By William McCulloch
Bull Fertility
For many herds a slippage in calving pattern over the past few years means that a high proportion of the herd now calves from March to May. With the herd at grass, Artificial Insemination (AI) and heat detection have stopped and a bull is being relied on to get these cows back in calf. What a shock it can be to pregnancy diagnose these cows at the end of the summer to find that the bull hasn't done his job effectively! Just because a bull worked well last year, don't assume that everything will be OK this year. He may have picked up an injury which prevents him working or an infection which reduces fertility.
Keep records of all observed heats and services. An excessive number of repeat services will alert you to a problem early. You could expect a conception rate of 60% over the first three weeks for those cows served in good body condition. Rates below 30% could indicate sub-fertility and requires immediate action, replacing the bull and culling or treating an identified problem. Using tail-paint on the cows or a chin-ball marker on the bull will help you to identify heats and services.
Carry out a pregnancy diagnosis nine weeks after turning out the bull on cows served by him in the first three weeks and which haven't been seen repeating to check they are in calf. This is particularly worthwhile if you are only identifying a small number of heats/services.
If you have purchased a new bull, check his fertility before you put him in with the cows – get the vet to take a semen sample.
Young bulls run with the herd should not be expected to serve more than 20 cows before being rested as they may serve some cows 5-6 times while on heat. An older more experienced bull could cover up to 60 cows before being rested.
Treat immediately for any signs of lameness as the bull must be mobile.
Grazing Management
Do your autumn calving cows still need to be fed concentrates? Under the current good grazing conditions cows should be eating 15 -16kgs of grass dry matter per day. On leafy re-growths cows could be expected to produce 22 - 23 litres of milk from this grass intake during June. Late turn-out and the exceptional grass growth during early May meant that many swards were poorly grazed out during the first rotation. Re-growth is stemmier than usual, leading to a fall in feeding value - where cows have to graze this low D-value grass allow for only 19-20 litres from grass. Cows in good body condition yielding below these levels, should now be off meal.
Higher yielders, especially April/May calving cows will require supplementary feeding with concentrates. The following table gives a guide to the amount of concentrates required where cows are grazing good quality grass during June. Allowance has been made for the reduction in grass intake as additional concentrates are fed:
Milk yield (litres/cow/day 22 25 30 35 40 Concentrates (kgs/cow/day 0 2 5 8 11
High yielding cows in early lactation have a target protein content of 17-18% in their overall diet. Grass protein levels drop from 23-19% in April/May to 17-15% in June/July. Feeding an 18% protein concentrate should allow the target protein content to be met. In mid lactation an overall diet protein content of 16-17% is adequate, with 15% acceptable for cows in late lactation – grass alone will meet these requirements.
A date for the diary ...
The Plant Breeding Station at Loughgall is holding an Open day on Wednesday 11th June. If you are intending to carry out reseeding or overseeding this autumn, a visit to this event will provide useful information to help you choose an appropriate seed mixture. Areas to be discussed include:
Breeding varieties which maintain high digestibility throughout the grazing season.
How well new varieties perform under grazing management.
The value of including white clover in grazing mixtures or red clover in silage mixtures; and
The possible role for lucerne on dry land.
BEEF AND SHEEP
ByGerry Donnelly
Quality Swards
Beef cattle will gain over 1kg liveweight on highly digestible swards during the summer months. Pastures which contain a high proportion of green leaf will have the highest digestibility.
Material Digestibility Green Leaf 70-85% Green Stem 60-70% Mature Stem 40-50% Dead Material 35-40%
Therefore, grazing leafy material and preventing seed heads from developing is very important in sustaining sward quality. Grazing swards down to 8
-10cms in early June generates more leafy material in later cycles. As a result of close grazing, surplus grass may accumulate ahead of the cattle. If so, this should be removed for silage as big bales. Topping will also over-come the problem of stemmy swards, provided it is carried out early in June to a height of 7cm (3").
Making Round Bale Silage
Due to the recent escalation in input costs, the fertiliser and harvesting costs alone of producing a round bale of silage is likely to increase to approximately £15 per bale. This is based on obtaining a yield of 25 bales per hectare (10/acre).
It is therefore imperative that every effort is made to produce good quality, well preserved silage while keeping the number of bales made per hectare to a minimum.
Avoid cutting grass too low to avoid contamination.
A fast wilt, where practical, will aid preservation and also reduce the number of bales per acre. Aim for 30% dry matter within 1 day.
To achieve a fast wilt, use a mower conditioner to cut the crop and/or tedd immediately once the crop is cut (weather permitting).
Produce dense, broad 'shouldered' bales by presenting a box – shaped swath for the baler.
Using a chopper baler will reduce the number and cost of bales per acre.
Ensure that the contractor has the baler density set to its maximum allowable position and travels slowly along the swath.
Harvest leafy material – saves on expensive meal.
Value of clover
Clover swards are particularly suitable for grazing on many farms where low levels of nitrogen fertiliser are used. The average nitrogen fertiliser use on NI beef and sheep farms is approximately 120kg nitrogen per hectare. An equivalent level of production can be achieved from clover based swards.
Clover swards lose quality more slowly than grass, dropping about two units of digestible value each week. This contributes to greater herbage intake. Up to 10% higher liveweight gain in cattle and 25% higher liveweight gain in lambs.
The production of swards can vary from year to year, but clover based swards could be expected to support up to 2 livestock units per hectare per year. This is equivalent to 2,000 – 2,400kg animal liveweight per hectare in the spring, declining to approximately 800 – 1,100kg per hectare in the autumn.
Establishing clover in swards
Direct reseeding - Plough before the end of August and use 25kg of perennial ryegrass with 4-5 kg of clover seed, sown at about 30kg per hectare.
Overseeding methods can be used to place seed into an existing sward. Techniques such as direct drilling using the Vertikator, very light cultivation followed by sowing with an air seeder such as the Einbock, or discing ground and broadcasting the seed have all been used successfully.
In all cases it is essential that competition is minimised by grazing the sward tightly (4-5cm) in late July, or by following immediately after a silage cut taken mid-July to late August.
Dosing sheep
More evidence of sheep wormers particularly the white drenches becoming less effective because of anthelmentic resistance.
Proper dosing techniques will slow down build up of resistance. The following guidelines will help.
Correct dosing practice – know the weights of lambs.
Use the most appropriate anthelmentic.
Only dose when necessary. Avoid dosing adult ewes during the grazing season except hogget ewes or individual thin ewes.
Use of clean pastures where possible.
Leave 10 percent of lambs undosed i.e. the heaviest and healthiest lambs.
Delay movement to clean pastures for several days after dosing.
Use faecal egg counts to indicate need for dosing – your sheep adviser has a kit for this purpose.
HORTICULTURE
By Graeme Cross
Experience of growing Osteospermums at Greenmount
Osteospermums (Cape Daisies) are a popular pot plant which can either be transplanted into the ground for summer display or be used in container planting. Their colours range from whites, yellows to purple hues with highlighted centres making them wonderful plants for beautifying the home.
Eight of these varieties were demonstrated at Greenmount Campus recently. They were potted into 13cm pots (42 pots/m2) during week 9 and those under glasshouse conditions were marketable by week 19 to 20. Those grown in tunnels were three weeks later giving the opportunity for either early or late crops. Growth habit for each variety is also different and needs to be taken into consideration when choosing which to grow.
For crops grown in the glasshouse growth regulation (0.4ml/l chloroquat applied as a drench) was required whereas those in tunnels do not require any. In general, reduced-peat growing medium (25% and 40% peat reduction) can produce a more compact plant which can further be enhanced by some application of a growth regulator. However, the two varieties tested responded differently.
The cost of plant material range from 13 pence to 51 pence per plug depending on the source (Table 1 below). Plants from all the suppliers produced quality crops at the point of sale. Production in 13cm pots have the added quality compared with the industry standard in 10.5 cm pots and makes them more saleable when there is an oversupply (and hence reduced price) in the smaller pots.
Table 1 Cost of plant material based on catalogue prices 2007/08
Supplier Variety Colour Number in plug tray Price per tray (incl. delivery) Price per plug A Summertime Blueberry Purple 204 £25.88 £0.13 B Summertime Yellow Yellow 204 £25.88 £0.13 C Dalina Blanc White 84 £19.32 £0.23 C Dalina Xanthe Purple 84 £19.32 £0.23 C Sunny Davina White 82 £18.94 £0.23 C Sunny Felix Purple 82 £18.94 £0.23 D Malindi Purple Purple 84 £42.76 £0.51 D Tambero Yellow Yellow 84 £42.76 £0.51 D Nuanda Copper Purple Purple 84 £42.76 £0.51 D Nuanda Dark Pink Pink 84 £42.76 £0.51
For further information on growing Osteospermums or using of peat reduced medium please contact Teresa Maguire, tel: 028 9442 6694 or email HYPERLINK "mailto:teresa.maguire@dardni.gov.uk" teresa.maguire@dardni.gov.uk
Top Fruit - Summer Health Check
May's exceptionally dry and warm days gave ideal conditions for pollination and fruit set. Such a welcome period of weather also has its potential problems.
Growers remarked on the rapid development of powdery mildew disease and fruit tree red spider mite pest (FTRSM) in some orchards. Powdery mildew responds well to demethylation inhibitor (DMI) fungicides (e.g.'Systhane') or triazoles such as 'Indar' and 'Topas'. These can be included in your regular apple scab spray programme. Control of FTRSM is also straightforward, but please bear in mind that the summer treatments of 'Masai' or 'Sequel' can only be applied once per year. For this reason it is wise to check if natural predators are present in the leaf canopy. Populations of these beneficial mites ('typhs' and Anystis baccarum) build up over time, so you may find that chemical control can be avoided if FTRSM is not a regular problem with your orchards.
Every year is different, but we can anticipate some of the likely health issues due to the prevailing weather conditions. In a hot, dry summer, you might expect the following pests and diseases to be of concern:
Fruit tree red spider mite
Aphids
Capsid bug
Leaf curling midge
Tortrix moth, Codling moth, Syndemis moth
Powdery mildew
If we have a cool and damp summer, it is more likely that you will find the following problems:
Apple scab
Nectria (stem and fruit) canker
Monilinia (mumified fruit) rot
Frequent walks through your orchards are good health management practice. Spotting symptoms early gives you plenty of warning to plan for effective action in time.
CROPS
By James Knox
Potatoes
Blight Control
It is time to plan this year's blight control programme. Key elements to any programme are the removal of infection sources and a spray programme timed to have maximum impact.
Hygiene
Minimise problems later by eliminating infection sources now. You should:
Plant healthy seed
Destroy potato dumps
Eradicate volunteer potatoes in cereal and vegetable crops
Fungicide programme 2008
Two types of systemic fungicides are approved for blight control: phenylamides (for example, metalaxyl-M in 'Epok', 'Fubol Gold') and propamocarb (in 'Merlin', 'Tattoo'). Systemics are most useful early in the season when crops are growing rapidly.
Strains of blight resistant to phenylamides (but not propamocarb) occur in Northern Ireland and reduce the benefit of using phenylamide products. To help limit the incidence of phenylamide resistance growers who opt to use phenylamides should apply no more than two phenylamide-based sprays and avoid their use after mid-July. Start the fungicide spray programme as soon as a blight warning is issued or when the crop meets within the drills (whichever is earlier)
Start with a product containing a systemic, either propamocarb (e.g. 'Merlin' or 'Tattoo') or a phenylamide (e.g. 'Epok', 'Fubol Gold'). If a phenylamide is used, do not exceed two sprays and switch to another product no later than 15 July.
Continue with either a protectant (e.g. 'Electis', 'Ranman', 'Shirlan') or translaminar (e.g. 'Curzate', 'Invader', 'Infinito', 'Revus')
Complete the programme with at least three sprays of a protectant such as 'Shirlan', or 'Ranman' to help prevent tuber infection.
Ensure protection is maintained by regular spraying until the haulm is dead.
Appropriate spray intervals and complete coverage of the crop are the key to successful blight control. In humid, wet weather favourable to blight, use shorter intervals as recommended on the product label for high risk conditions. Nozzle selection can influence the efficiency of application and the volume of water used. Angled jets give better canopy cover at all stages of growth but particularly up to and including full canopy cover.
At the end of the season, if there is blight in the crop, destroy the haulm as soon as possible to reduce the risk of tuber blight and wait at least three weeks before lifting.
Spring Barley
A very dry April and May have left most of the barley looking poor. Uneven germination and severe drought stress seems to be the norm across the country. This will cast its shadow at harvest, because barley that's had a hard time soon after emergence rarely seems to yield. Although I would love to offer a quick fix for stressed spring crops, there is only one solution...rain and good growing conditions. Foliar feeds may help for a couple of days, but are no substitute for a few showers. Herbicides should generally be applied at an early stage of growth to maximize yield, but this year I would delay until the crop has lifted out of stress as a herbicide will only make things worse.
Fungicide Programme
For spring barley crops with high yield potential, a two-spray fungicide programme should be used. This is based on the use of reduced rate fungicide applications. The first application should be applied from late tillering to the start of stem extension. The second fungicide application should be made three to four weeks after the first at around GS 39 – 49 (flag leaf emergence – first awns visible).
Mixtures of triazole and strobilurin, for example, Mobius or Fandango at a reduced rate, are appropriate for both first and second treatments. The inclusion of Bravo at the later treatment will significantly help disease control.
For growers adopting a single fungicide approach this single application should be made at the earlier timing as this usually gives the best financial return.
Winter Wheat
T3 fungicide
Last year many of us were tempted not to apply protection at ear emergence as conditions were dry. However, this proved costly, as wet weather returned and caused a lot of damage with ear diseases. This final spray should always be applied before diseases are visible, the best timing is usually when the ear has just finished emerging and is starting to flower.
