The transition phase in dairy cows: when prevention really pays off
The transition phase — that delicate period spanning the last three weeks of the dry period and the first thirty days of lactation — is the real ‘litmus test’ for any dairy farm. During this period, the cow undergoes profound hormonal, metabolic and digestive changes: a critical phase in which even the slightest management error can lead to metabolic disorders, drops in production and significant financial losses.
Among the critical factors, the management of calcium metabolism and energy balance is undoubtedly the most important.
What is the most robust scientific evidence available today for managing the CLOSE-UP period and the onset of lactation as effectively as possible? How can we turn prevention into a real financial return for the farm?
Calcium metabolism and the negative DCAD turning point
In the 24 hours leading up to calving, a cow’s daily calcium requirement is around 20 grams, which is necessary for foetal growth and maintenance. Immediately after calving, to meet the demands of colostrum and milk production, this requirement suddenly rises to over 52 grams a day.
To compensate for this ‘sudden change’ of over 32 grams, the cow’s body must urgently activate its endocrine mechanisms: parathyroid hormone (PTH) signals the kidneys to retain calcium, activates vitamin D and stimulates the bones to release the mineral into the bloodstream.
If the pre-calving diet is alkaline (rich in potassium or sodium), blood and urine pH levels remain high (> 7.50). In this context, the tissues lose their responsiveness to PTH: the cow is unable to mobilise her bone reserves promptly and develops hypocalcaemia (which, in almost 50 per cent of multiparous cows, occurs in a subclinical form, often undetectable but highly damaging).
Adopting an acidogenic diet with a negative DCAD in close-up groups alters the animal’s acid-base balance, inducing mild compensated metabolic acidosis. This condition increases the sensitivity of PTH receptors, enabling the cow to immediately draw on bone calcium and accelerate the absorption of nutrients from the feed.
What is the target urinary pH?
As confirmed by research carried out by Prof. Jesse Goff (Iowa State University), the average urine pH of the entire group in the close-up phase should be between 6.2 and 6.3 (with an acceptable range of 6.0 to 6.8). Lowering the pH to below 6.0 offers no benefits and risks causing excessive acidification, leading the cows to reduce their dry matter intake.
The impact on income
Studies show that a good protocol for negative DCAD generates a 3:1 ROI (return on investment). Against the cost of anionic salts and appropriate supplementation, the dairy farm gains an average of 1.5 kg/day more milk (approximately +450 kg per lactation) and drastically reduces the incidence of postpartum collapse, retained placenta and abomasal displacement.
Anionic diet for heifers in Close-Up: yes or no?
In modern cattle sheds, it is not uncommon for pregnant heifers to share the same close-up pen with multiparous cows, receiving the same steaming-up ration. There has long been debate as to whether the use of anionic diets might harm or benefit primiparous cows.
Research findings from the University of Florida (published in the Journal of Dairy Science) have shed light on this issue:
- Uterine health and disorders: heifers fed a moderately negative DCAD diet (-50 mEq/ks SS) showed a marked reduction in the risk of metritis (25.6 per cent compared with 36.3 per cent on traditional diets) and lower overall morbidity.
- Beware of going to extremes: formulations with highly acidified formulations (matching urinary pH) offer no benefits to heifers and may adversely affect feed intake and energy metabolism.
Advice for the cattle shed: when heifers and multiparous cows share the same pre-calving group, the best approach is to adopt a partial DCAD diet (between -50 and -100 mEq/kgSS): a balanced solution that protects the uterine health of first-calf heifers without risking a loss of appetite.
The fresh cow: the importance of metabolisable protein and calcium propionate
Once calving is over, the challenge shifts to managing the Negative Energy Balance (NEB). Milk production rises rapidly, whilst feed intake increases more slowly, forcing the cow to draw on her body reserves.
Research presented by Ohio University shows that, during the first 25 days of lactation, the real limiting factor is not just energy, but the intake of Metabolisable Protein (MP) and the correct balance of essential amino acids. Feeding rations that are rich in MP and balanced in terms of amino acids increases voluntary intake (+1.1 kg DM/day) and limits excessive loss of body mass.
At the same time, to support the liver as it works to break down NEFAs (non-esterified fatty acids) and prevent the formation of ketone bodies, the oral administration of calcium propionate proves to be a valuable aid. By acting both as a source of soluble calcium and as a direct precursor of glucose (via propionic acid), it helps to maintain blood glucose levels, reduces hepatic stress and promotes milk production.
Tecnozoo’s proposal for your transition
For over forty years, Tecnozoo has been supporting livestock farmers with nutritional solutions designed to meet the animals’ physiological needs during the most critical stages of the production cycle.
To manage the dry period as effectively as possible and prepare the cow for calving, the Tecnozoo range offers two key products:
- CLOSE UP HA: A mineral feed specifically designed for the final three weeks of the dry period. Its formulation is balanced to provide the correct anionic salts needed to lower blood pH and stimulate calcium metabolism. It contains a carefully calculated level of magnesium – a key element for the proper functioning of endocrine receptors – combined with a blend of vitamins and minerals designed to support the immune system in the pre-calving period.
- COW DRY PLUS SE NEW: Designed for the entire dry period, this mineral feed meets the cow’s vitamin and mineral requirements whilst providing the added benefit of heat-treated linseed, which is rich in essential Omega-3 fatty acids. The presence of soluble fibre, sugars, brewer’s yeast and oligosaccharides stimulates the ruminal microflora, helping to restore normal digestive balance before the new production cycle.
Conclusion
Managing the transition is not simply a matter of changing the feed ration, but requires a holistic approach that combines precision nutrition, housing comfort and constant monitoring (such as regular checks of urine pH and space in the cubicles).
Contact Tecnozoo’s technical support team to analyse the transition process on your farm and draw up the integration programme best suited to your needs.
