Last week, CAFRE in partnership with AFBI hosted a calf rearing open day at the dairy centre at Greenmount, providing advice and tips for rearing calves as dairy replacements or for beef.

The calf-rearing journey starts with getting cows into optimum body condition when drying off, followed by the diet fed in the weeks prior to calving.

Not only does this reduce the level of problems cows experience during labour and post-calving, it significantly increases calf vigour.

Pre-calving

This autumn-winter, dry cows on the CAFRE unit have been fed a diet based on round bale silage grown without any slurry, wholecrop silage, 2kg of straw, 1.4kg of a pre-calver ration, 100g magnesium chloride and pre-calving minerals.

Cows are moved to a purpose-built calving unit five days before predicted calving date, where they have access to a straw-bedded lying area.

Once calved, cows remain in the calving area for another five days, aiding transition into early lactation.

Colostrum

As soon as a cow calves, she is milked on a mobile unit. Four litres of colostrum, or 10% of the calf’s bodyweight, are fed to the calf via a stomach tube within three hours of being born. Colostrum is checked regularly using a refractometer for quality.

Second and third milkings are done through the parlour, with the colostrum taken from the cow labelled, refrigerated and fed twice daily (5l per day) over four days using a teat bucket, which is washed, disinfected and allowed to drip dry after every use.

Each calf only gets colostrum from its dam, thereby avoiding any potential transfer of disease such as Johne’s disease.

Stage one

At five days old, calves are offered five litres/day of a 26% protein milk replacer split evenly between morning and evening.

Milk powder is mixed at a rate of 170g per litre and again fed via a single-teat bucket.

Calves are tagged, weighed and moved to individual pens within 12 to 24 hours after birth. They are also fitted with a calf jacket to help regulate core body temperature.

Speakers outlined that the air space between the calf’s coat and the jackets was 6°C higher than normal air temperature, resulting in calves burning less energy to stay warm.

Straw is also available from day one in racks to stimulate rumen development, as is calf concentrate.

Stage two

At eight days of age, milk is built up to eight litres/day at which point calves are moved to one of six group pens.

Each pen accommodates 15 calves and all animals are fed via an automatic feeder for 30 days. Calves are weighed each time they feed and restricted to a maximum milk intake of 3.5 litres at any one time.

Again, straw and concentrate are available at all times, as is clean drinking water.

Group pens are located in a purpose-built unit, which is open on all four sides to allow unrestricted airflow. During periods of high wind, round bales are used to provide shelter.

Each pen also has an igloo to provide shelter, with the opening turned 90 degrees away from the prevailing wind.

Internal air temperature of the igloo is normally 3°C higher than that externally.

Each pen has a sloped floor with a one in 50 gradient, draining any seepage from calf bedding into a tank.

Each igloo is steam cleaned after 10 weeks, disinfected and allowed to dry. The entire unit is steam washed at the end of calving.

Stage three

After 30 days being fed eight litres/day, milk is gradually tapered down over a 10- to 16-day period to prepare calves for weaning. At this stage, calves are eating an 18% protein coarse ration and ad-lib straw.

However, it was stressed that each group is only weaned once the smallest animal in each pen reaches target weaning weight.

The aim is to double the calf’s body weight in the first 40 days of life. The minimum target weight gain is 0.8kg per kg of milk replacer fed.

Average birth weight for dairy heifers on the CAFRE unit is 36kg and weaning weight is approximately 90kg at 60 to 65 days of age. Milk powder fed from birth to weaning averaged 60kg per calf this winter.

Calf health

At 10 days old all calves get an intranasal vaccine for RSV, PI3 and IBR with a booster given four weeks later.

At 11 to 12 weeks, a further respiratory vaccine is given, while at 16 weeks animals are vaccinated against ringworm.

In addition to the vaccines, every step is taken to ensure good hygiene in calf sheds.

Straw bedding is applied liberally and stocking densities are at least 2.5m2 per calf.

Moisture should ideally sit around 65% humidity

Airflow is vital to remove pathogens from the shed.

Calves lack the size and heat generating ability of mature cows, so they cannot produce the stacking effect that allows air to rise and exit the shed.

As a result, assisted ventilation needs to be considered using fans, air tubes and opened sided sheds to improve airflow.

Farmers were advised to keep airspeed between 0.1m/s and 0.3m/s with an outlet space on the ridge of the roof of 0.04m2 per calf housed.

Moisture should ideally sit around 65% humidity with air temperature between 8°C and 18°C to avoid any negative impact on calf performance.

At higher moisture levels, either due to higher stocking rates, wet bedding or condensation accumulating on side and roof sheets, weight gain will be significantly compromised in cooler conditions.

Re-run of calf rearing event

There was a big turnout of farmers at the CAFRE event last Thursday, but with driving conditions difficult, not everyone was able to attend.

For those unable to make it, the event is being re-run on Wednesday 1 February. The first tour starts at 10.30am, with groups every 30 minutes. The last group will leave at 12.30pm.

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