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Livestock eNews July 2000 Livestock e-news is derived from SAC Sheep Beef Notes.
SUMMERTIME TUNE-UP FOR RAMS
Rams are kept on farms through the year in the expectation that they will perform to a high standard during a relatively short period at tupping time. However the common problem of lameness is one which can often have a detrimental effect on a rams general mobility and willingness to work. This can mean a decrease the ram's overall fertility and may easily result in poorer flock lambing figures the following spring.
In common with the rest of the flock the predominant cause of lameness in rams is footrot, and summer time presents the ideal opportunity to tackle footrot problems in a concerted way. The drier pasture conditions make life difficult for the bacteria that cause footrot and the general level of this infection within the flock is usually at its lowest at this time. With careful treatment and attention to detail it should be possible to get the ram group into tiptop condition for their call-up in the back-end.
As a starting point all rams should be turned and have each foot checked, the use of a suitable cradle making this job much less daunting. Judicious paring should aim to remove any overgrowth and to expose under-run horn to the air. The use of antibiotic, in an aerosol and where necessary in an injectable form, is justified if signs of footrot are present. Subsequent foot-bathing on one or more occasion will usually cure the majority of cases. Where more complicated problems such as interdigital fibromas or granulomas are apparent, specific advice and treatment should be sought from your vet.
Such is the importance of sound feet in rams that some vets recommend the use of footrot vaccine within the ram group as a matter of routine. If this is to be done then vaccination should take place no later than two months before the start of tupping. This will allow the full effects of the vaccine to be felt by the time the rams join the ewes.
As with many common diseases there is evidence to suggest that susceptibility to footrot may have a genetic component. It therefore follows that rams with "good" feet that are free from clinical footrot make better sires than rams which suffer from "bad" feet and repeated bouts of footrot. A sensible culling system is therefore recommended to remove any rams with problem feet. Not only should this improve fertility levels within the ram group, but it will also prevent his progeny from perpetuating the problems though future generations.
GB
MASTITIS AT WEANING
The post-weaning check-up of the lambing flock should always include an examination of the udder of each ewe to check for signs of mastitis. Chronic mastitis detected now as a firm swelling in one or both quarters is rarely a recent occurrence. Indeed research indicates that very few cases of mastitis develop after weaning. Instead evidence of chronic mastitis almost certainly reflects an infection which took place much earlier in the year, usually in the first month after lambing. Previous mastitis is almost certain to leave the affected quarter compromised and liable to produce little or no milk next season. Mastitis is therefore a prime reason to cull ewes.
Udder infections are usually caused by one of two common species of bacteria, that gain entry to the mammary gland via the teat canal. These bacteria originate either in the environment in which the ewes are kept or from the mouths of the sucking lambs themselves. Injury to the teats, caused by lambs or infections such as orf, can predispose ewes to mastitis by making the entry of bacteria more likely.
In the small number of flocks where post-weaning mastitis is a recognised problem the technique of using a long-acting intramammary antibiotic as "dry ewe therapy", has been shown to be useful. Some of the well-known dry cow intramammary tubes now have recommendations for use in sheep - generally half the cattle dose infused into each quarter. The tubes are normally given to ewes shortly after all the lambs have been weaned.
Dry ewe therapy must be carried out with the strictest levels of hygiene, since it is easy to introduce bacteria into the udder at the time of treatment and end up with worse mastitis than if you'd done nothing. The tubing process requires at least two operators, with one person dedicated to handling and turning the ewes. The other person must first wash their hands and keep them clean by washing throughout the operation. Their job is then to wash and disinfect the teats, swab the teat orifice with surgical spirit and then express a small quantity of milk to act as a lubricant. The end of the intramammary tube is then gently introduced into the teat orifice and the dose administered. The area of udder around the teat should then be gently massaged to distribute the antibiotic up into the udder. This accumulation of long-acting antibiotic should "mop-up" any pre-existing mild mastitis and give protection against further infections during the weeks following weaning.
GB
CHOICE OF TREATMENT FOR SHEEP ECTOPARASITES
The treatment of sheep for flystrike, sheep scab, tick infestation and keds is better approached by prevention rather than cure At this time of year it is essential in most flocks to use therapy to prevent attack by either ticks, mites, flies or keds. When choosing a product do not always be attracted by prices but rather ensure that the preparation will do what you want and has a license for use from the Veterinary Medicines Directorate - usually a data sheet. All licensed products have undergone rigorous testing regimes to ensure that claims made are accurate,do not expect untested products to give effective control. Although there are cheaper unlicensed products available will they do the job required? At the end of the day a parasite free sheep is more likely to leave a profit.
SC
TAGGING - THE PLUS POINTS
The latest fashion statement is Body Piercing and fashion conscious 'Blackies' will not be left out!! The most 'hip' of those 'cool dudes' (and 'groovy chicks') we see each year at Lanark and Newton Stewart have obviously been 'hanging out' with the 'Style Gurus' in Brussels - yes, because of an EU directive, all sheep leaving the holding of birth will soon have to be wearing 'the latest EU fashion accessory' - an ear tag!!!
In the very near future (tags available in September) every animal will have to have a tag noting its holding of birth when it leaves that farm. Obviously, this could be done as the sheep goes onto the float, but there are ways to make the new regulations work for us.
If all stock ewe lambs were tagged, with a tag, which has the required information on it, it can also be used to help management for the next few years. If a different colour tag was used for each year's crop of ewe hoggs entering the flock, the tag colour could be used for drafting cast ewes, perhaps more easily than using horn cuts. Other ideas are using ear-marking pliers to notch the tag if the ewe needs to be culled early, and using different colours for different hefts etc. By using colours in a memorable order, eg the rainbow, it is possible to make identifying the age of a ewe easy.
So, what are the benefits of tagging and what choices do we have to make?
ú Type of tag - This can have an amazing effect on tag retention. Different tags are better for different breeds. Metal tags - tend to get infected and fall out and when you are beyond a certain age they are difficult to read - I am told! Plastic tags - also vary considerably in ease of use, size of pliers, retention, many people have a catalogue of trial and error stories. Having decided to use plastic tags then the ideas regarding colour can be considered.
ú Individual numbers - What about using an individual number for each animal? It costs only pence more to have tags printed with consecutive numbers.
Size of tag - Do you want the tag to be distance readable? Then perhaps you could use the ewes' individual ID at other times - particularly as these days any one person is responsible for much more than just a 'hirsel'. Imagine you spot a ewe with a poor wee lamb on the hill in July - just note her number, say Yellow 418. Come September when Yellow 418 is the fittest ewe in the flock at least you know why (hardly been "milking off her back" has she?), and an appropriate management decision can be taken.
It is not possible or desirable for every farmer to be considering these options and many will be using some of these ideas or others anyway, but could YOU make some of it work?
At Mossfennan, we have been tagging sheep in some form since 1978. At first, we used small tags with individual identities to help us record ewes which had had problems and those nursing twins. Having some records, but by no means comprehensive ones, we began recording with Signet (at the time, MLC, Sheepbreeder) in 1985. This year will be our 14th lambing tagging lambs at birth, all outdoors (and in all weathers!).
Extract from an article written by Ann Welsh of the Blackface Sire Reference Company for the Blackface Sheepbreeders Association Journal.
JV
ENHANCING THE ACCURACY OF SHEEP GENETIC
EVALUATIONS USING CT
This year, for the first time, CT predictions of carcase lean and fat have been used to enhance the accuracy of the genetic evaluations for several of the Sire Reference Schemes in the UK.
CT (Computer Tomography) is a non-invasive procedure, similar to x-ray, that allows cross-sectional images of a living animal to be obtained. The amount of muscle, fat and bone in the animal's body can then be estimated much more accurately than when ultrasound measurements are used alone.
Use of ultrasound scanning to measure fat and muscle depths, together with index selection, has proved to be highly cost effective in improving sheep meat quality. Most British terminal sire Sire Reference Schemes are now achieving an average of about 7 Scheme Index points progress per year. SAC research has shown that each increment of 10 index points is worth œ44 to œ66 per ram over his productive life to a commercial buyer. These benefits are a result of progeny from high index rams achieving higher growth rates and producing more carcases that meet target fat levels.
Selection for lean growth using CT measurements has the potential to increase the economic benefits of genetic improvement by up to 50% per year compared to selection on ultrasonic measurements. However, it is not cost effective and, to an extent, impractical to CT scan all lambs in a breed. A two-stage selection programme has consequently been introduced this year in which most animals are scanned ultrasonically and then the best males submitted for CT scanning. This allows much of the benefit from CT to be obtained at a fraction of the cost.
The use of CT to enhance the accuracy of EBVs and Indexes should result in faster rates of genetic improvement within breeds, and greater availability of high quality rams for use by commercial producers. The wider use of high index rams in commercial flocks will, in turn, lead to faster growing crossbred lambs and more carcases meeting market specifications.
JC
Acknowledgements
The CT development work is a LINK project under the Sustainable Livestock Production Programme and the uptake of CT in the major terminal sire breeds is being subsidised by MLC levy for a period of three years.
USING GENETICALLY SUPERIOR RAMS
The next breeding season is fast approaching and commercial producers should shortly be taking steps to plan their ram requirements for the 2001 crop. Early and March lambing flocks should certainly be taking active steps to source genetically superior rams now to enable them to get the most profit out of their sheep systems.
Producers should be actively looking for rams with high Estimated Breeding Values (EBVs) available from Pedigree Flocks using the Signet Sheepbreeder Recording Service.
Why?
Because these rams are proven to grow quickly and carry more lean tissue which means their lambs grow quicker, weight better at a given age and kill out better reaching finish weights in a shorter period - leaving more profit.
What are we looking for?
Rams which have +5 kg to +6 kg on their scan weight EBVs and +2 mm to +3 mm on scan muscle EBVs is a good start. 50% of this genetic potential is passed to the crossbred generation which means that when the crossbred lamb is finished they should be 2 or 3 kg heavier at around 5 to 6 months of age as well as carrying more lean meat - or they can be sold 2 to 3 weeks earlier at hopefully a better price.
Several factors need considering:
ú Producers very rarely change ewe breeds to the only opportunity to improve profits and enterprise margins through breeding is by using superior rams.
ú From July to December 1999 lambs averaged around œ30 per head for a 38 kg (liveweight) 18.5 kg (deadweight) lamb (80p/kg live). So selling lambs late in the season was to no advantage.
ú The 2000 season looks like repeating this trend.
ú Lambs can be finished earlier or at better weights and the money put in the bank. An extra 1 kg at 80p is œ800 on a 1000 lambs.
ú Savings are made by not having to worm and vaccinate lambs into October/November/December for no extra return. It cost around 40p to 50p per lamb every time we treat lambs in medicine product and labour costs.
ú Labour costs/lamb are reduced.
ú Better grazing is available for flushing and tupping ewes ready for the 2001 crop. Most enterprise profit is decided by getting the tupping right and producing good numbers born and reared with ewes in the right condition and able to milk well.
ú Avoid the danger of thinking you have plenty of grass at the moment, make sure you keep lambs growing at their maximum potential to point of sale.
ú Opportunities will exist for some producers to purchase and finish store lambs if the home product has been sold early, leaving spare grass or the opportunity to grow forage crops. This all helps the sheep enterprise profits.
ú Purchased rams from sales are usually well fed and in forward condition, so ensure they continue on a reasonable concentrate diet. Turning them straight out to ewes with no concentrate feed is a recipe for severe stress, infertility and no lambs by that ram - genetically superior or not!
Names and addresses of Sheepbreeder members in your area can be obtained from Signet Farm Business Consultancy HQ on 01908 670339 or fax 01908 609825.
MJ
SILAGE QUALITY AND SUPPLEMENTARY FEEDING
This year in some areas the weather has played havoc with silage making. Some crops were cut late and were more mature than is ideal with high fibre and low protein contents. Other crops were lifted in dull, wet conditions resulting in low dry matter and sugar contents. These adverse factors can lead to poorly fermented, low nutrient content silages with carry over effects on the amount and type of supplement required to maintain animal performance targets next winter.
The examples below demonstrate this:-
1) Average silage (23.5%DM; 10.8MJME/kgDM; 14%CP in DM)
Store (350kg; 0.7kg/d) Finisher (500kg; 1.0kg/d)
Silage kg/d 26 27
Barley kg/d 0.76 3.5
2) Poor silage (18%DM; 9.5MJME/kgDM; 10%CP in DM)
Silage kg/d 24 24
Barley kg/d 2.6 4.9
Rapeseed meal kg/d 0.16 0.73
To establish the amount and type of supplement to balance your silage next winter it is essential that you know your silage quality. If you have doubts, contact your advisor so that a sample can be taken for analysis.
CM
COCCIDIOSIS
Most species of animals have their own coccidia, parasites that mainly affect the gut. However the coccidia that infect one species will not affect another ie cattle coccidia don't affect sheep and vice versa. Only a few types of coccidia cause sufficient damage to the gut to cause disease. They cause damage to the second half of the gut that results in diarrhoea. This is sometimes bloody and the discomfort the animals experience results in them straining. Damage to the gut can be severe enough to be life threatening, but in most cases the animals will self heal quite quickly. Calves younger than 4 weeks or older than 12 months are unlikely to be affected by coccidiosis.
The infective oocysts or eggs are passed in the dung and develop quickly in warm situations to become infective. They are also resistant to drying and can survive for long periods of time. However for calves to get a heavy enough infection to cause disease they must be exposed to reasonable degree of contamination with dung. This can be on their coats, on grass or other feeds.
In grazing situations calf creep areas should be moved regularly to prevent a build up of dung. In an outbreak it may be necessary to temporarily fence off the areas that calves have been choosing to lie in. Where outbreaks have occurred indoors you should clean the area and remove all traces of dung . Follow this with a disinfectant specifically designed to act against coccidia e.g.Oocide (Antec).
GC
LUNGWORM IN CATTLE
Lungworm is an important condition of grazing animals. Wet and warm conditions favour this parasite and disease is therefore more of a problem in the wetter areas of Britain. Disease is usually not seen before July, but from this month on coughing in grazing animals should be taken as a sign that lungworm could be affecting your cattle. Failure to take prompt action can result in permanent damage to the lungs and therefore failure to thrive, but some outbreaks are of such severity that deaths occur. Mature cattle are occasionally affected by the disease and, when they are, feed intake and milk production is adversely affected.
Infection: Larvae are picked up from the pasture where they have overwintered. In addition the adult parasite can survive over the winter in the lungs of cattle that have grazed infected pastures the previous year. These worms then result in more larvae being passed in the dung of the animal at turnout. Therefore new infections at grass can be started where cattle were not treated with a wormer at the previous housing. The larval stages can survive for prolonged periods and can be spread from adjoining fields through the action of a fungus that expels its spores and with it the lungworm larvae into the air.
Safe Pasture: Where fields have not be grazed by cattle in the previous year they should be considered safe. However, as small numbers of larvae can be spread between fields (see above) few fields can be considered to be completely clean.
Resistance to Infection: Animals develop a strong immunity to the disease after they have been exposed to infection. However in certain situations worm control may have been so effective that cattle may not be exposed to sufficient infection to stimulate this resistance. This is considered to be the explanation behind outbreaks of disease in adult cows. Because of this resistance, vaccination has proved to be an effective control strategy for lungworm.
Diagnosis: Where coughing occurs at grass suspect lungworm. Prompt action is required and you should consult your vet immediately. Lungworm is not the only condition that can cause grazing cattle to cough and establishing a diagnosis with the help of laboratory tests may be required.
Treatment: Most of the modern wormers are effective against lungworm. Where animals are coughing and in distress you should consult your vet for advice on the most appropriate product to use.
Control: Vaccination is recommended for calves destined to be breeding animals. In suckler herds where lungworm is a recognised problem vaccination is also advised. Again for best use of vaccine consult your vet. Suppressive strategies such as boluses or appropriate treatment with single dose wormers in the first half of the grazing season are generally very effective. Care should be taken where cover from these does not extend throughout July as lungworm may then become a problem later in the grazing season
GC
SUMMER MASTITIS IN SUCKLER HERDS
This is most commonly but not exclusively a disease of dry cows and heifers at grass during the summer months of July, August and September. Occasionally even bulls and steers can be affected. Arcanobacterium pyogenes plus a variety of other bacteria are the cause of severe mastitis involving one or more quarters. The affected animals are usually unwell and appear stiff and lame. The affected quarter is very hard, hot and painful with a swollen teat. The strippings are initially brown liquid becoming yellow thick foul smelling pus later. Sometimes abscesses burst out through the side of the udder. Animals can be so severely affected that they die, abort or have to be culled.
Urgent veterinary treatment of all cases is therefore advocated. This will usually involve antibiotics but drainage of the quarter is also important to remove the toxic material within. This can be achieved by very frequent stripping or teat surgery. The vast majority of quarters are so severely affected that they permanently lose their ability to produce milk. Flies appear to play a major role in the transmission and cause of summer mastitis. The causative bacteria can be found in the gut of the head fly for several days after infection. The incidence of summer mastitis varies from year to year, some years being much worse than others, particularly those with hot summers. Thought should be given to prevention now. This can be achieved by a combination of the following:
1 Fly Control. Avoid keeping susceptible stock on pastures with high fly numbers such as those containing woodland, ponds or marshy areas. Insecticides such as sprays, ear tags and pour-ons are advocated. However, cows teats have no sweat glands and it is through sweat that the insecticide in pour-ons and ear tags spreads around the body. Therefore the most effective (but most labour intensive!) method is weekly application of a fly repellent directly to the udder. Housing susceptible stock is a useful strategy especially during bad summer mastitis years because the head fly is reluctant to enter buildings. The fly is not active at night so these animals could be turned out overnight. (An alternative for protecting teats is to use polyurathane varnish as a teat dip.)
2 Infusion of long acting antibiotics into each quarter at drying off is frequently practised in dairy herds but not suckler herds. Nevertheless it is a very effective preventative method and should be considered in a bad year or during an outbreak on a particular farm. Infusions can be made during the dry period and to heifers. Consult your vet.
3 Frequently inspect stock to identify cases early. This is important for two reasons. Firstly, the earlier the animal is treated the more likely it is to recover. Secondly, the infected quarter is a source of infection which could be spread by flies to other animals in the group, so the sooner it is isolated the better.
MC
TB
Badgers do suffer from TB the same as cattle. As the disease progresses in badgers they may excrete vast amounts of infection in their dung and urine (up to 300,000 TB bacilli per ml of urine), increasing the risk of TB spreading to cattle. Heavily infected badgers tend to become loners looking for easy meals etc and this can often encourage them to spend more time in and around farm buildings. One way of reducing the risk of TB is therefore to prevent badgers gaining access to cattle sheds and feed stores.
MRH
ARE AGGRESSIVE COWS BECOMING MORE COMMON?
The behaviour of cattle is determined by two factors -
1 their breeding/genetics, and
2 their experiences in early life.
Unfortunately there are "families" in all breeds which are more excitable and potentially more aggressive. (Hopefully we will soon have EBVs for animal behaviour traits which will allow us to more accurately identify such families and cull them out).
Regardless of breeding, experiences in early life also have a major effect on the future temperament of the animal. A good example of this would be bucket reared calves producing less excitable, more placid cows. This is one reason why in the past aggressive cows have not been a major problem, with the majority of replacements coming from the dairy herd where they have been bucket reared.
The trend towards using suckled heifers as replacements is undoubtedly one reason why cow behaviour has become more of a problem. (Going back 40 years or more when again the majority of suckler replacements came from the suckler herd, cows in many herds were tied by the neck in byres over the winter so the young suckled calf had more contact with humans. In addition, in those days cows were much smaller compared with cows of today!)
It is difficult to be sure how much wild/aggressive behaviour is due to breeding and how much is because of the early experiences of the young replacement suckled heifer. For example, a potential heifer replacement born to an aggressive cow will learn aggression from its mother etc.
Ways to eliminate behavioural problems in suckled heifer replacements
1 Do not keep heifer replacements from nervous/aggressive cows.
2 Always handle cattle, particularly future heifer replacements, firmly but quietly.
3 Where possible feed concentrates to calves from inside the pen from as early as possible so that they
associate you with food.
4 When you do feed them from either outside or inside the pen, talk to them so that they associate your voice
with feeding.
With a little thought, taming homebred heifer replacements as young calves can often be easily built into the routine management of the herd with little or no cost but with large long term benefits in terms of placid breeding cows which can be safely handled.
BL
TAMING HOMEBRED REPLACEMENTS
At a recent suckler cow group meeting we were discussing the apparent increase in cases of aggression in homebred suckler cows compared with bucket reared replacements. An interesting suggestion raised by one of the group was to use self locking feeding yolks to train young heifers over the winter. The proposal was to put in a row of four to five self locking yolks, replacing a standard diagonal feed barrier. This section would be shut off from the rest of the pen and four or five young heifers fed through the feed yolks for two to three weeks. They would be shut into the yolks automatically as they came forward to feed and left there for two to three hours before being released. Each time they were shut into the yolks, 5-10 minutes would be spent walking behind them and carefully handling them. When the heifers had quietened down they would be replaced by another group etc with the process continuing over the winter.
Initially this suggestion sounds very labour intensive but if it is successful in producing more placid easily handled cows the long term cost benefit could be tremendous with homebred heifers having a productive herd life of over eight years.
BL
¸ The Scottish Agricultural College 1999 ISSN 0956 1900
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.
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