‘There is no point in over-feeding weanlings during housing’ – Teagasc research

As part of Tuesday evening’s segment of Teagasc’s Virtual Beef Conference 2020, the topic on ‘achieving target performance for weanlings during their first winter’ was discussed.

The evening was chaired by Michael Slattery from Drummonds, while the topic was discussed by Teagasc researcher, Dr. Mark McGee, and Teagasc beef specialist, Martina Harrington.

Dr. McGee gave a run through of trials, which illustrated that excessive meal feeding to weanlings at housing is not going to achieve the benefits in additional performance once these animals have been turned out to grass.

Maximising compensatory growth

Maximising compensatory growth was one of the key messages to take away from Dr. McGee’s presentation.

According to Dr. McGee, the studies found that of the weanlings that were trialed, the animals that were fed lower levels of concentrates and had a slower growth rate during the housing period, achieved faster growth rates during the grazing season.

The presentation reviewed individual trials conducted on dairy-beef and suckler-beef weanlings.

As part of the study, groups of dairy-bred weanlings were fed between 1kg/head up to 4kg/head at housing. The weight gain performance of these animals was then monitored over their housing period and further on during the grazing season.

The graph below illustrates the trial results for these dairy-bred animals.

Dairy-beef weanling liveweight gain performance at housing vs. at pasture. Image source: Teagasc

As can be seen above, the weanlings that were fed additional meal in excess of 2kg/head/day averaged off at similar weights at the end of the grazing season.

Commenting on the results of the dairy-bred weanling trials, Dr. McGee explained:

“There was a substantial increase of liveweight at pasture in animals fed from zero to 1kg of concentrates per day at housing.

Comparing the groups fed 2kg/head vs 4kg/head of concentrates per day, we essentially were feeding a quarter of a tonne of meal and gained no advantage when comparing winter and pasture liveweight gains.

“There was no benefit at all in feeding greater than 2kg/head of concentrates per day to these animals.”

Suckler-bred progeny

The suckler-bred steers and heifers were fed two concentrate winter feed levels of 0.5kg/head and 1.5kg/head a day over the winter.

At the end of the winter period there was a 23kg difference in liveweight between the two levels of feeding, in favour of the group fed 1.5kg per day.

The difference in these animals’ weight gains were minimal by the end of the grazing season, however, as Dr. McGee explained:

“We found that the animals that had a slower growth rate during the winter, had a higher growth rate at pasture. So much so that the 23kg difference in liveweight had been reduced to just 7kg by the middle of the grazing season. By the end of the grazing season this had reduced further down to 4kg.

This clearly shows there is no point in over-feeding any class of weanlings [during housing], due to the compensatory growth effect.

“A lot of the advantage in over-feeding these animals and gaining in excess of 0.6kg/day is wasted, as it disappears during the grazing season.”

Mark McGee went on to state that the ideal average daily liveweight (ADG) targets should be from 0.5kg/day to 0.6kg/day for all class of weanlings.