LICE CONTROL

A heavy infestation of lice causes severe skin irritation and will reduce the performance of cattle. In some cases, 
particularly in younger calves, sucking lice will cause anaemia. Lice control is therefore an important routine 
treatment for cattle. The following should be considered when deciding the best way to control lice in your herd.

? Lice only thrive in the winter. This is due to lower skin temperatures favouring the survival of the parasites. 
During the summer only a few lice survive in places like the ears. These rapidly multiply and spread as the 
temperature falls.

? Spread is aided by the close contact between animals at housing. Other factors such as under-nutrition will 
also increase the number of lice on the cattle.

? Louse eggs (nits) are fairly resistant to treatment, but they hatch in around 7-10 days. Therefore for 
treatment to be effective the product must have a persistent action that goes significantly beyond this period 
or a repeat dose is required at 14 days.

? The avermectin group of wormers can be used to control lice. In most cases one dose as sufficient, but in 
rare cases a second dose may be required at 4 weeks or later. These products have a place for the 
treatment of animals that may also need to be wormed. Adult cattle in general don't need to be wormed and 
therefore these products may be unnecessary and expensive for treating adult cows.

? Non-wormer pour-on products may offer the most cost beneficial option where cattle do not need to be 
wormed at the same time. They are split into two types - either the organophosphates (e.g. Poron) on the 
permethins (e.g. Spot-on) both groups are effective, but the organophosphates must be repeated at 14 days*.

? Remember that cattle that are out-wintered will still require to be considered for louse control.

? To decide on your policy consider the need for worming in the stock you have and the cost of handling where 
repeat dosing is required, and relate that to the costs of the products.

? Information on products and costs can be obtained from pharmacies or your veterinary practitioner. The 
latter is the best person to advise on tailoring the control programme to the requirements of your herd.


WHAT YOU CAN DO TO PREVENT THE SPREAD OF CLA

? Carry out a regular physical examination of the whole flock, ideally this should be undertaken every 3 months 
or at least each time the flock is handled for other purposes.

? Shear and dip young sheep first and tups last (dipping is not advisable within the first fortnight after shearing).

? Try to segregate the young sheep from older animals into separate flocks so that if the disease does appear 
you have more chance of protecting youngstock.

? Inspect all bought in animals thoroughly - the potential purchaser is advised to examine all sheep but in 
particular rams for lumps or discharging abscesses around the jaw and neck. The lumps can be present 
elsewhere in the body but they are often harder to spot under a thick fleece.
? Any animals with lumps should be isolated until checked over by a vet and lab tests have given them the all 
clear.

? Abscesses should never be cut or lanced - this can spread bacteria into the environment.

? Affected sheep should be culled - in infected flocks it may be possible to establish a clean flock by 
separating lambs from the main flock after weaning. Recent evidence suggests that lambs rarely become 
infected pre weaning.

? Clipper blades should be cleaned and disinfected between flocks and between animals suspected of being 
infected and those which are clear.

Although never reported in the UK, human cases of caseous lymphadenitis do occasionally occur in other 
countries. These rare infections tend to afflict those who come into close contact with sheep, for example 
shearers. Although it is important not to overstate the risks, it would be wise for those dealing with CLA affected 
sheep in this country to be aware of the zoonotic potential of the disease. Taking extra care with hygiene and in 
particular avoiding the contamination of skin with pus from abscesses, for example by wearing plastic gloves, 
should remove any slight risk of infection.

GB

SCRAPIE ERADICATION PLAN - CONSULTATION

A major consultation exercise on the first phase of a National Scrapie Plan was launched by Agriculture 
Departments at the end of last month. This first phase comprises a voluntary ram genotyping scheme which 
involves the selection of breeding rams with scrapie-resistant genes. It forms part of the Government's Action 
Plan for Farming launched by the Prime Minister earlier this year.

The aim of the National Scrapie Plan is to reduce and eventually eradicate scrapie in Great Britain. It will have 
three phases:

Phase 1 - breeding for genetic resistance (ram genotyping scheme);
Phase 2 - checks for scrapie on scheme farms;
Phase 3 - programmes to help scrapie affected farms.

Over time, the ram genotyping scheme will increase the resistance of the national flock to all known types of 
TSE, including scrapie and BSE. Research suggests that one form of a particular gene in sheep (the PrP gene) 
confers this resistance. Rams with the TSE resistant genes would be identified using genotyping - a DNA test 
using white blood cells. Farmers would then use TSE resistant rams in their breeding programmes.

Scrapie has been endemic in the national flock for over 200 years but has no known link to human disease. It 
causes serious welfare problems in affected animals and is always fatal. Although it usually occurs at low levels 
in a flock, it can affect a significant proportion if the flock is genetically susceptible. Although farmers are 
required by law to report suspect cases under reporting is significant.

The consultation period ends on 31 October 2000. Agriculture Departments aim to have the ram genotyping 
scheme in place around the turn of the year with the genotype testing starting as soon as practicable thereafter.

Reprinted with kind permission from BSE Enforcement Bulletin 49

SCAB CONTROL IN THE ABSENCE OF OP DIPS

Organophosphorus dips have been withdrawn and, until research has been carried out to disprove that these 
products, used correctly, are harmful to human health, they are unlikely to be re-licensed. The products available 
to control or treat sheep scab are shown in the table below. The choice of product will depend upon many 
factors, such as the number of animals to be treated, the closeness to slaughter, the need to treat other parasites 
e.g. blow fly, ticks, keds and lice or intestinal and lung worms.

If dipping remember to keep the sheep in the tank for at least one minute and to submerge the head. Take great 
care to avoid contact with the skin especially of the neat compounds and dispose of the waste safely not into 
water courses. Dips are often made up to the correct strength to start but operators sometimes fail to top up as 
recommended. Incorrect dipping will be ineffective and may lead to drug resistance problems.

Injections may be more suitable for small numbers of animals. Take great care with the technique. It is very 
easy for the needle to penetrate a fold of skin twice so that the dose is wasted. Weigh some animals. 
Underestimating the animals' weight will lead to ineffective treatment.

If you suspect any licensed product is not working please report it to your vet and local SAC Veterinary Centre so 
that the possibility of resistance can be investigated.

Timing treatments is important. All sheep should be treated at least once annually, usually prior to tupping. If 
blow fly is a problem a summer dipping 2-3 weeks after clipping will be required. If in a community or shared 
grazing co-ordinate so that everyone treats within a few days. Treat any animals added to your flock or returning 
from grazings. Treat affected animals and any sheep they could have contacted promptly.

Further information about the products available can be obtained from your veterinary surgeon. The use of 
sheep dips requires a certificate of competence. 
PRODUCTS AVAILABLE FOR SHEEP SCAB CONTROL OR TREATMENT


GB
SECOND CALVERS - A COMMON CAUSE OF BARREN COWS

Tradition says that the most difficult animal to get in calf is the first calved heifer. However in many suckler herds 
the fertility of first calved heifers can be very high - in our herd at Bush the first calved heifers normally have the 
highest conception rates and the lowest barren cow rates.

The main problem group, often giving rise to a high proportion of barren animals, is more likely to be second 
calvers. Where this occurs the reason is almost certainly their poor condition at calving as second calvers - a 
reflection of inadequate management of first calved heifers.

The situation can best be explained by following the heifer through the first years of her life:

- Heifers are normally calved down in reasonably good condition.

- When they are re-mated, about two months after calving they are still in reasonably good condition and 
fertility tends to be good with the majority of first calvers getting rapidly back in calf.

- The main problem occurs when they are overwintered either as dry cows in spring calving herds or as 
heifers with calves at foot in autumn calving herds.

- Where first calved heifers are overwintered with mature cows they will be underfed due to their higher 
feed requirement, for their own body growth, while being unable to compete with mature cows for 
restricted winter feed supplies.

- The end result is very lean pregnant, first calved heifers by the end of the winter.

- In spring calving herds these very lean second calvers can not regain sufficient condition quickly enough 
to successfully get back in calf.

- In autumn calving herds the poor condition of pregnant first calvers at turnout results in them being very 
lean at calving as second calvers, significantly depressing their fertility when they are re-mated later in 
the autumn.

- The second calvers which do become pregnant, probably early in the mating period will run an increased 
risk of being barren as third calvers a year later.

To avoid the problem the target must be to have all second calvers at the correct condition score at calving. To 
achieve this target it is essential that the winter ration of first calvers is carefully managed, ie it is essential that 
first calved heifers must be housed and fed separately from mature cows. As a general rule of thumb first calved 
heifers should be fed at least 10% more over the winter compared with mature cows. For autumn calving herds 
this will be equivalent to around an additional 1 kg of barley per head per day and an additional « kg per cow for 
spring calving herds.




Grouping

- In spring calving herds in-calf heifers must be overwintered as a separate group and as they calve, 
moved into a group consisting of only first calved heifers. Ideally first calvers should also be grazed as a 
separate group on the best pastures available.

- In autumn calving herds heifers should again be taken out into a separate group as they calve and 
supplementary feeding offered immediately.

- In both cases, if there are insufficient first calved heifers to make up a winter group, the leanest of the 
second calvers should be used to make up numbers.

- In autumn calving herds it is more critical to house first calvers separately rather than to house on the 
basis of calf age.

Calving heifers before the cows

Calving heifers two to three weeks before the main cow herd can be beneficial in autumn calving herds - but not 
in spring calving herds. Where heifers are calved before the cows it is essential that they are weaned earlier than 
the cows. In many cases it will be sensible to wean autumn calving heifers at turnout to allow them to regain 
adequate condition over the summer before they calve down the following autumn.

How well are you managing your heifers?

If you think you are managing your heifers well - do your heifers agree? Heifer management must be checked 
every year by simply:

- Listing the ages of all barren cows and 
- Checking the condition of first calved heifers at the end of every winter.

BL

THE IMPORTANCE OF KNOWING THE WEIGHT OF YOUR COWS

As part of a major project to develop maternal EBVs, Signet have been weighing and condition scoring nearly 
20,000 suckler cows. Around ó of these cows are purebred, from the main beef breeds with the remainder 
commercial crossbred cows.

A very quick glance at some of the cow weights last autumn (when cows are likely to be at their heaviest weight) 
showed that many pedigree cows were well over 800 kg with many crossbred cows over 700 kg! In simple terms 
the figures suggest that many of todays beef cows are considerably heavier than we think.

So what?

The obvious long term effect of cow size is the impact it has on the efficiency/profitability of suckled calf 
production - for example the effect it has on the weight of calf weaned per 100 kg cow liveweight maintained over 
the year. Obviously as the data is analysed we will hear a lot more of this aspect over the coming months.

However the immediate importance of cow weight is its effect on winter feeding to ensure the cows we currently 
have, perform efficiently, and in particular maintain high levels of fertility. The following table shows the rations 
required for small and big spring calving cows with zero liveweight change over the winter.

Spring calver
0 liveweight change
10 weeks off calving

Cow size (kg)
550
750
straw
4
4
silage
15
11
m.gluten
1.2
3.2
ME (MJ/day)
73
87

The heavier cow obviously requires more feed over the winter. If she was fed the same ration as the 550 kg cow, 
she would lose around 0.5 kg/head/day over the winter so that by calving she would be nearly 60 kg lighter. The 
heavier cow would then have to gain an extra 60 kg at grass next summer.

To maximise output ie the fertility from the cows we already have, it is therefore essential that their true 
liveweight is used when calculating winter rations. Underestimating cow liveweight will simply result in leaner 
cows, poor fertility and higher barren cow rates.

BL


SAFELY WEANING SUCKLED CALVES AT GRASS

Unfortunately in recent years there has been an increasing number of fatal traffic accidents involving vehicles 
hitting suckler cows wandering around the road. In all cases the suckler cows had just been weaned and had 
"escaped" looking for their calf.

The cow-calf bond is extremely strong in suckler cows which means that even normally placid cows will jump or 
break through field boundaries to get back to their calf. It is therefore important that suckled calf producers take 
extra precautions when weaning calves over the summer.

Some general guidelines would be -

NEVER separate cows from their calves across a road.

NEVER separate cows and calves so far apart that they cannot see or hear one another. If an animal should 
break out then it is likely to wander around looking for its mother/calf and could end up on a road. Weaning cows 
and calves so that they can hear one another ensures any animal which breaks out will go directly to its 
mother/calf.

ALWAYS carefully check all fences, gates etc. of fields used for newly weaned cows or calves, both before 
weaning and daily for the first few days following weaning

Some systems for weaning cows to minimise the risk of animals escaping or getting onto the road would be -

1 To wean across a strong field fence. Several producers use two adjoining fields separated by a strong 
fence, often with an electric scare wire either side of the fence for weaning cows. This allows cows and 
calves to still see one another and minimises the risk of animals escaping.

2 Gradual weaning. Other producers wean cows in batches, removing around a third of the cows from the 
group each week. The cows are then shut up to dry them off and returned to another group of cows and 
calves ie not to the group containing their own calves. This ensures the weaned calf is always running 
with cows and stays in the field in which it has been grazed for most of the summer.

3 Creep feeding calves into an adjacent field. Another approach is to graze cows and calves prior to 
weaning in two adjacent grass fields with one field being used as a creep for the calves by replacing the 
adjoining field gate with a conventional "pop hole" barrier. This allows autumn born calves to be trough 
fed concentrates in the creep field. If it can be arranged that the creep field has more grass than the field 
grazing the cows then the calves will gradually spend more and more time in the creep field so that 
eventually the adjoining "pop hole" can be shut off to wean them.

4 Housing weaned cows. In extreme cases it might be necessary to house the cows to wean them, leaving 
the calves outside. Ideally, in this situation the cows and calves should be grazed for at least a week in a 
field adjacent to the building where the cows will be housed. This will ensure that the calves are 
accustomed to the field and, should they escape then they will simply stay around the shed holding the 
cows. After four or five days the cows can be turned back out and ideally grazed in a field next to the 
weaned calves for a further two weeks until both groups are fully settled. 

5 While the main objective is to avoid cattle getting onto roads and causing fatal traffic accidents, it is 
important to remember that avoiding cattle breaking out can save considerable time/labour chasing 
animals around the country and will minimise the check in growth rate the calf receives when it is 
weaned.

BL




INTRODUCING CATTLE TO AD LIB CONCENTRATES

The normal way of introducing cattle to ad lib concentrates is to start feeding concentrates twice daily, gradually 
increasing the amount fed to between 2 and 2 « kg at each feed. For small cattle, below 200 kg liveweight this 
will result in some concentrates being left over from the previous feed, when the next feed is given, ie they will be 
on ad lib concentrates. However for bigger cattle (eg weaned spring born suckled calves) it is necessary to go to 
a third feed per day eg last thing at night, and gradually build this meal to between 2 and 2 « kg until there is 
feed left in the trough by the next time they are fed. In general it can take up to three weeks to successfully 
introduce cattle to ad lib concentrates.

One farmer has overcome this problem by initially mixing sawdust in with the concentrates and making the mix 
available ad lib as soon as the cattle are housed. Over a two week period he gradually reduces the amount of 
sawdust added until the animals are on straight concentrates ad lib.

The sawdust, being almost completely indigestible, fills the cattle up so they eat less dry matter per day and 
therefore fewer concentrates. For the system to be effective it is important that the sawdust and cereals are well 
mixed. Only sawdust from wood NOT treated with preservatives should be used.

Unfortunately the farmer is reluctant to state exactly how much sawdust he includes but a reasonable estimate 
would be to start off with a 1/3:2/3 mix of sawdust and concentrates. Every two or three days the proportion of 
sawdust included can be reduced by 10% so that after two to three weeks the cattle will be on straight 
concentrates ad lib.
ML
¸ The Scottish Agricultural College 2000 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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