With neonatal calf mortality and disease a major drain on dairy farms, effective management strategies to reduce the problem, and associated consequences, bring huge benefits.

According to speakers at a webinar presented jointly by the University of Nottingham and Trouw Nutrition, 15% of live born heifer calves die before their first lactation and while it is impossible to eradicate mortality, steps can be taken to reduce the impact and cost.

Young calves are particularly vulnerable due to their immune status at birth says Georgina Thomas from Trouw Nutrition, adding that 50% of all heifers lost in the first 24 months die in the first three months of life.

“There is a particularly high-risk period from days 8-14. This is when they move from passive immunity, which is the short-term immunity resulting from the antibodies from colostrum, to active immunity which develops as they come into contact with pathogens and their immunes system produces antibodies. This period can be extended if low quality colostrum is fed and therefore successful passive transfer is not achieved.”

She says if passive immunity fails then calves are twice as likely to die and are 1.5 times as likely to be treated for diarrhoea. She advises getting colostrum tested and only feeding high quality colostrum,

“Get the vet to blood test calves. IgG levels of less than 10g/litre at 48-hours-old are an indicator that passive immunity has failed and that either colostrum quality is poor or that colostrum management needs to be improved.”

Diarrhoea remains a major cause of losses and reduced performance. Vet Emily Payne from the University of Nottingham, says 90% of dairy farms experience scours every year and it causes the death of up to 2% of all calves born.

She advises paying close attention to calf behaviour for early signs of sickness as it is the only way calves can communicate distress.

Reduced milk intakes, slower drinking speeds or not drinking at all are early indicators of a problem. Other signs will include droopy ears, sunken eyes and a general reduction in activity.

“If a calf doesn’t finish its milk, ask yourself why as this is all they want to do. Any change in behaviour is a sure sign of a problem and will be commonly seen 4-5 days before you will see obvious physical problems like changes in faecal consistency.

“As soon as you see any of these signs, it is time to intervene with the priorities being rehydration, ensuring warmth and pain relief.

“In trials, treating calves with non-steroidal anti-inflammatory drugs, such as Meloxicam, helps get the calves back on the feed and eating and drinking more quickly, boosting dry matter intakes and liveweight gains.

When treating calves with scours she stressed the importance of understanding the cause of the scouring. Nutritional scours are a consequence of feeding and feed management, while infectious scours can be causes by a range of infectious agents including Cryptosporidia, rotavirus, e coli, salmonella, and Clostridia.

“There is still a tendency to treat scours with antibiotics. Not only does this increase overall antibiotic usage on farms, but it is not an effective intervention in many cases. You need to know the cause of the diarrhoea. Antibiotics are of no value in cases of nutritional scours and viral infections.

“They can be of value with bacterial infections but should be used in a targeted way, for example with calves showing other signs of distress such as a fever.”

The other key to helping calves recover is prompt and effective rehydration. It is not diarrhoea itself that kills calves, but the associated dehydration and metabolic acidosis it causes.

Dehydration disturbs many of the key pathways in the animal, reducing blood sugar, causing malnutrition, and increasing the risk of hypothermia. It can also affect the absorptive capacity of the intestines, leading to poorer use of feed, reduced growth rates and poor feed conversion.

As soon as calves show signs of dehydration, Dr Tennant advises feeding a hypotonic oral rehydration solution (ORS) to help calves recover quickly.

“Many ORS contain extra glucose. This can make them hypertonic, meaning the water is less readily absorbed and the product is therefore less effective at tackling dehydration. There is no need to add surplus glucose to an ORS as the sole purpose is rehydration, not providing energy which calves should be getting from milk.”

She advises using an ORS to replace a milk feed, but never totally removing milk to calves.

“Some farmers feed the ORS mixed in milk to save time, but this should never be done. Mixing an ORS with milk produces a hypertonic solution and actually reduces the effectiveness of rehydration. For most effective rehydration use a simple ORS mixed in water.