Social Posts (1200 x 800 px)-1

Reproductive Inefficiency

Extended days open are a clear sign of reproductive inefficiency and can significantly impact the economic performance of a dairy operation. Delayed conception increases non-productive days, raises feeding and management costs, and disrupts optimal calving intervals. Supporting cow health, particularly immune function during critical reproductive periods, plays a key role in improving conception success and reducing days open.

On this page:

Definitions
Symptoms
Cause and effect
Solutions
Treatments

DEFINITIONS & MEANING

What is reproductive inefficiency?

Reproductive inefficiency in dairy cows refers to delays or difficulties in achieving pregnancy after calving. It is commonly expressed through extended days open, indicating that cows are not conceiving within the desired timeframe. Factors such as health challenges, immune stress, metabolic disorders and disruptions around the oestrous cycle can reduce conception success. When reproductive inefficiency persists, it leads to longer calving intervals, increased costs, and reduced overall productivity of the herd.

How to recognise reproductive inefficiencies

Symptoms

Reproductive inefficiencies can be recognised through delays in cows becoming pregnant after calving. When conception does not occur within the expected timeframe, it signals that reproductive performance may be off track.

One of the most common indicators is an increase in days open, which reflects reduced conception success during the oestrous cycle. Herds may also experience repeated inseminations, irregular or weak heat expression, or a growing number of cows remaining open beyond target breeding windows.

These patterns are often linked to underlying health challenges or immune stress. When cows are fighting disease or physiological strain, normal reproductive function can be disrupted, ultimately reducing overall herd reproductive performance.

Veterinary surgeon about limiting the disease's extent of Mastitis

"Good fertility starts in the dry period by limiting inflammation and supporting immunity, as cows face major stress at calving."

 

Arnout Dekker, Ruminants Business Manager, Phibro

CAUSE AND EFFECT

What causes reproductive inefficiencies?

Reproductive inefficiencies often originate from health challenges that place stress on the cow’s immune system. When cows are required to divert energy and resources toward fighting pathogens or disease, fewer resources remain available for normal reproductive processes. As a result, conception during the oestrous cycle becomes less likely, increasing the number of days open.

Immune stress during critical reproductive periods plays a particularly important role. Health events occurring around oestrous can interfere with hormonal balance, heat expression, and successful conception. Even when signs of illness are not severe, subclinical challenges can still reduce reproductive performance by disrupting the physiological conditions needed for conception.

In addition, repeated or prolonged immune activation can have cumulative effects on reproductive outcomes. Cows experiencing ongoing health pressure may require multiple inseminations or fail to conceive within target breeding windows. Over time, this leads to extended days open and reduced reproductive efficiency at the herd level.

By addressing the underlying immune challenges that affect cows during the oestrous cycle, dairy operations can reduce the risk of delayed conception. Supporting immune function helps minimise health events during these critical periods, improving the likelihood of successful pregnancies and contributing to better overall reproductive performance.

Jonathan pic 3

“Fresh cow diseases may interfere with reproductive performance for up to 4+ MONTHS. That is why prevention is so important.”

 

Jonathan Junginger, Key Account Manager, Phibro

Solutions

How to prevent reproductive inefficiencies?

The preparation of optimal reproduction starts in the dry cow period. Make sure you have a well calculated, very palatable dry cow diet. Start by testing the macromineral content of all the forages which will be fed to the dry cows. Select forages with low potassium content. Formulate the ration to minimise potassium content of the ration as much as possible and use palatable ingredients.

AniStart helps to reduce (sub)clinical milk fever. An optimised calcium metabolism around calving results in healthier, more productive dairy cows.

By adding AniStart to the dry cow ration, your cows can mobilise more calcium and can start their subsequent lactation with more milk and fewer health events.

Preventing reproductive inefficiencies begins with maintaining cow health during critical reproductive periods. When cows are healthy and not burdened by disease challenges, they are more likely to conceive successfully during the oestrous cycle. Reducing health events around breeding is therefore a key step in minimising extended days open.

Supporting the immune response plays an important role in this process. Cows that experience immune stress while fighting pathogens may have reduced fertility, as energy and physiological resources are diverted away from reproduction. By improving immune response, health challenges during the oestrous cycle can be prevented, increasing the likelihood of timely conception.

Proactive health management before and during breeding helps create more favorable conditions for reproduction. Preventing immune challenges rather than reacting to disease supports normal reproductive function and reduces disruptions that can delay pregnancy. This approach contributes to fewer days open and more consistent reproductive performance across the herd.

By focusing on cow health and immune resilience, dairy operations can improve conception success and prevent reproductive inefficiencies. Supporting cows through nutritionally driven immune support helps maintain reproductive performance and supports optimal herd productivity.

Treatments

Treatments for improving conception

OmniGen AF® nutritional specialty product helps improve conception rates in dairy cows by supporting immune function during critical reproductive periods. When cows are fighting off pathogens and disease, conception becomes less likely¹. OmniGen AF addresses this by improving the uterine environment² and embryo quality³, resulting in 10 fewer days open for cows fed the supplement⁴. The product works by modulating the immune response to prevent health events during the oestrous cycle.

1. Riberio et al., 2016. J. Dairy Sci. 99:2201–2220.
2. Jorgensen-Muga, 2018. J. Anim. Sci. 96(E-Suppl. 3):51.
3. Snider et al., 2019. Anim. Reprod. Sci. 210:1-9.
4. Casarotto et al., 2020. Anim. Feed. Sci. Technol. 267:1-9.
Chiel welkom-1

Get an immunity assessment for your herd

If you’d like to find out more about how we could help you to optimise your herd’s performance, please submit your telephone number to request a callback. We’ll call you within three working days to set a date for a telephone or face-to-face meeting to discuss the following:

1

Current situation analysis

We’ll work with you to understand your herd’s current status and to identify areas for improvement.

2

Designing a plan of action

We’ll recommend where improvements can be made and how our products can unlock your herd’s full potential.

3

Evaluation

We’ll carry out a detailed review to make sure the changes we’ve put in place are working effectively and, where necessary, provide additional support and advice to enable your herd to continue to improve.

Arrange your immunity assessment Get an immunity assessment