Most dairy herds in Northern Ireland house their cattle during October and do not turnout until late April. Some years ago a group of advisors from New Zealand came and critisised our grazing methods. This encouraged ourselves and the Agricultural Research Institute of Northern Irelannd at to review our whole method of grazing. The changes implemented resulted in an extenstion of our grazing season which now lasts on average from the 1st March to 12th December. This has led to considerable savings in silage. Key to the whole system is the rationing of grass. The dairy grazing area of about 87 acres is divided up into 26 "one-day" paddocks. Although 3-4 of these are closed off except at the beginning and end of the grazing season for other uses (such as silage or for the suckler herd). During the peak grass growing months of May, June and July these are subdivided by means of an electric fence into a daytime and nighttime grazing (usually about 60% / 40%). this means that the cows have fresh grass after each milking.
It is important that the paddocks are well grazed down. However if you force your lactating cows to scavange too much you can reduce yields. We use the dry cows and older replacements to clean up behind the dairy herd. We call them vacumers and it is supprising how they can prosper on the grass left behind by the main herd. This close grazing helps encourage regrowth and maintains sward density reducing, and if well managed, eliminating the need for reseeding (Many of our paddocks have not been reseeded for over 25 years). This gives a recovery period for each paddock of 21 days.
Preparation for extended grazing begins during August when the grazing rotation is lengthened with the cows given a third of a paddock after each milking. This is to take into consideration the slower grass growth at this time of year and builds up a reserve bank of grass. This slows down the rotation to about 30 days. By the end of September the grazing rotation has slowed further to 40 days.
Essential in extended grazing is a good network of lanes. All but two of our paddocks are reachable directly from a concrete lane. This leads to a significant reduction in sward damage through poaching especially important in the early spring and late autumn when the ground can be quite soft.
During October the cows are housed at night and fed silage. This buffer feeding can lead to excellent milk compostitional qualtity. Protein levels of 3.63% and Butterfat levels of 4.44% have been recorded at this time of year. Rotation is extended to 60 days by the end of October. During November the cows only graze for about 4 hours a day, the aim being to graze all paddocks cleanly at the last grazing. The object is to have grazing completed by the 10th December. The actual closing dates for the past five years have been 5 December, 13 December, 12 December, 13 December and 10th December.
The 1st March is the target date for spring turnout. Actual dates for turnout for the past five years have been 22nd February, 13th March, 14th March , 26th February and 24th February.
This picture shows the cows grazing soon after turnout in early spring. As you can see the hedges behind them are still devoid of any foilage at this early time of year.
We try and make sure that the first paddock the cows graze each spring is some distance away fom the yard so that the cows are tired by the time they reach the field and do not race around too much. The cows are given a third of a paddock a day. At this time they are still housed at night. This gives a great deal of flexibility in that the cows can be held back so that they do not have to return to the first paddock for 75 days. Around the 14 April the cows are turned out day and night and the dry cows and replacements placed behind to clean up as detailed above. In 1995 the cows returned to the first paddock on the 25 April, 35 days after turn out.
The benefits of extended grazing are that there is less reliance on silage (a saving of 2kg of silage dry matter per cow), improved grassland management and reduced costs of milk production (a saving in concentrate feeding and improved milk protein with a net saving of £30 per cow.). Thus the beneifits are improved profit margins and a higher premium price for milk due to higher protein.
Page created 6th January 1996
Page updated 1st November 1997