Heifer

What is a heifer?

A heifer is a female bovine that has not yet calved. Before she is served she is often called a maiden heifer, and once pregnant an in-calf heifer. Up to about weaning the animal is a calf, after that she is part of the youngstock, and from puberty onwards she is a heifer. After her first calving the heifer becomes a first-calver, also called a first-lactation cow.

On a dairy farm, heifers are your own replacements. They replace the cows that leave the herd. How many heifers a farm needs depends on the replacement rate and the age at first calving.

Insemination and age at first calving

Heifers are inseminated once they are heavy enough, in Holsteins usually at 13 to 15 months. As a rule of thumb this is about 55 to 60 percent of the later cow weight. After nine months of pregnancy they then calve at 23 to 25 months. Before her first calving a Holstein heifer should weigh about 630 kg.

The age at first calving has a big effect on costs. In the German state of Schleswig-Holstein the average was 27.2 months in 2024, and rearing a heifer there cost €2,659 on average, 56 percent of it feed. Every month less saves feed and space. Read more in Outsourcing of youngstock rearing?

Good rearing starts with the calf

You only reach an early age at first calving if you aim for high growth in the first weeks. Calves that gain at least 800 grams a day before weaning grow faster, are inseminated earlier and give more milk in their first lactation. This is called metabolic programming. Diarrhoea and respiratory disease slow this development down. A heifer calf with diarrhoea costs at least €150, through treatment and a week without growth.

Later on, the best way to follow her development is regular weighing or a weigh band. That way you see early on whether the feeding matches the target curve. Heifers that are too fat are a risk: they have more difficult calvings, udder oedema and metabolic problems.

The heifer before calving

The last weeks before calving shape the start of lactation. Heifers should calve at a BCS of 3.0 to 3.5. Udder oedema is more common in heifers than in older cows. Plenty of space to walk around helps, and the potassium level of the ration also plays a part. Talk to your nutritionist about it. Many farms get the heifers used to the milking parlour or robot and to the cow group before calving, so the move causes less stress.

Around calving, heifers need a lot of energy, because they are still growing on top of producing milk. In practice you often see an energy dip with low feed intake at this stage. You can read an example from a Dutch farm in KetoCare at the start of lactation.

Rear your own or buy in?

Some farms outsource heifer rearing to save space and labour. Others buy in in-calf heifers. Both can work, but you lose some control over health and feeding. Bought-in animals can also bring new pathogens into the herd. If you outsource, put the target weight, age at first calving and health status down in a contract.

Frequently asked questions

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