By Katrina Henderson of SRUC

THE EARLY nutritional management of new-born dairy calves has a major impact on health and survival – reducing profitability, efficiency and animal welfare. 
Half of recorded losses of dairy-bred calves occur in the first six weeks – and the true figure is higher, as many unregistered calves die as neonates.
The importance of pre-weaning nutrition and growth rates reaches beyond the rearing period – for every 0.1kg increase in average daily liveweight gain (lwg) prior to weaning, heifers produce 107kg more milk in their first lactation. They calve at a younger age and are more likely to achieve the optimal calving age of 22 to 24 months. 
So improvements in the efficiency of the process reduce costs significantly.

Traditional milk feeding focused on providing low levels of milk (two litres twice daily) or milk replacer (400g to 500g per day) to encourage starter intake. However, providing higher levels of milk replacer has significant benefits for calf health, productivity and longevity in the herd. 

Benefits of better milk feeding: 
Greater pre-weaning growth rates.
Improved feed conversion efficiency.
Reduced disease incidence.
Improved welfare.

More rapid recovery and better growth during a disease outbreak.

Table shows the growth rates achievable at different levels of milk feeding for a 45kg calf under three weeks. These figures apply to calves fed at 15

Growth rates      Gms of milk

(kg/day)            replacer fed    

400                       0

650                     0.4

800                     0.6

950                     0.8

Achieving high levels of milk fed and improving growth rates:
Feed whole milk or the equivalent in milk replacer to at least 15% of bodyweight.
Calves can comfortably be fed whole milk at up to 20% of bodyweight giving growth rates of approximately 1kg per day, compared to 0.45kg in milk restricted calves.
Energy density of milk replacers can vary, but in general, feeding milk replacer at 125 g per litre is equivalent to whole milk.

Graph shows grams of 20MJ/kg of DM milk replacer to support differing levels of growth rates in a 45kg calf less than three weeks

The Scottish Farmer:

Addressing concerns:
Suppressing starter intake – calves in the first three weeks eat little concentrate feed so appetite suppression is not relevant.
Difficulty weaning – this can be managed by stepped or gradual weaning where the reduction in milk intake is accompanied by a surge in concentrate intake. 

Milk or milk replacer may be fed to calves, though consider that while whole milk may be cheaper than milk replacer, depending on milk price, replacer is more consistent and carries a reduced risk of disease transfer. 
There are a variety of replacers on the market, but though the ingredients are listed in order, the exact proportions are rarely given. 

What to look for:
Protein and fat levels – 20-26% crude protein and 16-20% fat.
Target growth of 0.8 kg per day or over require 26% crude protein; 20% is adequate for growth of 0.45 kg per day.
Plant-based proteins have reduced digestibility, particularly for calves under three weeks. Fibre levels over 0.2% suggest plant proteins are included.
Soya protein contains anti-nutrient factors and can cause scours when fed in excess.
Pea proteins tend to sediment out and buckets should be inspected for residues.
There is no evidence that skim-based powder is superior to high quality whey-based products.
Ash above 8% indicate poorer quality ingredients.

Calves must be fed twice daily. Fed only once, they are unlikely to drink the whole volume unaided, milk is consumed faster rate and digestion impaired. 
Calves under four weeks must be fed milk at least twice daily. The only exception to this is ad-lib feeding. Aside from the legal requirement there is a robust economic argument to support this practice.