The intestine of a calf is still developing throughout the first few weeks of life, and production of digestive enzymes are increasing with age. The calf doesn’t obtain all the nutrients available in liquid feeds for a period after birth.
Whether it is beef or dairy it is important to grow calves efficiently to meet slaughter weights sooner. Standard target weights of pre-weaning weights are greater than >0.7kg/day and post-weaning DLWG of >0.8kg/day - >1.0kg/day for dairy or beef respectively.
There is no such thing as a silver bullet balancing for Amino Acids in calf milk replacer.
Amino acids are certainly the buzz word in ruminant nutrition, and rightly so. Nevertheless, will AA supplementation change the world of calf milk replacers too?
There are two overarching themes in research and ongoing farm trials:
We expect our calves to be able to cope and adapt to shifts in their nutrition throughout the pre-weaning phase, the first being from colostrum to whole milk/milk replacer and the last being from liquid to solid feed. Weaning is without doubt one of the biggest transformations the Gastrointestinal tract (GIT) will undergo and therefore understanding when and how we can best manage this juncture to avoid growth checks and impaired GIT health is important to the productivity of our calves.
Colostrum is a hot topic in calf rearing and rightly so. Feeding 10% of the calf’s bodyweight in high-quality colostrum as quickly as we can ensures the greatest level of Ig absorption. However, the biological role of colostrum extends far beyond the transfer of immunity.
Many farmers prefer to use whole milk to feed their calves. Some find it more convenient, others believe it to be a more natural product that is best suited to the calf – nature’s original liquid feed strategy.
Avoid the risks of exceeding nutrient tolerance. The graph shows at what level calves reach their nutrient tolerance for lactose. The red line represents a typical high plane of nutrition using a typical calf milk replacer where, especially early in life, there is a risk of exceeding lactose tolerance, leading to nutritional diarrhoea.
The calves natural feeding behaviour is to suckle off their dam little and often like an ad-lib system. Suckled calves would have around 10/15L of milk a day which is always fresh and warm, giving them more than 1.5kg of dry matter per day from milk. This is coupled with lower solid feed concentration intake and gradual rumen development.
An increasing number of studies are suggesting we should be feeding our jersey cattle and smaller stature calves differently to holsteins and larger breeds. As crossbreeding within the dairy industry is becoming more popular, the number of smaller stature calves is increasing.
Unfortunately, we cannot shy away from increasing feed costs but we can pay less attention to daily feed costs or cost per ton and more attention on costs per kg daily live weight gain.
Nutrients are valuable, whether this is through milk replacer, starter feed, minerals or forage, they all come at a cost!
