Maximising the value of milk produced from every kilogram of feed will be critical as herds face forage shortages and higher feed costs this winter, claims Dr. Derek McIlmolye, AB Vista’s EMEA Ruminant Technical Director.

“Improving rumen function for better feed efficiency and to boost milk income needs to be a top priority,” he stated.

The threat when forage is in short supply is that rations end up less well balanced, and rumen function is less well supported as a result, with knock-on effects for production and cow body condition.

According to Dr. McIlmoyle, what’s needed is a feeding strategy that balances energy release in the rumen, and so limits the dramatic rumen pH drop associated with high intakes of starchy concentrates.

It also needs to promote the production of milk fat pre-cursors to ensure the cow is supplied with the energy and raw materials needed to support butterfat production in the udder.

“The aim is to provide as stable a rumen pH as possible, minimising the time spent below pH 5.8 to optimise fibre breakdown in the rumen,” he explained.

“The overall diet must also balance both the amount and rate of energy and protein release in the rumen, with rapidly fermentable energy – primarily sugars and starch – particularly important in balancing the rumen degradable protein in grass silage.

The diet should also include a good supply of energy from digestible fibre from feeds like soya hulls and sugar beet feed, and be sufficiently palatable to encourage high intakes.

“The addition of a slow-release rumen conditioner like Acid Buf or a metabolically active live yeast such as Vistacell can also be worthwhile. This will help reduce the rate and extent of any rumen pH drop, and so minimise the negative impact on rumen fermentation efficiency.”

Proven research results

According to research carried out at Schothorst Feed Research (SFR) in the Netherlands, using Acid Buf and Vistacell together can produce gains that exceed those of Vistacell alone.

This included a substantial improvement in rumen pH, volatile fatty acid (VFA) production and butterfat yield (see Table 1), resulting in a 3% increase in fat-corrected milk (FCM) production per kg of dry matter intake (DMI).

Table 1: Effect on milk production and feed efficiency (Source: Schothorst Feed Research). 1 Vistacell at 4g/cow/day; 2 Vistacell AB = Vistacell at 4g/cow/day + Acid Buf at 88g/cow/day.

“What’s particularly interesting is that the combination product didn’t increase DMI, but did increase milk yield and butterfat production,” Dr. McIlmoyle added.

“It’s an increase in overall feed conversion efficiency that’s a direct consequence of an improved rumen fermentation where both the yeast and conditioner were included.”

Figure 1 shows the clear reduction in time that rumen contents spent below certain pHs following addition of the yeast and conditioner, with pH 5.8 being the critical point below which fibre digestion is compromised.

Below pH 5.5 is the point at which cows are considered to be suffering from sub-acute ruminal acidosis (SARA).

Figure 1: Effect on rumen pH (Source: Schothorst Feed Research).

Increased margin potential

“For milk producers looking to boost butterfats, maximise milk value and improve overall feed efficiency, this research has important implications,” Dr. McIlmoyle concluded.

“What’s clear is that it’s no longer a simple question of whether a yeast or a rumen conditioner will be the best option to help maintain good rumen conditions and milk fat production.

“It appears that there’s a benefit to using both at the same time, with the potential performance advantage more than sufficient to justify the additional cost.”

Further information

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