Animal data essential for efficient heifer calf rearing

Efficient and profitable heifer calf rearing can be achieved by basing management decisions on actual data relating to body weight, diet and health status, rather than perception.

According to ruminant specialist Alex Bach, farmers too often rely on judgement when it comes to their heifer rearing and don’t give this important aspect of their enterprise the same level of attention as they would their lactating cows. “It’s a huge loss of opportunity,” he told delegates.

Data

He urged farmers to make the best use of data to achieve goals, because the feeding methods and management practices applied to today’s calves will have a major influence on the herd’s future milk yield and economic performance.

Dr Bach, director of the Department of Ruminant Production at Institut de Recerca I Tecnologia Agroalimentaria, Spain, said the most common objective is to calve a heifer at between 22 and 23 months at 650kg. Currently, the average age at calving in the USA is 27 months and in Europe between 25 and 29 months.

By reducing the age of first calving, costs could be significantly reduced, but this should not be done at the expense of body weight.

Dr Bach advises against using an average body weight; the optimum weight at breeding should be 55%, and 82% after first calving.

Feeding costs are the highest contributor to the overall costs associated with heifer rearing, therefore small improvements in feed conversion can result in large savings.

Feed efficiency

Feed efficiency is greater in younger animals, so it is cheaper to put weight on stock earlier.

“It is better to spend £100 on a heifer in the first few months of life than at 14 months of age,” said Dr Bach. “In the first two months of life animals have a feed efficiency of 60%, so for every 100g they eat they will gain 60g in bodyweight. At 16-20 months they are 7% efficient, so will only gain 7g in bodyweight for every 100g of feed consumed.”

Research shows that on average calves gaining 1kg a day can be expected to produce about 1,000kg more milk during their first lactation than calves gaining 500g a day. They are also more likely to reach a second lactation.

Dr Bach recommends feeding calves six litres of milk a day and giving them access to 2.5 litres of water a kg of dry matter.

A diet of pellets rather than a mix is more digestible and he advised against offering weaned calves a high-quality forage, because their rumens are not developed sufficiently to digest it.

The transition period should start with a 5% inclusion of forage, rising to 15-20% at four months of age. The diet at this stage should include about 2.73Mcal/kg of ME and 17% protein.

Housing

Housing also has an influence on calf health and future productivity. Taking advantage of social facilitation to encourage feed intakes could be an effective tool to ease the weaning process. Moving calves from individual hutches to groups while reducing milk replacer feeds to one a day can be preferable to reducing intakes while the calves are individually housed.

“Calves should be housed individually initially, but putting them into small groups before weaning encourages the uptake of hard feed. There is no evidence that this will have a negative effect on disease,” Dr Bach explained.

Animals should be grouped according to their previous history of respiratory diseases to minimise the risk of infecting calves that have not had a case of pneumonia or BVD.

“For every respiratory infection a calf gets, its productive life decreases,” said Dr Bach. A calf that has had four cases or more should not be retained as a replacement.

Stress

Another factor that may compromise heifer fertility is social stress. Heifers are commonly kept in pens and moved to a breeding pen at insemination time. This change of pens and social acquaintances can cause social stress and have a negative effect on reproduction. Dr Bach recommends moving heifers to a breeding pen two weeks before insemination.

Once a heifer is pregnant, farmers should avoid overfeeding to correct any growth mistakes. “It is a big mistake to feed more when a heifer is in calf – the more they grow at this point, the less milk they will produce. The homework with heifer rearing starts at day zero and ends at day 400. After that, there is no more homework,” he said.