Livestock eNews JUNE 2001

Livestock enews is derived from SAC Sheep Beef Notes. Please credit SAC with copyright if articles are reproduced in newsletters substantially unchanged. The views expressed are not necessarily those of Intervet UK ltd.

1. SHEEP OUTLOOK

2. PARASITE CONTROL IN SHEEP - 2001

3. SCOURING PROBLEMS IN STOCKPILED LAMBS

4. RESTOCKING THE HILLS

5. WHAT ARE THE BEST BREEDS OF SHEEP? - RESULTS FROM HILLSBOROUGH

6. WORKING DOGS – UNSEEN VICTIMS OF FOOT & MOUTH

7. CAN WE DEVELOP EASIER LAMBING SYSTEMS?

8. FOLLOW UP TO EASIER LAMBING SYSTEMS ARTICLE

9. BEEF OUTLOOK

10. HAVE YOU CHECKED YOUR FENCES?

11. RE-STOCKING A SUCKLER HERD - DISEASE PREVENTION

12. GUT WORM ALERT!

13. AGE STRUCTURE FOR A "TYPICAL" SUCKLER HERD

14. THE DIFFERENCE BETWEEN AI AND NATURAL SERVICE

15. TIPS FOR USING AI IN THE SUCKLER HERD

16. AI FOR SUCKLER HERDS IN INFECTED AREAS

SHEEP OUTLOOK

As there is no statutory requirement on abattoir companies to report prices, unlike the auction companies whose data is used by the EU for calculating the sheep annual premium payment. Only informal pricing is being reported by the MLC. Nevertheless, this informal pricing shows that, for those producers who can move animals, prices have recovered and are currently slightly better than this time last year. Indeed prices reported to the EU for sheep annual premium purposes show a price improvement of 6% on this time last year. However, without exports (see below) one would expect prices to have fallen unless availability was down. MAFF slaughter estimates show weekly sheep slaughterings to have fallen by 15% between the last week of March and the third week of April to a figure of around 118,000 head but recovered in the final week of April to 172,000. Nevertheless this is still around 30% lower than a year earlier. Three contributory factors are likely to be at play. Firstly cull ewe numbers are reported to be low because they traditionally move through the auction system and not on a direct deadweight basis. Secondly some of the places hardest hit by FMD are likely to be early lamb producing areas and thirdly the cold spring will have delayed the growth rates on new season lamb. Equally, however the slaughter data supports the assertion that readily accessible animals have been moved and the low volumes held by the smaller farmers (and the low volumes of new season lambs produced by specialist producers) are difficult to schedule into the abattoirs without the assistance of collection centres.

As long as lamb and mutton availability remains some 25-30% below last years levels, the loss of the export market may go unnoticed. The table below shows that the lowest level of exports occurred in May when around 22% of production was exported and the highest level of exports occurred in December, at 30%, for most of the rest of the year exports were a fairly constant 27-28% of production. Data for the year 2000 show that Great Britain produced some 360,000 tonnes of lamb and mutton and exported some 97,000 tonnes in addition an estimated 750,000 lambs were exported live. The strength of the pound combined with a smaller lamb crop contributed to a fall of almost one-third in the number of lambs exported live.

Sheepmeat production and exports 2000

When considering prospects for prices later in the year we must remember that a significant part of the GB sheep price is underpinned by export trade and without that trade prices will inevitably fall. Culling of breeding sheep, and lambs, within the FMD control measures will inevitable reduce availability of lambs this autumn. Retention of ewe lambs for sale at breeding sales will further reduce availability. At the time of writing, some 2m head of sheep had been slaughtered in Great Britain. The December census recorded a UK (not GB) sheep population of 27.5m if we assume the same proportion of breeding sheep to "finishing sheep" have been slaughtered as were recorded in the December census then perhaps 1.4m breeding sheep have been culled reducing the potential lamb population by say 1.5 –1.6m and reducing annual lamb slaughterings by perhaps 10% - 15%. Allowing for increased flock retentions then lamb availability this autumn may be 20 –25% down. This level of reduction is likely to be similar to the size of the lost export market and therefore the home market may be in balance but without competition from export buyers prices are still likely to be lower than last year. Store lamb producers will be similarly affected by the prospects of no export market next spring. However, on the basis that exports could restart 3 months after the last case of FMD the prospect of some export trade next January to March is a real possibility. Store lamb prices may therefore be very sensitive to the speed of reduction in FMD cases.

When we consider how prices are moving in other parts of Europe the impact of FMD in Great Britain becomes more apparent. Indeed it must be remembered that immediately before FMD revealed itself GB prices had been some 15% better than a year ago. The loss of GB supplies in France and elsewhere has created a demand for lamb from other sources. Thus, Irish lamb prices are 25-30% higher than this time last year, French prices are 20-25% higher and Spanish prices a remarkable 40% higher. In deed it is only in Finland and the UK that EU representative prices are reported to be lower than this time last year. The inevitable consequence of this is that the sheep annual premium will fall. Thus, it is no surprise that the recent announcement by the EU shows the first instalment of the 2001 SAP to be £2.42 and the advance of the LFA supplement to be £3.67. This give a full year estimate of the SAP to be around £8 compared to last years £10.70. On a slightly brighter note MAFF have announced that a further round of agrimoney compensation payments are to be made and that these are worth £0.65p per 1999 SAP claim and £0.21 per 2000 SAP claim. LFA supplement recipients will receive £0.18 for 1999 claims and £0.07 for year 2000 claims.

The EU has also published their proposals for the reform of the Sheep Annual Premium. As expected, the proposal outlines a need for a flat rate premium to simplify the system by reducing the administrative burden. The proposed rate of premium is 21 Euro; around £12.90 at the current exchange rate, with a slightly lower rate for those sheep farmers whose main purpose is the production of milk for dairy products. The LFA supplement, or "Rural World Premium" in EU jargon, will be retained and is in fact proposed to increase to 7Euro (around £4.30 at current exchange rates). Also retained is the quota system, which arguably has controlled the production of sheep meat through out Europe.

The FMD crisis has resulted in the UK agriculture departments issuing a consultation document on the idea of imposing 20-day movement restrictions of store livestock. While this is not the place discuss the merits or otherwise of the discussion document it is clear that as a result of this document the tagging of sheep (or some other form of permanent marking) and recording of movements will rise quickly up the agenda. To add fuel to this debate is the decision of the Irish government to press ahead with a proposal that all Irish sheep will be tagged with a visible ear tag that gives an individual and flock number. The proposal is for temporary tags for movement from farm of origin to abattoir and permanent tags for store movements. The proposal requires that from the middle of May, all Irish sheep will be tagged on leaving the holding of origin. Sheep remaining on the holding should be tagged by December 15. This is a rather more onerous tagging arrangement than currently exists in the UK where we only need to mark them with a tag identifying farm of origin when they leave the premises of birth.

SA

PARASITE CONTROL IN SHEEP - 2001

The Foot and Mouth outbreak this year has resulted in many sheep flock owners having to restructure their grazing programme. The FM restrictions have caused sheep to be retained longer than expected on some fields whilst others have not been grazed as they should have. There will also be the problem as the summer progresses of uncertainty with sale dates and movements of sheep off farms. There are many cast and barren ewes still on farm which would normally have been sold in the earlier part of the year.

Since many of the restrictions placed by the FMD outbreak have been eased, sheep grazings on many farms have already been compromised and owners are having to look for alternative methods of keep. Silage and winter fodder fields are being grazed, while others have been ploughed and grain sown. As a result, sheep may have to be kept tighter on grazings and for longer on the same fields. This will impose challenges on the animals from various diseases.

The worms which cause Parasitic-Gastro-Enteritis (PGE) will be a greater threat to lambs and adults if sheep are retained longer on grass parks or kept at a higher stocking density than usual. Worm egg burdens on pasture will increase and this pose problems for animals in their first grazing season. All sheep should be treated with a suitable anthelmintic when they are moved from one grazing to another and kept in the handling area for as long as possible to allow the chosen preparation to work effectively killing worms and eggs. This should give the new grazing a better opportunity to retain the animals before becoming heavily infested with the parasite.

It is suggested that dung samples be collected and analysed at your local veterinary centre to determine the level of parasitism since it is only recommended to treat sheep when there are worms present. It is also good practice to have dung samples from sheep which are scouring tested since it is vital to know which endoparasite is the cause, eg Ostertagia, Nematodirus or Coccidia since treatments will vary accordingly.

The grazings for sheep later in the year should be earmarked now since it is possible that lambs will have to be kept for longer periods than normal if sales are not held at the usual dates. These grazings should be kept sheep free at present and possibly used for silage/hay first. It is also important to keep some grass for ewes after weaning and before tupping.

There are some other diseases to be aware of if sheep are kept at higher stocking densities. Pasteurella pneumonia can be a problem but fortunately there is an effective vaccine available. Ectoparasites will spread more easily when sheep are closer together and any wool loss or skin irritation should be investigated immediately. Farms with ticks on hill ground may not be able to expose animals to ticks at the usual time to enhance their resistance so provision should be made to protect the sheep if grazing these infected pastures later in the year.

It will not be an easy year for many sheep owners but with a little thought and planning now and advise from your vet, life can be made much more simple compared with trying to address problems as they arise.

SC

SCOURING PROBLEMS IN STOCKPILED LAMBS

Where lambs have had to be stockpiled under intensive conditions, then the risk of coccidiosis becoming established increases, but equally worms could be involved. It is important to follow up quickly on scour outbreaks in lambs in May and determine the cause. Occasionally where both nematodirus infection and coccidiosis occur, lamb deaths can follow.

A bulk faecal egg count based on collecting a teaspoonful sample from 25 droppings or rectal samples should be made from lambs (do not sample ewes). A random one and another concentrating on the scouring lambs can be informative. Faecal egg count (FEC) will show accurately whether worms are involved and if nematodirus is the culprit (nematodirus eggs are bigger than other strongyles and thus easily diagnosed). However, diagnosis of nematodirus infection based on worm egg counts is difficult as the worm is not a prolific egg layer and developing worms in a severe outbreak can cause death before the worms reach sexual maturity and produce eggs. Thus observation of lambs is important. Severely infected lambs are dehydrated and seen around the troughs with a tucked up appearance and might have a slimy mucous-type diarrhoea or scour. Nematodirus is passed from last year’s lambs to this year’s lambs. Ewes are solidly immune so are not a source of infection. If lambs have had to run on last year’s summer grazing areas due to the stockpiling, then nematodirus can be a risk. However, young calves can also spread and maintain a nematodirus infection and some nematodirus eggs can survive on pasture for two years, so it is always well to be on guard against this parasite. In a late spring like this, the worm hatch is concentrated as it requires a temperature of over 10?C for 24 hours to develop. If a delayed hatch occurs when lambs have started grazing, this results in a much bigger challenge, typically appearing on pasture in early May, with lambs showing symptoms in mid-May and eggs appearing in faeces about three weeks after infection.

Coccidiosis can also be diagnosed from a faecal egg count sample as the oocysts are visible but they are far too many to count. Also, it is difficult to tell whether the ones present are of the pathogenic strains without extensive studies so again it is back to looking at symptoms in lambs. Lambs with severe coccidiosis are usually four to seven weeks old and appear dull and unthrifty. They lose their appetite and are in pain. They lose weight and condition and, although only some lambs show symptoms, all will be infected. The disease is caused by lambs picking up a few oocysts (eg when stockpiled) that divide within the gut to produce millions within two to three weeks. The problems they cause result in scouring and the gut’s capacity to regenerate is impaired, producing an unthrifty lamb that will fail to finish off grass.

The difficulties of diagnosing these similar conditions highlights the need for treatment to be based on information (faecal egg count) and veterinary guidance. Nematodirus can be treated with either the white or clear drenches, which are both highly effective and cheap.

Coccidiosis can be treated with Veccoxin. Usually a single dose is given at 4-6 weeks, with the option of a further dose three weeks later. Costs rise rapidly with larger lambs so it’s best not to delay giving the first dose. Deccox added to feed for creep fed lambs is an alternative preventative measure usually applied for four weeks from 3-4 weeks of age.

JEV

RESTOCKING THE HILLS

Hill flocks are unique to their areas and over generations sheep become hefted to their own bit of land. I once asked a hill shepherd what he thought was meant by the term ‘heft’ and he suggested it meant the ewes suffered from Hyper-Every-eFfing-Thing. He did have a pretty awful hill, mind!

If ewes are hefted, the question arises ‘How did the first ones get there?’ – bringing up images of shepherds of the past in their plaid staying with the flock continuously. However, there have been recent examples of completely unstocked hills being restocked quite successfully and quickly. This can also happen where a stock is removed and neighbouring sheep move in from the edges and take over.

Completely restocking with bought-in stock has been successfully achieved where hoggs have been fed on an area of hill with beet pulp nuts in April for three to six weeks. This will establish them on that area provided some reasonable grazing appears by May. Complete age groups of sheep can similarly be acclimatised. Some important points to bear in mind:

Don’t buy sheep within sight or smell of their home ground – they could likely find their way back.i

f you have got a tick problem, take veterinary advice. Louping ill could be a problem with unacclimatised sheep.

Use feeding of hay or nuts to establish the natural gathering points during a storm period. Hefted sheep know which way to run in a gather. Blocks can be used to encourage ewes onto the areas that need to be grazed.

If draft/cull ewes are obtainable from the original home stock, bring them in to act as a nucleus.

Only put out sound sheep with a full mouth to the hill and have them clearly marked.

The longer a hill is left ungrazed, the rougher it gets. Deer can come in as a result and may bring ticks with them. It is likely that the better hills will carry less stock or produce smaller lambs if unstocked for a period of over a year. Poorer hills will not change as much. Destocking for six months is not likely to have great long-term effects.

JEV

WHAT ARE THE BEST BREEDS OF SHEEP? - RESULTS FROM HILLSBOROUGH

Comparative work on sheep breeds in the UK is in short supply so it is welcome to see work from Northern Ireland evaluating output of crosses out of Blackface (BF) and Cheviot (C) ewes.

Crossbrds evaluated (mated to high and low index Suffolk or Texel Sires)

Lambs born	Lambs born	Weight of lamb weaned/ewe (kg)	Conformation class	Fat depth over back (mm)
Mule (BFL X BF)	173*	46.5*	2.75*	2.5
Texel X BF	147	39.6	3.15	2.4
Suffolk X Cheviot	146	39.4	3.04	2.6
Texel X Cheviot	141	38.2	3.12	2.2*

*Indicates significantly different from the rest

Mules were more prolific and produced 20% more weight of lamb but with a poorer conformation. Lambs out of Texel X Cheviot ewes had the best conformation. The value of extra production from the Mules (+ 20%) was much greater than the losses due to downgrading for slightly poorer conformation. Lambs bred from high index rams of the Suffolk and Texel terminal sires compared to controls were finished two weeks earlier and with better conformation. Overall, the Texel had better conformation and killing out percentage. The reduction in lambing percentage from using a Texel vs Bluefaced Leicester at 26% was close to an expected reduction of 30% based on breed averages and demonstrates the risks of buying replacements with 50% of genes from terminal sires.

However, the Texel X Mule ewe is reasonably prolific and having a proportion (up to 25%) of the flock as this cross is unlikely to reduce output significantly. The results show our traditional crossbreeds produced from the BFL ram on hill ewes are the most productive and that breed improvement via the selection index is having real effects.

JEV

WORKING DOGS – UNSEEN VICTIMS OF FOOT & MOUTH

"Border Collie Rescue", a charity based at Richmond, North Yorkshire, has set up a registration system for sheepdogs which face being destroyed following the loss of flocks. Dogs will be disinfected, quarantined for 3 weeks, assessed and then offered for re-homing. If you are aware of any working dogs that face an uncertain future as a consequence of Foot and Mouth disease please raise awareness of this. For further information contact 01748 850025 or email hq@bordercollierescue.org.

BL

CAN WE DEVELOP EASIER LAMBING SYSTEMS?

A lowland farmer phoned the office to question whether his lambing system was sustainable. Was the huge effort and intensive management of the three groups of sheep at two locations economic?

Ideally he would like a less labour intensive system for his 1,000 ewes, and would accept a lower lambing percentage. One of his main problems was having too many triplet lambs which took a lot of time to foster on to other ewes.

Some of the more progressive NZ sheep farmers are now rearing 160 – 180 % lambs on a minimal shepherding system. Could we make life easier by adopting some of their methods?

Before listing some of the main principles behind their management systems, we should bear in mind a quote from a top New Zealand sheep breeder "You either have intensive or minimal shepherding – a compromise does not work".

Selection
Most New Zealand farmers have closed flocks (apart from buying tups). They are able to cull out "difficult" ewes and select for ease of lambing. Can we move to homebred replacements on low ground flocks through use of composite tups or breeds like the Lleyn?

Genetic improvement
Most tups are sold on the basis of recorded figures for performance traits. Many farmers are now using crossbred (e.g. Suffolk x Texel) or composite (e.g. the "Highlander" – 50% Romney: 25% Texel: 25% Finn). Could we use crossbreds to breed replacements on low ground farms?

Scanning and nutrition
Great improvements in lambing percentage have been achieved through improving ewe condition at critical times by matching pasture availability to sheep requirements. Swards are regularly assessed in terms of forage availability measured in kg. dry matter per hectare.

Minimum disturbance
Ewes are spread out as thinly as possible. Farmers avoid disturbing ewes unless absolutely necessary and tag those which have given problems. Ewes and lambs are left to bond on the birth spot and are not moved or mixed for several weeks.

Shelter and climate
Although the climate is more favourable they do get a lot of windy days and a big effort has been made to provide shelter in exposed fields. Ewes cannot be spread out effectively without adequate shelter in ALL fields.

Can we convert to an easier lambing?

Long term measures

This will only be possible if we can cull out problems and select for easy lambing ewes.

We currently rely on a stratified system sourcing crossbred replacements from hill and upland areas. This does not provide information on genetic merit for an easy care system, and can increase the risk of buying in disease from unaccredited flocks. However before we consider abandoning the stratified approach we should consider its advantages – including hybrid vigour, the retention of hardiness due to natural selection, and the economic lifeline that breeding stock sales provide in hill areas.

Technologies such as electronic tagging could allow feedback of information on crossbred ewe performance to Bluefaced Leicester and Hill breeders. In the meantime genetic work funded by MAFF and the MLC on developing a multitrait selection index for longwool crossing sires should soon provide hard figures on possible progress with maternal traits, such as lambing ease and mothering ability.

The Lleyn is a possible contender for easicare selection in the UK. As a prolific breed only a proportion of the flock would need to be bred pure allowing the real progress made in terminal sire breeding to be exploited on the rest. This might include a pure bred Lleyn flock, Lleyns crossed to Texel tups, and Lleyn x Texels mated to Suffolk tups.

Short term measures

Key management strategies that address the immediate concerns of overworked lowland farmers might include – lambing later in better weather to tie in with grass availability, developing clover based finishing systems which maximise numbers finished off grass, and establishing more shelterbelts.

IWR

FOLLOW UP TO EASIER LAMBING SYSTEMS ARTICLE

A Borders farmer phoned in his first experiences of minimal shepherding after reading the above article.

He has successfully introduced a minimal shepherding system for his late April lambing flock by adopting several of the principles shown above – spreading ewes out before lambing, limiting intervention to twice daily inspection and marking ewes which had caused problems.

He has a variety of breeds at present including pure Lleyns, Mule X Lleyn and Texel X Lleyn, but favours the Mule X Lleyn mated to terminal sires. The late lambing ewes scanned at 170% and reared 150% so there is scope for improvement in this area in future.

Three of the points he made are listed below:

1. Terminal sires
The tup provides half of the lambs genes and survival will be enhanced if terminal sires could be selected for hardiness and have been reared on a similar system to his own. Few breeders can provide this at present.

2. Mating ewe hoggs
Ewe lambs are well looked after to ensure that the maximum number can be lambed as ewe hoggs. Hebridean tups were used to produce small lambs which minimised lambing problems. This helped ensure that these sheep would be better mothers as gimmers when they are more prolific.

3. Teat size
The ewes generally had plenty of milk but large teats could be a problem for young lambs suckling. They have therefore selected for ewes with smaller teats.

Has anyone else got any experiences of making lambing easier. If so please contact Iain Riddell on 01835 823322 and we can continue this theme in the next edition.

IWR

BEEF OUTLOOK

As mechanisms for the movement of finished stock direct to slaughter are becoming familiar to producers and, hopefully, the number of farmers under complete movement restriction reduces, more market prices from deadweight centres become available and become more representative. Over the past four weeks some improvement in deadweight prices has occurred. However, from the MLC price reporting from a sample of deadweight centres it is interesting to note that the number of animals reaching these centres has declined. For example, during the last week of March the MLC sample of abattoirs recorded 10396 animals killed. By the second week of April this had reduced to 9905. This statistic would provide some support for abattoir concerns that the immediately available stock has been moved and supplies are know more difficult to access. Equally, the statistic also highlights the situation faced by small scale producers trying to move small numbers of finished livestock, and the need for collection centres, and the high numbers of healthy stock "trapped" in restricted movement zones – although, at the time of writing some of these restrictions are slowly been lifted. For those farmers who can move cattle the reported prices for steers and heifers are very similar to those of a year ago and at worst only 1-2% lower. In contrast young bull prices are down by around 5%, as the volume of young bulls reaching the market has increased. In the first quarter of 2001 MAFF slaughter statistics show young bull slaughterings to have increased by almost 30% although the level of increase has reduced to nearer to 10% in late March as FMD movement restrictions began to bite. As restrictions are lifted from some infected areas allowing movement to abattoirs within infected areas a short surge in availability could be envisaged leading to short term weakness in prices. However, because of restrictions on which abattoirs some producers can use, some abattoirs may continue to be short of stock.

Although some finished cattle are moving, we should not underestimate the problems remaining for the industry. Many producers are finding it impossible to move OTMS cattle. In the week ending 15 April, 4548 OTMS cattle were slaughtered in the UK, in the same week last year 14,048 animals were killed. Although it is too simple to say that OTMS cattle are backing up on UK farms at the rate of 10,000 head per week, because several OTMS cattle will have been slaughtered under FMD controls, it must be recognised that considerable cost is being faced by the industry through having to feed animals which would normally have been sold into OTMS. Equally, while finished stock may move there are many cattle finishers who cannot buy store cattle to replace those finished cattle they have sold. There is a prospect that some farm-to-farm movement of store stock may be possible in some areas by the time this edition of MES reaches readers but a considerable volume of store animals will still be within restricted zones. Considerable disruption to the finished cattle availability profile is likely to exist for perhaps two to three years. In the short term the "trapping" of store cattle on farms not equipped to finish them will slow down the rate of finishing. In the longer term, the retention of heifers previously intended for slaughter to be used as replacement breeding stock will further reduce availability and their progeny will not be reaching the market for perhaps three years.

In the midst of all the media and political debates about the handling of the FMD crisis, it is sometimes difficult to remember that other policy and marketing issues continue to unfold. Consequently, many readers may have missed the MAFF announcement that a further tranche of agrimoney compensatory payments are to be made during April and May. These amount to: £6.88 for the Suckler Cow Premium, £1.17 for the Slaughter Premium, £7.04 for young bull BSP and £5.37 for steer BSP. Top ups are also being paid on extensification at £1.30 for the heavier stocking density and £2.60 for the lower stocking density.

FMD continues to have a high profile around the world. Last month the EU imposed a ban on beef imports from Argentina because of a breakdown in their FMD status. That ban has now been extended further. Neighbouring country Uruguay has had its "FMD free without vaccination" status removed following the announcement that FMD virus had been found in cattle there and most recently the discovery of FMD in Southern Brazil has resulted in that country having trade restrictions imposed upon it. All three countries adopt a vaccination programme as a means of control. During 2000, Brazil was the second largest supplier of beef to the UK after Ireland, although at 35,000 tonnes Brazilian supplies were only one-fifth of the level of Irish imports to the UK.

Irish exporters are reported to be finding steady demand for their beef in many parts of Europe because of the absence of Dutch supplies resulting from their FMD problems. However, the EU have now relaxed the restrictions on Dutch beef trade and so Ireland may find the market more competitive again. Although still well below last autumn levels, demand for beef in France is reported to have improved on account of consumers showing less interest in lamb, which appears to be suffering an FMD effect based on the slaughtering of lambs imported from GB.

In general, some increase in European demand for beef is reported by the EU who declare that consumption of beef is now 18% lower than last autumn when the mainland Europe BSE crisis was at its peak compared to a 23% decline reported in March. However, European beef prices still remain some 20% lower than last autumn. European prices will also be helped by Russia’s decision to allow beef purchases from EU Member States which have not had an FMD case. This may ease the requirement for safety net purchases of beef, which have seen EU beef intervention stocks accumulate to over 200,000 tonnes. Furthermore, it reduces the extent to which low priced beef will be available in the UK and provides some encouragement that prices paid for finished cattle in Great Britain will remain similar to last years levels with some potential for improvement. On the other hand, abattoir operators are increasingly indicating that the supermarkets are buying on forward contracts and abattoir operators have to buy on the spot market. Reconciling the two marketing methods is not always easy and may lead to more level pricing throughout the year.

SA

HAVE YOU CHECKED YOUR FENCES?

Each year there are several road traffic accidents involving cattle which have broken out of fields where they were grazed. Unfortunately in some cases these road accidents are fatal. In many, but not all, cases the cattle involved are cows and calves who have just been weaned, with the cow breaking out to go looking for her calf.

Perhaps the next most common reason for cows breaking out onto roads is a shortage of grass. This commonly starts by cattle grazing through the fences and putting more pressure on them until they eventually give way. This situation is perhaps more likely to occur this summer due partly to the slow late Spring and, on many units, the high numbers of stock currently having to be grazed due to the FM restrictions. Do check all fences of grazing fields but in particular roadside fences. If there are signs of stock grazing through the fence consider erecting an internal electrified scare wire. Finally do ensure all field gates are kept shut including arable fields adjacent to fields grazing cattle.

BL

RE-STOCKING A SUCKLER HERD - DISEASE PREVENTION

The advantages and disadvantages of re-stocking with different age groups were discussed in the May edition of Sheep and Beef Notes. This article considers ways of avoiding buying in disease when re-stocking.

Factors affecting the risk of buying in disease:

Age/reproductive status (see May article)

Health status - stock of unknown health status are a greater risk

Number of sources - building up a herd from several sources is a greater risk

The risk can be reduced by buying in stock of high health status e.g. herds in SAC's Premium Cattle Health Scheme (PCHS). However, the number of herds in the PCHS is currently insufficient to allow re-stocking from these herds to be an option for all wishing to re-stock.

Quarantine
Before any purchases are made, set up a quarantine facility. In most instances, stock will be purchased from more than one source and quarantine will decrease the risk of stock from one source infecting those from another.

Use one or more separate buildings as quarantine areas, with stock from each source undergoing quarantine separately.

Strict disinfection is required between batches of stock.

A field which does not allow contact with other stock is a poor alternative as pasture contamination could occur and to be safe, the field would have to be left for 12 months before use for another batch of cattle.

A quarantine period of 4 weeks is sufficient for most diseases.

Make use of this period for routine worm and fluke treatments and testing for specific diseases.

Use separate footwear and clothing in each quarantine area or disinfect clothing between visits to separate batches of stock.

The diseases
Bovine virus diarrhoea (BVD), Johne's disease, infectious bovine rhinotracheitis (IBR), leptospirosis and Campylobacter (Vibrio) abortion are the five most important diseases to avoid introducing during re-stocking. All can be tested for during the quarantine period. Do not forget to check bulls as well as females.

BVD causes reproductive failure, foetal abnormalities and mucosal disease. Calves that survive infection in the first third of gestation become carriers (persistently infected [PI] animals) which shed the virus throughout their lives and are the major source of infection to others in the herd. It is very important that no PI animals are purchased and blood tests can be used to pick up such animals so they can be culled before the end of the quarantine period. All purchased animals over 4 months old should be screened for BVD as only one PI is sufficient to cause major problems with this disease. Purchase of pregnant animals is not recommended because of the risk of a PI foetus being present.

Leptospirosis is associated with infertility and abortion and is a cause of disease in humans. Blood testing can allow the presence of active or previous infection to be detected. If so, vaccination may be an option as a test and cull policy is not reliable for control.

Johne's disease is a chronic wasting disease with a very long incubation period. Cattle are usually infected when young but do not usually show signs of diarrhoea until 2-4 years of age. Unfortunately, cattle are rarely positive for blood and faecal tests for Johne's disease until the late stage when they show symptoms. Thus carriers are very difficult to detect. However, since the consequences of introducing the disease are serious, animals should be sourced from herds with no clinical evidence of Johne's disease. Adult animals should be blood sampled on arrival and reactors should not be allowed to enter the herd.

IBR is a viral respiratory disease but can also manifest as poor fertility and abortions. Recovered animals can still shed virus intermittently throughout their lives. Sourcing all your stock from IBR-free herds would currently be very difficult, so most sources will show evidence of previous infection when blood tested. Vaccination is effective and whether it is necessary in your situation can be discussed with your veterinary practice.

Campylobacter is a bacterium causing infertility and abortion. Cows and bulls can act as carriers, maintaining infection in the herd from one breeding season to the next, with first calvers and older bulls being most susceptible. Tests are available for detecting infection in cows (vaginal mucus test) and bulls (sheath washings) but virgin animals will not be infected. If AI is an option, its use for the first two breeding periods will ensure that any infected cows clear themselves of infection. Alternatively, use of a young bull will decrease the likelihood of his introducing and spreading infection.

PCHS Once the herd is established, consideration should be given to maintaining its health status by routine monitoring and maintenance of a closed herd policy. Flexible programmes are available for BVD, IBR and Johne's disease monitoring/eradication, BVD and IBR accreditation and leptospirosis monitoring within the PCHS. For further information on the PCHS and other health matters, contact your local SAC Veterinary Centre.

EM

GUT WORM ALERT!

Intestinal worms which cause parasitic gastroenteritis (P.G.E.) are likely to be a greater problem among grazing cattle and sheep this summer. These parasites usually cause ill thrift and scour among livestock during their first season at grass, especially where there is heavy stocking. Older animals usually become immune following exposure however this immunity can breakdown where there is a very high level of exposure to the worm larvae (with overstocking). Older sheep and cattle might also be adversely affected where their immune systems are compromised due to poor nutrition or mineral/trace element deficiency.

Why do we think there is going to be an increased risk this year?

1. Because many farms are overstocked particularly those which were forced to retain store cattle because of FMD this spring.

2. Because of the cold, late spring grass growth has been poor and increased the risk of grass shortages.

3. Producers have been forced to graze some of their silage ground because of food shortages, so no silage aftermaths will be available late in the summer.

All this means that there will be high stocking densities of lean cattle on mean pastures late in the summer. The worms will be in their element and PGE is likely to be a problem.

If you think you are at risk then it would be wise to consult your veterinary surgeon now and plan a management strategy for PGE. Use management and strategic anthelmintic treatment to avoid trouble.

If you suspect a problem during the summer then arrange for worm counts to be carried out on dung samples from young stock and take appropriate action using anthelmintics.

GG

AGE STRUCTURE FOR A "TYPICAL" SUCKLER HERD

When considering replacing or putting on a new suckler herd one of the many points to consider is whether to start with:

maximum cow numbers all at a same age, eg 100% in-calf heifers, OR

to purchase a proportion of cows at various ages and fully stock the unit in one year, OR

to build up numbers gradually, eg by purchasing a group of bulling heifers every year.

Each approach has its advantages and disadvantages but in making the decision of which choice best suits you we need to know what is the normal age structure for a typical suckler herd.

The truthful answer is that nobody knows but the following table gives an indication of a reasonably normal herd age structure.

Theoretical age structure of a suckler herd

Parity (calvers)	% of Herd
1^st	15
2^nd	14
3^rd	13
4^th	12
5^th	11
6^th	10
7^th	9
8^th	8
9^th	7

The figures are simply based on 15% of the herd being first calvers with 1% being culled each year. Using this simple system 7% of the herd would be ninth calvers ie 11 or more years old, (and to make it up 100% one tenth calver).

I appreciate that in practice cows are not culled on such a regular basis with less middle aged cows being culled and more older cows. Nevertheless the figures are sufficiently close to use as a guide as to what is a normal herd age structure when setting up a new herd.

THE DIFFERENCE BETWEEN AI AND NATURAL SERVICE

The important difference between AI and natural service by the bull is where the semen is deposited in the cows reproductive tract.

The critical part of the cow’s reproductive tract is the cervix – which is effectively a large cork which blocks access to the cow’s uterus/womb from the outside. In the centre of the cervix there is a small corkscrew passage which, when the cow becomes pregnant, is sealed with mucus to keep the developing embryo completely sterile. (When the cow calves, the muscular cervix relaxes completely to allow the calf through.)

When the cow is served by the bull, his penis deposits sperm on the outside of the cervix, the penis being unable to penetrate through the cervix. The sperm then has to find the small opening through the cervix, and swim through into the womb. Then the sperm has to move up the womb and into the tubes joining the womb to the ovary before it meets the egg and fertilisation can occur.

In comparison an AI inseminator can carefully thread the small diameter insemination gun through the channel in the cervix and deposit the sperm directly into the base of the womb. Effectively the AI inseminator is giving the semen a "lift" for the first half of the journey the sperm has to travel. This means that all the sperm in the straw reaches the base of the uterus. In comparison only a small proportion of the sperm deposited by the bull reaches the base of the uterus, the vast majority failing to locate and successfully swim through the small hole in the cervix. This explains why AI companies are able to produce between 300 – 500 straws of semen for each ejaculation – all of which would be put into the cow in a natural service situation.

The "lift" given to the sperm by the inseminator means that if it is to arrive at the base of the uterus at the same stage of the cycle compared to semen deposited outside the cervix by natural service then cows should be inseminated approximately 12 hours after they would be naturally served by the bull. Hence the advice is to inseminate cows at the end of their standing heat. In practice, using a single daily insemination service the advice would be:

cows seen in season the previous day and first thing in the morning ie before around 8am, should be inseminated that day.

cows seen in season after 8am should be inseminated the following day.

BL

TIPS FOR USING AI IN THE SUCKLER HERD

Successful artificial insemination of beef cows requires:

accurate heat detection

correct insemination

minimising stress

Heat detection can be eliminated by synchronising oestrus so that all cows come into season at the same time and hence can be inseminated on the same day.

Oestrus detection

There are many indicators of cows which are in season eg their general behaviour, marks on their hide etc. However the only certain indication of a cow being in season or more precisely in STANDING HEAT is when cows STAND TO BE RIDDEN BY OTHER ANIMALS. It is not the cow who is doing the riding who is in season. The only exception to this would be where a cow’s head is being ridden by another cow in which case it is the cow doing the riding who is likely to be in season.

The basis of heat detection is careful observation. The normal recommendation would be to observe groups of cows for at least 10 minutes, four times daily, eg first thing in the morning, midday, teatime and last thing in the evening. It is important to observe cows while they are not being distracted eg being fed. As a result the late evening observation period tends to be the most successful and hence the most important.

There are several heat detection aids available on the market. They are all stuck onto the tail head of the cows and either change colour or "raise a flag" etc when the cow is ridden by another animal. One problem which can occur when these are used in suckler cows is that the calves, jumping on their mother’s backs etc can trigger the detectors giving a false positive reading ie the detector says the cow has been ridden when in fact she is not in season.

A simple, cheap heat detector, which we routinely use on the SAC farms, is tail paint. Specialised tail paint can be purchased but we tend to use old tins of paint (which are lead free and preferably not gloss paint) which have been left over from home decorating. A strip about 4" wide and 6" long is painted on the tail head of the cow where it will be rubbed when she is ridden by another cow. (It is also possible to buy tail paint in an aerosol spray can).

All of these aids can be useful but it is important to remember that they are just aids and that the only certain sign of a cow being in season is when she stands to be ridden.

Correct insemination

Professional inseminators are well trained and their performance (in terms of pregnancy rates) regularly monitored. However their success rate is entirely dependent on producers putting forward cows for insemination at the correct stage of the cycle. The ideal target is for animals to be inseminated 12 hours after they have been in standing heat – see previous article.

Minimising stress

There are two stages where stress can seriously reduce fertility.

1. Around insemination
The sperm cannot reach the egg to fertiliser the cow by itself. It is dependent on the uterus undergoing rhythmic muscular contractions which "sucks" the sperm towards the egg. Stress can reduce or even stop these contractions, reducing the chance of the cow becoming pregnant. It is therefore essential to minimise stress particularly prior to and for 24 hours after AI.

2. 14 days after insemination At this point the hormones in a cow which has not become pregnant begin to change bringing the cow back in season three weeks after she was inseminated. In comparison if the cow did become pregnant through the AI then three weeks later the cow needs to know so that her hormone production can be adjusted to maintain a pregnancy rather than for her to come back in season. The way the cow knows she is pregnant is from a hormone produced by the two week old foetus! Obviously the amount of this hormone which can be produced by a two week old foetus (which is invisible to the naked eye) is minute. Hence any stress to the cow around this time blocks out the hormone message from the calf so that the cow does not realise she is pregnant and comes back in season.

A programme for AI

1 month before mating (AI) is due to start
Contact your local AI centre to inform them of the number of cows etc you hope to inseminate. Select the bulls you want to use. Where large numbers of cows are to be inseminated over a short period, eg 60+ cows over three weeks. it may be possible to contract cheaper insemination costs with the AI company.

3 weeks before mating starts
Tail paint cows and observe once daily to record animals in season from either observation and/or removal of the tail paint.

Draw up a piece of paper with four or five columns each of three weeks. This will act as a ready reckoner to check which animals are likely to be in season in three weeks time eg

Date	Bulling	Date	1^st AI	Date	2^nd AI	Etc
APRIL		MAY		JUNE
Mon23		Mon14		Mon4	*
Tues24	719	Tue15		Tues5
Wed25		Wed16	719 AI	Wed6
Thur26		Thur17		Thur7

* on Monday 4th June I know to pay particular attention to cow number 719 who was first AId three weeks earlier on Wednesday 16th May.

Some AI companies will provide these "breeding charts" free.

Consider turning out a yearling steer with each group of cows. Often the presence of even a castrated male can help increase the activity of cows when they come into season and make heat detection easier.

Depending on the grazing layout, some people find it useful to shed out cows and their calves as they are seen in season into a separate group. For example there could be four groups, one being cows seen in season in the first week observation starts, the second group being seen in season during the second week etc and with the final group being cows not seen in season. The potential benefits of this approach are that:

the group which is expected in season this week can be grazed close to the handling facilities and replaced with the next group a week later.

heat detection can be concentrated on just two groups, the group previously seen in heat three weeks ago and the group never seen in heat.

2 weeks before mating starts

Organise where/how the cows and calves are to be handled for insemination. Where necessary erect temporary handling pens in the field or temporary fencing at gateways to help "funnel" cows out of the field for insemination.

Start of mating

Groups should be checked at least three times daily. Cows in season should be penned with their calf, as close as possible to the expected time of arrival of the inseminator. Arrangements should also be made with the inseminator for him to release the cow and her calf back to the group or field as soon as he has inseminated them, ie minimise the time the cow and her calf are shut up away from their normal grazing group.

Some producers who only use AI for the first three weeks of the mating period and then turn out bulls to sweep up, tend to turn out, cows which have been brought in for AI, into other fields further away from the handling facilities ready for the bull being turned out a few days later. This has the advantage of gradually reducing numbers of cows which have to be regularly checked for coming into season.

BL

AI FOR SUCKLER HERDS IN INFECTED AREAS

Routine insemination of cows on a day to day basis using observed detection of oestrus is prohibited in infected areas. It is however possible to inseminate large groups of cows on a synchronisation programme provided permission is given from the local divisional veterinary officer at least 7 working days prior to the inseminations occurring. (If necessary the AI companies themselves can obtain this permission but they require as much advance notice as possible).

The restrictions placed on the inseminator are:

He cannot return to that farm for the next 7 days (he is however allowed to return the next day to inseminate cows twice eg at 48 and 72 hours).

He can only bring sufficient semen onto the farm to inseminate the exact number of cows available. No straws of semen can be brought back off the farm.

The inseminator obviously has to go through a whole disinfection routine both on arrival and departure.

In addition the farmer has to sign a declaration given to him by the inseminator, agreeing that disinfection standards etc have all been followed.

Producers wishing to inseminate individual cows on observed heats

This service cannot be provided by professional inseminators in infected areas. To overcome this problem Genus have developed a specialised syringe and semen diluent which contains three times the amount of semen compared with a normal AI straw.

When a suckled calf producer rings up Genus, they will arrange to deliver syringes to the farm gate. It is essential that the syringes are used immediately to maximise fertility. The farmer inserts the syringe into the vulva of the cow and tries to deposit the sperm at the neck of the cervix (in the position that a bull deposits sperm – see above article). For beef semen the cost is £17/syringe – almost identical to the normal cost of a daily inseminator plus semen service. However pregnancy rates are likely to be around 35 – 40% compared with the average of 55%+ achieved by the inseminator.

BL

Produced by The Scottish Agricultural College, Farm & Rural Business Division, Greycrook, St Boswells,

TD6 0EU

SAC receives financial support from the Scottish Executive Rural Affairs Department