Managing your farm through dry weather conditions – Considerations for dairy farmers

Dry and hot weather conditions currently experienced across the province are having a real impact on grass growth and supply on farms, writes Conail Keown, Senior Dairying Adviser, CAFRE.

Friday, 23rd July 2021, 8:53 am
Zero grazed grass mixed with silage for housed cows – Grass away from the farm and not normally available for grazing can be fed by zero grazing, either mixed with silage or on its own.
Zero grazed grass mixed with silage for housed cows – Grass away from the farm and not normally available for grazing can be fed by zero grazing, either mixed with silage or on its own.

Some Grass Check sites in the south east have recorded zero rainfall so far in July, and with record temperatures forecast to continue for the next ten days grass supply will become limited as soil moisture deficits continue to impact on growth.

Grass Check shows that growth is well below the previous 10 year average. Growth rates on farm have dropped significantly with average farm cover now well below target on many farms. This has restricted grass supply on farm already and it’s now likely to have serious implications on winter fodder stocks – especially in the east of the province.

Given the risk of sustained dry weather, it is important that prompt actions are taken to manage the situation.

Conail Keown, Senior Dairying Adviser, CAFRE

Grazing management tips

The main priority now is to reduce daily grass demand to below daily growth rate. This will help to hold grass cover on the farm, protecting current growth and speeding up recovery when rain arrives.

Rotation length should be maintained at 25-30 days, this means grazing no more than 4% of the grazing block on your farm daily. Assess the grass available on this area and supplement with forage/concentrate to balance herd demand.

If there is a larger deficit between growth and demand it will be necessary to temporarily reduce demand further by reducing grazing stocking rate and feeding extra silage.

Paddock 4 weeks post grazing in East Down – Many farms in the east are experiencing significant shortages of grass with little growth over the course of the last rotation.

Increasing rotation length beyond 30 days may lead to much reduced grass quality in current conditions

Maintain normal fertilizer N applications after grazing if possible. However, if drought conditions persist to greater than 60mm soil moisture deficit it is advised to delay N until rain is forecast, this is currently the situation in the East of the province.

Hints and tips on feeding out forage supplements in dry weather

Currently on many farms where average farm cover has significantly dropped the only option is to feed additional forage and supplement the herd to maintain production. Each farm will have its own preference (based on facilities/machinery/labour) but the main aim remains to reduce total daily grass intake to the level of daily growth or below. Some of the best options for feeding include:

1. 100% silage and meal in a shed or a convenient paddock, this may be a paddock marked for reseeding later in the year. A small area of fresh grass can be allocated to the herd daily. Some farms have used a temporary wire feeding rail to good effect. This approach simplifies grazing management of the main group. However, there is a risk of injury due to slippery concrete floors if feeding in a shed and adequate space is needed.

2. Offer silage to all cows in the grazing paddock, placing silage along perimeter fencing if possible. This works best where feed can be allocated with a diet feeder. Silage allocation should be calculated to balance available grass on the paddock daily. Forage should be spread along a long linear distance (1m per cow) to reduce bullying.

3. Feeding silage swards or zero grazed grass from outlaying blocks can fill a grass supply deficit. However, this should be based on pre grazing cover. If silage swards have surpassed ideal pre-grazing grass cover and are nearing cutting stage then it is preferable to leave for silage cutting at this stage;

4. High fibre straights can be offered such as palm kernel, soya hulls, beet pulp or other forage reducing straights. These are best fed in mobile troughs or as part of the mixed ration.

5. With the hot and dry conditions ensure full access to clean water, if feeding in a paddock additional water access maybe required.

Whichever actions are chosen, it is vital to act now to ensure that any remaining grass supply is rationed out as early as possible. Also plan to supplement with forage and concentrate until grass growth exceeds demand.

Feeding additional concentrate during drought conditions:

Parlour-fed concentrate will form a major part of daily feed allowance in drought conditions. Some guidelines for this include:

· Feed additional parlour concentrate up to a maximum of 50% of the diet dry matter. This is a relatively safe level provided adequate water is provided.

· Crude protein should be decided based on overall composition of the diet. In normal circumstances a 14-16% high energy ration would be adequate at grass. However, during a drought it is likely that lower protein ingredients will form a significant part of the diet with a small percentage of the diet actually fresh grass. Also, where grass is drought stressed and lacking N uptake, it is possible that sward protein content could be lower than normal. Therefore, it is recommended that a higher protein ration be used if grass intake is restricted for example 16-18% protein.

Other management issues

If dry conditions persist into August consider offloading problem cows that are already in line for culling;

Do not neglect youngstock - total dry matter intake requirements are small relative to the milking herd but nonetheless adequate feed must be offered daily.

If silage must be fed for a few weeks in summer, complete an early fodder budget. This will allow plenty of time to take action if there is a risk of feed shortages later in the year.

On Tuesday 27th July at 8:00pm, CAFRE is hosting a webinar looking at options to help you manage your farm through the current period of dry weather and to plan for the longer term impact this will have on winter feeding and fodder supplies. Pre-registration is required – you can register at www.cafre.ac.uk/managingdrought