A study conducted on 66 dairy farms in Northern Ireland has found that growth rates in calves are running below what should be expected from their dietary intakes.
The survey, which was conducted by Aaron Brown from the Agri Food and Biosciences Institute (AFBI), indicates that environmental factors are holding back calf performance on commercial farms.
“Calves were growing 140g/day less than their diets were predicting, so there was significant energy loss happening,” Brown said.
He said that to achieve more efficient feed conversion, the calf rearing environment needed to be designed and managed to minimise physical stressors and disease challenges.
Speaking at an online event organised by the College of Agriculture, Food and Rural Enterprise (CAFRE), Brown highlighted five key factors that the calf rearing environment needs:
Ventilation – relative humidity under 80% and an air speed of 0.15-0.3m/s – anything more is considered a draught.Dry – fresh, deep, dry bedding with adequate drainage in floors.Warm – a temperature above or equal to 15°C and no draughts.Clean – routine hygiene with feeding equipment and thorough cleaning and disinfecting of pens between batches of calves. Stress free – social contact between calves and routine procedures relating to feeding.On ventilation, the principle behind good air movement is to remove stale air, which contains excess moisture and disease-causing bugs known as pathogens. It is particularly important in pre-weaning calf houses, because young calves do not produce enough heat to create an upward air movement through the stack effect.
“In our survey of calf houses, 41% had no air outlet whatsoever. In terms of ventilation, that is not going to work because air is coming in, but it has got nowhere to go. At the other end of things, 15% of calf houses had outlets that were more than twice the required size,” Brown said.
The aim should be for an air outlet that equates to 0.04m2/calf. If the ridge at the top of the shed is too big, it will lead to wind blowing into the shed, which stops stale air moving up and out.
Stocking density
The average stocking density in the calf sheds surveyed was 2.3m²/calf, although Brown suggested 3m2/calf should be targeted in pens where calves are staying until weaning. He cited research from the US, which found that 3.3m2/calf was the ideal stocking density in calves for air quality and pneumonia risk.
Dry floors are needed throughout calf sheds, including areas that calves do not have access to, such as passageways. This is because wet floors anywhere in the house are ideal for pathogens to multiply, which will lead to moisture and bugs in the air.
Brown recommended plenty of tracks and drains in solid floors and having a slope of 1:20 to allow moisture to drain away quickly. In 94% of the sheds surveyed, this was not the case.
“Lighting is not often discussed, but it has a benefit to calves. Previous studies have found that as you increase from 20 lux to 130 lux, there is an increase in feeding behaviour, increase in social behaviour and less time spent lying,” the PhD student said.
His advice was to take advantage of natural light, given that it is free of charge. This includes use of Perspex sheeting and painting walls white. He also suggested leaving the lights on for set periods each day, if adequate natural light is not available.
Calf jackets to manage cold
Calf jackets must be thoroughly cleaned, disinfected and dried before they are re-used.
The survey of calf accommodation by Aaron Brown found that air temperatures were below the 15°C target 92% of the time on participating farms.
Cold temperatures are a key reason why growth rates are lower than expected in many sheds, as calves put energy into keeping warm instead of growing.
Brown strongly advises using plenty of deep straw bedding to allow calves to nest and create a microclimate.
He also recommends the use of calf jackets and heat lamps in pens if temperatures are regularly below 15°C.
The benefit of calf jackets is sometimes debated, as research has generally found there is no significant impact on calf health or performance.
However, calf jackets are often recommended by local vets and are widely used at CAFRE’s new calf rearing facilities at Greenmount College.
“AFBI research did show that calf skin temperature was approximately six degrees higher for calves fitted with jackets, indicating that using jackets for the first four to six weeks should help calves manage cold conditions,” said Martin Mulholland from CAFRE. “Where calf jackets are used, provision must be made for cleaning the jackets before re-use to avoid disease spread,” he added.
Two more calf rearing webinars
CAFRE is holding two more webinars as part of its winter calf rearing series. The next one takes place today (Thursday) and will focus on feeding calves for accelerated growth.
The final online event is about disease control in calf sheds and takes place on Thursday 3 December. Both webinars are free and run from 8pm to 9pm. See www.cafre.ac.uk for login details.
Weekly round-up
Dairylink farms have fitted thermometers in calf sheds to monitor air temperatures.Older autumn-born calves are being weaned on programme farms at present.Winter breeding is starting in autumn-calving herds this week.
A study conducted on 66 dairy farms in Northern Ireland has found that growth rates in calves are running below what should be expected from their dietary intakes.
The survey, which was conducted by Aaron Brown from the Agri Food and Biosciences Institute (AFBI), indicates that environmental factors are holding back calf performance on commercial farms.
“Calves were growing 140g/day less than their diets were predicting, so there was significant energy loss happening,” Brown said.
He said that to achieve more efficient feed conversion, the calf rearing environment needed to be designed and managed to minimise physical stressors and disease challenges.
Speaking at an online event organised by the College of Agriculture, Food and Rural Enterprise (CAFRE), Brown highlighted five key factors that the calf rearing environment needs:
Ventilation – relative humidity under 80% and an air speed of 0.15-0.3m/s – anything more is considered a draught.Dry – fresh, deep, dry bedding with adequate drainage in floors.Warm – a temperature above or equal to 15°C and no draughts.Clean – routine hygiene with feeding equipment and thorough cleaning and disinfecting of pens between batches of calves. Stress free – social contact between calves and routine procedures relating to feeding.On ventilation, the principle behind good air movement is to remove stale air, which contains excess moisture and disease-causing bugs known as pathogens. It is particularly important in pre-weaning calf houses, because young calves do not produce enough heat to create an upward air movement through the stack effect.
“In our survey of calf houses, 41% had no air outlet whatsoever. In terms of ventilation, that is not going to work because air is coming in, but it has got nowhere to go. At the other end of things, 15% of calf houses had outlets that were more than twice the required size,” Brown said.
The aim should be for an air outlet that equates to 0.04m2/calf. If the ridge at the top of the shed is too big, it will lead to wind blowing into the shed, which stops stale air moving up and out.
Stocking density
The average stocking density in the calf sheds surveyed was 2.3m²/calf, although Brown suggested 3m2/calf should be targeted in pens where calves are staying until weaning. He cited research from the US, which found that 3.3m2/calf was the ideal stocking density in calves for air quality and pneumonia risk.
Dry floors are needed throughout calf sheds, including areas that calves do not have access to, such as passageways. This is because wet floors anywhere in the house are ideal for pathogens to multiply, which will lead to moisture and bugs in the air.
Brown recommended plenty of tracks and drains in solid floors and having a slope of 1:20 to allow moisture to drain away quickly. In 94% of the sheds surveyed, this was not the case.
“Lighting is not often discussed, but it has a benefit to calves. Previous studies have found that as you increase from 20 lux to 130 lux, there is an increase in feeding behaviour, increase in social behaviour and less time spent lying,” the PhD student said.
His advice was to take advantage of natural light, given that it is free of charge. This includes use of Perspex sheeting and painting walls white. He also suggested leaving the lights on for set periods each day, if adequate natural light is not available.
Calf jackets to manage cold
Calf jackets must be thoroughly cleaned, disinfected and dried before they are re-used.
The survey of calf accommodation by Aaron Brown found that air temperatures were below the 15°C target 92% of the time on participating farms.
Cold temperatures are a key reason why growth rates are lower than expected in many sheds, as calves put energy into keeping warm instead of growing.
Brown strongly advises using plenty of deep straw bedding to allow calves to nest and create a microclimate.
He also recommends the use of calf jackets and heat lamps in pens if temperatures are regularly below 15°C.
The benefit of calf jackets is sometimes debated, as research has generally found there is no significant impact on calf health or performance.
However, calf jackets are often recommended by local vets and are widely used at CAFRE’s new calf rearing facilities at Greenmount College.
“AFBI research did show that calf skin temperature was approximately six degrees higher for calves fitted with jackets, indicating that using jackets for the first four to six weeks should help calves manage cold conditions,” said Martin Mulholland from CAFRE. “Where calf jackets are used, provision must be made for cleaning the jackets before re-use to avoid disease spread,” he added.
Two more calf rearing webinars
CAFRE is holding two more webinars as part of its winter calf rearing series. The next one takes place today (Thursday) and will focus on feeding calves for accelerated growth.
The final online event is about disease control in calf sheds and takes place on Thursday 3 December. Both webinars are free and run from 8pm to 9pm. See www.cafre.ac.uk for login details.
Weekly round-up
Dairylink farms have fitted thermometers in calf sheds to monitor air temperatures.Older autumn-born calves are being weaned on programme farms at present.Winter breeding is starting in autumn-calving herds this week. 
This is a subscriber-only article
SHARING OPTIONS: