With some regions in Victoria experiencing heavy rainfall, and in some cases on top of recent floods and storms, there's an increasing risk of pugging in paddocks.
Pugging can reduce pasture growth by 20 to 40 per cent and pasture use by 40 to 60 per cent, due to damage and soiling of pasture. Pasture production in the following spring and summer may also be impacted by 20 to 80 per cent, depending on the severity of pugging damage. Pugging may also lead to increased animal health issues including mastitis and lameness.
Pugging occurs as very wet soils have reduced strength or structural integrity, making them more easily damaged by cow hooves and machinery. When soils are pugged, compaction occurs reducing the rate of water infiltration.
The severity of damage will depend on soil type, degree of waterlogging and most importantly grazing management. The greater the severity and extent of pugging damage, the greater the set-back and cost of pasture restoration.
Modified grazing techniques and on-off grazing are two strategies which can be employed to minimise the physical and economic impacts of pugging damage.
Modified grazing techniques
Maintain good grazing management with cows grazing pasture at the two to three-leaf stage and leaving a post grazing residual of 4cm-6cm is critical in wet conditions. This will assist to achieve a minimum grazing height of 10cm with an ideal height of 15cm to 20cm. This height allows the cows to take big bites of pastures, reducing their need to walk and create associated damage. The techniques below can further assist.
- Allocate day and night feeds separately: Offering two-thirds of the 24-hour allocation throughout the day, and the remaining one third at night, will allow cows to have access to clean, un-fouled pasture for the night feed. This will mean less walking is required, therefore less pugging will occur.
- Offer the 24-hour allocation all together: This allows cows to spread out over the paddock for the entire 24-hour feed reducing stocking density. When using this method there needs to be sufficient feed in the paddock to reduce cow movement.
- Feed cows before they enter the paddock: Some farmers ensure that cows have had a good feed in the shed, on a feedpad or from a feeder in the laneway before they enter the paddock. The theory is, with a full belly, the cows will be more settled and start grazing later in the morning with less walking, resulting in less pugging damage.
- Allocate a larger grazing area: This can be a useful option, but only for a short period of time. If done for too long, this speeds up the pasture rotation, reducing the amount of pasture available in the next rotation. With this strategy, the density of hooves is reduced, therefore potentially reducing pugging damage. Avoid using this technique in very wet and windy weather as damage may be increased as cows search for shelter.
- Graze free-draining paddocks first: Some farmers are fortunate to have some soils which are less prone to pugging, such as sandy rises. These can be grazed in wet conditions thereby taking pressure off the paddocks more prone to pugging.
- Graze vulnerable paddocks before it becomes too wet: Use the weather forecast to monitor rain events and graze vulnerable paddocks which are close to the top of the rotation early as you may not be able to graze them when they are ready to graze. This may mean grazing just before two leaves, but better to do this than pugging the paddock.
- On-Off grazing is an alternative approach to minimise pugging damage. This involves allowing the cows to have a short period of grazing before removing them from the paddock to be held in an "off" area.
In On-Off grazing, cows usually graze pastures for two to four hours and are then removed before severe pugging damage starts to occur.
Research has shown on well-fertilised pastures at the two to three-leaf stage, after two hours grazing cows consume 70 per cent of the pasture that they would eat over a full 12-hour grazing period, and 77 to 88 per cent over four hours. After the four hours, little extra intake occurs, but the rate of pugging increases drastically. Therefore, it is best to remove the cows and save the pasture for the next rotation. However, when using this strategy, the animals will need to be topped up with a high-quality supplement to avoid loss of milk production.
There needs to be somewhere for the animals to go in the "off" period. Farmers may have a suitable area or can be very innovative in setting up a site for the "off" cows. This can include places such as feedpads, unused silage pits, tree lots (watch for ringbarking and avoid edible parts of conifers), sawdust pads, laneways, sand banks, hard standing areas and cow yards. Each site has its own pros and cons which need to be considered and managed.
Consider which strategies would work on your farm. If you get the chance, discuss the various options with other farmers who have tried these, or they may even have other ideas not discussed here.
