Mid-season management of the dairy herd
Ireland has seen dramatic changes in the weather this year — a wet spring followed by a period of dry weather and soil moisture deficits of anywhere between 30–100 mm across the country. It has turned into a typical ‘Irish summer’ over the past few weeks, however, with more rainfall and grass recovering somewhat from the dreaded drought. Various microclimates have dictated some farms needing to include a buffer or an increased level of concentrate, while others managed to avoid this.
Maintaining milk production
Breeding should be finished up this month in a spring calving herd, which means a lot of the most stressful time of the year is over. At this stage, it is important to take a step back and pay closer attention to the cows. Take note of how they have milked up to now, when they have peaked and what was the rate of decline from their peak. The maximum drop in milk past peak milk production should be 2% per week. If the drop is greater than this, it is most likely due to a lack of dry matter intake (DMI). Reflecting on end-of-year Co-Op reports, for example, a herd peaking at 28 litres in May should not be under 23.5–24 litres in July. There is a lot of high-value milk to be produced for the next few months, so it is important that there is not a shortage of DMI to maintain milk production.
Supplementation and grassland management
While supplementation was increasing only a month ago, things can change very quickly on farm level. Grass growth was nearly at a standstill, and not much surplus had been taken out. Cows were asked to graze 500–800 kg DM covers when usually they would be grazing double this. On a lot of farms, residuals were met, which means paddocks coming back into the rotation now should be more like after-grass and excellent quality. The surge in growth will mean that there will be surpluses. This will be excellent quality (>75 DMD) if taken out at the correct cover. As is usual, the farm needs to be walked to ensure proper utilisation of these excellent quality covers. Walking twice per week is advisable during periods of high growth.
Supplementation will still play a crucial role as there is a maximum grass intake of anywhere between 16–18 kg DM. Some herds will need over 20 kg of total DMI to maintain body condition and milk production and, following the rule of thumb, 0.11 kg concentrate/litre milk. If you need to supplement above this, then it would be worthwhile bringing in silage or a forage to meet the DMI.
The quantity of intake is crucial, but quality needs to be taken into consideration. Energy shortage in grass/buffer can be diagnosed when the milk protein is dropping. Choose the parlour concentrate protein level based on grass growth; if there is a high level of growth as of now, then the protein level needs to decrease. You can also use milk urea as an indicator for protein in the diet. It should be in the range of 20–35 mg/dl. If greater than 35 mg/dl, then there could be an issue with fertiliser not being taken up by the plant, or excess protein through supplementation. If lower than 20 mg/dl, it could mean old, low-protein pastures are being grazed, or there is not enough protein in the supplement.
July is an optimum time of year to measure silage stocks and budget efficiently for the winter months. While there may have been a lot of silage fed over the past month, there were surplus paddocks taken out early in the year, which should have been prioritised for filling the feed deficit we experienced. If first cut silage has been eaten into, it is more important to pay close attention to a feed budget as there is time now to replenish reserves.
To complete an accurate feed budget, you will first need to calculate the amount of stock on the farm. You can follow Table 1 below, which will give an outline of different animal groups and silage requirements per month. This should be done on a farm-by-farm basis, but it is recommended to plan for a five-month winter. Measuring the silage pit shown in Table 2 [Length (ft) X Width (ft) X Height (ft) divided by the factor], based on the DM of the silage, will give the tonnage in fresh weight. Work out the amount required versus the amount in stock. You can then plan based on this figure.
Table 1: Feed Demand
Table 2: Feed Supply
If you are coming up short, and to simplify the decision making, you could use the following rule of thumb: If you need over 100 tonnes of forage, you will need to buy silage. At less than 100 tonnes, you can bridge the gap with concentrate or alternative forages. One ingredient found on every farm is straw. Every 1 kg of straw will replace 4–5 kg of silage. There is a requirement to make up a feed value deficient in some classes of stock — but if we use 50 round bales of straw, we could save 4–5 acres of silage.
- Maintain milk production (insufficient DMI is the main culprit of significant production failure)
- Manage surplus and deficits on-farm efficiently by walking your farm regularly
- Feed budget now to assess what silage stocks are currently on the farm, calculate requirements of all stock and plan accordingly