Minimising wet silage problems

This is the third week of the Farmers Weekly/Keenan Blue Chip Competition, offering four lucky readers the chance to have use of a Keenan mixer wagon of their choice, plus full Keenan Rumans nutrition advice completely free for six months.

This week, all you have to do is read the advice on feeding wet silage, a topical subject for this year’s crops, and answer the simple question at the end of the article. Look out for next week’s question in Farmers Weekly and all four questions will be repeated in Farmers Weekly on 14 September with an entry form to complete and submit.

Feeding Wet Silage

Given the unpredictable nature of the weather during silage making in late June and July, we are more likely to be faced with problem silages this winter. Wet, poor quality silages are in many clamps.

These types of silages, when fed, can lead to all types of problems: An acidic, or butyric fermentation in the pit, balling up in mixer wagons or having a low dry matter silage, which can compromise animal performance and efficiency.

Depending on the type of mixer wagon on farm, balling up during processing can be minimised by following a specific loading order. However, where it is seen, balling up of silage during mixing will typically lead to variance in animal performance, most notably showing as variation in the dung of animals and financially impacting as reduced milk yield. This includes milk quality – acidosis can lead to reduced butterfat levels when concentrate is consumed in favour of forage.

These problems arise from the animal having the ability to select from the ration offered. Key to minimising this is employing the correct loading order when filling the machine and not allowing the mix to be over-processed. By the very nature of mixer wagons, the longer you leave wet silage to mix the more likely it is to form into balls and give animals the ability to select concentrate separately from forage.

Physically, a low DM silage, in the range of 18-22% DM, can lead to a dense presentation of the ration – typically where overall ration DM is below 40% – and this, as at the feed fence, will sit heavily in the gut of the animal.

When coupled with the likelihood that silage will have a somewhat acidic fermentation simply due to the nature of the forage, then correct incorporation of structurally effective fibre in the form of straw into mixed rations becomes even more important.

Nutritionally, the incorporation of straw into a mixed ration offers no direct benefit, but it is through the physical difference it makes to the ration that benefits can be seen. Straw will open a ration up making it more appealing to the animal, while once in the rumen it will work to slow rumen flow rate, but more importantly add scratch to the ration, stimulating cud chewing.

The benefit of this is two-fold – giving increased physical breakdown of the ration, therefore, allowing more of the nutrients to be used for milk or beef production, while production of saliva as a result of increased cud chewing works as a natural rumen buffer. A dairy cow can produce more than 150 litres of saliva a day, containing more than 2kg of bicarbonate provided cud chewing is at it’s optimum, aiding buffering of what may have otherwise been an overly acidic silage.

Other feed out issues with wet silages, such as intake potential and actual nutritional value, can be improved, particularly this winter, by adding molasses. This route will be of great benefit this winter, while molasses has remained one of the cheapest feeds available it also helps to improve ration palatability while also adding sugar to those silages made in less than optimum silage making conditions.

Questions 3

How many kilograms of bicarbonate can a diary cow produce daily, providing cud-chewing is at its optimum?

a. 2kg
b. 2.5kg
c. 3kg

*All four questions and an entry form will be printed in next week’s Farmers Weekly

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