Spring Animal Health Issues

At the end of the calving season it is a busy time on farm between getting paddocks set up for grazing, getting slurry and fertiliser out and still having a few cows to calf it can be difficult to manage everything including animal health issues.

The end of the calving season can be a difficult time for young stock on the farm. After getting over the bulk of the calving you may feel the concerns of health issues with young stock may be behind you but now is the time when issues such as coccidiosis, clostridial disease, and pneumonia start to creep in.

Pneumonia

Pneumonia is one of the most prevalent illnesses in claves. Any level of impaired respiratory health can impact a calf for its entire life leading
to reduced growth rates, later finishing times and lower milk yields.

Ventilation within the calf shed is key to reducing the risk of this disease. Good ventilation reduces moisture and humidity build-up in the calf shed. Moisture and Humidity create ideal conditions for pneumonia causing bacteria and viruses, especially this time of year when the temperature is starting to gradually increase but we are still experiencing damp wet weather.

Additional stress factors in calves can trigger a pneumonia outbreak. Some of these stress factors include mixing groups of calves, transport, overstocking, sudden changes in diet, poor hygiene/ drainage, disbudding and castration. It is essential to insure that the calves have a clean dry bed of ideally deep straw. A good guideline is that if you kneel down on one knee in the pens and your knee is damp, the bedding is too wet and is in need of changing.

There are a wide range of pneumonia vaccines available and some of them you can give to calves from as young as a week old to kickstart your calves protection. Discuss with your vet a suitable vaccination programme for your farm.

Clostridial Disease

Animals under 12 months at age are most at risk of mortality from Clostridial Disease and as always prevention is better then cure. Clostridial Diseases includes blackleg, , tetanus and botulism and can play a part in calf bloat. Sources of Clostridial Disease on farm range from the soil and animal housing to chicken litter used as fertilizer on neighbouring tillage farms and the animals own gut flora.   When vaccinating against Clostridial Disease it is important to use a broad spectrum vaccine such as Tribovax 10 that will protect against various strains of clostridia, however it does not provide cover against botulism.

In young calves from dam not vaccinated against Clostridial Disease prior to calving, the general course of vaccine is an initial dose from 2 weeks of age followed by a booster dose 4-6 weeks later. It is important the booster dose is given within the allowed time period  to achieve up to 12 months of protection against the various clostridia by the calves.

Coccidiosis

Calves should be dosed against  coccidiosis if they have been exposed to the parasite. Calves exposed should be dosed with coccidiostats such as Dycoxan, Bovicox, Vecoxan  . When dosing against coccidiosis it is not just the calf showing symptoms who must be treated but all the calves in the vicinity of that calf will now have been exposed to the parasite also. Dosing should occur 2 weeks after first exposure , this will prevent clinical issues but will still allow the calves to develop a level of immunity against the parasite. You will need to monitor the calves over the grazing season as this issue can crop up a number of times through out the year. 

If you have a history of coccidiosis in the herd you will be aware of the condition and know to look out for the dark coloured scour or traces of blood in the calves’ dung. If you have not previously had this issue on farm but you suspect it may be prevalent it may be worthwhile getting a faecal sample tested by your vet or local lab to identify the cause and treat accordingly.

For calves who develop severe coccidiosis and suffer from scour, they will require the general treatment which you would offer to all calves suffering from scour. They will need electrolytes and fluids to recover from dehydration alongside their normal feeding regime. Sick calves shed high numbers of coccidia and should be isolated in order to limit exposing more calves to the disease.

Leptospirosis

It is vital to vaccinate your herd against Leptospirosis. Outbreaks of Lepto can have a detrimental effect on the overall profitability of your  farm. This disease causes abortion, infertility, mastitis and drops in milk yield. Research has shown that herds vaccinated against Lepto are €10 more profitable per cow than unvaccinated herds.

The standard vaccination course against Lepto is two 2ml doses under the skin 4-6 weeks apart around the start of grazing and at least a few weeks before breeding for heifers with a top up dose of 2ml per year a few weeks before breeding for adult cows. Leptospirosis is a zoonotic disease meaning it can be spread to humans which can be very serious if this occurs. Vaccination of cattle against lepto will limit the possible spread to humans. Two suitable vaccines against Lepto are : Leptavoid H and Spirovac.

Grass Tetany

Grass tetany is an acute deficiency of Magnesium in the blood, most common in lactating cows. It is often fatal, and for this reason much more beneficial to prevent rather than to try treatment.

The main causes of Grass Tetany are poor feed intake, cold and wet weather, high potash applications in springtime results in excess K uptake by the grass plant, which reduces Mg uptake, greatly increasing the chance of Grass Tetany.  It is common during springtime as animals are grazing heavy lush low fibre paddocks. Stress on cows can also leave a cow more susceptible to developing Grass Tetany. These stress factors include rapid changes in the diet (silage to grass) or cows bulling for example.

Grass Tetany can be prevented by ensuring the cows have access to sources of Magnesium. Magnesium can be offered in many forms such as the provision of magnesium licks or blocks, in supplements in drinking water, through boluses, dusting pastures with Mg, in concentrates or through offering hay or straw. It is important that cows are offered a daily supply of Mg in order to prevent grass tetany as cows cannot store Mg in the body.

Symptoms of grass tetany include frothing at the mouth, staggering, and body tremors. If you see a cow displaying these symptoms it is important she is treated rapidly with magnesium sulphate in order to avoid death your vet will often also administer a sedative to control the cow’s tremors and prevent fatal convulsions.

First Published: 25 March 2022