18 June 2013

4 minute read

Pasture Utilization

Pasture is an excellent low cost means of feeding livestock, but requires proper management of both the forage and the livestock. The forage must be managed to optimize growth, while the livestock must be managed to optimize utilization. Your goal as you manage your pastures is to grow as much grass as possible and have it consumed at the point of optimum nutrition and quantity with minimal waste.

How much of the pasture growth is actually eaten/utilized by the grazing livestock is going to influence the success (profitability) of your pasture business - producing a lot of growth is of little benefit it is not utilized by livestock!

Factors That Affect Utilization

• Forage that is over mature will not be effectively utilized, since mature tall grass is both hard for the animals to bite off and also difficult to digest.
• Forage that is too short (less than 5-7 cm) does not allow the animal to get a big bite, so they spend extra time walking to get enough forage.
• Forage that is contaminated by feces or urine will not be eaten.
• Forage that is tramped or laid on is less likely to be eaten.
• If there is a wide choice of plants to graze, then the most palatable will be eaten and the less desirable will be left behind. These plants then have a chance to continue growing and over time will dominate the pasture.

Ways to Influence Utilization

• Minimize the area and amount of grass that is available at any one time - this means there is a higher proportion of fresh grass available to the animal.
• Smaller paddocks reduce walking/tramping and encourage grazing and resting.
• Provide water in the paddock to minimize the amount of time spent away from the pasture you want them eating.
• If there are significant manure patties that are not breaking down consider harrowing to spread these patties out and speed up the breakdown. Cattle eating grass that is optimum for performance will have loose manure that will not be in dried patties.
• If there are mature plants including weeds, clipping can improve utilization.
• Livestock grazing a "new" or "fresh" paddock focus on grazing, become full quicker and will spend more time resting rather than wandering looking for another bite of palatable grass.
• Intake of high quality forage is much better than low quality - increased ADF decreases intake because of slow digestive passage.

Number of Paddocks and Frequency of Moves

Two factors that influence utilization are the number of paddocks and frequency of moves.

From the Purdue Extension Forage Field Guide:

• A continuously grazed pasture will result in 40 per cent utilization of the forage
• A 4 paddock system will result in 45 per cent utilization
• An 8 paddock system will have about 60 per cent utilization
• A 12 paddock system will have about 65 per cent utilization
• And moving to a 24+ paddock system will bring the utilization rate up to about 75 per cent

This is a huge increase in productivity of your pastures!

Increasing the number of paddocks allows you to increase the frequency of moves to fresh pasture. Also from the Purdue Extension Forage Field Guide we see that:

• Moving every 3 days to fresh pasture will give a 70 per cent utilization rate
• Moving every 7 days reduces the pasture utilization rate to 50 per cent
• 14 day moves results in only 40 per cent utilization of the pasture.

These two factors go together - the more paddocks you have the more frequent the moves and the longer the rest period for the grass to recover from the previous grazing and grow fresh grass for the next grazing.

These are seasonal utilization rates, at each grazing pass the best results are achieved when you have the livestock remove about 50 per cent of the available forage. When removing just 50 per cent of the available forage the plant can quickly recover and re-grow. There is minimal impact on the root system with the loss of about 50 per cent of the top growth but once more than 50 per cent is removed the impact on the roots is much more significant.

The more paddocks you can organize for each group of livestock and the more frequent the moves to a fresh paddock the better the performance you will see from your pastures.

June 2013