What's New In Calf Rearing?

1 Jul 2019
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Calf rearing is a forever-changing topic as we constantly learn and improve how calves are reared. Below is a summary of what’s new in calf rearing, some hot topics and buzzwords.

Osmolality of calf milk replacer
Osmolality of milk powder is being talked about across the industry and is something that is very important to calf health and performance but it needs a proper introduction, so we can fully understand its implications.

Osmolality is the concentration of solute particles in a solution - and is calculated by adding the concentrations of sugars and minerals in mOsm/kg of solvent. Lactose content in calf milk replacer (CMR) is the main contributor to the final osmolality value. CMRs with elevated levels of osmolality can damage gut integrity, increase the risk of abomasal bloat (because of slower gastric emptying) and exacerbate diarrhoea severity in sick calves, calves fed once per day on an increased concentration are especially at risk. To maintain gut integrity, it is thought that calves are better receiving a higher volume rather than a higher concentration of milk replacer. Therefore, it is recommended that the concentration of milk powder does not exceed 175g/L and recommend CMR to be of 135g/L-150g/L in between 6-10L. There is no difference in glucose tolerance high volume fed and low volume fed dairy calves at 4, 7, or 10 weeks of age. Feeding dairy calves an elevated plane of nutrition in 2 meals of milk replacer per day does not decrease insulin sensitivity. Also feeding larger meal sizes has been shown not to have any effect on stool consistency.

Osmolality levels: risk factor for calf scour

Water Quality
Something that isn’t often discussed is the quality of the milk replacer. Water is the most important nutrient for calves as it features all of life’s processes such as transport of nutrients, digestion, metabolism, elimination of waste, and is also critical for rumen development. However, water quality for calves is often overlooked. Water is the most important nutrient for calves as it features in all of life’s processes; such as transport of nutrients, digestion, metabolism, elimination of waste, and is also critical for rumen development. Poor water can impact consumption, starter intake, health, and the value of milk replacer and electrolytes.

Providing calves with clean fresh water is an integral part of their nutrition.

Water hardness can have a big impact on calf health - calves are sensitive to sodium! Water that is hard or water that has been through a softener, can lead to neurological and central nervous system derangement. Osmolality of water can vary depending on its source (mains, borehole etc). If the calves are on an accelerated feed programme ensuring the water is osmotically balanced is vital. It is recommended that water that is used for calves is tested annually, for mineral content, osmolality and bacteria.

E.Coli and Salmonella can be present in poor water and can cause an outbreak, especially if the water has been soiled in. Water with a high iron content is at increased risk of salmonella contamination. Providing calves with clean fresh water is an integral part of their nutrition.

Electrolytes- what do we need to know?
There has been much debate recently on mixing electrolytes into milk but this is a huge no-no. Based on what we discussed above on osmolality, adding electrolyte solution to milk or milk replacer will change the osmolality of the solution, and in turn could actually exacerbate scour rather that help the calf overcome it.

Always feed electrolytes separately to milk or CMR. The most current advice is to continue feeding milk as normal - do not remove the milk feed. The milk feed gives calves the energy and calories it needs to overcome a bout of scour and to effectively utilise the salts and sugars in the electrolyte feed. A suggested recommended feeding protocol is as follows:

- Milk feed AM
- Electrolyte feed Midday
- Milk feed PM
- Electrolyte feed evening

With calf scour, it is often the dehydration that will kill the calf not the disease itself, so by keeping a calf properly hydrated with care and attention, death from scour can be reduced as well as reducing the duration of an incidence of scour.

High-energy diets - “Energized calf milk”
With the release of our new milk powder Elixir, which is an energized calf milk, we should know why higher energy diets are working so well. Fats are key for digestion and the health of a calf.

Fat in CMR is comprised of short, medium and long chain fatty acids, a more diverse profile than whole milk. The structure of these fats depends on how well a powder is digested. Newborns digest short and medium fatty acids more efficiently than longer chain fatty acids - with calves developing the ability to utilise the longer chain fatty acids after about 3 weeks of age. In calf rearing, energy is often a limiting factor to calf growth and development, and calves fed a high protein/low fat diet are often less efficient per KG of DLWG as they have to convert the protein as an energy source. There is a requirement to have enough energy from fat and sugar to fuel growth and development of the mammary tissue and reproductive tract.

Calf rearing is an ever-evolving topic, and we are learning more all of the time and striving for excellence is an integral part of building a successful, profitable future herd.

If you have any questions about any of the topics discussed in this article, contact your local Calf & Youngstock Specialist who can answer your questions.