Investigating the underlying factors of dairy reproductive performance is a lot like peeling an onion – the more you look, the more layers you find.
Of course, nutrition is one such layer that has considerable effects on reproduction. And nutrition can be a complicated, multi-faceted area with far-reaching implications that touch every part of animal performance.
To focus, let’s peel back the layer of essential fatty acids (EFAs) and hone in on how they, when offered as rumen-inert fat, can help promote more vigorous immune systems, improved uterine health and greater reproductive success.
EFA essentials
First, it must be understood that EFAs cannot be produced using other available nutrients or chemical pathways by the animal. They must be provided by the diet.
However, cows may not consume enough EFAs through commodity feed sources typically included in rations to make a significant impact. While several feedstuffs – like cottonseeds and whole soybeans – contain various levels of EFAs, the EFAs are often altered in the rumen through biohydrogenation. This process makes them unavailable and useless to meet daily nutrition requirements.
That’s why it’s important for diets to include research-proven feed ingredients containing both omega-3 and omega-6 EFAs that are protected so they are not biohydrogenated and remain available for absorption from the intestine.
All of this is important because EFAs have three vital roles that significantly impact reproduction and immune function. EFAs:
- Aid in the production of specific reproductive hormones like progesterone, which enhance the physical signs of estrus as well as ovarian follicle growth
- Aid in the production of prostaglandins, which help establish estrus cycles and enhance the visible signs of heat
- Promote the maintenance and function of cellular membranes
Immune function and reproduction
It only makes sense that cows with strong immune function are healthier and more productive in every way. These are the animals that successfully navigate the transition period and breed back in a timely fashion. They have fewer metabolic disorders or other health challenges – and as a direct result of their improved health status, fewer breeding issues.
The opposite is true, too. Cows with lowered immune function usually have increased health challenges and often struggle with reproductive performance. For instance:
- Cows with milk fever are more than five times more likely to contract clinical mastitis compared to cows without milk fever.
- A University of Florida study found cows that had clinical mastitis during the first 45 days postpartum were at 2.7 times greater risk of abortion within the next 90 days compared to those without mastitis.
Physiologically, this is understandable. It appears from studies performed in many species that local immune and inflammatory processes have a major impact on fertility in the female, explains David Hurley, University of Georgia large-animal medicine molecular biologist.
For example, he notes that “prior to fertilization, inflammatory and immune activities in the reproductive tract alter the interaction between egg and sperm. Changes in the viscosity and physical/chemical composition of uterine mucus can alter sperm penetration and survival.
“Increased inflammatory cell activation can create a hostile environment for sperm, reducing the duration of their viability and damaging their membranes so that they are less capable of fertilization,” he adds.
“Furthermore, strong inflammatory responses in the uterus may block implantation. High levels of prostaglandin E2 tend to predict poor conception rate in dairy cows.”
Nutrition’s influence
Researchers have investigated the effects of EFAs on health and performance for nearly 100 years. Although there is much left to learn about how mechanisms work and how to take greater advantage of EFAs, we are able to see positive results of their use on-farm.
Lately, much research has focused on including both omega-3 and omega-6 EFAs in the transition diet to improve reproductive parameters linked to improved immune function, like:
- Reduced embryonic death
- Improved reproductive performance
- Increased pregnancy rates
- Lowered blood beta-hydroxybutyrate (BHBA) level, which is linked to improved metabolic performance during the transition period
In recent years, a number of on-farm nutrition trials from across the U.S. show how the targeted addition of omega-3 and omega-6 EFAs to the ration positively influence cow health and productivity.
Each farm in the trial series followed a different management philosophy, grouping strategy, base ration and set of standard operating procedures. They were located in several areas of the country, meaning geography and climate were very different.
The dairies fed the EFAs at the same rate (0.25 pound per head per day) for the same amount of time prepartum (21 days), but the time and amount fed postpartum varied across farms.
- one herd measured blood BHBA levels. But the dairy noted that the inclusion of EFAs lowered this measure by 44 percent.
- On a herd level, BHBA is a useful indicator of the ability of cows to deal with metabolic challenges in the transition period. For individual cows, increased serum concentrations of BHBA around calving have been associated with lower milk production and impaired early reproduction.
- Each dairy showed lowered early embryonic deaths, often cutting this incidence in half or more.
- Each dairy also showed significant gains in pregnancy rates. Results ranged from 7 percent increases to 9 percent increases in this parameter.
- Lastly, directly correlated to increased pregnancy rates, herd conception rates for the farms in the trial series also rose by 7 percent to as much as 15 percent.
The results indicate that the inclusion of omega-3 and omega-6 EFAs – especially in transition diets – can be a strong partner in enhancing reproductive programs. The use of EFAs has resulted in healthier cows with increased productivity. PD
PHOTO: It’s important for diets to include research-proven feed ingredients containing both omega-3 and omega-6 EFAs that are protected so they are not biohydrogenated and remain available for absorption from the intestine. Photo by Emily Caldwell.
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Joel Pankowski
- Manager - Technical Services Eastern Region
- Arm & Hammer Animal Nutrition
- Email Joel Pankowski
