Once a day feeding in calves

Once-a-day (OAD) milk feeding is not just a labour-saving method suitable for healthy calves from 28 days of age, this system also promotes earlier rumen development, prepares calves for weaning and makes more time for calf husbandry.

How OAD feeding works

Instead of splitting liquid feed into two meals, calves receive their full daily portion of milk or milk replacer in one concentrated morning feed. Research shows calves naturally prefer to consume more feed in the morning, which then digests slowly throughout the day (Quigley, 2025).

This approach encourages calves to eat more solid starter feed during the day. This stimulates the growth and function of the rumen, allowing for earlier weaning of approximately one week. 

Management considerations

Using a OAD feeding system allows for an increase in attention to detail when it comes to calf rearing areas such as housing, bedding and illness. Calves will still need to be checked twice a day for any ill health.  

Key feeding guidelines:

To be effective, OAD feeding depends on several factors:

• Use a milk replacer made from low-heat, high-quality skim and milk-derived proteins. These promote effective clotting and coagulation in the abomasum, which releases nutrients gradually throughout the day.

• Ensure calves always have access to clean water and fresh feed.

• Keep the feeding schedule consistent. Calves should be fed at the same time every day.

• Maintain the same concentration and temperature of milk replacer daily.

Benefits of skim and buttermilk proteins

A combination of buttermilk and skim milk proteins works particularly well for OAD feeding:

• Buttermilk and skim milk proteins are digested slowly, creating a sustained source of proteins calves can utilise throughout the day.

• Both proteins form a clot in the abomasum, which breaks down slowly. This provides a steady flow of amino acids and energy throughout the day.

• Lactic acid in buttermilk reduces digestive disturbances and feed refusals, promoting better gut health.

• Lecithin in buttermilk acts as an emulsifier, improving the digestion of fats. It may also enhance the calves’ immune system and gut health by promoting beneficial bacteria and providing lipids similar to colostrum.

• Research shows using buttermilk in a CMR can reduce the infectivity of rotavirus, lowering the risk of gastrointestinal disease.

In contrast, whey protein is digested too quickly – reaching the small intestine about an hour after consumption – making it unsuitable for OAD feeding.

Research evidence

French study (Julien, C. et all, 2015)

A study compared OAD and TAD feeding from birth to weaning. It looked at growth, intake, rumen development and ruminal metabolism. Results showed no difference in body weight or total feed intake. However:

• OAD calves had lower ruminal pH from day 42 to day 56. This is beneficial as it encourages the growth of bacteria that ferments starch in calf starter feed, leading to the production of volatile fatty acids (VFAs).

• OAD calves had a significantly higher butyrate ruminal concentration from day 21 to day 63. This promotes gastrointestinal tract development, enhances feed efficiency, improves immune function, and reduces the incidence of diarrhoea.

• OAD calves had a higher papillae density, which are vital for absorbing VFAs and energy. It also strengthens the gut barrier, modulates the microbial community, and acts as an antioxidant and anti-inflammatory agent.

Harper Adams University trial

A trial in beef calves compared OAD and TAD systems using 600 g of skim and buttermilk-based milk replacer, plus ad-lib starter feed, straw, and water. Calves in this trial aged between two and three weeks old. Results at 12 weeks showed:

• OAD calves were weaned five days earlier.

• They were 7.8 kg heavier at 12 weeks.

Table one below shows their findings on calf performance up until 12 weeks. 

	OAD group	TAD group	Difference
Starting weight (kg)	56.5	56.7	0
Weaning age (days)	46	51	– 5
12 week weight (kg)	132.2	124.4	+ 7.8
DLWG 0 – 12 week weight (kg)	0.9	0.81	+ 11%
Dry feed intake (kg)	185.2	173.7	+ 11.5%
Rumen girth (cm)	140.6	136.5	+ 4.1
Incidences of scour	0	+
Cost/kg gain (£)	0.94	0.98	– 0.04
FCR	2.66	2.88	+ 8%

References:

Julien, C. et al. (2015) ‘Effects of feeding programs based on one or two milk replacer daily meals on growth, solid feed intake and rumen fermentation and development of dairy calves,’ Scientific Research Publishing [Preprint]. http://dx.doi.org/10.4236/as.2015.612139 (Accessed: September 1, 2025). 

Quigley, J. (2025) ‘Daily variation in calf starter intake,’ Calf Note. https://calfnotes.com/en/2025/08/11/calf-note-260-daily-variation-in-calf-starter-intake/  (Accessed: September 1, 2025).