A cow will reach her highest daily milk output six to eight weeks after calving, but she will only reach her highest intake of dry matter (DM) 10 to 12 weeks after calving.

She will use energy from her fat reserves (‘milking off her back’) to make up the energy deficit for several weeks. However, if she loses too much body condition in early lactation, it can reduce her chances of getting back in calf again.

Undoubtedly, grazed grass is our most cost-effective feed on Irish farms, and it should be maximised. However, it must be recognised that grazing grass diets will only support approximately 19-20L of milk.

Therefore, in higher yielding herds, grazed grass must be supplemented to avoid a negative energy balance, which leads to huge herd issues in the long term.

The main objective of feeding cows is to meet their energy requirements as efficiently as possible. If total energy intake is reduced at any stage during lactation, milk proteins drops.

A major drop in protein percentage and/or low milk protein (below 3%) can be an early warning sign that cows are underfed, and corrective action should be taken quickly to avoid subsequent fertility issues.

There are a number of potential reasons why cows may be underfed in early lactation, including:

  • Feeding poor-quality silage, which has a low dry matter digestibility (DMD) and UFL value;
  • Grass intake may be overestimated in early lactation; poor grass growth, or perhaps poor grazing conditions (wet paddocks) contribute to overestimation;
  • Concentrate supplementation can be reduced too quickly in spring due to overestimation of grass.

It’s important to maintain concentrate feeding levels to match grass growth. Feeding a high-starch concentrate will also aid milk protein production. Minimising body condition loss is important between calving and start of breeding – maximum body condition score (BCS) loss should be 0.5.

Even though grazed grass is the most economical way to feed cows, supplementing with concentrates when grass is tight or grazing conditions are poor is necessary and cost-effective in the long run.

As well as an increase in milk yield, it is a guaranteed way of supplying magnesium (Mg) in the diet, as well as other essential minerals and vitamins that are vital for herd health and fertility.

Look after the rumen

It is critical for the rumen to work as efficiently as possible so it can appropriately use the energy being fed to the cow.

The increase in levels of starch and sugars in the diet while at grass will cause an increase in the pH levels in the rumen. The use of Yea-Sacc® from Alltech has been proven to give a significantly higher rumen pH when fed to cows at grass in early lactation, meaning more feed is digested.

Figure 1: Yea-Sacc significantly higher rumen pH (p=0.0037)

Maximise immunity and health

Some cows will have a higher risk of uterine infections due to retained placenta and metritis after calving. Uterine infections and ovarian problems will inevitably have an effect on fertility.

Trace minerals such as selenium (Se) play a key role in maintaining a healthy immune system in the period around calving. Copper (Cu) plays a key role in ovulation and cycling; if there is a deficiency, then anoestrus is a real possibility.

Research has proven that feeding these trace minerals in their organic form – such as Alltech’s Bioplex® Cu and Zinc (Zn), and Sel-Plex®, an organic form of Se – leads to these minerals being better absorbed, stored and utilised by the animal.

This trial carried out at University College Dublin (UCD) shows that cows fed Bioplex Cu and Zn, and Sel-Plex, led to cows returning to first service 6.6 days faster, having a 7.5% increase in conception rates and 4.9 fewer days between calving and ovulation.

Figure 2: Effect of Sel-Plex, Bioplex Zinc and Copper on reproductive performance. (O’ Donnell, Boland and O’ Callaghan, 1995)

Reduce milk urea levels

High levels of rumen-degradable protein at grazing can lead to high levels of rumen ammonia, which gives rise to high blood urea levels, and this can be seen as high milk urea.

Quinns has included De-Odorase® in its Supreme Spring Breeder mineral package Rumi Pro S. De-Odorase® is a natural yucca extract and trial results have shown it can reduce rumen ammonia levels, therefore reducing blood and milk urea levels.

Tips for feeding cows in spring:

  • Energy is the golden ticket to a successful grazing season, so make sure your cows are being fed enough to avoid energy deficits, which can lead to a string of problems in the long term;
  • Measuring grass is the only sure way you have of knowing that your cows are getting the correct amount of grazed grass;
  • Monitor your milk solid levels continuously, as they will quickly give you signs if there is something wrong;
  • Speak to your nutritionist and get them to run a diet formulation for you so you can be assured that you are feeding the correct concentrate;
  • If you are feeding forage in the early spring, make sure it’s analysed so you know exactly what quality it is and balance accordingly;
  • Feeding concentrates has the added benefit of providing Mg and other essential minerals to cows at grass.

Further information

Please contact Quinns for further details on its summer dairy feed range. Simply call: 059-6481266; or email at: [email protected].