Research shows that essential fatty acids have a positive impact on immune function and reproductive performance.
By Dr. Joel Pankowski, Manager, Field Technical Services
Arm & Hammer Animal Nutrition
The physiological changes and stresses surrounding calving can disrupt immune function and leave cows susceptible to a variety of disorders that can lead to management challenges later in lactation—like greater days open and lower pregnancy rates, as well as cows prematurely leaving the herd.
One proven nutritional tool is to feed bypass Omega-3 and Omega-6 essential fatty acids (EFAs). Research repeatedly shows that these EFAs have a positive impact on immune function and reproductive performance when adequately and properly supplied to the cow.
On-Farm Case Study
A recent on-farm case study1 that included more than 2,000 cows on two New York dairies took a look at the impact of feeding EFAs on immune function, reproductive performance and milk production. The premise was if a dairy could increase immune function and cows’ ability to fight disease in early lactation via improved nutrition, the dairy would be able to improve reproduction and production performance and efficiencies.
To verify this, these EFAs were substituted for other supplemental dietary fat sources from 21 days prepartum to 100 days postpartum; all diets were equal in energy content. Cow performance in the treatment group was tracked for nine months and compared against herd baseline data from the same months a year prior.
DHIA test results, in conjunction with Dairy Comp 305® records, were used to collect and monitor data for the following parameters:
• Individual cow blood β-hydroxybutyric acid (BHBA) at seven days postpartum
• Adjusted first milk yield
• First linear somatic cell score (SCS)
• First service conception rate
• Incidence of early embryonic death at up to 35 days post-insemination
It is important to note that individual cow BHBA levels were of primary interest when examining the data due to their impact on immune function. Blood levels of BHBA are useful indicators of the ability of cows to deal with metabolic challenges in the transition period.
The data showed cows fed EFAs pre- and postpartum exhibited significant reductions in early embryonic death (67%), BHBA levels (44%) and first linear somatic cell score (12%).
As expected with healthier cows, reproductive performance, milk production and component yields also increased. Cows fed EFAs had significantly higher conception and pregnancy rates. They produced more than 6 pounds more milk per day (a 4-pound increase of fat corrected milk) and pounds of fat and pounds of protein also rose.
The Bottom Line
Using a partial budget for the dairies, these improvements in immune response, reproductive performance and milk production carried a significant economic advantage. The overall net benefit of feeding Omega-3 and Omega-6 EFAs for these operations was $176 per cow per year, or a 15:1 net benefit ratio.
a Solids Corrected Milk Income: Corrected volume (up or down based on 3.5% fat and 3.2% protein) was calculated using MilkPay.com on October 30, 2012.
b Cost of Pregnancy Loss: 67% less pregnancy loss (EED) at $207 per loss (De Vries, 2006) with a 3.4% baseline EED incidence rate.
c Value of Pregnancy Rate: 2.1 percentage points improvement valued at $6.00 per point (Fricke , 2005) with a 24% baseline Pregnancy Rate. Value of pregnancy rate improvements will differ depending on individual herd baseline value.
d Cost of Pretreatment Bypass Fat: $1,600 per ton (October 30, 2012) fed prepartum (21 days at a feeding rate of 0.25 lb. per head per day) and postpartum (100 days at a feeding rate of 0.75 lb. per head per day).
Cost of Omega-3, Omega-6 EFAs: $1880 per ton (October 30, 2012) fed prepartum (21 days at a feeding rate of 0.25 lb. per head per day) and postpartum (100 days at a feeding rate of 0.75 lb. per head per day).
Similar economic analyses for herds in other areas of the country using local milk price data have also resulted in positive net benefit ratios from including EFAs in pre- and postpartum rations.
Even considering the economic response based on improved reproduction alone, the addition of these EFAs to the diet resulted in a 3:1 net benefit ratio.
The field study demonstrates the positive impact of EFAs on postpartum immune function in lactating dairy cattle and reinforces the premise that healthier cows perform better. The results are consistent with previous research in which animals with increased BHBA around parturition experienced a higher risk of milk loss at the first DHIA test and impaired early lactation reproductive performance.2
1 Pankowski J, Noble J, Brennan P, Jarrett G, Block E. Effects of ruminally inert essential fatty acids on postpartum immune-related functions and productivity in lactating dairy cattle. J Dairy Sci 2013; Abstract accepted.
2 Chapinal N, LeBlanc SJ, Carson ME, Leslie KE, Godden S, Capel M, Santos JEP. Herd-level association of serum metabolites in the transition period with disease, milk production, and early lactation reproductive performance. J Dairy Sci 2012;95:5676–5682.