Beef trial: 30 versus 60-day winter rotations

Angus herd 15 May 2017

Part two of a two-part series looking at the first year’s results of a B+LNZ Beef Profit Partnership trial focusing on managing pasture quality. This week we look at rotation length and its impact on pasture quality and animal production.

This trial involved two mobs of beef bulls – one on a 30-day rotation, the other on a 60-day rotation – and the results were compelling, showing a clear advantage to the longer rotation length.

Project facilitator, AgFirst consultant Gareth Baynham, says they grew significantly more quality grass under the 60-day, which meant better animal growth rates. Pasture covers on the 30-day rotation were consistently 200-300kgDM/ha lower those in the 60-day treatment.

Conclusions

  • Rotation length has a major impact on pasture growth - faster rotations grow less grass
  • Stocking rates should be lower on fast rotations to avoid underfeeding in winter and spring
  • Faster rotations can reduce feed quality in winter
  • Between April and October, the bulls on the 60-day treatment gained 105kgLW, while the animals on the 30-day rotation gained 73kgLW, a difference of 32kg.

The Demonstration was abandoned in October as the 30-day bulls were not gaining enough weight, and it was costing the farmer money.

Both treatment areas were mown in April to control Kikuyu, however the bulls on the 30-day rotation had a higher proportion of low quality Kikuyu stem and stolon in their diet through winter. In contrast, the bulls on the 60-day rotation controlled this Kikuyu on the first rotation and had a higher proportion of ryegrass in subsequent rotations. This was reflected in the higher ME of the pasture under the 60-day rotation treatment.

Between April and October, the bulls on the 60-day treatment gained 105kgLW, while the animals on the 30-day rotation only gained 73kgLW, a difference of 32kg.

Gareth says the bulls on the 30-day rotation had poor feed conversion efficiency, so a large proportion of the feed they consumed was used for maintenance, rather than liveweight gain.

An adjunct to this trial was one carried out by Whangarei-based BPP members James and Kate Donaldson, as part of the Red Meat Profit Partnership programme.

Donaldson compared the productivity, profitability and pugging damage in set-stocked and rotationally-grazed bull finishing systems and again, there were clear advantages to rotational grazing, particularly on wet, vulnerable soils.

Lessons from the dairy industry

While only one year in, Gareth says the Beef Profit from Pasture trial work has highlighted the gains that can be made through simple pasture management.

“The numbers are significant.”

The BPP project came about after a dairy farmer spoke to a group of bull-beef growers about pasture management.

Realising they were falling short in this area, the group sought to seek some answers about best practice pasture management and the productivity and profitability gains available to them.

While based in Northland, Gareth points out that the principles can be applied on any sheep and beef farm anywhere in the country.

Next year the group will be looking at ways to reduce pugging damage over winter by comparing the pasture growth under R1 and R2 bulls over a wet Northland winter.

They will also be addressing stocking rates. Emulating what is happening in the dairy industry, they will look at the impact reducing stocking rates will have on animal performance and per hectare productivity and profitability.

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