Hazell Mullins: Cows are what they eat - so make sure you know what's in their feed
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What a difference a year can make; I remember this time last year, all the cattle were in, it was a constant battle with rain, and the fields resembled mud planes. I was happily milking the cows this week in my shirt - not a raincoat or woolly hat in sight.
When it comes to the silage we are feeding this year, it is also a very different picture from last year. You may remember reading about my low pH silage, causing the cows to regurgitate cuds all over the cubicles. It was a sight every day that was so disheartening and their milk production was also a sight for sore eyes.
The silage sampling last year was able to tell me that it was too high in acidity as preservation was not the best, most likely due to high Nitrogen levels at harvest. This year, we tested the crop before harvesting for nitrogen, and it seems to have helped.
I got the third-cut tested at the Tirlan open day in Castlelyons, as the pit was open. The night before, I filled up a zip lock bag to the brim with fresh silage from the pit face, taken from points along a 'W' shape to get the most representative sample.
It is a fantastic opportunity to get silage sampled at these events. We will also get the other cuts sampled using a core technique over the next few weeks.
With the knowledge of what we are feeding our animals, we are removing the guesswork out of winter feeding, benefiting the animal and also our pocket in the long run.
Before even getting the result from the co-op, I had a feeling that it would be good news just by how eager the cows were to eat the silage. Palatability is such a key driver of intakes and so important, especially post-calving, to keep dry matter intakes up to prevent post-partum metabolic diseases.
You can tell a lot by picking the silage up and looking at it: does it smell sweet, how dry is it, or is there any visible mould present? A badly preserved silage will have a very distinct rancid smell due to high levels of butyric acid and can be a dark black colour. Some silages that I encounter on farms smell so good you would be tempted to try some yourself.
When it comes to preventing metabolic disease next spring, what we do now during the dry period with feeding can play a huge role, particularly in milk fever prevention.
The mineral content in the silage is crucial to know as it can be used to predict the likelihood of clinical and subclinical milk fever cases on the farm next spring. when it comes to preventing milk fever, particularly when it comes to magnesium (Mg), potassium(K) and calcium (Ca) levels. After a cow calves, her demand for calcium rises up to sevenfold which means that the calcium upregulation system has to be primed and ready for action once the cow calves.
When the ratio is 20:1 (K:Mg) this means that the silage is very high in K and a severe risk of milk fever cases developing. When it comes to Calcium levels in silage the opposite of logic is the case, very low levels of calcium (Less than 1%) are required before calving to trick the body into upregulating calcium after calving.
If silage reports suggest a mineral imbalance, discuss with your vet measures to prevent milk fevers, such as high magnesium mineral supplements, the addition of straw in the dry cow diet and calcium sources at calving.
Ensuring the correct body condition score, ideally between 3-3.25 BCS at calving, can also prevent milk fever and other complications like dystocia.
The Dry Matter Digestibility or DMD is a crucial measure for the feeding value of the silage can knowing its value can prevent cows from being over-conditioned this winter.
Silage generally ranges from 65-75% DMD; my silage tested at 69%, which I am very happy with for a third-cut silage. It is a good silage for my milking cows and weanlings currently, but maybe it is a little high in energy for my dry cows, especially those that are calving later in spring.
There is a lot of advice on feeding rates on the Teagasc websites. Chat with your vet and nutritionist for the best advice that is suited to your farm.
Imagine eating food and never knowing any of the nutritional value; my diet would almost certainly be 100% chocolate and we all know that would not end well.
This week, I am Tullamore bound for the Veterinary Ireland 'Future of Veterinary' conference, where the theme is One Health, One Welfare; it should be a fantastic day of discussion of the 'One Health concept" and how Vets play a vital role in both animal and human health.
I am also back in Mitchelstown this month, how I missed the beautiful Galtee’s and O Callaghan for a delicious lunch.
- Hazell Mullins BVM BVS, is a large animal vet based in Carrignavar, Co Cork.
