Why are in-calf rates are so low?

Subclinical ketosis is one of the most widespread diseases preventing cows getting in calf. There is no doubt it’s impacting farms across the country, with 75% of cows falling victim in spring1.

The problem is our farmers cannot see this disease, it just ticks away in the background robbing herds of energy, compromising their performance and health.

A farmer’s vet or feed supplier is the only person who has the knowledge and experience to both inform them and help offer solutions. Without this vet/supplier-farmer conversation, subclinical ketosis will continue to affect in-calf rates in the majority of herds.

Recent NZ studies of subclinical ketosis revealed a decreased 6-week in-calf rate of


Simply put, research shows

3 out of 4 cows

will have significantly reduced reproductive performance without farmers being aware.

With in-calf rates well below the national target, this presents a significant opportunity.

In addition to good feed management and achieving optimum body condition scores, introducing specialist products such as Rumenox® will help support higher in-calf rates by significantly reducing subclinical ketosis.

It is recommended to introduce Rumenox® pre-calving, or if not practical, adding to water or feed at calving through to the end of mating.

Rumenox® is also widely used throughout lactation for controlling pasture bloat.

1. Dairy NZ, Is elevated blood BHB a suitable indicator of poor performance in grazing cows? Accessed 3 May 2022, available at https://www.dairynz.co.nz/about-us/research/pillars-of-a-new-dairy-system/elevated-blood-bhb-as-an-indicator-of-poor-performance/
2. Compton et al. Subclinical ketosis in post-partum dairy cows fed a predominantly pasture-based diet: defining cut-points for diagnosis using concentrations of beta-hydroxybutyrate in blood and determining prevalence, accessed 3 May 2022, available at https://www.tandfonline.com/doi/abs/10.1080/00480169.2014.999841?journalCode=tnzv20

Ketosis — a condition of energy deficit

It’s normal for a cow to lose weight post-calving because of the mismatch between what she can physically eat and the feed supplied to meet her requirements. Ketosis takes this to the extreme.

When a cow begins breaking down fat faster than she can cope with, it can lead to a severe negative energy balance. This can compromise health and condition including fertility rates.

Subclinical vs clinical ketosis

Sub-clinical ketosis is simply ketosis without the clinical symptoms of poor condition, lethargy or bad breath.

Reduced fertility and milk production still occur.

Rumenox® can help

Rumenox® helps a cow’s rumen function better, adjusting fermentation to a level more beneficial to the overall health of the cow. With rumen function in balance, cows are less likely to be affected by ketosis.

In fact, Rumenox® reduces the risk by 40%, the flow-on effect supports higher in-calf rates.

Rumenox additive products