Cattle & Sheep
Potstown data shows mixed growth rates, with most calves reaching their target weight, some doing very well, and some outliers at 0.2–0.3kg/day.
Overall Weight Gains by Age
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Growth Rates by Age
Optimising calf health: Farmers and vets share experiences Potstown Farm in Middlebie, Dumfries and Galloway, is working closely with its local vet to improve calf growth rates – with the aim of starting a youngstock selling enterprise. Sarah Kidby attended a virtual meeting about progress so far. Scottish dairy farmer Gareth Owen milks 160 pedigree Holsteins, and 100 Danish Jerseys with four robots at the 380-acre Potstown Farm, which has supplied Yewtree Dairy since 2016. It operates a fully housed, all-year-round calving system and became an AHDB Strategic Dairy Farm in October. Mainly grassland, it also grows 40-60 acres of wholecrop to feed to cows and youngstock and the herd averages 8,500 litres/cow. Working closely with local vet Callum Cameron has been very beneficial, Mr Owen said. Potstown currently rears calves in a shed which comes with certain limitations, Mr Cameron noted, but recording birth weight and growth weights every two weeks, plus testing colostrum levels for every calf born has been very valuable. Colostrum is measured before freezing, which is done as cleanly as possible, ready to be thawed when needed and tested again with a Brix refractometer. Calves are generally stomach tubed in the first four hours. Bucket feeding means they struggle to get as much powder in as they’d like – averaging around 750g/calf/day at 150g concentration – but historically they have seen increased scouring when trying to push more milk powder, so Mr Cameron said there are concerns over rumen drinking and he is keen for them to switch to teat feeding. Looking at data from SRUC surveillance centres in Scotland,
SRUC’s veterinary centre manager Colin Mason said it was a surprise to see rumen drinking listed in the top 10 most common causes of mortality in pre-weaned dairy calves. The cycle of rumen drinking can begin at birth, in which case intravenous bicarbonate administered by vet can help. Teat feeding can slow down drinking speeds, avoiding the problem of milk spilling over into the rumen. If feeding individual calves, feeding 1 litre then another 2 litres can also slow the process down. Rumen drinking can be a vicious cycle – the more milk ends up in the rumen, the more acid is produced, meaning the oesophageal groove works poorly, leading to more milk in the rumen, and more acid being produced. It’s important to stop this cycle before it gets out of control, Mr Mason said. William Fleming, of Hillhead Farm, said he was previously unaware of rumen drinking until a recent AHDB farm meeting but he has since switched to teat feeding, and while it is early days, he has found calves are more vibrant. Commenting on how much colostrum to give, Mr Mason recommended 10% of bodyweight in the first six hours. In terms of milk/ milk powder, Jimmy Goldie, of Carrs Billington, recommended 5–8 litres/ calf/day in a minimum of two feeds, though suckled calves will drink much more, and 750g–1kg total milk powder per calf per day. Starter feed should be available ad lib from
day one to ensure calves get used to it. There will be minimal intake in the first two weeks, rising to up to 1.5kg/head/day by weaning, and although calves are not able to digest a lot of forage, a little should be added as a scratch factor for rumen development. Mr Goldie favours straw (around 100g is sufficient) as feeding higher nutrient value forage tends to cause pot bellies. Research also shows calves with free access to water eat 31-60% more dry matter; gain 38% more weight from birth to four weeks; have 31% higher average daily weight gain from 0–10 weeks of age; and have fewer scour days. In fact, each extra litre of water leads to a 56g increase in weight gain per day.
Variations in growth rates Potstown data shared during the webinar showed growth rates are
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mixed – with most calves reaching their target weight, some doing very well, and some outliers at 0.2–0.3kg growth rate/day. Mr Mason questioned whether the outliers could be a sign of early or sub-clinical disease. Mr Cameron said his practice actively encourages the use of calf jackets for at least 2–3 weeks if the ambient temperature is below 10ºC. Calves below the lower critical body temperature of 8ºC will be burning energy to keep warm – and if there is any dampness or drafts, the LCT will only increase. Potstown are now using jackets on all of their calves following a successful early trial; when every other calf was given a calf jacket, those with jackets had much higher growth rates. Mr Cameron also plans to scan all weaned calves’ lungs to check for sub-clinical pneumonia, which could explain some of the lower growth rates on the farm. Dairy farmers are well aware that a cow’s future productivity and profitability is set in the first few weeks and months of life and a lot can be gained by getting them off to a good start. Monitoring growth rates and performance and ensuring adequate nutrition to support growth and rumen development, can be key to making improvements. FG
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