Autumn syndrome in dairy cows: understanding the causes to protect the farm
As summer draws to a close and temperatures finally begin to cool, one would expect an immediate and natural recovery in milk production and the herd’s general health. However, on-farm data and international literature reveal a very different reality: the months of September, October and November are often characterised by a failure to recover milk production, an increase in post-calving diseases and a peak in the incidence of lameness and mastitis.
This complex phenomenon is known in the industry as ‘autumn syndrome’ in dairy cows. It is not a single event, but rather the cumulative effect of metabolic, digestive, environmental and hormonal stresses that have built up over the summer months.
Let’s take a closer look at what happens in a cow’s body after the summer and how the farmer can take strategic action.
The legacy of heat stress: digestive physiology and tissue damage
To understand ‘autumn syndrome’, we need to look back at the hot weeks.
We now know that the heat stress limit (THI) is no longer set at 72, as it was in the 1980s. With advances in genetics and increased production yields, the critical threshold for high-yielding dairy cows has fallen to a THI of 68 (equivalent to just relative humidity).
When the THI exceeds this threshold, the cow undergoes peripheral vasodilation to dissipate heat. Studies (including the well-known research by Baumgard at Iowa State University) show that this phenomenon is accompanied by vasoconstriction in the visceral and intestinal systems. The reduced supply of blood and oxygen to the digestive tract causes a deterioration in the integrity of the mucosa and the contraction of the intestinal villi.
In addition to this, there are:
- Reduced feed intake and acidosis: a decrease in dry matter intake, combined with hyperventilation (which disperses and reduces the buffering capacity of saliva), increases the risk of ruminal and intestinal acidosis.
- Oxidative stress: strain on the digestive system leads to an imbalance between the production and neutralisation of free radicals, causing oxidative stress and cell death in the tissues.
- Loss of ruminal efficiency: the bacterial flora reduces the ability to synthesise microbial protein, digest fibre and carry out the biohydrogenation of fatty acids, thereby compromising both the quantity and quality of the milk produced.
During the summer months, the use of antioxidants and balancing agents is essential for neutralising free radicals, supporting metabolism and maintaining normal ruminal function.
Overcrowding and newly calved cows: the risk of ketosis in autumn
Another key aspect of the autumn syndrome relates to reproduction. High summer temperatures disrupt the regularity of oestrus cycles, leading to an unusual concentration of births between the end of summer and throughout the autumn.
This gives rise to two serious management issues:
- Overcrowding in the pens: too many animals crammed into the same spaces.
- Increase in the number of fresh cows: the high number of cows at the start of lactation increases the number of animals exposed to a physiological energy deficit.
In autumn, as feed intake does not increase at the same rate as the lactation curve, the animal draws heavily on its fat reserves, releasing enormous quantities of non-esterified fatty acids (NEFAs) into the bloodstream.
The trap of ketosis and fatty liver disease
NEFA reach the liver cells, where they are converted into energy in the mitochondria (the Krebs cycle). However, this process requires specific transport molecules and catalysts:
- Carnitine (via the enzyme carnitine acyltransferase) is essential for transporting NEFAs into the mitochondria.
- Vitamin B12 and glucose precursors are essential for facilitating chemical reactions.
If the metabolic pathway becomes saturated or these key molecules are lacking, the build-up of acyl-CoA leads to the formation and release of ketone bodies into the bloodstream. Furthermore, excess unprocessed fat is re-esterified within the liver in the form of triglycerides, resulting in hepatic steatosis and severely compromising the organ’s vital functions.
Targeted nutritional impact
To reduce the risk of ketosis in fresh cows, it is essential to use ingredients with different rates of availability: fast-acting energy sources (propylene glycol) and slow-release energy sources (glycerol), sugars for the ruminal microflora, vitamin B12, niacinamide (vitamin PP), rumen-protected choline and bypass methionine (to limit the accumulation of lipids in the liver), and L-carnitine to transport fatty acids into the mitochondria.
Lameness and laminitis in autumn: the delayed onset
Why do lameness cases peak between late summer and early autumn (affecting even a high proportion of the cows in the barn)?
The answer lies in a combination of three factors experienced over the summer:
- Metabolic factors: fluid loss due to hyperventilation reduces buffering capacity, triggering micro-acidosis and the release of toxins that cause foot inflammation (laminitis).
- Mechanical factors: in order to dissipate heat, the cow spends much more time standing than lying down, placing excessive strain on the hoof structure.
- Environmental factors: the constant use of hand showers and summer watering creates damp environments and slippery floors, which soften the horn on the foot, making it vulnerable.
As the hoof takes around two months to grow and for any damage to become visible on the surface, ulcers, white-line lesions and severe lameness tend to appear in the autumn.
To prevent problems and support hoof regeneration, the diet must provide highly bioavailable organic zinc (essential for cell structure and tissue healing), biotin – which is vital for keratin synthesis and the mechanical strength of the hoof – and iodine.
Postnatal udder hygiene
The autumn season brings with it the stress accumulated over the summer, changes in the animal’s physiological state and a decline in the cow’s immune defences. In this context, mastitis and elevated somatic cell counts pose a real risk to milk quality.
Combining an appropriate diet with a rigorous hygiene and health protocol during milking — through the use of film-forming post-dipping treatments and highly stable disinfectants (such as formulations based on chlorine dioxide or iodine) — is essential for protecting the teat sphincter from bacterial infections.
Tecnozoo’s nutritional solutions for autumn
To assist farmers in managing the risks associated with autumn syndrome, Tecnozoo offers formulations designed to support the herd’s normal physiology, metabolism and feed efficiency:
- KETONIC: a dietary supplement formulated to reduce the risk of ketosis in dairy cows. It combines the rapid and sustained energy release of propylene glycol, glycerol and sugars with the inclusion of vitamin B12, niacinamide, rumen-protected choline, bypass methionine and L-carnitine, thereby promoting the utilisation of fatty acids by the liver.
- REMEDIUM AC: a complementary feed for ruminants, ideal for helping animals cope with periods of metabolic stress, thereby minimising problems associated with reduced efficiency in the barn.
A balanced supply of zinc and biotin promotes keratin synthesis and supports the natural mechanical strength of the hoof.
- AGECON PLUS: a mineral feed containing organic acids and zinc in an organic chelated form. Thanks to the synergy of its components, it promotes physiological cellular stability and supports metabolism, helping to optimise the efficiency of the feed ration.
- PODALIK PLUS: a nail hygiene solution containing copper salts, zinc and glutaraldehyde.
- HEPATOS: its new formula has been improved to provide greater support for liver function. With the inclusion of betaine and methionine, as well as B-group vitamins and yeasts that play a role in detoxification processes, Hepatos helps maintain liver metabolism during periods of metabolic stress, such as seasonal changes. Furthermore, extracts of milk thistle, a source of silymarin, and artichoke, a source of cynarin, are traditionally used to support liver and digestive function.
Autumn syndrome is not an inevitable fate of the modern dairy farm, but a complex physiological condition that can be anticipated and managed. Monitoring feed intake, protecting the liver from the risk of ketosis, supporting hoof keratinisation and maintaining udder hygiene are the cornerstones for ensuring the herd’s continued productivity and welfare.
Contact Tecnozoo to analyse the parameters of your livestock housing and draw up the feeding and supplementation plan best suited to your farm.
