In general, there is a 5:1 saving from preventing disease as opposed to treating it. The old saying definitely holds true -- prevention is better than cure.
Calf health optimisation
The prevention of calf disease is based on two main principles:
- Maximising immunity
- Minimising challenge
Maximising the immune status of the calf can be done by attending to several key areas, which include:
- Colostrum Feeding
- Reducing concurrent disease and stress
- Dry cow feeding (to ensure good quality colostrum and healthy strong calves at birth).
(i) Colostrum management and feeding -- The importance of the early intake of good quality colostrum, and in sufficient quantities, by calves after birth has been known for quite some time. However, poor or inadequate colostrum intake still remains one of the main underlying problems behind many outbreaks of calf diarrhoea, calf pneumonia and septicaemia.
When an analysis was carried out into antibody levels in all calves which were scour tested in the regional laboratories in 2007, it was found that only 23pc of these calves had good colostrum levels (ZST test).
All calves should receive 10-13pc body weight in colostrum in the first 12 hours after birth, and ideally up to 20pc bodyweight in the first 24 hours -- after that the antibodies in the cow's milk cannot be absorbed by the calf to give protection from disease.
The importance of ensuring that calves take in colostrum as soon as possible after birth cannot be overstated, as the absorption of antibodies by the calf's intestinal tract reduces by almost 50pc every six hours.
In simple terms, the calf (45kg) should receive -- preferably by sucking but otherwise by stomach tube -- two litres in the first three hours after birth, followed by at least another two litres by 12 hours and another two to four litres after 24 hours of life.
(ii) Reducing concurrent disease and stress -- One of the most common underlying diseases which can lead to increased calf disease and mortality is Bovine Viral Diarrhoea (BVD). BVD leads to immuno-suppression, resulting in calves being more prone to disease and responding poorly to conventional medical treatments.
The BVD virus is spread in herds by persistently infected animals (PIs). PIs are born infected with the virus after infection of their mothers at three months of gestation. These PIs shed BVD virus throughout their lives and are the root source of all associated disease. Apart from immuno-suppression, BVD is associated with congenital deformities in calves, including retinal dysplasia, cataracts, micro-ophthalmia, cerebellar hypoplasia, arthrogryposis and hydrocephalus.
Consultation with your vet will allow for the implementation of a herd health plan designed to detect the problematic PIs in the herd for culling, and deciding on a vaccination programme for the herd in question.
(iii) Dry cow feeding -- Increasing calf immunity begins with maximising the cow's immune welfare. If its immune system is primed then she will produce good quality colostrum, high in antibodies and containing antibodies against a wide range of pathogens. Apart from BVD, malnutrition and mineral deficiencies are common causes of impaired immunity.
After a difficult summer and autumn last year, cows have entered the dry period with lower body condition scores (BCS) than the target BCS of 2.5-3.0. It is likely that protein-energy malnutrition will be a big problem this year unless particular attention is taken to feed more to thin cows to ensure that they calve at BCS 3.0.
The most common mineral deficiencies in Ireland are copper, selenium and iodine. Veterinary advice should be sought so that identification of mineral deficiencies on your farm can be made, together with advice on proper on-farm supplementation.
Minimising the challenge is centred on two main aspects: housing and hygiene.
(i) Calving pen -- Keep it clean, change bedding frequently and disinfect thoroughly as often as possible to prevent navel ill, joint ill and calf diarrhoea as a result of E-coli and Cryptosporidia.
(ii) Calf housing -- Keep it clean and maintain correct stocking density -- crowded calf pens are ideal for the transfer and build-up of disease pathogens. Use plenty of clean bedding and disinfect as often as possible.
(iii) Management and calf rearing/mixing -- Keeping batches of calves running together is more preferable to mixing batches of calves. When a new batch of calves is mixed in with older calves, it commonly results in an increase in calf diseases such as diarrhoea and pneumonia.
(iv) Feeding -- Calves must be fed sufficient milk to ensure growth, weight gain and the maintenance of a strong immune system. Underfed, thin calves are much more prone to the stresses of cold weather, draughts, overcrowding and infection pressure from a contaminated environment.
(v) Vaccination/disease control programmes -- Adherence to vaccination and disease control programmes will ensure the best chance of reducing calf disease in your herd. The cost of calf disease cannot be overemphasised.
(vi) Sick calf treatment/ management stockmanship/ isolation pens -- Move sick calves to isolation pens to prevent disease transfer to in-contact calves. Cryptosporidia, a common cause of calf diarrhoea, is so contagious that as little as five oocysts can infect a new calf, while an infected calf can excrete up to a billion during a typical cryptosporidial infection.