Bar Tech May 2021

Despite the inclement weather recently, grazing is well underway across the country. A few wet nights and days have forced livestock back indoors briefly, but thankfully this has only been short term in most cases. The two biggest factors to affect grazing systems so far this year are rainfall and cold weather. Cold weather, especially at night, has prevented regrowth on already grazed paddocks and when this is coupled with heavy rainfall the situation will be made worse by poaching and sward damage.

Early spring grazing

Research by Lively et al, (AFBI 2007), has shown improved livestock performance by turning cattle out earlier in the spring. Not only is there an increase in liveweight gain due to the highly nutritious value of spring grass but there is the added benefit of reduced feed costs and lower ammonia emissions. We recommend selecting grass mixtures with varieties that are designed for early spring growth with good sward density which will benefit your farm, even in a year like this.

When to graze & cut

In order to get the most out of grass, the quality of the sward is dependant on stage of growth. Grass that is to be grazed should be targeted at 3 leaf stage. A sward of grass grazed at 10cm will give somewhere between 3000-3300kg DM/ha. Anything over 3500kg DM/ha will be grasses at 4 leaf stage and these should be mown and round baled to allow new regrowth for the next grazing cycle. Stock should be removed from a grazed sward at 4cm or at 1600-1800kg DM/ha again to allow for sufficient regrowth for the next cycle.

Check your sward regularly for composition. Weeds are less palatable and will often be overlooked by livestock and should be replaced or boosted with new grass and herbal leys to increase livestock performance, health, and farm productivity.

How to improve the sward

Poor composition swards or those damaged from poaching and weather can be overseeded with varieties to improve density or simply to improve the life of the sward by increasing its yield, quality and palatability and preventing infestation of weeds and weed grasses.

If the field is badly poached, it might be a simple case of broadcasting seed and rolling it in. Other cases may need to be harrowed in and then rolled; a visual assessment of the sward will soon determine what method is required. In any situation where bare soil can be seen broadcasting will suffice, harrowing is required if any thatch and/or dead material needs to be removed to allow seed-to-soil contact. Either way, for seed to germinate, it must come into contact with the soil, scratching it in or broadcasting it over a mat of material simply will not work.

It is important to remember that as soil temperatures are increasing, now might be a good opportunity to introduce clover to the sward. Establishing clover in soil temperatures over 10°C, can fix up to 150kg N/ha from the atmosphere as well as providing a more palatable bite for grazing animals. Clover blends of 2 or 3 varieties are best suited as the varieties will adapt to the management of the sward and ensure constant clover cover throughout the year.