Calving heifers for the first time at two years old is a key efficiency driver for one Dorset-based herd. So how do they ensure they keep growth on track to hit that target?
TEXT PHIL EADES
New entrants Nick and Marilyn Tuke came to dairying with no preconceptions, but a realisation that efficiency, throughout their herd and business, is everything.
They run their 166-cow herd, plus 90 followers, on a 100-hectare unit at Mappowder, in Dorset. “We had no preconceptions about how to farm but knew we had to focus on efficiency to allow us to grow the business, and this meant looking at the science,” says Nick. “We have always considered the latest developments and different ways of doing things, looking at the research and making sure that everything we consider is peer-reviewed.”
The Tukes’ pedigree Lowerthurn herd is block calved from August until mid-November and is currently averaging 9,500 litres of milk, at 4.35% fat and 3.45% protein. Milkers peak at between 50 and 55 litres although Nick is looking for a flat lactation curve averaging 36 litres per day.
“We run the herd on an autumn-calving system in the winter and as a spring-calving set up after turnout,” he explains. “Cows are housed as they calve and we ‘push’ them through the winter on a TMR that’s fed once a day, with dairy compound in the parlour flat-rate fed to a maximum of 5kg per day.
We typically turnout at the end of March and we then expect the cows to milk off grazing, with no buffer feed, and just compound in the parlour, as required.” All cows are genomically tested and bred based on the data this reveals using a sire-matching programme. Topend cows are served a maximum of twice to sexed semen and the lower-genetic-merit end of the herd is served to beef. These resulting calves are sold to Blade Farming. “Ensuring that our high-genetic-merit heifers calve for the first time at two years old – and at the start of August’s calving block – are the foundations of our system,” stresses Nick. “We need them to grow well throughout the first 15 months of their life so they are ready to be served in November.”
And, with 45 heifers calved each year at two years old, he is achieving this. But how? To calve at 24 months, at 90% of an adult body weight averaging 625kg, heifers need to achieve a daily liveweight gain of 0.8kg from birth to calving. “Key to this is to maximise pre-weaned calf growth,” says Nick.
After attending an AHDB calf management workshop he researched the use of milk replacers that are fed at an elevated rate, and made the decision to switch to TBA’s Britannia Energized milk replacer. This is formulated to ensure optimal nutrient supply on high-feed-rate systems. The company’s Trevor Birchall explains that feeding preweaned calves on an elevated plane of nutrition offers a one-off window of opportunity for accelerated growth and development. “The pre-weaning period provides a unique chance to exploit the full genetic potential of calves,” he says. “Trials show that a higher plane of nutrition preweaning results in higher milk yields when heifers finally enter the herd. This can range from an additional 300kg to 1,300kg during the first lactation.”
Trouw Nutrition’s research also revealed that when calves are fed at a higher rate pre-weaning they develop faster and develop larger key organs, including the heart, lungs and liver, and this is not just due to them being larger cattle. All the organs were larger when expressed as a percentage of body weight. They also had better mammary gland development, which is essential for their future productivity as a cow.
“The research also shows that calves fed at lower rates pre-weaning never make up for the shortfall in growth rate and organ development,” he adds. “Chasing growth in older calves is less efficient and more expensive as they are poorer converters of feed.”
Nick and Marilyn’s daughter Laura came back to the family farm during the pandemic and took responsibility for calf rearing. At that time they were feeding four litres a day of a traditional milk replacer, mixed at a rate of 125g per litre, and calves were growing at an average rate of 0.65kgLW per day, with high intakes of starter pellets. Calves are now fed six litres a day, mixed at a rate of 150g per litre. Milk is split across two feeds, with dairy heifers bucket fed and beef calves teat fed. Laura also ensures that starter pellets, clean water and straw in racks are available ad-lib.
Strict health protocols are also followed because good nutrition is only part of the picture. Cows are vaccinated to help prevent scouring in calves. This works by boosting the levels of antibodies in colostrum, which is fed to newborn calves. Non-steroid anti-inflammatories and rehydration therapy are used as required to treat scouring calves, and antibiotic use is low. Growth checks are kept to a minimum and mortality is close to zero. Calf growth is monitored by using a weigh band at birth, three weeks and six weeks old. Calves are weaned at approximately eight weeks old. They average a daily liveweight gain of 0.9kg during this time, with the fastest growing hitting 1.2kg per day.
Calves are weaned during a seven-day period, starting at seven weeks old, and target weaning weight is 100kg. By this time calves must be consuming 2kg day of calf-rearer pellet. After weaning they move on to straw and 3kg of cattle-rearer pellet until turnout at 250kgLW, having had a leptospirosis vaccine, Huskvac and worming boluses.
Beef calves are sold at a minimum of 45kgLW, and achieving higher growth rates means they spend less time on farm, freeing up space and labour to rear dairy heifer replacements.
At grass, Nick is looking for a minimum of 1kg/day liveweight gain, with concentrates fed depending on grass growth. Heifers are measured with a weigh band again when housed in early October, with a target weight of 400kg, one month before the start of the service period. At this time they are also vaccinated for BVD, wormed, fitted with a pedometer, and freeze branded so they are ‘settled’ before AI begins.
Second summer: replacements graze before moving onto the transition-cow ration
Once housed they are fed baled silage and 2kg of rearer concentrates until confirmed in calf, when concentrate is cut back. During their second summer heifers will graze before joining the transition cows and moving onto the transition-cow ration.
“This year we calved 40 heifers and 29 calved in the first two weeks of the August block, which is essential to helping us maintain a tight pattern,” says Nick. “They all calved in the first seven weeks and have peaked at between 30 and 35 litres of milk. But our system does not depend on very high peak yields. They have got back in calf better than in previous years.
“Getting calves off to the best start has helped us achieve our objectives of calving heifers for the first time at 24 months old and maintaining a tight calving block,” he concludes. “Genomic testing gives us information about our calves’ potential, and switching to a high-feed-rate milk replacer system has played a key role in helping us to realise it.”