Herbs in mixes increasing in popularity

Mark Palmer, Stephen Pasture Seeds, Northern VIC & Southern Riverina NSW

With the increasing interest from consumers in pasture fed livestock, a desire to increase total dry matter, and improve daily live weight gains are all contributing factors to the increase in popularity of including forage herbs in pasture mixes.

With their high nutritive value and rapid rumen degradation rates, as well as solid dry matter production, they bring a lot to the table. They can also prove to be a good tool for managing variable climatic conditions and accessing soil nutrients through their agronomic features which are detailed below.

There are two main species of forage herbs which are represented in the Agricom portfolio, Tonic plantain and Choice chicory. The flexibility they bring to mixed pasture swards can vary between them.

Tonic plantain

Tonic plantain is a very hardy, adaptable herb in that it has the ability to handle a pH of 4.2-7.8 (Troelstra & Brouwer 1992), meaning it is suitable to many of the soils in which ryegrass and clover are found. The ability of Tonic Plantain to withstand periods of moisture stress, and poor fertility situations due to its fine yet dense root system, also makes it highly compatible with cocksfoot and phalaris. Tonic also thrives on the availability of nitrogen therefore partners well with pastures containing legumes.

A particular feature of Tonic plantain is its ability to produce dry matter through the winter months similar to that of perennial ryegrass (Moorhead & Piggot 2009). Where it can really add value is its ability to respond to summer and autumn rains. Moorhead & Piggot (2009) found that a Tonic based pasture sward produced significantly more dry matter during the trial compared to ryegrass based pastures. The extra dry matter produced is also of very high quality providing significant animal performance benefits. Tonic plantain will produce the bulk of its dry matter from autumn through spring and this should be taken into consideration when choosing to include it in pasture mixes.

Judson et al (2009) demonstrated that lactating ewes grazing Tonic plantain had both a higher lamb weaning weight, and a higher ewe live weight change. Lambs coming off perennial ryegrass had an average weaning weight of 33.9 kg/head, whereas Tonic plantain had an average weaning weight of 41.1 kg/head, an increase of 22% per head in year one of the trial. The improved weaning rate ranged between 10% and 34% (Judson & Moorhead 2011). Over the course of the four year trial with regards to the ewe live weight change on perennial ryegrass, ewes on average lost 7.5 kg/head, however when grazing Tonic plantain they gained 6.6 kg/head during the lactation period. Whilst we acknowledge the above work was completed using pure stands of both Tonic plantain and perennial ryegrass, the work still highlights the potential contribution forage herbs can make in a mixed pasture sward.

Choice chicory, on the other hand, is a warm season growing plant, offering the bulk of its dry matter production from mid spring through to autumn. With its deep tap root, similar to that of lucerne, it has the ability to access moisture from deep in the soil. This allows it to produce quality dry matter during summer even when irrigation or rain are in short supply. The deep tap root on Choice chicory also helps to extract and utilise nutrients at depths that other species may not be able to access.

Other key features of Choice chicory is that it is one of only a few perennial chicories on the market, making it ideal for mixes with other perennial species. Other cultivars on the market tend to be biennial, meaning their expected life span is only 18 months to two years. Chicory also has a very high tolerance to insects. With its strong spring through autumn production this can be a highly beneficial attribute when considering the likes of diamond back moth and aphids.

With both forage herb options the total seasonal dry matter yield is similar to that of perennial grasses, with potential yields ranging from 14 to 18 tonnes of dry matter. Although their seasonal growth curves are different depending on the grass it is compared to. It is important to remember that best practice management is required to achieve any species full potential.

Key influential factors behind the improved animal performance of both forage herbs is their high feed quality and rumen degradation rate. The feed quality that is achievable by both Tonic plantain and Choice chicory is similar to that of most clovers. With typical Metabolisable Energy (ME) values of 11 to 12 ME and Crude Protein (CP) levels of 16- 24%, both herbs have the ability to raise the forage value of a pasture sward.  This is particularly true late in the season when grasses have begun to go reproductive, at which stage they significantly decline in feed quality. Coupled with this is the fact that both Choice chicory and Tonic plantain have a rumen degradation rate of 2.5 hours. This is less than half that of perennial ryegrass at a degradation rate of 6 hours, or kikuyu and paspalum at 10 hours.

Herbs can be quite adaptable as companion planting species. Both Tonic plantain and Choice chicory are very successful when mixed with perennials such as ryegrass, tall fescue, cocksfoot and phalaris. Depending on the individual situation the inclusion rates range from between 1 and 6 kg/ha. They are also a fantastic addition to forage crops aimed at finishing off livestock. When mixed with the likes of clovers, lucerne or brassicas they can provide a very highly digestible, nutritious forage source. The inclusion rate in these targeted finishing crops is higher than the perennial mixes. Rates can range from 5 to 8 kg/ha depending on the situation. The latter mixes also provide a brilliant grass weed clean up opportunity prior to sowing down to perennial grasses. In these instances the herbs can actually persist and make up a component of the perennial pasture sward.

So if you are looking for a way to increase live weight gains, improve the general health of your livestock, and their overall efficiency then forage herbs would be a worthwhile addition to your pasture system.

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