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.
It has been estimated that between three to four million lambs die each year, with hypothermia or starvation being the main cause of deaths on hill and upland farms, with some farms having a mortality of over 30%. Recent work carried out by ADAS Redesdale, Northumberland over the last couple of years have looked at feeding extra vitamin E to ewes over the last six weeks of pregnancy and the effect that this had on lamb vigour and survival and also performance to weaning.
In these trials Scottish Blackface ewes were housed in late pregnancy and fed baled silage plus ewe nuts for the last six weeks, with the ewes and lambs turned out within 24 hours of lambing in late April. Different levels of vitamin E were included in the ewe diets to provide between 50 and 300 IU (International Units) of extra vitamin E per day.
The main conclusions from this trial were that:
| Extra E tended to increase lamb vigour |
| Lambs born to supplemented ewes were on their feet about 15 minutes earlier than those from unsupplemented ewes and also supplemented lambs started suckling about 25 minutes earlier than the control lambs |
| There was no difference in lamb survival rates between the various vitamin E levels, with lamb mortality ranging from 5-13% in the different groups |
| Supplemented lambs grew faster and were 1kg heavier at weaning. |
It should be remembered that these trials were done with housed ewes with the ewes and lambs being turned out the day after lambing and it is not known what effect extra vitamin E feeding would have on the survival of ewes lambing outside. However it would be expected that the increased lamb vigour found on the high Vit E diet would be much more important in reducing lamb losses when lambing outside.
No firm recommendation as to how much extra vitamin E should be fed came out of these trials but the general consensus of opinion was that about 100 iu/day would be a sensible level to aim at. Depending on how much concentrates are fed in late pregnancy, the vitamin E level in the concentrates should therefore be in the range of 150-200 IU/kg. feed and some compounders have this level in their ewe feeds.
The next question is, of course, how much will this cost and will it be worthwhile? Vitamin E is an expensive Vitamin to add to feed and the cost of adding 150 IU should be in the region of £4.50/tonne extra, while adding 200 IU/kg should cost about £6.00/tonne extra. For a flock of, say, 600 ewes fed an average of 15 kg of concentrates in late pregnancy, this amounts to a total of 9 tonnes of concentrates. At an additional cost of, say, £5.50/tonne, the total cost of adding extra vitamin E will be £50 for the whole flock.
This means that the cost of feeding extra Vitamin E can be recouped if only about four lambs from the whole flock are saved. Another benefit, which could be much more important is the reduction in time spent in mothering up lambs - so important now with high costs of skilled labour.
Viewed in this way, feeding extra vitamin E to ewes in late pregnancy would seem to be a very sensible thing to do. Any benefit in terms of improved lamb growth rate would of course be additional to that estimated here.
All English sheep farmers have recently received a booklet 'Sheep: Codes of recommendations for the welfare of livestock'. Scottish farmers will most likely have to comply with a similar document in future. Note some of the important points.
| The Code stresses the importance of the right breed for the environment. |
| No constraints on the numbers of sheep per shepherd are made, but numbers should reflect the environment facilities and the competence and time available of the shepherd. |
| Water should always be available. Relying on roots is inadequate. |
| A written health and welfare programme is needed. |
| Segregation in a quarantine area for four weeks is required for newly introduced sheep. |
| Need for records. |
| The frequency of looking at sheep should depend on the risk factors present, eg more frequently when there is flystrike danger, backing etc. |
| Significant numbers of lowland sheep below condition score 2 or hill sheep below condition score 1½ are a welfare issue. |
| Castration and tail docking should only be carried out where necessary. |
| Slats for newly born lambs should be bedded. |
| Sheep houses should provide adequate natural daylight, eg through roof lights. Where supplementary lighting is made available, it should not be on 24 hours a day. |
| Sheep should be in pens of no more than 50 pre-lambing. |
A knowledge of compliance with the welfare codes is a pre-requisite for farm assurance. Most of the changes to the codes are sensible and reflect the general increase in concern in the UK for animal welfare. Unlike pigs and poultry, there are unlikely to be major costs associated with compliance on most farms.
Sheep scab outbreaks and lice infestation in sheep are increasing problems for many flock owners. At this time of year these infestations have the potential to damage the future profits from this year's lambing. It is important to identify which ecto-parasite is causing sheep to itch since the treatment for scab and lice can vary depending on which is found. To make a proper identification samples of fleece and scab from a number of sheep should be examined by your vet or veterinary investigation centre. Failure to correctly identify the cause can lead to wasting money with an inappropriate treatment.
In some parts of the country away wintered young female sheep will be returning to the flock of origin and may bring with them parasites which they could do without. Sheep scab and lice could be picked up at the overwintering farm or from the vehicles used to transport the sheep home. It is best practice to assume that these returning animals are infected and to treat them for scab and lice preferably by plunge dipping in a suitable product. It pays to carry out this job correctly since the cost and inconvenience of introducing sheep scab to a clean flock is costly.
Plunge dipping remains the treatment of choice for ectoparasites in sheep giving effective treatment and control against lice, scab mites and possibly ticks and keds at this time of year. The other methods of treatment are both broad spectrum and the parasite involved must be correctly identified before a cheaper narrow spectrum treatment is used.
It is worth speaking to your vet about ectoparasite problems in sheep since it is vital that a correct diagnosis is made to allow the correct treatment to be administered.
It is well known that ewes in late pregnancy will have reduced appetite and therefore need feeds which are high in both dry matter and energy. Loss of body weight generally indicated an imbalance between feed input and the animal's demand for maintenance and production.
As a general guide, a ewe requires a ME of:
8 to 10 MJ for maintenance
16 to 20 MJ in late pregnancy
up to 30 MJ in early lactation.
Other causes for loss of body weight could be:
| Shortfall in feed supply - analyse forage and carefully plan rations. |
| Shortage of trough space - allow 18" per ewe for concentrate feeding. |
| Mixed age groups - separate out all younger ewes. |
| Tooth defects - reassess your replacement policy. |
| Mineral deficiency - this will only rarely be a cause of poor condition in the ewes, but it is worth checking to make sure the ewes can satisfy the lambs requirements. This should be discussed with your vet. |
| Concurrent disease - breathing difficulties could be indicative of Maedi Visna, Pulmonary Adenomatosis or Chronic Pasteurellosis. Digestive problems could be associated with Fluke, Johne's Disease, Gastro-intestinal worms or poor teeth. |
Dealing with an unexpected abortion in a lambing flock creates a dilemma for the shepherd. Is the abortion a "one-off" event, occurring from time to time in a large flock, or might it be the first sign of an impending abortion outbreak. I have always felt that investigating all abortions at the earliest stage is a wise precaution. For me the most compelling argument for early investigation is provided by enzootic abortion of ewes (EAE) which is the leading cause of abortion of UK sheep. The prompt treatment of the lambing flock with antibiotics can greatly lessen the severity of an EAE outbreak, but this can only be the case if an early diagnosis is made.
A number of steps should be taken immediately an abortion is identified. Firstly the ewe concerned should be placed in isolation, well away from the lambing shed. With many of the common conditions which lead to abortion the affected animal can be a source of infection to others for days or even weeks after the abortion itself. For the same reason the products of the abortion should be carefully cleared from the lambing shed and destroyed by burning or burial (if not submitted to the Veterinary Investigation Lab). Removal of all visibly contaminated bedding is essential and the use of disinfectant on the area should be carried out wherever possible.
In most cases V.I. Labs can swiftly identify the cause of an abortion outbreak if they receive sufficient material to examine. This may mean that two or three different submissions are required before a diagnosis is reached - few outbreaks will remain unexplained if this is done. Ideally if a ewe aborts, all of the foetuses and the associated cleansing should be submitted to the lab. If the placenta cannot be found then a sample of vaginal discharge collected on a swab can be useful. Your vet may also ask for a sample of blood from the ewe herself, and including this along with the aborted lambs might save time later.
Finally the zoonotic potential of infectious abortion in sheep should never be forgotten. A number of the most common causes of abortion will also lead to illness in humans, with the risks to pregnant women particularly acute. Even apparently normal newborn lambs may carry infection. The hazard extends not only to farm workers but also to those with whom they come into contact, particularly during breaks when work clothes are still being worn. Boots and protective clothing should always be removed before entering kitchens for example. Cases of infection being passed via work clothing while it is being washed have been recorded and those doing the washing should be reminded of this.
Organic farmers have to take different approaches to worm control. They should use the faecal egg counting route to get an indication of where the problem is coming from. Not all ewes are the same; some put out a lot more eggs than others. Our recent research indicates that animals which are underfed protein due to demands for growth and reproduction produce the most worm eggs during late pregnancy/early lactation. Such ewes may be gimmers that are growing and reproducing at the same time, and thin, twin-bearing older ewes. Sort these groups into a separate mob and do a faecal egg count and compare it with a composite sample from the rest of the flock. If the faecal egg count tests show that you have identified the main contaminators of pasture then it is possible to run them as a separate mob on ground which will not be grazed by ewes and twins the following year, thereby breaking the cycle. Also by feeding extra supplementary protein, the faecal egg count of these sheep can be reduced. Worm control in practice is simplicity. The important thing to do is to avoid putting susceptible animals onto infective pasture. By identifying the ewes which are producing most of the infection and separating them and treating them it is possible to break the cycle and to use far less anthelmintics and reduce the potential for developing resistance.
Feed and forage account for around 60% of the total variable costs of lowground and upland sheep flocks and, for traditional Spring-lambing flocks, the majority of feed costs are incurred around lambing time. When choosing feeds for sheep it is important to consider their cost per unit of energy and protein, and the ease with which they can be fed as this may influence wastage and handling costs. It is also important to remember that sheep are ruminants, and that the requirements of the rumen micro-organisms have to be satisfied in addition to those of the animal. Ideally sheep should be fed a forage-based diet with concentrates provided as necessary.
Forage quality is notoriously variable and analysis can help ensure that the best material is kept for late pregnancy and early lactation when ewe nutrient requirements are at their peak. Forage analysis can also highlight any deficiencies or excesses; for example, a shortage of protein which can be compensated through appropriate choice of concentrate, or a high ash content which may indicate soil contamination and the possible risk of listeriosis.
Ewe nutrient requirements increase by around 50% in a ewe carrying a single, and 70% in a ewe carrying twin lambs during the last 6-8 weeks of pregnancy. Requirements must be met from feed rather than mobilisation of body reserves as the breakdown of body fat provides energy in a form that is not readily available to the foetus. Protein release from body fat mobilisation is negligible. Pregnancy scanning, carried out ~80 days after the start of mating, can help ensure that requirements are met and that feeds are used efficiently. Feeding ewes according to requirements gives the additional benefit that they lamb down in good condition and do not produce over-sized singles and/or under-sized multiple lambs, reducing lambing problems and associated mortality.
Most ewe concentrates are formulated to contain around 12 MJ metabolisable energy per kilogram dry matter and 16-18% crude protein. The level of concentrate supplementation required during late pregnancy will depend on forage quality, ewe size and the number of lambs carried and is likely to be in the region of 300-800 g/ewe/day. Feeding concentrate 'little and often', even at relatively low levels, can promote the more efficient capture of nutrients in the rumen stimulating forage intake and helping ewes to maintain body reserves for lactation. Feeding cereals whole can also improve diet digestibility by reducing fluctuations in rumen pH which are detrimental to fibre-digesting micro-organisms. For silage based diets however, significant amounts of whole cereal may pass through the animal undigested as a consequence of reduced rumen retention times. Light processing is therefore beneficial, especially where the quality of the silage is high.
Both beef and sheep production is still considered, even by scientists, a traditional, low input and hence low technology enterprise. As a consequence while high technology is being developed rapidly for other livestock enterprises, perhaps the best example being automatic milking stations for dairy cows, there have been no high tech developments for either the beef or sheep industry.
Another example of high technology developed for intensive livestock systems was launched recently at a major European agricultural show. It was an automatic body temperature measurement for automatic calf milk feeders. The nipple through which the calves drink milk contains a temperature sensor which measures the temperature of the calf's mouth while it is drinking. Each calf's temperature is recorded each time it drinks in a processor attached to the automatic calf feeder. Should the temperature of the calf suddenly vary, either up or down, an alarm is triggered!
Beef and sheep producers are soon likely to be "forced" into the high technology age with the probable introduction of electronic identification (EI) for all stock. Although the objective of this will be to further improve traceability of saving costs in administering the various subsidy schemes it will also offer the potential to use new technology to help improve efficiency at hopefully a lower cost. Some examples would be to automate cattle handling facilities ie to allow automatic shedding of animals and possibly to help automatically identify cows in season for AI. Many dairy herds already use pedometers (to measure the activity of dairy cows) to identify cows in season. Undoubtedly the inventiveness of beef/sheep producers will result in other ways in which technology can improve our performance once the basic problem of accurately identifying each individual animal is solved with the universal introduction of EI for all stock in the country.
On a recent visit we were discussing the amount of bedding straw which could be saved by having a unbedded, concrete feed stance which could be scraped once or twice a week. The farmer made an interesting comment that when he had been using the shed for ad lib silage feeding he had to scrape the feed stance at least twice a week to clean out the large amount of slurry which the cattle produced while they were eating. As a result ie with less dung being dropped on the bedding he felt the system was making significant savings in the amount of straw required to bed the cattle.
In the last two years however he has housed steers on an ad lib concentrate system in the shed. He now finds that he hardly ever needs to scrape the feed stance ie there is very little dung deposited there. His view was that on ad lib cereals the cattle rapidly take many small meals, walk onto the bedded area and sit down and chew the cud. When they stand up they then stretch, dung and eventually move off for another meal. As a result although he is using considerably less bedding in total for animals on ad lib cereals compared with silage diets he feels that the scrape stance is now saving little if any bedding straw.
With cattle taking much longer to eat when fed silage ad lib it appears that they do deposit more dung while they are eating and hence on silage based diets the scrape feeding stance will significantly reduce bedding requirements.
(This observation is interesting in relation to outside woodchip corrals. Perhaps there would be no need at all for a solid feed stance area in corrals used for finishing cattle fed ad lib concentrates and even if they were standing on the woodchips to feed, the lower amount of dung deposited while they are feeding might allow the woodchips to work effectively in digesting dung for many years?)
At a couple of recent meetings groups of farmers have discussed the various injection sticks - basically a syringe on the end of a pole, for injecting cattle without restraining them in a crush. All farmers who had purchased one found them a good investment. Perhaps surprisingly the majority used them most frequently in housed cattle, rather than grazing animals.
There are apparently a range of different models/makes on the market, varying in syringe capacity from 10 cc, 20 cc up to a maximum of about 30 cc. In general farmers found the 30 cc capacity unit the best.
(This summer I got an injection stick to test in our suckler herd at Bush - supposedly free of charge. However three months later I received a bill! When I went to the farm and told the stocksman I was sending the stick back his attitude was "no way are you getting it back - it's too useful". Unfortunately therefore I have had to purchase it.)
During a recent suckler cow group meeting, the point was made that the herd were surprisingly uniform in terms of their condition ie there were no excessively lean or excessively fat cows. The farmer felt that the main reason for this was that for the last five years he has always split his spring calving cows into three groups, based on their condition and adjusted the level of concentrates fed, on a straw and concentrate diet accordingly ie feeding less to the fat cows and more to the lean cows and first calved heifers.
The other interesting point he made was that he now finds that the performance of the cows from year to year, is more uniform. Previously he found that a proportion of the cows would have a tremendous calf one year, resulting in them being very lean when they were weaned, by a poor calf the next year after which they would be in much fitter condition when they were weaned etc. Since he has been grouping and feeding cows over the winter in terms of their condition he claims that this good - bad - good calf syndrome has disappeared with the cows producing a more consistent, quality calf every year.
We all know the problems associated with cows who have large, bulbous teats! (The same problems also occur in ewes.) It has just been pointed out to me by a knowledgeable Yorkshire producer that looking at the teats on a bull/ram will give a good indication of how big teats will be on his daughters.
Like all simple, good advice, now it has been pointed out to me, the logic is obvious. It is obviously the same genes which control teat size/shape in the male as in the female - the only difference being that in the male they do not develop to their full size. So next time you are considering a bull or a ram to produce replacements, why not add teats to the list of things you should check before you purchase him.
For whatever reason it does appear that we are gradually getting warmer, wetter winters (and perhaps summers). If this continues we need to consider how we might change the management of our stock to maximise any possible benefits and minimise any potential disadvantages. Some areas to consider might be:
These are just a few factors we will all have to consider as our climate changes. Working with rather than against nature has always been and will continue to be the basis for a successful farming business.
There are three things you should consider before you finally select your bull. Does his estimated breeding value (EBV) provide what your herd needs for example in terms of ease of calving, calf performance, carcase quality or maternal qualities? Is his health status such that he will arrive in your herd free of the diseases that would otherwise shorten his productive life and bring down the productivity of your herd? Ask whether the herd he comes from is accredited free of Johne's disease and BVD. Finally, does he have the physical attributes that will allow him to survive and perform in your herd?
Good stock is pleasing to the eye, but this is not a beauty show - assess the physical appearance as below:
| General Appearance: The bull should be bright and interested in his surroundings. Excitable bulls and excessively docile bulls should be avoided. |
| Mouth: Make sure he is neither overshot nor under shot. He may have managed to eat well enough to grow with this abnormality, but the defect may be genetic and his calves are unlikely to perform so well in the commercial situation. |
| Feet: The claws should be even in size and there should be a straight face to the wall ie it should not be hollow. There should be no obvious ridges running across the hoofs. Beware of excessively thin claws, particularly on the outside claws of the hind legs. |
| Legs: The front lets should be straight with no evidence of bowing or turning in or out. The back legs should neither be too straight when viewed from the side or excessively curved. The point of the hock should lie in a line dropped from part of the pelvis that is furthest back (see diagram). Good legs are necessary if the bull is to have a long working life. Without them, chronic arthritis and early culling through lameness is the prospect. |
| Testicles: These should be equivalent in size, firm and contain no abnormal bumps or swellings. Circumference around the widest part of the scrotum can be measured using a tape measure. This measurement correlates well with semen output. Blondes and Limousins have smaller testicles than Charolais, Simmental and traditional breeds, but a minimum threshold of 30cm should be used for bulls of 18 months to 2 years of age. Most people are naturally reluctant to handle and measure the scrotum, but at least a visual comparison can be make between bulls of a similar age and breed. |
(At all society approved sales the bulls should have had their mouth and testicles examined prior to display).
Young bulls are frequently found to have poor fertility in their first season. This stems from two main causes, firstly they often encounter virus infections from the time they leave their herd of origin to the time they are put to cows. This knocks their fertility for around 2 months.
The second reason is their inexperience and immaturity. They may serve cows too often and end up exhausted or more likely they may not quite know how to do the job.
To overcome these problems the following course of action should be followed.
| Quarantine the bull for 4 weeks and test him for BVD and other diseases as advised by your vet. |
| Allow the bull 3 months of acclimatisation on your farm before you use him. |
| Restrict the number of cows in his first season, ideally to 10, but certainly no more than 15. |
| Remember that purchased heifers may also bring infection with them and they too should be allowed a 3 month period of acclimatisation period along with any health screen or vaccination your vet may advise. |
Always buy a bull a minimum of three months before you plan to use him and in his first breeding season restrict the number of cows put to him.
With a lot of grain being treated with urea this autumn care must be taken with any spare urea solution which is left over. The liquid contains high levels of urea which is reasonably attractive to inquisitive cattle who can easily drink sufficient to kill themselves if they gain access to it. Only around 3 pints of the solution, taken in one "drink" is sufficient to kill a mature cow - and there is no anti-dote. (Urea treated cereals are a very safe due to the low levels of urea used to treat the grain).
If you have any urea solution left over from treating grain do make sure it is safely stored out of reach of cattle. Do not use it as a replacement for other urea liquid feeds, eg urea pour-on supplements. Propriety urea based liquid feeds are safe as they contain much lower levels of urea and are fed in a restricted manner eg through wheel licks etc to ensure urea poisoning cannot occur. If you do want to use up any remaining urea solution it should be used as a liquid fertiliser containing 10kg of nitrogen/100L.
The ideal way to supplement cattle in terms of minerals, trace elements and vitamins is to feed a correctly balanced mineral supplement so that each animal receives the correct amount on a daily basis. The easiest way to achieve this is to trough feed minerals and vitamins by sprinkling them on top of either the concentrate or silage part of the diet rather than incorporated into the concentrate mix.
For example, if a diet needs to be supplemented with 60 g of minerals and vitamins per animal per day and there are 10 animals in the group, then the total daily requirement of minerals and vitamins for the group will be 10 x 60 = 600 g (0.6 kg/day). At the start of the winter the required amount, in this case 0.6 kg/day, should be carefully weighed into a plastic container or a bucket which is then marked or cut off at the appropriate level. A bag of minerals and the container should then be left in the passageway in front of the cattle.
Then each day after the concentrates have been put down the trough (or when no concentrates are fed the silage has been put down the trough) the mineral container can be filled to the appropriate level and the minerals simply sprinkled on top of the concentrates or silage.
The advantages of this system are that:
| It ensures as near as possible that each animal receives the correct amount of minerals and vitamins for each day. |
| It means that levels of concentrate feeding can be increased or decreased, depending on the performance required, without worrying about changing the mineral content of the mix. |
| It enables the same mix of concentrates to be fed to differing groups of cattle, at differing rates, whilst still ensuring that each group of animals gets the correct mineral/vitamin intake in relation to its requirements. |
A coffee time discussion prompted this article. The question posed is "apart from feed costs what is the marginal cost of keeping winter finishing cattle an extra week?"
It has been assumed that the cattle are 550 kg and could be sold fat at £1/kg, with a finishing ration of silage, barley and beans.
£/hd/wk |
|
Drinking water @ 70p/m3 |
0.16 |
Bedding @ £40/t |
2.24 |
Man hours to feed, bed, look etc @ £6.60/hr |
0.92 |
Electric light @ 7p/kW hour |
0.07 |
Diesel of tractors etc @ 17p/l |
0.02 |
Additional interest on not selling cattle @ 8.5% pa |
0.90 |
Total |
4.31 |
Equivalent to 0.6 kg/day LWG.
If the cost of the feed is taken at 70p/day, a LWG of 1.3kg/day is required just to break even. In this case there is NO benefit of keeping the cattle that extra week unless the market is rising.
Why not work out your own costs?
Recent problems in the supply of the live Toxoplasma vaccine Toxovax have left some farmers with a tricky decision to make on alternative forms of toxoplasmosis control. With monensin no longer available for use in sheep, the only remaining preventative treatment is decoquinate sold as the food additive Deccox. The manufacturers of Deccox recommend that to protect a flock from toxoplasma abortion, decoquinate should be fed to pregnant ewes at a rate of 2mg/kg body weight per day continuously for the last two thirds of pregnancy. Apart from the obvious expense of this regime, an immediate problem is created for shepherds who would not normally feed their sheep for so long.
However, things are not quite as bad as they might at first seem. To start with, on most farms with a history of toxoplasmosis, Toxovax is only used on new breeding females as they are introduced to the premises. Older ewes are known to be protected for at least two years post-vaccination and are likely to have this immunity "topped-up" through exposure to naturally occurring infection. The major worry for this year is therefore gimmers (and any ewe lambs) introduced to the lambing flock in the Autumn. These would be the animals most likely to become infected if not protected. A sensible approach would be to separate this group from the rest of the flock and feed decoquinate mixed into a token amount of concentrate from 14 weeks before the start of lambing. As the amount of concentrate fed increases towards lambing the inclusion of decoquinate must of course be adjusted.
The question will then arise, should these young sheep be vaccinated with Toxovax next year? A proportion of this group is likely to encounter natural Toxoplasma gondii infection over the following twelve months and go on to develop protective immunity. However to guarantee maximum protection they should of course be vaccinated next year.
© The Scottish Agricultural College 2000 ISSN 0956 1900
Produced by The Scottish Agricultural College, Farm & Rural Business Division, Greycrook, St Boswells,
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