When does waste milk have a true cost? When it’s fed to dairy replacements, says XL Vets’ Joe Henry, of the Alnorthumbria Vet Group.

“If dairy producers check out the cost of calf milk replacer, they will find it will look far more attractive than feeding discarded milk. Waste milk is high risk from a health point of view furthermore feeding quality CMR unleashes growth potential of heifer calves, so they maximise production and health potential as milking heifers,” he says.

As many as one-third of farmers are feeding discarded milk, a recent survey carried out by Volac shows. Of the 740 livestock farmers interviewed, 35% used waste milk, 28% offered saleable whole-milk, while the remaining 37% fed calf milk replacer. About 30% of the farmer respondents used a combination of calf milk replacer and waste milk to rear their calves.

“For those continuing to feed waste milk there’s a difference between what is perceived to be cheaper and what is cost-effective,” says Mr Henry.

Dairy cows

He recommends that if dairy farmers are to truly exploit their dairy heifers’ lifetime potential, then they should adopt the following three-point plan when weighing up the options of what to feed, immediately after each calf has received quality colostrum, tested by a colostrometer, for the first three days.

That included an essential six pints within the first six hours.

Eliminating antibiotic resistance

If waste milk includes milk discarded from antibiotic-treated cows or cows with mastitis, then it should not be fed to calves because the risk of producing antibiotic resistance is increased immeasurably. DEFRA’s Code of Recommendations for the Welfare of Livestock specifically advises against this practice.

Avoiding disease transmission

“If Johne’s disease, Salmonella dublin or Mycoplasma bovis are present in the herd, waste milk feeding will be detrimental to its health. Indeed, I would argue that you should not even consider feeding waste milk unless you are sure that the herd’s status for each of these three diseases is negative.”

Achieving improved performance

Calves will grow faster if they are fed quality calf milk replacer on a cold ad-lib basis compared with waste ad-lib milk. The University of Central Lancashire, Myerscough College found calves fed calf milk replacer weighed more than 15kg heavier at six week weaning in recent trials.

“To maximise first lactation yield, fertility and longevity, potential heifers should be targeted to calve at 24 months, and Holsteins should weigh 600kg,” says Mr Henry. “Missing the 24-month target will result in a cost of £50 a month for the duration of the catch-up period.

“So it makes economic sense to invest in feed costs when they weigh 40kg rather than trying to play catch up with a 500kg heifer which is struggling to make the weight at two years old when her feed conversion efficiency has more than halved.”

While feeding waste milk may appear attractive for more than one-third of producers, they should realise nothing comes free in life, says Volac’s milk replacer specialist, Maggie Gould. “In the first instance, producers should remember it costs an average £750 to rear a replacement from birth to first calving. Therefore, it raises the question why are so many farmers prepared to take on the health and performance risks associated with feeding waste milk?” she says.

“Frequently these costs are hidden in lower returns. For example, it is not easy to measure the impact of reduced growth rates and increased health problems on overall profitability.”