More isn’t necessarily better when it comes to protein levels in calf milk replacers. The latest research shows that lower concentrations of protein, but with a specific balance of amino acids, can improve growth rates in pre-weaned calves, while reducing milk replacer costs and ‘waste’ nitrogen.
Calf nutrition is really changing, according to Cargill’s Dr. Jim Quigley who, after more than 25 years in the industry, says that he’s seeing more progress now than ever before.
“People have challenged the protocols that we’ve followed for many years. This is good – it’s led to one of the most comprehensive reviews of calf nutrition for many years.”
Quigley, who is an international authority in calf and heifer rearing and spends 50% of his time on research projects and the other 50% communicating the latest knowledge through Cargill specialists globally, has recently been in the UK to disseminate the latest developments in calf milk replacers with precisely balanced amino acid supplementation and lower protein concentrations.
“Pre-weaned calves receive nearly all their daily protein intake from milk or milk replacer. Essentially all the amino acids needed for growth will come from the liquid diet.
“Complete milk proteins – casein plus whey – have been considered ideal. When corrected for digestibility, this amino acid profile matches that in lean tissue growth. Until recently, we’ve believed this to be a ‘perfect’ match,” he said.
Amino acid led
However, the components of milk protein can have different amino acid profiles. These can be limiting in certain essential amino acids.
“This is already well researched in the pig and poultry sectors and it has allowed them to improve feed efficiency, reduce wasted nutrients and minimise feed costs.
“Even dairy cow rations are formulated to optimise amino acids for maximum milk yields with lower protein concentrations. Yet until now we haven’t adequately specified amino acid requirements for dairy calves.”
Calf milk replacers in the UK are typically between 22% and 23% and 26% for a high-protein milk replacer. Some may even have protein levels of 28%.
“But more isn’t necessarily better,” said Quigley, adding that the company’s latest trial work looked at key components in calf nutrition:
- How much calf milk replacer can we feed and what sort of response can we get?
- Can we improve growth rates and productivity with a better combination of constituents?
- What’s the best balance of amino acids for growth rates and performance?
Trials using combinations of amino acids with a range of milk replacers of varying protein content were trialled on calves at Cargill’s Nurture Research Centre in New Paris, Ohio.
Calves were fed on milk replacer and starter from two days old through to weaning at four to six weeks, using multiple titrations of amino acids under many different feed programmes.
Weight increase of 18%
Combinations of lysine, methionine and threonine – often referred to as limiting amino acids where a lack of one results in a ‘gap’ in the diet that limits growth – were used, plus other important amino acids such as arginine and histidine.
Calves were measured for daily liveweight gain and skeletal size – height, circumference and hip width. These growth measures provided a valuable measure of performance.
Results showed that calves up to four weeks old achieved an 18% increase in average daily weight gain where a specific amino acid supplementation was added to 24% and 26% crude protein milk replacers (as shown in Figure 1).
These calves achieved average daily weight gain above that delivered by a 28% crude protein milk replacer. All milk replacers contained 17% fat and were fed at 0.7kg/head/day up to weaning.
“This showed us that lower concentrations of protein but with specific amino acid supplementation can produce better results, more cost-effectively and with less waste,” he said.
Figure 1: Effect of amino acid supplementation in milk replacer on calf growth rates
Cargill’s research went on to develop its amino acid balancing technology, AmNeo™, and include more amino acids in the evaluations, leading to an improved amino acid balance.
The performance of groups of calves with these varying levels of amino acid supplementation in an optimal 24% crude protein milk replacer at 17% fat were compared.
Figure 2: Effect of low and high amino acid supplementation included in AmNeo™ balanced package on calf growth rates
(Calves fed on a 24% crude protein and 17% fat milk replacer at 680g/day. Weaned at 42 days)
Results, shown in Figure 2, indicate a 10% average increase in total weight gain and a 13% increase in frame growth where the additional amino acids were included.
Better protein use
Quigley added: “And when we consider costs, we can see a better return where calves are fed a milk replacer with optimal protein (24%) and the latest package of balanced amino acids compared with a 28% protein milk replacer and no supplementary amino acid balance.
“This is because feed costs and cost per kilo of weight gain are less in the lower protein ration.”
Another advantage of feeding lower protein is the improvement in nitrogen efficiency.
“There’s less waste – a 28% milk replacer creates more waste nitrogen than a 24% protein product that, based on our trials, we consider ideal. More waste is uneconomical and has environmental and stewardship implications.”
Quigley considers that they have arrived at protein levels with a balance of amino acids for calf milk replacers that will improve performance and reduce the cost per unit of body weight gain through more efficient protein use.
New-look milk replacers
Cargill UK and Ireland calf and heifer specialist, Bianca Theeruth said: “Work in the US has demonstrated the benefit of balancing calf milk replacers for amino acids rather than formulating to protein.
“Trial results show that we can achieve the same performance in calf development on a lower protein calf milk replacer balanced for amino acids compared with a higher, more expensive, protein replacer with no additional amino acid supplementation.
“The advantages also include better use of protein and contribute to a more sustainable industry.”
These latest developments in calf nutrition have been put into practice in the Cargill’s ProviMilk™ milk replacers.
“These are now formulated to an amino acid requirement and not protein per se and will help producers achieve more protein-efficient and cost-effective growth rates,” she added. Click here for more information
