Completing the first grass walk of the year is important for a number of reasons on grass-based dairy herds.
Grass is the jewel of the Irish dairy sector, and to obtain the most benefit from it, it needs to be measured.
In many areas, ground is not suitable for grazing, however, it is important to get a picture of what is happening on your grazing/milking platform.
Completing a grass walk gives you an opening cover, helps to identifies areas best areas for grazing, and also identifies areas that may be suitable for slurry.
Grass walk
During autumn, paddocks were closed in order to allow for spring grazing, however, in many cases, the weather would have hampered this.
Ideally, the first few paddocks that cows are turned out onto have low covers. This is for a number of reasons, but most notably because intakes of cows just after calving will be low.
Getting cows to grass early and paddocks grazed off early has a number of benefits.
Some of the benefits include:
- Stimulated grass growth;
- Reconditioned swards for the year ahead;
- Reduced feed costs;
- Increased milk output.
The grazing targets set out by Teagasc are: 30% by the end of February; 60% by March 17; and 100% by early April.
These should be tailored to suit your farm and the weather conditions during spring.
Grass in the diet
You should be trying to get your area grazed and the farm set up for the grazing season ahead.
Research from Teagasc has shown that there is a production benefit from having grass in the diet from an early stage.
A trail which took place during the first 12 weeks of lactation looked at whether the rate and timing of silage supplementation had an effect on milk production.
For the first six weeks, cows on the high grass treatment were offered a high daily herbage allowance with low silage supplementation, and cows on the low grass treatment were offered a lower daily herbage allowance with high silage supplementation.
From week seven to 12 of the experiment, cows on the high grass treatment were offered a high daily herbage allowance with no silage supplementation, and cows on the low grass treatment were offered a lower daily herbage allowance with 3kg of dry matter (DM) silage/cow/day.
During the first six weeks of lactation, there was a difference of 2kg DM/cow/day in silage DM intake (DMI) between the high grass and low grass treatments; however, this had no effect on milk production.
Cows on the high grass treatment for weeks seven to 12 had significantly higher milk yields compared to cows on the low grass treatment.
Total DMI was the same for both groups during this period, however, the inclusion of silage in the diet reduced feed quality, which had a negative impact on milk yield for the low grass treatment.
The high grass treatment milk yields remained higher for a further eight weeks once the experiment was finished and all cows had the same diet consisting of 17kg DM/cow/day grazed grass plus 1kg concentrate.
The trial also determined that the protein content was significantly higher for the high treatment (3.51%) compared to the low grass treatment (3.40%) from week seven to 12, due to the inclusion of silage in the diet of the low grass treatment.
The high grass treatment also had significantly higher grass DMI (+ 3.4kg) compared to the low grass treatment.
The reduction in milk protein content is caused by the lower protein content and nitrogen (N) retention of grass silage compared to grazed grass.