11 January 2010

8 minute read

Introduction

As we are at the start of a new year we should undertake an in-depth analysis of our farm systems and strive to begin 2010 with a revised focus. The fundamentals of higher farm profits should be re-examined. Grazed grass (as good as, if not better than concentrates in quality terms) costs approximately 7c/kg dry matter (DM) compared to grass silage at 13c/kg DM and concentrates at 22c/kg DM. Therefore, its proportion in the cow’s diet in early lactation must be maximised. Low levels of grass utilisation is related to issues such as stocking rates, levels of concentrate supplementation, poor grassland management, low levels of reseeding, and significantly, a low number of days at grass. Currently we achieve on average 220 days or a little over seven months grazing. Therefore, issues relating to this need to be addressed.

The achievement of early turnout is fundamental. A survey carried out in 2009 focusing on grassland management in Ireland found that partial turnout occurred on average on the 26 February with full turnout occurring on the 17th of March. The main reasons given by farmers for delayed turnout were grass availability and soil conditions. Good farm infrastructure and the implementation of management techniques such as use of On/Off Grazing will help overcome difficulty with soil conditions. The use of a spring rotation planner will ensure grass availability in March and April will not become an issue.

Increasing the proportion of grazed grass in the diet of the cow in early lactation will result in increased total DM intake and higher milk solids production. Early turnout to grass also increases sward quality in subsequent rotations and most importantly increases farm profitability by €2.70/cow for each additional day at grass. This financial reward relates to production gains such as improved milk composition/yields and to a greater degree on reduced concentrate and silage costs.

On/Off Grazing, turning cows out for three to four hours after morning and evening milking, is a key management tool on wetter more difficult farms and when used in conjunction with the spring rotation planner offers enormous potential to increase the number of days cows are at grass. A good farm road network, along with multiple paddock access points are prerequisites. It is also important to remember that grazing conditions in the months of February and March of the past two years have often been better than those experienced during our summer months, and hence represents a missed opportunity if cows remain indoors until mid March. Demand for grass from lactating cows in February is low as it includes a large number of freshly calved cows and a large proportion of heifers. This combined with a current National average stocking rate of 1.8 LU/ha and six-week calving rate of 53 per cent, means that on the majority of farms overall grass demand per hectare in the first rotation is low. Therefore with the implementation of a simplified grazing plan one can determine the date on which the 1st rotation is completed, ensure grazed grass forms a large part of the cow’s diet in early lactation and maximise grass growth rates. Furthermore, the planner works regardless of farm location, stocking rate or herd calving pattern.

How does the Spring Rotation Planner work?

The spring rotation planner relies on the principle of grazing a set area each day and adjusting herd demand to grass availability. Defined weekly and monthly targets relating to the proportion of the farm to be grazed are given.

The aims of the planner include:

• Simplify spring grass management
• Inclusion of grass in the lactating cows diet every day in Spring
• Maximisation of farm grass growth rates
• Avoid uncertainty in relation to grass availability in April
• Achievement of an 18 to 20 day rotation in late April
• End 1st rotation at the beginning of April
• Set up the farm for quality grass production for the year

By adhering to the planner it ensures that any paddock which is grazed gets adequate recovery time before it is re-grazed. Paddocks grazed in early February will not be re-grazed again until mid April. This allows approximately 60 days regrowth and thus ensures adequate pre-grazing yields. February grazing also encourages improved growth, especially important with stagnant paddocks. It is important to realise that the area grazed in February represents the area which will be grazed at the beginning of the second rotation. Therefore this area should be grazing area rather than silage area.

For the planner to be most successful, one must:

• Close paddocks in the previous October (middle two weeks of month) to provide grass in February
• Turn out freshly calved cows fulltime from 1 February (7-10 days later in more northern or wetter farms)
• Stick to your target area; do not graze more or less per day
• Have 33 per cent of the farm grazed by 1 March
• Have 60 per cent of the farm grazed by 17 March
• Use a strip wire to allocate grass on a 12-hour basis
• Adjust supplementation to grass supply

Grazing pressure or post grazing height should be used to determine if supplementation is required. Where grazing conditions permit, it is essential to achieve a post-grazing height of 4cm (mobile phone on its side). The grazing area should be back fenced in wet weather to avoid damage and cows should be housed after three to four hours of grazing during inclement weather conditions without silage.

Table 1 below is the 2009 spring rotation planner for this farm highlighting the proportion of the farm to be grazed each week. During the first week of February, approximately 0.36 of a hectare (0.89 acres) or 3,600m2 (0.36 x 10,000) must be allocated to the calved cows each day. By the end of the week the target grazed area is 2.5ha or 7 per cent of the farm with 11.5ha (32 per cent) of the milking platform to be grazed by the end of February. For the week commencing on the 1 March, 1/68^th of the area or 0.53ha of the farm must be grazed each day.

Table 1. SPRING ROTATION PLANNER for the farm outlined above with 72 spring-calving cows on 36ha

The main focus is to graze the set area each day to the desired post grazing height and adjust herd demand accordingly. If the cows have too much grass and fail to graze out paddocks properly, supplementation must be reduced. In a case where targets are still not being achieved more animals may be turned out (replacements or dry cows, etc). In order to achieve the target area grazed by March some paddocks with low covers may be grazed.

On occasion where cows are short of grass and consequently being forced to graze too tight, supplementation must be increased. Extra areas of the farm perhaps not intended for grazing with the dairy herd could also be grazed or perhaps more use could be made of the silage area if near the parlour.

For this farm, if we compare fulltime turnout on 1 February as opposed to mid March this represents almost €4,000 additional farm profit, with this figure improving as more cows are calved in early February. 1 ha = 10,000 sq metres (e.g., 100m x 100m) = 2.471 acres.

Table 2 below is a blank copy of the spring rotation planner for your use next spring

Table 2: Spring Rotation Planner for your farm in 2010

For a computerised version of the table above go to the link below, enter your own data and print off your planner or contact your adviser to do so: http://www.agresearch.teagasc.ie/moorepark/Articles/springrotationcalculator.xls