Calf Rearing Techniques

Rearing calves with milk replacers is time consuming and adds to work intensity around and after calving on dairy farms. It’s a job that requires good animal and management skills, and industry-wide, there is a shortage of calf rearers. As well, many hand-reared heifers don’t reach desired growth targets. A possible alternative is to run calves with their dams in the milking herd, but how does that work? Is it economic, and does it save a lot of labour? On Te Kunenga ki Pūrehuroa Massey University’s Dairy 1 research farm, a team has been trying to find out.

For three years, a study based at the Dairy 1 research farm has been comparing the performance of 20 heifers reared on their dams with 20 similar heifers hand-reared on milk replacer. The cow-reared calves grew faster during rearing, were weaned earlier, reached puberty earlier and maintained a weight advantage at least until first calving. Their dams produced less saleable milk during rearing time but compensated for that after weaning. Overall, labour requirement for cow-reared calves was less, although milking times and weaning needed additional careful management.

Team leader Dr Natalia Martín explains they wanted to compare calf growth, behaviour and early development under the two systems. For the cow-fed group, this meant calves moving alongside their dams to the milking shed and back to the paddock, cows grooming and looking after their calves that were sucking and learning some behaviours from their dams.

“We measured and recorded the weight and body size of heifers, milk harvested from the cows while rearing (or not) calves, milk replacer allocated to calves artificially reared, cyclicity and pregnancy outcomes for the cows and growing heifers, and some behaviour data, among other things,” says Dr Martín.

“Three years of monitoring have shown clearly that the cow-reared calves grew faster, could be weaned earlier, and retained their weight advantage through to mating and first calving as 2-year-olds. They reached puberty earlier and at a lighter weight, but by mating time, the hand-reared heifers had caught up some of the weight deficit and their conception rates were similar. Stress and growth check at weaning were significantly greater in the cow-fed group, and managing their weaning required careful planning.”

Milk production from both groups is being monitored to determine whether the early advantages of the cow-fed heifers lead to long-term gains in milk yield and productivity.

It was a relatively small study involving a total of 40 heifer calves and their dams. As calves were born, they either stayed with the cow or were allocated to the hand-reared group. The aim was to choose 20 matched pairs, each pair born about the same time, from a mix of dairy breeds (Holstein Friesian, Jersey or crossbreed) and sizes. Calf growth rate was monitored, and milk production and reproduction data from their dams, and subsequently from the calves as they matured, has been recorded. This is ongoing to see if there is any difference in lifetime productivity.

Another aim was to examine the management of cow-reared calves to see how it differed from hand rearing. The hand reared calves were in a shed protected from the elements and they had plenty of room to move around. A person was feeding them twice daily to start with. Dr Martín says that for each cow/calf pair the first couple of weeks were the most challenging because the young calves were very slow walking to the milking shed, and the cows would be constantly looking to see where their calves were.

“Then it was quite tricky to draft out the calves and put them out of sight in another shed while the cows were being milked. However, the calves soon learnt to rest in the shed for about an hour, where they had shelter and access to water and meal. Once the cows were milked, the calves were released and they would walk to the next paddock together,” she says. “Initially drafting the calves out was difficult, but after about two weeks the calves were used to it and almost drafted themselves.”

Weaning

The cow-fed calves reached weaning weight at 68 days on average, while the hand-reared calves reached that weight about a month later.

Weaning of cow-fed calves needed careful management. Rather than abrupt weaning, calves were taken off the cows after milking on day one, and on day two the cows and calves were put back together for an hour, day three was for half an hour, and day four for 15 minutes. This approach proved very stressful with both calves and cows breaking out of their paddocks searching for each other.

In contrast, the hand-fed calves were weaned by skipping milk feeding every other day over a week and seemed much less stressful. The separation from the cow had already happened (just after birth, when the bond between the pair was not as strong).

Economics

Saleable milk from the cows feeding calves was down until weaning, but then there was some compensatory extra production, so full season milk yield was similar to that of the other cows. Comparing the costs of the cow-reared and hand-reared systems is difficult, and the outcome depends on the cost and availability of labour, milk payout, and stock handling facilities. It also depends on the value put on faster growth.

“The cow-fed calves had growth rate, puberty onset, and 2-year-old weight and frame advantages,” says Dr Michaela Gibson. “Their conception rates were the same as for hand-reared calves but, given that a lot is demanded of cows throughout their productive lives, there may be advantages setting them up with a stronger musculo-skeletal frame through ad lib consumption of mother’s milk. In this sense, any additional cost of rearing calves this way could be viewed as an investment.”

Although this trial is relatively small, it does show clearly the growth advantages of rearing heifers on cows. Reproductive performance and milk production data from both trial groups are being recorded to see if there will be any significant lifetime productivity differences.

Whether the system or something similar is worthwhile for an individual farm will depend on many factors including whether using once- or twice-a-day milking, labour availability, payout, yard and shed facilities as well as personal preferences. The Massey group is interested in hearing from farmers who are rearing calves on their dams to find out what variations in management are being used.

Te Kunenga ki Pūrehuroa Massey University would like to thank Beef+Lamb New Zealand for their support of this research.