Effects of Extended Grazing on Dairy Cow Performance

Since first publishing my page on Extended Grazing I have ben asked about the changes in milk production. The follwoing are statistics from the Agricultural Research Institute of Northern Ireland on performance and I thought I would share them with you.

The ARINI at Hillsborough is a well renowned independant research station run by the Department of Agriculture for Northern Ireland. This information is taken from a booklet written by Dr Rosemary Agnew of the Department of Agriculture's Agriculture Technology Services at Greenmount College. The research at ARINI was carried out by Dr C.S. Mayne.

"Results of Hillsborough Research during the 1992/93 winter are shown below. The aim of the research program was to examine the feeding value of autumn grass, offered in addition to the grass silage concentrate-based ration, with early lactation cows. Initial results from the trial suggest a saving if 2kg of silage dry matter per day or alternatively a saving in concentrate feeding of 1.7 kg/cow and improved milk protein."

Research at ARNI, Hillsborough has also examined the effect of early turnout to grass in spring on milk yield and composition with both November and January-February calving cows.

"Early turnout in February resulted in major increases in milk yield (2.2 kg/day with January/February calvers, 3.1 kg/day with October/November calvers) and gave significant increases in milk fat and milk protein concentrations. The results indicate an average increase in the value of milk produced of 77p/cow for January / February calvers and 88p/cow for Novemebr calvers for each day dairy cows were turned out between 26th February and 16 April in additions to savings in silage."

Note: The experience on our own farm is that butterfat levels rise during extended grazing in autumn as well as spring.

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Page Created 2nd June 1996
Minor corrections 1st November 1997