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Sustainability was the buzz word at the Volac calf-rearing conference in the Princess Royal Centre, Ayr, Scotland, last October.
The focus of the event was on the latest developments in calf rearing for a sustainable dairy industry and many of the speakers emphasised the need to be sustainable in every aspect of production.
Alastair Macrae, head of dairy herd health and productivity service in the University of Edinburgh, made the case for sustainability when he highlighted the fact that the most sustainable farms are the most profitable farms.
“Sustainable farms have less input for more output and therefore have a lower carbon footprint,” said Alastair.
One way of being sustainable in the dairy and beef industries is by aiming to have all heifers calving at 24 months for their first calving.
Dr Jessica Cooke, the young-animal technician with Volac, said the optimum age for heifers to calve down is between 23 and 25 months. Heifers that calve at this age will be the best in terms of lifetime milk production, fertility, and survival over their first five years.
A growth rate of >0.75kg/day is needed for a 24-month first-calving system from birth through to calving. Jessica said that to achieve these growth rates heifers should be on a high-protein diet and should be weighed regularly (see Table 1).
She said these young heifers are excellent for contributing extra revenue to your farm. Because they survive longer in the herd and spend a higher proportion of their time in milk, the heifers will produce an extra £2,010 in milk revenue over five years compared to a 30-month calving heifer at current milk prices.
Frank O’Sullivan warned calf rearers about the threat of Johne’s disease. This is a highly infectious disease that causes chronic diarrhoea and the loss of condition in animals until the animal dies. Frank pointed out that the main way Johne’s is spread from dairy cows to newborn calves is through the pooling of colostrum (mixing several cows’ colostrum and feeding to multiple calves).
Frank advises to feed colostrum from the calves’ dams to avoid spreading the disease and feed milk replacer thereafter. Colostrum from cows that are suspected of having Johne’s should never be fed to any calves.
Dr Alex Bach, director of ruminant production of IRTA (Institut de Recerca i Technologia Agroalimentaries) in Spain, highlighted the danger of calves getting type two diabetes if they are fed too much milk in one feed. Feeding four litres of milk in one feed increases blood glucose and insulin resistance. If calves become type two diabetics they are more inclined to become over-fat as they get older and not go in-calf at breeding.
Calves with type two diabetes would be less suitable for beef production because their carcases would risk becoming over-fat at lighter weights. Dr Bach advises people if feeding eight litres of milk to split it up into three to four feeds during the day.
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