cost, milk price and other economic factors.

Many factors are responsible for better reproductive performance on U.S. dairies, including improved reproductive management with implementation of estrous and ovulation synchronization protocols along with improved transition period management and a greater focus on health and fertility traits during sire selection for artificial insemination. 

These considerations, while important and noteworthy, provide optimal results when underpinned with a strong nutritional foundation. The value of enhanced nutrition programs that use targeted strategies to foster immune system function so that cows are healthier in all facets of life cannot be underscored enough.   

Health Implications
As researchers, nutritionists, veterinarians and producers learn more about immune function, it’s become apparent that this is an area where improved nutrition management can achieve excellent results. 

When proper nutritional support enhances a properly functioning immune system, transition cows are less likely to develop clinical or subclinical diseases, particularly those caused by infectious agents. This also helps prevent the cascade of interrelated health events that can derail cow performance on every level.

For instance, researchers at the University of Florida have noted the cumulative effects of subclinical hypocalcemia (SCH) on secondary transition health disorders and management challenges. They found3 that cows with SCH were more likely to have:
• A 3.2X  increased risk of metritis
• A 2.4X  increased risk of postpartum fever 
• Increased postfresh concentrations of blood beta-hydroxybutyrate (BHBA) (1.0 vs. 0.7 mmol/L). Blood BHBA is the ketone body most commonly used to diagnose ketosis and subclinical ketosis. 
• Longer median days open (124 vs. 109 days)

Additional research4 has found that elevated concentrations of non-esterified fatty acid (NEFA) and BHBA around the time of calving are predictive for subsequent clinical mastitis and the development of displaced abomasum, clinical ketosis, metritis and retained placenta.

Finally, data5 from the University of Georgia show that days open increased by 33 days for cows diagnosed with metritis. Plus, pregnancy rates for these cows dropped by 4.5 percentage points as compared to pregnancy rates for healthy cows.

Role of EFAs
Several nutritional strategies have been proposed to improve reproduction of dairy cattle with no detrimental effect on milk production performance, explains Dr. José Santos, University of Florida professor of animal science. 

“Maximizing dry matter intake during the transition period, minimizing the incidence of transition period problems, adding supplemental fat to diets and manipulating the fatty acid content of fat sources are expected to benefit reproduction in dairy cattle,” he adds.

An excellent way to boost cow health and immunity during the transition period is with scientifically proven feed ingredients that include Essential Fatty Acids (EFAs).

EFAs are essential for cow health and productivity; they cannot be synthesized by the animal and must be provided by the diet. When included in rations in explicit combination EFAs can result in increased gains in transition performance and overall productivity, allowing cows to perform at increased levels. 

For instance, EFAs, specifically Omega-3 (18:3 linolenic acid) and Omega-6 (18:2 linoleic acid) fatty acids, serve important functions related to dairy cows’ reproductive health and performance. 

These Omega fatty acids:
• Support the production of specific reproductive hormones, especially prostaglandins, which influences pregnancy maintenance. 
• Linoleic acid aid in prostaglandin F2a production, which has roles on ovulation corpus luteum regression leading to a subsequent estrous cycle. 

“In our studies, we’ve found that manipulating Omega-3 and Omega-6 in the diet influenced lactation performance and fertility,” notes Dr. Santos. “The inclusion of Omega-3 and Omega-6 resulted in greater yields of milk and milk components and improved pregnancy per artificial insemination. The benefits to fertility were observed primarily because of reduced pregnancy loss in the first 60 days of gestation.”

However, achieving these benefits can be challenging as cows may not consume enough EFAs through commodity feed sources typically included in the ration. While several feeds, like cottonseeds and whole soybeans, are rich in linoleic acid, they are often altered in the rumen through biohydrogenation, making them unavailable in their original form and useless to meet daily nutrition requirements for those essential fatty acids.

EFAs in Action
In a series on-farm trials conducted across the country under different management conditions, these specific EFAs used in combination:
1. Lowered BHBA levels, resulting in lower incidence of metabolic disorders. On a herd level, BHBA is a useful indicator of the ability of cows to deal with metabolic challenges in the transition period. At the individual cow level, increased serum concentrations of BHBA around calving have been associated with lower milk production and impaired early reproduction.
2. Lowered 1st Linear Somatic Cell Score for each herd.
3. Reduced embryonic death.6
4. Increased pregnancy and conception rates. Pregnancy rate improvement ranged from 7% to 9% increases and herd conception rates rose from 7% to as much as 15%.
5. Improved first milk weights for dairies that tracked this parameter.

These results show a direct correlation to a stronger immune system, which helps reduce incidence of disease and metabolic challenges. These healthier cows are better able to perform in virtually every measurable management metric.

Therefore, for optimum results, think of reproductive management in a more holistic fashion. Success usually requires more strategy than simply tweaking a synchronization protocol. True reproductive achievement is built on a firm nutritional foundation that’s based on scientifically proven ingredients and principles, then interwoven with the tools and strategies needed to get the job done. 

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1 Galvao KN, Federico P, DeVries A, Schuenemann GM. Economic comparison of reproductive programs for dairy herds using estrus detection, timed artificial insemination, or a combination. J Dairy Sci. 2013. 96:2681–2693.
2 Ribeiro ES, Galvao KN, Thatcher WW, Santos JEP. Economic aspects of applying reproductive technologies to dairy herds. J Animal Reprod. 2012. 9:370-387.
3 Martinez N, Risco CA, Lima FS, Bisinotto RS, Greco LF, Robeiro ES, Maunsell F, Galvao K, Santos JEP. Evaluation of peripartal calcium status, energetic profile, and neutrophil function in dairy cows at low or high risk of developing uterine disease. J Dairy Sci 2012;95:7158-7172. 
4 Waldron MR. Enhancing Immunity and Disease Resistance of Dairy Cows through Nutrition. In Proceedings. 2013 University of Florida Ruminant Nutrition Symposium. Available at: Accessed December 22, 2015.
5 Overton M, Fetrow J. Economics of Postpartum Uterine Health. Available at: Accessed December 22, 2015.
6 Early embryonic death defined as animals returning to service at 35 days postinsemination following a diagnosis of pregnancy.

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