Pasture testing confirms that green is still good

On Monday 15th August, Matt Lieschke (South East Local Land Services) and Brett Littler (Central Tablelands Local Land Services) presented a webinar responding to producer feedback and concerns about livestock performance through the current season.

Over the last 2 months pasture samples have been collected across the Southern and Central Tablelands covering a range of pasture types, with samples sent to the NSW Department of Primary Industries laboratory for analysis. The results of the pasture testing were presented during the webinar and the impact on livestock performance was discussed.

The results confirmed that green feed is still good in terms of nutritive value, with dry matter digestibility ranging from 66 - 76%, 10.5 - 12.5 Megajoules of Metabolisable Energy (ME) and 16 - 28% protein. These levels are typical for temperate pasture species at this time of the year. In contrast, the dead feed that was tested had very little nutritive value, with digestibility ranging from 39 - 48% (5-7 ME). As a reference point, cardboard has a digestibility of around 45%.

Livestock will do their best at selecting out the green component in the pasture – the question is, can they readily access the green or do they need to take some dead with it? This is a bigger issue for cattle than sheep, as sheep are much better at selecting out the green material. Even if animals are largely eating green material, it doesn’t take much dead feed in the diet to really pull back livestock performance.

In seasons like this it is critical that graziers pay close attention to pasture quality and closely monitor what stock are grazing, particularly for young and lactating stock. For both sheep and cattle, Grazfeed modelling shows that pasture digestibility of 65% or above is required to drive lactation, growth rate of the progeny and to prevent excessive weight loss in mum (Tables 1 and Table 2). If you are concerned about pasture quality with young and lactating stock, it is best to offer a supplement with good energy and protein (e.g. grain/pulses, pellets, protein meals, dried distillers grain etc.).

In sheep, pregnancy scanning and separating singles from twins has obvious advantages in dry years when feed is tight, but can also be a big advantage is years like this as you can direct twin bearing ewes to the paddocks with better quality feed. As shown in table 2, twin bearing could lose almost a full fat score by lamb marking when pasture digestibility is around 65%. In contrast, at 70% the ewes only lose 0.4 of a fat score.

Watch the webinar recording.

Table 1. Impact of pasture digestibility on cow and calf performance.

The values in the table have been predicted using Grazfeed and are a summary after the first 8 weeks of lactation.