Fat cows will have less inclination to eat at calving and will mobilise fat quicker, causing metabolic pathways to become blocked.
They will then be pushed into a state of ketosis, with high levels of ketones in the blood suppressing intakes further.
It is this which puts these cows at risk of metabolic disease and suboptimal milk production. They are then more likely to suffer from poor fertility, leading to a longer lactation and a propensity to get fat again.
Hefin Richards, of Rumenation Nutrition Consultancy, says it is crucial to break this cycle by improving transition cow management.
He says: “This means feeding diets to suit transition cows and possibly introducing choline or methionine to help liver function and using a monensin bolus on high risk cows after discussion with a vet.”
All the basics, such as reducing overcrowding and providing plenty of feed and water space, also still apply. As soon as these at risk cows calve, it is important to adhere to good reproductive management to ‘keep the momentum going’.
This means doing post-calving checks to identify any cows with poor rumen fill or running a high temperature, then follow up to identify cows that are not cycling by the end of the voluntary waiting period.
Any problem cows can then be managed appropriately with the view to getting them bred at 70-150 days in-milk.
“Then you reduce the risk factor for the next lactation so you have cows with acceptable lactations, rather than long lactations.”
Getting a good number of cows in-calf by 100 days in-milk will help breed fertility into the herd.
This will reduce the need to hold on to sub-fertile cows caused by a desperation to breed adequate replacements.
References: Raboisson et al, 2015 and Walsh R.B. et al, 2007.
Elanco currently analyses milk recording data from about 200 herds, representing 33,500 cows across England, Scotland and Wales. Analysing individual cow milk fat to protein ratio gives an indication of whether an animal may be affected by ketosis. A ratio of >1.4 suggests excess body fat may be being mobilised. The problem can then be investigated.
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