TAKE HOME MESSAGES
- The cereal varieties and winter gap fill blend provide livestock with substantial feed during autumn and winter, then go on to produce high quality hay in spring.
- Clover, medic and forage brassica varieties provide nutritious feed over winter, spring and into early harvest time. These varieties also offer a disease break in a cereal rotation.
- Nutritional value of varieties was exceptional and would provide an excellent feed source for lactating ewes and lambs.
BACKGROUND
With varying rainfall and late autumn breaks, growers are faced with obvious feed gaps throughout the year. Feed gaps pose a risk to livestock producers: during these times they may be forced to supplementary feed grain or hay.
On any farm there may be several different pasture and feed sources (annual pasture, native or introduced perennial grass pastures, lucerne, grazing cereals, forage crops and crop stubbles) that can provide forage at different times of the year. Total farm feed supply determines how well a livestock enterprise and associated stocking rates match your growing season. However, it is important to also consider the quality of the pasture at different times of the year. Each different fodder type offers various rotational benefits and requires different grazing management strategies to suit its growth.
Previous BCG research, undertaken through the Grain & Graze 2 program, has showed that cereal varieties can successfully be grazed and either used for hay production or harvested for grain. This trial looks to assess other pasture and crop types, including legume pasture varieties, which may provide growers with added benefits in their rotations, help fill feed gaps and limit supplementary feeding.
AIM
To assess and evaluate a range of different pasture varieties at three different sites.
METHOD
Table 1. Management practices used in these trials at three locations.Â
Trial management is described in Table 1 and pasture varieties are described in Table 2. Dry matter (DM) production was measured at various times at the three sites for each variety and crop type. Biomass cuts were taken immediately prior to simulated grazing using a mower which enabled complete and even grazing. Tissue samples were also taken at these times for feed testing.
Dry matter cuts taken at peak biomass were used as an indication of hay production. Peak biomass for most species occurs at flowering. After flowering, biomass is rapidly lost during the drying off phase.
Using DM and feed tests, dry sheep equivalent (DSE) grazing days were calculated as follows:
DSE grazing days = DM (kg/ha) – 30 (kg/ha; physically unavailable DM) x feed test metabolisable energy (ME) / 8 MJ, which assumes that each DSE requires 8 MJ/day.
Table 1. Variety information for all pasture varieties sown at Marnoo, Hopetoun and Watchupga East, 2013.
RESULTS AND INTERPRETATION
All three sites were exposed to different rainfall and soil conditions. Marnoo received considerably higher growing season rainfall (GSR) than the other two pasture sites (Figure 1), which meant that more measurements could be taken due to earlier growth.
Figure 1. Growing season rainfall data for Marnoo, Hopetoun and Watchupga East pasture sites, 2013.
Watchupga East and Hopetoun sites
The Watchupga East and Hopetoun sites received only 221mm and 192.4mm GSR, respectively. These levels of rainfall are well below what is recommended for all varieties. Due to the late break at both of these sites, an early grazing was not possible. Peak biomass (with the exception of lucerne varieties) at the Hopetoun site was recorded on 17 September and at the Watchupga East site on 16 October. Cereal or ryegrass varieties were the highest yielding varieties at both sites (Table 3). These species tend to offer more feed during this feed gap due to early vigour after emergence. The lucerne varieties were not yet at peak biomass; more growth was seen in the spring.
Under tough seasonal conditions, winter cereals (Outback oats and Moby forage barley) and ryegrass varieties produced more feed than clover, medic or lucerne varieties (Table 3). Winter gap fill blend (Moby forage barley 75%, Jivet Tetraploid annual Italian ryegrass 15%, Cavalier Spineless Burr medic 7% and Bouncer brassica 3%) measured a high dry matter production due to the 75% of Moby barley. Although having adequate dry matter production, clovers, medics and lucerne varieties were relatively low compared with cereal and ryegrass crop types . This could be due to low rainfall and slightly alkaline soil types.
Table 3. Summary of dry matter production at peak biomass production for each variety at the Hopetoun and Watchupga East sites.Â
Marnoo
Emergence was very even across the Marnoo site, in response to 344.2mm GSR. Most of the  varieties showed amazing growth in response to regular rainfall events. Varieties all had good early vigour (Figure 2) and were able to be ‘grazed’ on 1 August. Moby barley, Outback oats and the winter gap fill blend had the most dry matter present at this first grazing, due to their early growth habit. Growth to the second grazing (25 September) was dominated by Tetrone, which produced an  additional 9.8t/ha after being grazed. All varieties recovered well from grazing and, in the majority of cases, biomass production at the second cut was more than three times that achieved from the first grazing, with the exception of Moby barley and winter gap fill blend. Peak biomass was measured on 31 October with Moby barley and outback oats measuring 16t/ha and 15.9t/ha respectively, indicating that these two varieties were exceptional cereal hay producers.
Figure 2. Dry matter production for varieties that were able to be grazed early.
These varieties are targeted for autumn/winter feed gap times. There was no peak biomass result for Sub Zero brassica due to sampling error.
All remaining varieties which were unable to be grazed early in August, were first measured on 25 September (Figure 3). The absence of early grazing value is due to the spring growth habits of these varieties. Perun festulolium provided the most biomass at this time of grazing. Turbo persian clover produced 1t/ha more than most of the other medic and clover varieties.
Figure 3. Varieties able to be grazed on 25 September. These varieties are targeted for winter/ spring feed gap times.
Most of the varieties exceeded the minimum nutritional requirements of lambs and lactating ewes (Table 4). DSE grazing days were calculated and a number of varieties produced over 5000 DSE grazing days, mainly in the winter spring feed gap period. Some earlier autumn/winter feed producing varieties were still able to produce between 1000 and 4000 DSE grazing days (Table 4).
Table 4. Dry matter production (t/ha) and grazing value of crops grazed at two different timings at the Marnoo site.Â
COMMERCIAL PRACTICE
There are a number of new varieties on the market capable of fitting into current mixed farming systems that experience feed gaps during harvest and in the early autumn. Numerous pasture types are able to meet the nutritional requirements of livestock systems at crucial times when supplementary feeding is most common.
Given favourable seasonal conditions, clover, medic and brassica varieties are able to provide nutritious feed over winter, spring and into early harvest. These varieties also offer a disease break in a cereal rotation. The cereal varieties and winter gap fill blend are able to provide substantial feed during autumn and winter, then go onto produce high quality hay in spring. Previous trial results have shown that Moby barley can be grazed as early as six weeks after sowing.
The nutritional value of varieties was exceptional and would provide an excellent feed source for lactating ewes and lambs. Clovers and medics are two nitrogen fixing pasture types that could replace vetch in rotations for increased grazing opportunities.
ACKNOWLEDGMENTS
This project is supported by Northern Victoria Grain & Graze 2 program (GRDC project BWD00018) funded by GRDC and Caring for Our Country. These trials were run in collaboration with Seed Distributors.
