Reproductive performance on dairies is one of many key areas that can have a huge impact on profitability. It is no surprise dairy farmers continue to look for ways to improve reproduction programs.

Many factors go into a good reproduction program. Some are seemingly simple, such as finding cows in heat and breeding them. Others may be subtle – what is your subclinical milk fever rate and is it impacting the breeding program?

Nutrition can play a role in the reproduction program, and the diet’s impact on breeding is often discussed. In these discussions, feed additives may sometimes be evaluated to determine if they have a fit within the nutrition and reproductive programs. Consider the following questions before deciding to use a feed additive.

1) What is your current pregnancy rate and what is your goal?

Pregnancy rate is one of the most-used metrics to determine the status of the breeding program. In simple terms, it is defined as the heat detection rate (HDR) multiplied by the conception rate (CR). Knowing your current reproduction metrics will make it easier to evaluate the impact of changes you make.

2) What is your HDR?

Herds that achieve high pregnancy rates typically experience HDRs above 60 percent with some reaching 70 percent. If you think HDR is an issue on your dairy, work with your veterinarian to evaluate whether you have an abnormal level of anovular or cystic cows in your herd. If you appear to have an issue, investigate the potential causes.


If the cows in your herd appear to have normal ovarian activity, investigate whether the method of heat detection (i.e., visual observation, tail paint, heat detection monitors, timed A.I., etc.), level of lameness or environment (i.e., slick floors, heat stress, etc.) could be impacting your HDR.

Feed additives likely will not have a direct impact on cows exhibiting signs of heat, but they can potentially impact ovarian activity depending on the cause of lower ovarian activity.

3) What is your CR?

To achieve a high pregnancy rate, CR will likely need to be above 40 percent. Many variables can impact CR, including timing of breeding, presence of uterine disease, heat stress, nutrition, timed-A.I. injection compliance, early embryonic death loss, etc. Work with your veterinarian and other consultants to search for any bottlenecks limiting CR on your farm. Depending on the cause, feed additives can sometimes help improve CR or embryo survival.

4) What is your level of transition cow metabolic disease?

The transition period of three weeks prior to freshening to three weeks post-fresh can have a huge impact on uterine health and ovarian activity. Milk fever, retained placenta, metritis, mastitis, ketosis, fatty liver and displaced abomasum have all been shown to have a negative effect on reproduction. Many of these diseases may also be present in a subclinical form, which can be harder to detect.

A certain level of these diseases is always present on any farm, so establish realistic goals and then investigate management, environment and nutritional factors that may prevent you from reaching your goals. Most feed additives that will have an impact on reproduction are fed during the transition period with the purpose of minimizing metabolic diseases, improving energy balance and improving ovarian activity.

Developing a plan to improve your reproduction program can sometimes seem overwhelming. Start by identifying your current reproduction parameters and transition disease incidence. Next, utilize your team, including your veterinarian and other consultants, to help discover your most limiting bottlenecks.

While evaluating your reproduction program, keep in mind that management and environment are often the biggest limiting factors. Improving management and environment often results in improvements in other areas of the operation in addition to reproduction. Feed additives can help improve reproduction, but choose additives that are likely to address the specific areas you think are limiting reproductive success. Finally, monitor any changes that are implemented to make sure they are worth the investment.  end mark

PHOTO: Photo by Peggy Coffeen. 

Andy Kniesly
  • Dr. Andy Kniesly

  • Veterinarian
  • Vita Plus