New Exciting Lucerne Cultivars

If optimisation of animal production is your goal, lucerne is one of the most effective options for achieving it.

Lucerne, the "king of fodder crops", is a perennial pasture legume with a strong deep root system that is well adapted to a mixed farming system. The biggest benefit of lucerne is the good quality hay it produces. It can be grazed with the correct livestock type if astute management practices are applied. Lucerne can be successfully cultivated under intensive high hay production conditions under irrigation or less intensively under dryland conditions as long-term grazing. Lucerne is well adapted to a variety of climatic conditions, but has specific soil requirements regarding fertility, drainage and acid saturation.

Lucerne is a legume that fixes nitrogen (N) from the atmosphere for its own use. It is important to remember that the lucerne plant itself does not fix nitrogen, it is achieved by Rhizobium bacteria in the soil living in symbiosis with the lucerne plant. In South Africa, the right Rhizobium species does not occur naturally in most soils. Therefore, the seed must be inoculated with Rhizobium spores to ensure that the bacteria is present in the root zone of the lucerne plant. The Rhizobium used to inoculate seed is daylight sensitive and therefore seed must be covered during the planting process. The lucerne seeds are small and should be planted shallow and rolled.

PANNAR now has two exciting new cultivars; PAN 4770 and PAN 4992. Cultivar selection is determined by the purpose of the crop. For example, is it being planted for hay production, grazing or for dual-purposes and how long should the stand last? Is it a permanent pasture or a rotational crop? Non-dormant (9) cultivars are usually used exclusively for hay production and are winter-active. Intermediate Dormancy (7) cultivars are semi-winter dormant and more hardy against cold damage.

PAN 4770 is an intermediate Dormancy Class 7 cultivar. It is a robust cultivar, equally suitable for top hay production or to be grazed and for production under dryland or irrigated conditions. It has two outstanding features, it is leafier compared to the older plant genetics (higher leaf to stem ratio) and produces relatively fine stems that retain their bottom leaves very well. In ARC trials conducted at Vaalharts and Upington, it performed very well and showed a great improvement on SARDI 7. It has good disease tolerance similar to SARDI 7 which it will replace. PAN 4770 seed is derived from dryland seed production stands, which ensures its dryland integrity and performance when it is grazed under dryland enterprises. The plant grows upright and should be utilised in a rotational grazing system. Apply a rest period of three to six weeks for sufficient regrowth and recovery of root reserves - this is beneficial for the sustainability of the planting.

PAN 4992 is a strong non-dormant Class 9-type cultivar, especially suitable for producing high yields of hay and silage, although it can also be utilised as grazing. This is a highly winter-active cultivar and a new benchmark for yield potential, destined as a market leader. It achieved the highest yields in Australian trials. It has very good disease tolerance which also includes tolerance to Anthracnose. PAN 4992 has an upright growth habit and a high leaf to stalk ratio, with good leaf retention when it is baled for high quality hay. Limit mechanical leaf loss on the land by cutting early in the day, raking it into rows before the lucerne has dried completely and reduce the tractor speed. Minimise handling during the curing process. Handle the hay early in the morning before the dew has evaporated or late in the afternoon when the humidity is higher.

Lucerne utilisation:

By managing lucerne correctly, production and use can be optimised. Utilise lucerne at regrowth (see illustration) and not at the 10% flowering stage. The Lucerne is ready for cutting or grazing when more than half of the plants show two centimetres of regrowth buds from the crown of the plant. Protect these new shoots by setting the cutting height for a minimum of seven centimetres. This is beneficial for optimal production as well as longevity of the lucerne stand.

If the regrowth is cut off, it will be detrimental to the next harvest, as the plants first have to produce new shoots before they can be harvested. Cutting the lucerne before the new shoots have formed drains the reserves in the roots, which in turn will lead to a reduction in production. This all contributes to a reduction in overall production and a shortened lifespan of the pasture.

Always remember that bloat is a risk associated with grazing of lucerne. Visit the animals regularly, apply high stocking rate with strip grazing. Avoid introducing hungry animals onto the crop, especially young lucerne. Give animals access to grass, crop residues or hay. If animals seem uncomfortable in any way, immediately remove them from the lucerne.

Bloat of animals when grazing lucerne:

There are many false perceptions about bloating when grazing lucerne and it is important that we have the right knowledge to manage the problem. Bloat is usually a seasonal problem in both cattle and sheep. The condition is usually precipitated by the rapid consumption of lush legume pasture species (especially clover and lucerne) in spring.

Bloat is caused by an increase in the gas pressure within the rumen (paunch) as these feeds are fermented. The gas cannot be belched up normally and death results from the pressure causing heart and lung failure. The gas is often trapped in the form of a stable foam.

Bloat through lucerne and other plants is mainly caused by soluble proteins and possibly saponins (plant components that form foam when shaken in water), which occurs in plants. Young, fast growing lucerne plants have cell walls that are very thin and digest quickly. Thus, the soluble protein is released at a rapid rate in the large intestine causing bloating due to the formation of foam. If the large intestine is in a state of very active fermentation, like when other carbohydrates are fed in conjunction with the lucerne, it will enhance the formation of foam and consequent bloating. Animals should therefore not receive a high carbohydrate lick or concentrates if they are going to graze on lucerne.

Traditional methods of bloat prevention rely on chemicals which break up the foam and release the gas. Various remedies are available on the market. If the animals eat sufficient roughage before they are put to the lucerne grazing, it will also reduce the risk of bloating. High pressure grazing on a small area will also force sheep to eat the whole plant, not just the high protein and soft areas.

Don’t confuse bloat with prussic acid poisoning - Lucerne does not contain prussic acid. Do not try to treat the sheep with flower sulphur in a lick and hypo in the drinking water. Sulphur and hypo are used for the treatment and prevention of prussic acid (cyanide in plants) poisoning.