Abrupt weaning is a source of stress on calves which can have an adverse effect on their immune system, making them 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.
The following management practices can help to reduce its impact on calf health and performance.
All parasites have a negative effect on the immune system of the calves. In particular, lungworm can cause damage to the lungs and increase the risk and severity of bovine respiratory disease (BRD).
Treatment for lungworm with a pour-on wormer with persistent activity, such as moxidectin, ahead of weaning allows time for gut and lungworms to be cleared and for any lung damage to repair while cattle are still under lower stress. Whilst liver fluke is not a parasite found in the lungs, active fluke infection in late autumn can depress calves’ immunity and make them more susceptible to BRD at housing.
Treating with triclabendazole prior to housing in early autumn alongside a wormer can reduce liver damage and the immune system suppression rather than delaying fluke treatment until after housing and increasing the risk. A recent study run by FAI on a low burden farm highlighted the importance of the subclinical impact of liver fluke on performance. Animals treated at housing with Cydectin TriclaMox outgrew the untreated group by 7.5kgs in the period four to eight weeks after housing1.
Cydectin® TriclaMox® Pour-On contains moxidectin and triclabendazole. If calves are housed within five weeks of dosing with Cydectin TriclaMox Pour-On, then no further treatment for stomach worm or lungworm should be required. Cydectin TriclaMox Pour-On has been shown to be 90% effective against early immature liver fluke, 99.5% against late immatures and 99.9% against adults, effectively reducing the burden of liver-fluke in a single pour-on treatment.
Control of infectious disease
Respiratory 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. Once the viruses have caused the primary damage, the bacteria can enter as secondary invaders resulting in extensive damage to the lungs.
BVD virus, whilst not a respiratory virus per se, can act as an important trigger because it suppresses the immune system and opens the door for the other agents that multiply and cause respiratory disease.
So by protecting against the four key 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 and housing.
For a quicker onset of immunity intranasal vaccines can be used. 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.
Pre-weaning nutritional management
If possible, plan to wean calves outdoors in the best possible weather and start introducing concentrates to the calves at least one month prior to weaning. Calves should be consuming at least 1kg/day at weaning time. Continue to feed concentrates after weaning.
Recommended weaning procedure
The presence of cows has a calming effect and prolonging the presence of cows is one way of reducing stress in suckled calves that are being weaned,
Don’t wean by moving the calves, instead 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. Removed cows should be moved out of sight and sound of the remaining group.
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, dehorning should be delayed until ideally at least 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.