Weaning stress has an adverse effect on the immune system, making calves more susceptible to disease, particularly pneumonia.
Weaning stress is often compounded by other husbandry practices occurring at the same time such as change of environment (outdoors to indoors), change of forage diet (from grass to silage), transport/ selling, dehorning, castrating etc.
How can you minimize stress at weaning?
1) Parasite treatment and Vaccination
All parasites have a negative effect on the calves’ immune system and lungworm in particular can damage the lungs and increase the risk and severity of bovine respiratory disease (BRD).
Treatment for lungworm with a long acting pour-on wormer such as Cydectin 0.5% Pour-On for Cattle ahead of weaning allows time for gut and lungworms to be cleared and for any lung damage to repair while cattle are still under low stress. If calves are housed within five weeks of dosing then no further treatment for stomach worm (Ostertagia) or lungworm should be required.
Viruses such as BRSV, PI3v and IBR can act individually or in combination to cause signiﬁcant lung and airway damage reducing the animal’s resistance to secondary bacterial infection. These three viruses are the most important primary pathogens. Once the viruses have caused the primary damage, the bacteria can enter as secondary invaders resulting in extensive damage to the lungs.
BVD virus can act as an important trigger because it suppresses the immune system and opens the door for the other agents that multiply and cause disease.
So by protecting against the key four viruses, we can have a dramatic effect on calf pneumonia outbreaks.
Rispoval 4 protects animals against BRSv, Pi3v, BVDv and IBR. Protection lasts six months. For cattle over three months of age two doses of vaccine should be given three-four weeks apart and, ideally, calves should complete the vaccination course at least two weeks before any stressful event such as weaning.
For a quicker onset of immunity cattle can be vaccinated with an intranasal vaccine. Rispoval® IntraNasal can be used from nine days of age and protects against BRSv within just five days and against PI3v within 10 days. Protection from a single dose lasts for 12 weeks.
In calves older than 10 weeks of age a single dose of Tracherine will provide immunity against IBR within just four days, with protection lasting a full six months.
2) Pre-weaning nutritional management
If possible, plan to wean calves outdoors in the best possible weather and start introducing concentrates to the calves at last one month prior to weaning. Calves should be consuming at least 1 kg/day at weaning time. Continue to feed concentrates after weaning.
3) Recommended weaning procedure
Don’t wean by taking away the calves, gradually remove cows away from the group. Up to a third of cows should be removed each time with a minimum interval of five days apart. Removed cows should be moved out of sight and sound of the remaining group.
4) Avoid additional stressors at weaning
Procedures such as dehorning and castrating will increase stress, therefore should not be done at weaning.
Ideally calves should be disbudded at an early age. If this has not been done early on, dehorning should be delayed until four weeks after weaning. Castration is best done in calves under six months of age or at least one month prior to weaning.
If the weather allows it, delay the housing of weaned calves for at least three weeks.
Don’t sell calves immediately after weaning, wait at least two weeks.
How can you reduce the risk of pneumonia in purchased weanlings?
In the current economic climate, beef finishers cannot afford any losses as a result of BRD.
A moderate case of pneumonia in a beef suckler calf at five to six months of age can be associated with 72 g of reduced daily liveweight gain per day, or 22 kg over a 10 month finishing period two. A severe or chronic case of pneumonia at five to six months of age may reduce daily liveweight gain by 202 g per day or 61 kg over 10 months and result in a carcass downgrade 3,4. Based on these facts, the economic returns from safeguarding a case of pneumonia have been estimated at £128 per calf for a moderate case and £263 for a severe case.
Therefore it is important to have a system in place that minimizes stress around purchases in order to reduce the risk of BRD.
Where possible, purchase weanlings which have been weaned prior to the sale and are BVDv tag tested to confirm they are not virus carriers (PI calves). Ideally, buyers should liaise with sellers at the marts and discuss weaning management practices.
Look out for the ‘Blue tagged calves’. These calves are part of the SureCalf Programme, a pre-conditioning programme aimed at minimizing the impact of BRD and improving the welfare of calves as they pass through market.
SureCalf Duo calves must be over 10 weeks of age, and are vaccinated one to three weeks prior to sale with a single intranasal dose of Rispoval® IntraNasal (against BRSv and Pi3v) and a single intranasal dose of TracherineTM (against IBR). The buyer benefits from up to 6 months ongoing cover against IBR and up to three months ongoing cover against BRSv and Pi3v ensuring protection going into the winter housing period.
On arrival the animals should be placed in a draft free, well bedded pen, with plenty of space and access to palatable forage-based feed with long fibre and clean water.