The British winter: predictably unpredictable - you can bet your bobble hat on it. What with all the rain and the long, grey January days, it might feel like your herd spent longer than normal in winter housing. But now Mother Nature is waking from her winter slumber and spring is nearly here.

Good news it is too. Freedom to roam the fields can offer some benefits. It can also save you up to £1 per animal per day on housing costs. Yet as your cows trot back out to the fields, you have a number of nutritional boxes to tick if you want to make sure your dairy herd remains healthy, fertile and productive.

1. Choose your first field carefully

You don’t need to be the most experienced dairy farmer to know that cows love munching on grass. That reduces your feed costs and gives your cows an all-natural nutritional kick too. (There are high amounts of fertility-boosting linolenic acid (or omega-3) in springtime ryegrass)

The most suitable fields for turnout tend to be those that have not been grazed since late September or early October. Take a good look at your fields and choose an option that has lots of grass available - obviously - with a sward length of around 8-10cm.

Also, consider the soil conditions and match the stocking density accordingly. Avoid damp fields in favour of dry, lighter soils. You don’t want your fields turning to quagmires as soon as your herd steps hoof on them.

2. Prioritise the youngsters

Yearlings and first-time grazers should be given the first share of the fresh fields at turnout. They’re smaller (and less damaging to the soil), they have high feed conversion efficiency and their vulnerability to worms means they are better-suited to grazing while the worm-burden is low.

3. Finding the fertiliser formula

Grass responds best to nitrogen fertiliser when soil temperatures at 10cm are higher than 5oC for at least four consecutive days. Applying 50kgs per hectare in areas that favour early growth (well-drained south-facing slopes with light soils) will garner good results. Avoid fertilising in wet conditions, when wheels can damage the grass.

Additional phosphate can enhance the performance of nitrogen fertiliser in low-phosphate soils. But avoid using potash fertiliser, which interferes with magnesium uptake and can increase the risk of grass staggers or hypomagnesaemia.

Speaking of which...

4. Test the nutritional value of your fields (and get hold of a magnesium supplement)

Grass staggers (or tetany) is deadly and can take hold rapidly. It’s caused by magnesium deficiency and, unfortunately, dairy cows are particularly susceptible at turnout. Grass is low in magnesium, while lactating cows also lose magnesium in milk. It’s a potentially deadly double-whammy that must be addressed.

Magnesium supplements are cheap and effective. Make use of them. To gauge how much you need - and identify the need for other nutritional supplements - it’s best to test the nutritional value of your soil and grass. That way you will know exactly how you can optimise your herd’s nutrition to keep them healthy, productive and profitable.

5. Know when to rotate

Did you know that cows stimulate sward growth as they graze? Unfortunately, the effect is not immediate. Once sward length has been grazed to 5-6cm it’s time to move your herd on to a different field while the grass recovers. Grazing to a uniform length of 5-6cm allows sunlight to enrich the next grass tillers and clover plants and boosts sward production. And they say there’s no such thing as a free lunch!

6. Good access to the wet stuff

Dehydration negatively impacts milk yields, so it’s important to make sure cows have access to water. Lots of it too - because dairy cows have one serious thirst. Each of the cows in your herd needs around 60 litres of water per day. High-yielders may guzzle as much as 100 litres plus. Ensure troughs are well-maintained and spread generously around your fields, dairy and feedout areas. 

7. Don’t forget fats

Dietary fat: maligned among humans but essential for cowkind. In fact, feeding the right type of fats has been proven to boost the immune system, improve fertility and - perhaps most importantly of all - increase milk production (particularly yield and milk fat %). Think what that could do for your profits.

>> More fat, more profit more profit: are you feeding enough fats to your dairy herd?

Grass contains around 3.5% fat, while cereals contain around 2 to 2.5% fat. Yet high-yielding cows may need around 6-8% of fat in the dry matter to remain as productive as possible. That means it may be worth considering a well-chosen fat supplement.

Megalac is a rumen-protected fat supplement that can bring research-backed benefits to your herd such as:

  • improved milk production
  • promotion of egg development
  • increased likelihood of embryo survival
  • improved fertility

And here’s the sciencey bit. Unlike fat in standard feed ingredients, rumen-protected fats like Megalac have no negative impact on digestive function. That gives you a safe way to increase your herd’s fat intake, without the negative effects on fibre digestion and performance that can occur when you overfeed traditional feed fats.

>> How to maintain a healthy rumen in dairy cattle

Over to you...

  • At turnout choose your first field carefully - ideally one with light soil and a sward length of 8-10cm
  • Yearlings and first-time grazers should be given the first share of the fresh fields
  • To boost the performance of nitrogen fertiliser, apply when soil temperatures will be a minimum of 5oC for four consecutive days
  • Use a magnesium supplement to protect against tetany and test the nutritional makeup of your fields
  • Once sward length has been grazed to 5-6cm, move your herd to a different field and allow the grass to recover
  • Ensure your grazing herd has access to plenty of water
  • Consider a well-chosen fat supplement to boost milk yields

You may also be interested in:
>> Quality in, quality out: how to get peak productivity from your dairy herd
>> How to improve dairy cow fertility through nutrition