The past six to eight weeks has been a challenging time for farmers, with periods of uncompromising difficult weather whilst also coupled with falling milk prices.

BY PAULINE O’DRISCOLL

As we approach the end of the lactation for spring calving herds, focus must now be given to ensure that cows are in good order coming into the dry cow period and that stock are managed during this time to ensure that the herd will reach its potential in 2026.

All cows need to be dried off for a sufficient period of time (10-12 weeks) pre-calving.

If this is not realised, then there is a risk that the cure rate of any infections in the udder and the efficacy of the antibiotic where used will be compromised.

Any cows that are below the desired BCS (Body Conditioning Scoring) of 2.75 will need an additional dry period over and above the recommended.

Cows calving down too thin will struggle to achieve their potential yield or go back in calf while overfat cows are at a very high risk of suffering from various metabolic disorders post-calving. 70% of metabolic problems occur at this time and consequently most culling for health problems occur around time of calving with issues such as milk fever, ketosis, displaced abomasum and retained placenta.

Management and sensible feeding in the dry cow period will help in the prevention and possibly in the reduction of the occurrence and severity of these metabolic disorders.

Silage quality is key to good animal performance, reducing winter feed costs and increasing profitability.

You cannot change the quality of the silage in the yard now but getting an understanding of its quality will help you to make some better-informed decisions about feeding your various categories of stock for a desired outcome.

The most important aspect of dry cow nutrition is to ensure the correct calving BSC for at least 90% of the herd.

In situations where BCS corrections are required in late lactation or at dry off, a plan should be put in place to ensure an appropriate energy allowance is offered over an adequate timeframe.

The first port of call here is to know the quality of what you’ll be feeding over the next number of months.

Silage analysis is relatively cheap and will provide you with valuable information.

Where pits are open the easiest method is to mix several samples from across a fresh pit face in a ‘W’ shape.

Equally representative samples should be taken from various batches of bales to determine the quality of the bales available.

The standard test results will give a good indication of quality (DMD, protein and fibre) and the preservation (pH, ammonia and lactic acid).

The mineral status of silage is very important for dry cows so when testing, request that a full mineral analysis be completed.

Metabolic disorders such as milk fever and subclinical hypocalcemia are because of a calcium deficit due to high demands around the point of calving.

Milk fever is a gateway disorder in that animals that suffer from milk fever are at a multiple times risk of developing and suffering from retained cleanings, displaced stomachs, or mastitis.

For example, a cow that has a case of milk fever is three times more likely to have a retained afterbirth, five times more likely to have an LDA and eight times more likely to have case of mastitis.

One of the most important aspects of maintaining control over milk fever and sub clinical hypocalcaemia is to maintain the BCS within the desired range at calving time.

Along with correct BCS, to control milk fever at farm level we need to feed our cows and in-calf heifers, magnesium and vitamin D in conjunction with other minerals, vitamins and trace elements.

Based on typical magnesium concentrations found in Irish grass samples, 20-25g of magnesium will be required from the dry cow mineral.

The next major mineral of importance in the dry cow diet is potassium.

If high levels of potassium occur in the silage it can make it more difficult for the cow to mobilise calcium and it can also tie up magnesium in the rumen, thereby leading to cases of milk fever.

The average potassium in grass silage is typically 1.8 to 2.4%. The advice is not to feed silage with higher potassium content (above 2.2%) in the final three-four weeks prior to calving.

Ideally, a well managed dry cow period results in all cows calving down at the optimum body condition and with optimum blood and body mineral status.

By planning now, and taking silage samples, analysing the results, and seeking advice from your advisor, nutritionist and vet and taking the right action, ultimately the calving season of 2026 will get off to a better and healthier start, all of which is better for man and beast.

Pauline O’Driscoll is a Business and Technology dairy advisor based in the Skibbereen Teagasc office.