It has become common belief and practice to restrict calves to 2 litres (L) of milk/replacer (M/R) per meal, due to concerns that abomasal overload risks M/R entering the rumen. However, this presumption has little scientific basis.
Why do farmers restrict meal sizes?
Calves are essentially born monogastric. As the rumen develops it becomes less desirable for the lactose-rich milk to enter as it can change the pH and microbiota, which can cause digestive problems and reduce growth. Until now it has been presumed that the capacity of the abomasum is around 2 L and that calf (milk) meal size should reflect this.
However, this is outdated thinking. Dr Michael Steele, Assistant Professor University of Alberta, Canada recently presented data from Ellingsen et al. (2016) reporting that three week old calves will voluntarily consume up to 6.8 L of warm whole milk in one meal without milk entering the rumen or any indications of abdominal pain or discomfort.
This enhances the data that confirms the abomasum has a high capacity to accommodate fluids significantly greater than 2 L at a time. Studies also show that calves have the ability to slow down the rate of abomasal emptying to control blood glucose, so post prandial hyperglycaemia is not a problem when feeding larger meals.
Time to rethink calf feeding
Dr Steele explained: "Traditional beliefs about restricting calves to 2 L of milk or replacer per meal to prevent the possibility of ruminal overflow are not correct and we can actually feed them significantly more per meal."
This supports Trouw Nutrition's LifeStart Program, which demonstrates the benefits of higher than traditional rates of calf feed intake and growth to aid improved lifetime performance. The science confirms that we no longer need to be so cautious when milk feeding our calves. Higher rates of feeding can be achieved even if only feeding twice a day.
It's time to rethink our calf feeding strategy!