8 November 1996

Slower growth

– healthier pigs

PIGS

LAMENESS in sows and boars may be prevented by careful rearing management and acclimatisation to outdoor or spacious indoor sow units, says Oxfordshire vet Richard Potter.

"When animals are grown fast on rearing units they are more prone to injury that can lead to arthritis in later life," he says.

He advises buying in replacements early and feeding them a special ration that is low in lysine to restrict growth rate. "This will stop them growing at the maximum rate, encouraging them to be fatter and more robust," he says.

When gilts reared indoors go on to outdoor units ensure the risks of injury are minimised at this time to prevent arthritis later. Ideally choose a firm, level site to limit injury risks, he adds.

TREAT mange by in-feed whole-herd treatments twice a year in preference to injecting sows before farrowing, says Richard Potter.

"Just treating stock before farrowing means other stock act as a reservoir for the parasites. It is best to reduce the background level." Mange is a costly disease, he adds. It can increase feed use, irritates sows, which can become aggressive, or when suckling they may be unwilling to feed their piglets.

STARVATION of piglets may occur due to failure to clip piglets teeth, reports Tony Andrews of the Royal Veterinary College. On one farm sows were found to desert their piglets and mortality rose to 15%, half of which was due to starvation.

CATTLE

RESPIRATORY calf disease outbreaks such as respiratory syncytial virus (RSV) and infectious bovine rhinotracheitis (IBR) will increase in damp, still winter weather, says Dr Andrews.

"It is essential to ensure calves have adequate ventilation and that they are kept in small groups of fewer than 30 without overcrowding," he says. "They should have no contact with cattle of other ages."

COWS calving outside on a diet of autumn grass are at risk of milk fever, warns Shropshire vet Clive Norrell, Minsterley.

"Autumn grass is high in protein and there is less control over the diet. When you have a run of milk fever it is best to house cows before calving or restrict them to a small area and feed straw. In this way they can have a low calcium diet and can adapt to their calcium demand."

For cows that suffer milk fever try to avoid leaving them down for too long after treatment and ensure they have enough grip to get up without damage, he adds.

SHEEP

REGULAR foot inspections are needed to combat foot rot in sheep flocks as the risk increases due to wet weather.

Cumbrian vet Matt Colston, Penrith, warns that foot rot must be treated. When 10% of the flock is affected, that 10% of animals will be lame, fail to put on body condition, is more prone to twin lamb disease, has low lamb birth weights and less milk – so the costs are high. Foot rot is also one of the biggest welfare problems on sheep units, he adds.

"Treatment must depend on the scale of the problem – for a few odd cases trim their feet and use an antibiotic spray," he says.

"When a significant number of the flock is affected regular trimming and foot bathing is needed." He advises using a specialist foot bath such as zinc oxide with a penetrating agent and to stand sheep in it for 20min after trimming.

That should be done at least twice, a month apart, or following the product guidelines. Vaccination can also help prevention, he adds.

LAMENESS PREVENTION

START lameness prevention measures early for housed and grazing stock to keep feet hard and solid so they are less prone to infection.

Dr Andrews says that when feet are wet they allow penetration by bugs. "A good hoof is a hard hoof," he maintains.

Stock inside and standing in slurry are in a soup of bugs that can infect the skin, the area between the hooves and the white line causing lameness. Try to ensure that passageways and yards are kept clean and dry.

"Use foot-baths, particularly when animals come in, so their hooves harden up," he says. "Formalin and zinc-sulphate are useful and will also kill off bacteria. Also check that feet are a good shape at housing so that animals can use their whole foot properly."

Stock still outside should be kept on fields that are well drained, and try to keep feeding areas clean or feed stock on concrete or hard-core, he says. &#42

Feed gilts on a low lysine diet to prevent arthritis in later life.


PIGS: WATCH OUT FOR


&#8226 Infertility.

&#8226 Treat for mange.

&#8226 Lameness.

&#8226 Respiratory problems.


CATTLE: WATCH OUT FOR


&#8226 Digestive upsets with diet changes.

&#8226 High levels of milk fever.

&#8226 Increased lameness when wet.

&#8226 Infertility.

&#8226 Respiratory calf diseases if weather is still and humid.


SHEEP: WATCH OUT FOR


&#8226 Condition score at tupping.

&#8226 Good nutrition for six weeks after tupping.

&#8226 Foot rot if weather wet.

&#8226 Pasteurellosis and clostridial diseases.


Parasite update

Liver fluke

Stock are at risk only on farms with a history of fluke. Rainfall has been below average throughout the summer, and although October has seen wet conditions it is too late to affect this seasons fluke cycle. With temperatures still above the critical 10C (50F) some snail breeding could have taken place on farms with suitable wet habitats to give a start to next seasons populations.

Worms

Wet conditions have enabled larvae to hatch, and dosing will be needed when animals are outside on dirty pasture. Young animals are most at risk. Lungworm is still causing problems, and where stock have not been treated farmers must be vigilant.