Farm Ireland
Independent.ie

Wednesday 24 January 2018

An assessment of grass growth is now vital

Mary Kinston

As the first spring calves hit the ground, many farmers have taken the opportunity to do a farm walk and assess the feed situation in the paddocks. This is one of the most important tasks that a farmer must do before calving gets into full swing.

It allows you to determine your average pasture cover and make any necessary adjustments to your spring feed budget in terms of the level of supplementary feeding required -- and your spring rotation plan as described last week.

Grass is an essential part of the feed supply throughout the spring if you are attempting to maximise profitability, yet it must be used strategically and with a planned approach.

It is unlikely, however, that doing the farm walk will put you in a positive frame of mind. The return of the bitterly cold weather this winter saw some of the lowest temperatures ever recorded in Ireland last month. Along with heavy snowfalls, this resulted in pasture covers being lower than desired. Many paddocks have actually lost pasture cover during the winter and some paddocks are also showing significant signs of winter damage.

These are the consequences of 'winter burn'. This is the desiccation of leaves and tillers, where the tissues dry out, shrivel and become yellow-brown in colour.

The extent to the damage can range from the leaf tips only, which is apparent on covers of less than 1,000kg DM/ha, to virtually all of the plant's above-surface vegetation. The latter is more extreme but evident in places where paddocks had a closing cover of 1,500kg DM/ha or more, or for proud patches around dung pats where paddocks weren't cleaned out.

Luckily, due to the physiological nature of the grass plant, most of the growing points are at, or just below, the soil surface, so, generally, grass tillers will usually survive. Initial growth will often be slower than from non-winter burnt material, but spring production potential may not be markedly affected. However, complete winter kill of grass tillers and roots can occur, with areas of dead grass and bare patches of soil becoming apparent as spring progresses. Where this is obvious, surviving tillers will often be thinned out and plant growth vigour reduced.

Milder

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The weather seems a degree milder than it did last January, and there is certainly potential for grass growth on the horizon. But now is the time for tough decisions, regardless of concerns about increasing feed and fertiliser prices. If you do nothing now, you are more likely to increase your requirement for expensive bought-in feeds later in the season. Listed below are some key action points to implement:

- Face your situation, and take action now -- walk the farm, find out the deficit, adjust your feed budgets etc.

- Use longer rotation lengths to maximise grass growth and reduce the decline in pasture cover. Do not speed up the rotation if pasture cover is dropping below your feed budget target. Revise your spring rotation plan by adding 10 days for every 100kg DM/ha of pasture cover that you are short at the start of grazing season.

- Use supplements to protect and build pasture cover, or reduce demand by milking once a day if feed is short or milk quota a concern. But if you are going down this road, use once-a-day from day one of milking freshly calved cows to avoid any spikes in somatic cell counts.

- If you are using straights such as citrus pulp, know the characteristics and limits of your feed type and diet inclusion rate to avoid nutritional upsets. Build up feeding levels slowly and be careful with fresh calvers coming into the milking herd when feeding levels are greater than 4kg/hd. Start feeding to dry or springing cows if it's of concern.

- Protect future pasture growth by minimising poaching.

- Do not reduce average farm pasture cover below 300kg DM/ha available cover to protect and maximise pasture growth rates. If covers are at 300kg DM/ha, this simply means that pasture demand must not exceed grass growth rates.

- Apply nitrogen to boost growth or applications of slurry less than 2,000ga. Aim to get out 16-20 units N/ac. Use fertilisers containing sulphate for low spring soil temperatures to boost growth.

- Monitor soil temperatures to aid your decisions. The threshold soil temperature for grass growth is 6 C.

- Monitor pasture cover weekly (no less than once a fortnight) and adjust your plan accordingly.

Dr Mary Kinston is a farm consultant based in Kerry. Email: mary.kinston@gmail.com

Indo Farming