The transition period is arguably the most critical phase in a dairy cow's production cycle, presenting substantial challenges that can impact health, fertility, and overall profitability. This phase spans from three weeks before calving to three weeks after and is marked by dramatic physiological and metabolic changes as cows prepare for calving and the onset of lactation. Careful management during this period is essential to mitigate the risks of metabolic disorders, suboptimal milk production, and poor reproductive performance.
A balancing act
During late pregnancy, nutrient requirements skyrocket as dry matter intakes (DMI) decline, creating a period of negative energy balance (NEB). This energy deficit forces the cow to mobilise body reserves, leading to weight loss and increasing the risk of metabolic disorders such as ketosis.
Kevin Doyle, technical manager at Phileo UK and Ireland, explains: “A period of negative energy balance in the first few weeks of lactation is completely normal. However, closing this energy gap quickly is essential to avoid metabolic disorders and maintain fertility. Aim for cows to not lose more than 0.5 body condition score.”
Simultaneously, the immune system is under strain with the hormonal and physiological changes that occur at and around calving, eliciting a non-specific systemic inflammatory response. While some degree of inflammation is natural and supports processes like uterine involution, prolonged immune activation diverts precious energy away from milk production and fertility. This exacerbates the negative energy balance faced by the cow and underscores the importance of minimising the energy gap and supporting immune health during this time.
The consequences of transition-related stress can be severe if left unaddressed. Cows that struggle during this period are more likely to experience illness, reduced milk yield, delayed return to oestrus and fertility issues. This can ultimately lead to early culling, increase costs and erode profitability.
Setting up for success through nutrition
The challenges of closing the energy gap, achieving peak milk yield and getting back in-calf on time remain critical after calving. Nutritional and management strategies play a pivotal role in determining the cow’s performance during the current lactation and her future productivity.
One of the most vital aspects of managing this phase is optimising rumen function. A healthy rumen microbiome ensures efficient feed digestion and maximises nutrient extraction, which is critical when intake is limited.
Success during the transition period hinges on careful diet formulation and feeding management. Kevin Doyle advises: “Maximising DMI with energy-dense, balanced diets is key. A glucogenic-based diet – supplemented with the correct balance of protein, trace elements, antioxidants and minerals – supports milk yield, minimises body condition loss and promotes immune function.”
Managing inflammation and immune response
Inflammation, a key feature of the immune response, can become a significant drain on energy reserves if prolonged. Studies estimate that a prolonged immune response can require up to 2kg of glucose per day—energy that would otherwise support milk production and fertility.
An immune response is a natural part of early lactation to deal with pathogens in the uterus and udder and help involution of the uterus. Inflammation is normal during an immune response, but is normally a short, sharp response to resolve infections quickly.
One of the major risks during transition come from clinical and sub-clinical ketosis due to excessive or prolonged energy deficit, which can have long-lasting effects into lactation. Clinical ketosis occurs in only around 2% of cows in the UK, however sub-clinical ketosis is present in around 30%.
This condition is largely invisible, but it has profound impacts on performance, including:
- Doubled chance of being culled within 60 days of calving
- Eightfold higher likelihood of displaced abomasum (DA)
- Fivefold increase in retained placenta
- 40% reduced chance of successful conception in the first 150 days in milk
- 22 days longer to first oestrus
- Up to 1,000 fewer litres of milk yield
The role of Actisaf® live yeast in transition success
Research shows that Actisaf® live yeast is an effective tool in managing transition challenges. It supports rumen health by stabilising the microbiome and enhancing fibre digestion, enabling cows to extract more energy from their feed. This helps minimise NEB and subsequent risk of inflammation, while also reducing the risk of acidosis.
Feeding 10g/day of Actisaf® during the transition period can deliver additional significant benefits throughout the lactation cycle, including:
- Optimised feed efficiency: Improved fibre digestion, stable rumen pH and more propionate supplied to the cow.
- Lower risk of subclinical ketosis: Trials have demonstrated that Actisaf® significantly improves blood ketone profiles.
- Stronger immune response: Lower inflammation levels, reducing energy diversion from milk production.
- Smoother diet transitions: Improved rumen function and microbial adaptation to dietary changes.
- Enhanced milk production: An additional 2.8kg/day of energy-corrected milk during early lactation.