NI dairy farmers have reduced age at first calving in recent years, but with the average still over 27 months, it remains ahead of the target to calve at 24 months.

Addressing the recent Fane Valley calf health conference in Armagh, ruminant nutritionist Laura McConnell said the delay in calving adds significant cost, while also having implications for subsequent animal performance.

Research shows heifers which calve in at just under 24 months will have significantly higher lifetime production and are much more likely to still be in the herd after five years.

However, to achieve this target, it is vital to get calves off to a good start, with 50% of skeletal growth normally occurring in the first six months of life. Getting high rates of growth early in life will also cost less given feed conversion efficiency drops with age – it only takes 2kg of dry matter (DM) to deliver 1kg of average daily gain in the first 10 weeks of life, compared to around 7kg DM when the animal is aged between eight and 19 months.


To ensure calves thrive post-weaning it is vital the rumen is properly developed, with the first 12 weeks critical, said McConnell.

Her advice is to introduce calf starter feed early on (day three or four), offering a small amount daily in a shallow dish, along with fresh water and a forage source.

“Build a positive association with starter feed – it has to learn to eat. Keep the feed palatable, fresh and accessible,” she said.

Clean and fresh water should be available at all times – for every 1kg of starter feed, a calf should consume four litres of water.

Fibre is also vital for rumen development, with the “ideal forage” being chopped straw, said McConnell. For every 50g of straw the calf consumes, it will eat an extra 0.5kg of the starter feed.

She said calves should be weaned when they are eating 2kg of concentrate, rather than at a specific age, and given they like a consistent diet, they should be kept on the same feed until two to three weeks post-weaning.

Her preference is to offer a pellet as calves can sort a coarse feed. In terms of pellet size, McConnell quoted research from Harper Adams University, which showed higher intakes and weight gains when calves were offered a larger pellet (6mm versus 3mm).

Role for colostrum substitute

Where a cow has low-quality colostrum, or where there is no fresh product available, the advice from speakers at the calf health conference is that a colostrum substitute is potentially a better alternative than feeding material which was previously frozen.

Speaking at the event, Dr Tom Barragry, a vet adviser to Omagh-based Provita, explained that newborn calves start with a sterile gut. Antibodies from the cow don’t pass the placenta, so must come from colostrum, while there is also a poor transfer of important vitamins, such as A, D and E.

As a result, the colostrum substitute products contain vitamins and minerals, as well as the antibodies which provide immunity to the newborn calf – known as immunoglobulin G (IgG).

The Provita product also contains immunoglobulin from hen eggs (IgY), although labelling rules require this to be labelled as added “egg powder”, explained Barragry.

Scour vaccines help control disease

Scour vaccines are not “gold bullets”, but where used correctly you have less disease outbreaks – and if disease does occur, it will be less severe, Kate Ingram from Virbac told the Fane Valley event.

She said scour affects up to 50% of dairy calves and causes nearly half of deaths in young animals. But as well as the cost of drugs, Ingram told farmers not to underestimate the cost of their time to nurse sick animals. Indirect costs include lower growth rates over the longer term.


The all-island animal disease surveillance report for 2021 showed that rotavirus is the most common cause of scour in calves aged up to one month. Vaccinating pregnant cows and heifers three to 12 weeks pre-calving can give effective control against rotavirus, coronavirus and E-coli. While the vaccine does not cover all scour pathogens, Ingram argued that bacteria and protozoa that cause scour are “opportunistic” and if the calf is fighting off one it is more likely to get impacted by another.

“If you can prevent one, you often will prevent both,” she said.

Peter Howard, Veterinary adviser, Boehringer Ingelheim.

Pneumonia comes at a “huge cost”

A single outbreak of pneumonia among a group of dairy calves can easily cost over £50/head in drugs, weight loss, vet fees, etc, maintained Peter Howard from Boehringer Ingelheim.

As well as the initial cost, pneumonia has a long-term impact on performance – when compared to healthy animals – research at AFBI has shown calves that succumb pre-weaning produce 4% less milk in their first lactation and 8% less in their second lactation.

Howard maintained that RSV tends to be the most common cause of pneumonia in calves, but once any of the pneumonia viruses damage the defence mechanisms, it is then that secondary bacterial infections can take over.

“That is what you often see after viruses have caused the initial problem,” he said.

He also quoted a Welsh study, which showed dairy heifers treated with a vaccine were 47kg heavier (274kg versus 227kg) than an unvaccinated group at eight months.

In the unvaccinated group, the calves had to fight off infection, “which uses quite a lot of energy,” said Howard.

Arjan Meijerink, area manager, Denkavit.

Crude protein in milk replacer

Buying milk replacer with a crude protein (CP) content of 26% and above will cost more money and is unlikely to deliver improved calf performance, maintained Arjan Meijerink from Denkavit.

He said that research coming out of the US, which has supported the need to feed the higher CP content, had led to his company taking “a deep dive” into the materials available in the US and how they compared to Europe. The work showed a difference in quality – the Americans have to feed 26% CP milk replacer to get the same digestible protein content as a 23% CP milk replacer in Europe.

“That advice is only applicable that side of the ocean – it is the right advice for the situation in the US. More is not always better.

“Don’t be fooled by labels – if something looks too good to be true then it is. Your animals will always tell you the truth,” said Meijerink.

Fane Valley launches AgriAdvance

The calf health conference in Armagh saw the launch of Fane Valley’s AgriAdvance programme.

It brings together a long-term strategy that has moved the farmer-owned co-op into the delivery of services to farmers across soil and plant health, animal nutrition and animal health.

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