 To gain an understanding of how and when grass grows and is utilised  To understand different grazing systems  To learn how to budget grass and measure grass covers  To gain understanding of how to plan grazing and stocking rates for ranges of stock

 The amount of grass grown depends on many factors 1. Soil temperature (>6° C) 2. Light 3. Water 4. Nutrient availability 5. Grass type/breed

 Perennial Ryegrass (most commonly sown grass type in NI) has 3 individual leaves on each plant  As the fourth leaf begins to grow, the first and oldest leaf dies  Hence new growth only replacing the lost dead grass

 At peak growth there is a new leaf every 4-5 days (May)  Peak growth all 3 leaves replaced in 2-3 weeks  Best time to graze is at 2 ½ to 3 leaves

 No point growing grass if we can’t get animals to use it properly!  Utilisation ranges from 50% to 80%+  Key is graze at right time, to the right height and with right amount of stock

 Not easy to achieve high utilisation 1. Poor sward composition (old grasses, weeds) 2. Previous grazing history 3. Dung and urine areas

 4 main grazing systems used 1. Set stocking 2. Rotational grazing 3. Strip grazing 4. Paddock grazing

Set stocking Rotational Paddock grazing

Animals have unrestricted access over a wide area throughout the grazing season

ProsCons Low management inputLower grass yield Low capital cost (1 drinking trough, external fence) Difficult to manage and maintain grass quality and height Can work well if sward height maintained at correct level Uneven manure distribution Lower utilisation due to trampling Weeds allowed to build up

Animals move around a small number of fields based on sward height or after a certain number of days

ProsCons Higher production than set stocking More fencing required Allows pasture to rest and recover Extra drinking troughs needed Can extend the grazing season Grass production and utilisation not optimum More even distribution of manure

Animals given a new allocation of grass each day by mean of electric fence

ProsCons Useful when excess of grass at points in the year Labour intensive. Fence needs moved each day Good utilisation of grass – very little trampling or spoiling of grass Water availability a problem Very good for forage crops like kale and rape Not ideal as cattle are usually allowed back over previous days grazings Hampers re-growth Can lead to trampling along fence line

Animals are moved frequently through a series of paddocks based on measured grass heights or grass covers

ProsCons Highest grass production and use Initial cost of fencing and water troughs High quality grass & higher stocking rates More intensive management – skill required More even manure distributionRequires careful monitoring Can extend grazing season Allows for excess grass to be cut out as silage (bales) Quieter/more manageable stock?

SystemAnnual Yield (t DM/ha) Utilisation (%) Usable yield (t DM/ha) % increase Set stocking Rotational % Paddock %

 Grass is usually measured in kg of Dry Matter  Grass availability measured in kg DM/ha  Lowland ground has the potential to produce 12 tonnes DM per hectare per year

 However, due to lower inputs and poor grazing management typical utilisation in NI is 5.0 tonnes DM/ha  Well managed farms 8-10 tonnes DM/ha realistic target  Daily grass growth varies from 5kg DM/ha in February to 100kg DM/ha in May

 Grass cover is the average amount of grass to ground level  This includes the grass available for grazing and that which is left after grazing  Important to know how much there is!

 Number of methods used 1. Sward assessment using rising plate meter 2. Visual assessment 3. Sward heights

 As rod is lowered into pasture, plate is supported by height and density of grass  This is averaged out over a paddock/field taking number of readings across field

 Walk each field in ‘W’  Take top leaf readings  Avoid gateways etc  Calculate field average and record  Keep record each week

1500 kgDM/ha 4-5 cm 2000 kgDM/ha 6-8 cm 2500 kgDM/ha 8-12 cm 3000 kgDM/ha >12 cm

 Pre-grazing cover of 3000kgDM/ha (12cm)  Exit paddocks at 1600kg DM/ha (4cm)  Available grass is therefore 1400kgDM/ha  If paddock is above 3500kgDM/ha then consider taking out for silage

Class of stock Grazing period Rotational grazingSet Stocking (cm) Pre-graze (cm) Post-graze (cm) Cows and calves Apr/May June/July Aug-Nov Growing or finishing Apr/May – 6 June/July – 7 Aug-Nov

After weaning Fat ewes – 1650 kgDM/ha (3cm) Thin ewes – 2450 kgDM/ha (6cm) Tupping 1800kg DM/ha (5cm) Mid-Pregnancy Graze down to 1500kg DM/ha (3cm) Lambing outside Onto 1800kg DM/ha (6cm) 4-6 weeks pre- lambing

StageCover kg DM/ha Sward height (cm) After weaningFat ewes Thin ewes Tupping18005 Mid-PregnancyGraze down to Lambing outside Move onto weeks pre- lambing 6

 Another method of grass budgeting  Examine fields or paddocks that a group of stock are grazing and estimate how many days it will be until they are back where they just left  12 days is adequate in May – over 14 should trigger considering taking out surplus  Lower than ten indicates a shortage  As move toward autumn grazing days ahead must increase towards 30

Stock carried per ha MarchApril-JuneJuly-AugustSeptember- October Cow & calf kg store kg store kg store4853

 Considerable research evidence which indicates benefits of early turn out  Could include grazing some of area to be harvested for silage up to start April  Later turnout leads to high grass covers being grazed and utilisation is lowered  Animal performance over grazing season suffers if cattle turned out later

 Preparation starts the previous autumn  Keep group size small  Don’t turn out all cattle  During wet weather subdivide grazing paddocks and move cattle every 1-2 days  Be flexible – if too wet after 10 days, bring cattle back in. 10 days feeding saved

Stock carried per ha MarchApril-JuneJuly-AugustSeptember- October Cow & calf kg store kg store kg store4853

 Options 1. Apply nitrogen 2. Introduce supplementary feeding 3. Sell stock or cull unproductive animals

 Options 1. Increase stocking rate 2. Close up area for silage/Take area out for round bales 3. Reduce supplementary feeding 4. Reduce fertiliser rate

 Options 1. Pre-mowing or topping 2. Higher stocking rate 3. More measurement & management