Why feed a supplement when pasture is plentiful?

The day light hours are increasing, and we begin the march towards Spring, changes are taking place on farm. Slow growing winter pastures start to kick into growth and with that we see pasture volumes in rations increase. While this is a very positive and a great source of ‘low-cost’ feed, we must be mindful of the full nutritional requirements of the animal.

One of the questions Tasmanian farmers often ask Michael Humble, Castlegate James’ Tasmanian representative is “why should I feed a supplement when I have lots of pasture available?” His answer is simple…nutritional balance.

Pasture is a fantastic feed with good energy levels and great mid-level protein levels. The challenge is the volume of pasture that we expect the animals to be consuming and converting into milk (or in the case of beef muscle tissue) doesn’t create a balanced diet and as such the animal is working hard to regulate the nutritional imbalance. Over time this has a noticeable impact on cow health, weight gain, milk production potential and in-calf rates going into mating.

Let’s get technical.

Consider a standard high pasture, low input dairy ration with around 17kgs/DM per cow of pasture being consumed daily. If the pasture tests at 12% metabolisable energy (ME) and 24% crude protein we would see cows gaining 204Mj ME of energy & 4.08Kg of crude protein. Take off a maintenance level of around 60Mj ME, we have around 144Mj ME left for milk production, equating to around 25 litres of milk produced.

Michael Humble.jpg

Michael Humble, Castlegate James’ Tasmanian representative

However, if we look at the make-up of the pasture protein (pasture is high in RDP, Rumen Degradable Protein) there is a requirement for around 18% protein in the total ration. In a pasture-based system we are achieving around 25%. That means this excess protein needs to be converted and excreted from the system. Which in turn uses up energy, that could/should be going into milk production. This will impact overall production, liveweight and most often reproductive performance.

By adding in a concentrated feed source or feed pellet, this can be a valuable tool to assist the cow in breaking down and better utilising the pasture available. A feed pellet is a convenient source of starches, grains, fibres and alternative proteins which all assist in helping to regulate the rumen activity and get the most out of the pasture available.

This nutritional balance is also important when it comes to rumen health. Consider the rumen as perhaps a car engine. It’s easy to run if you put petrol in it, however an engine also needs oil and coolant. Without these other ingredients, the car might run, but not for long and not efficiently.

The same issue can be experienced with a cow with in-calf rates. If the diet isn’t balanced, the ideal Rumen environment will not be achieved and as a result, cows may take longer to get in calf or may not get in calf at all. The same thing can happen with milk production if the cow is having to convert valuable energy to excrete the excess protein there will be a loss in potential milk production or weight gain.

Michael and the local Tasmanian CJA sales representative team are ready to discuss how the CJA range of Proteena pellets can provide a cost-effective option to get the most out of your cows, your pasture and the season.


  • Published: 28/08/20
  • Author: Tasmanian Country, August 2020
  • © Castlegate James