Investing in an optimum age at first calving

Reducing the age of first calving of heifers is not only beneficial to their health and welfare; it also makes financial sense. How you manage youngstock will have a major influence on the age you can achieve.

Andrew and his team at Statfold Farm currently milk 260 cows in an all year round calving system producing just under 11,000 litres at 3.9% fat and 3.3% protein. Most of the herd are Holsteins, with some Swedish red and PRO cross included.

Our calf to calving initiative showed that lowering age at first calving can improve a cow’s lifespan, reduce problems at calving and decrease heifer rearing costs by around £2.87 per day.

A lower first calving age also increases the amount of milk produced over the lifetime of a cow. Cows with the same genetics have the potential to give, on average, 5000 extra litres over their lifetime compared to those that are two months older whey they calve for the first time.

“The first 10 weeks of a heifer’s life are the most important when it comes to age at first calving,” says Andrew. “Unless a heifer doubles its birth weight by eight weeks it won’t be able to achieve its genetic potential.”

At Statfold, the team are optimising conditions for their youngstock by improving housing on the farm.

“The heifers were housed in the old Victorian brick and tile buildings. These were great for ventilation, but we couldn’t offer them the feed space or lying space they needed. The TMR was tipped into troughs which provided 0.4m of feed space per heifer,” says Andrew.

A new eight-pen, open-sided shed now houses calves from weaning to 13 months and Andrew is confident that this has already helped reduce the age at first calving and increase efficiency.

“Because of the large group sizes, the older animals would put on too much condition at the expense of the younger, smaller ones. In the new shed they can all feed at the same time and self-locking head yolks prevent bullying.

“Heifers are kept in individual pens for two weeks then paired until weaning when they’re formed into groups of eight. At around five months they are moved into groups of 14, and then groups of 28 from 12 months.”

They are seeing improvements to growth now the youngstock have better access to both feed and living space. Heifers are weighed at birth, weaning, six months and 12 months using a weigh band; birth weight is more than doubling in the first eight weeks.

“Calves are fed via a stomach tube with four litres of pasteurised colostrum given as close to birth as possible. Antibody levels are measured using an optical refractometer and the bag of colostrum is labelled with the resulting score,” says Andrew.

Calves are initially fed four litres a day, split over two feeds, the milk replacer is made up of 150g of powder per litre, which is a blend of skim and whey, 22.5% protein and 25% fat. Concentrate is also available to the calves from birth. When they are a week old, milk replacer is doubled to eight litres, again over two feeds. At eight weeks old the volume is reduced to four litres, with weaning occurring at 10 weeks.

Heifers in an AYR herd should be 55-65% of their mature weight, and at least 13 months at first service. At Statfold Farm Andrew is targeting, growth of 950g liveweight per day from birth to weaning. If heifers have put on either too much or too little condition at six months old, energy levels in the TMR are adjusted accordingly.

Pressure on space also caused problems with the heat detection collars worn by the heifers, since it was hard to identify which heifers were in heat. This resulted in lower conception rates.

“We use SCR Heatime heat detection collars on the heifers,” explains Andrew. “These are put on the heifers by 350 days at the latest. We need the collars on for at least 14 days pre insemination for enough activity and rumination data to be stored so we get accurate heat data. If heifers have not been inseminated by 427 days we run them with an angus bull. The conception rate of the herd is currently 67% which has improved from 50% in the winter.”

Andrew produces his own replacements, using genomic testing to improve the genetic merit of his herd. “All heifers are genomically tested and a breeding plan is set up accordingly. Only the highest ranked heifers and cows are inseminated with sexed dairy semen.”

Conception rates are used to work out how many eligible animals they need to inseminate to provide 90 heifer calves. The rest are then put to an Angus bull.

Following the success of the new sheds, Andrew has made further additions to the building, which he hopes will increase the herd’s conception rate. LED lights are being added to the areas housing yearling heifers expected to come into heat. Light will be maintained at 200 lux for 17 hours, followed by seven hours of darkness, allowing for optimum conditions for heifers holding to serve.

Andrew hopes to reach an average age at first calving of 22 months by late summer 2021 without compromising on weight at first service. And by reducing rearing costs by two months, the new buildings should pay for themselves within the next two to three years.

Andrew’s top tips

• Review youngstock housing to identify potential improvements
• Optimise access to feed to achieve good growth
• Providing the right environment allows heifers to have space to move and reduces the risk of disease
• AHDB’s KPI Express tool will help you calculate your average age at first calving