The cows that leave the milking parlour last and go onto grass could be regularly eating lower-quality grass, a new study by the University of Sydney has found.

It also found that cows last out have less to eat, with approximately 70% of grass consumed before they leave the parlour.

The study was conducted on a 350-cow dairy farm and was designed to test systems seeing cows returning straight back to graze following milking.

The University of Sydney research found that cows back to the pasture first accessed grass with a fifth more crude protein and 15% lower acid detergent fibre levels.

The study was conducted on a paddock grazing system on Kikuyu pasture (often found in hotter environments) and it also found that daily rumination time increased by 23 minutes for those cows returning to pasture last.

This was presumably due to the greater proportion of fibre on offer in the pasture and associated increased requirement for rumination to break down particle size, the study found.

Kikuyu pastures were depleted by 36% to ground level and 70% to post-grazing pasture mass during the time between first and last cow.

Senior researcher, Dr. Cameron Clark, said that as the milking order of dairy cows is relatively consistent, the objective of this study was to determine the effects of milking order on the quality and quantity of pasture accessed by dairy cows.

“Two experiments were conducted. The association between milking order and time of paddock access was evaluated in the first experiment.

“The second experiment determined the association between the order in which cows entered the paddock and the quality and quantity of Kikuyu pasture ingested by cows after milking,” he said.