Turnout should be a gradual process – a slow transition to allow the rumen bugs to adapt to the changing diet, avoid sub-acute acidosis and reduce the impacts on productivity. Remember unlike grass silage, grazed grass is potentially high in nitrogen and low in fibre, writes Dugdale Nutrition Veterinary Technical Manager, Dr Debby Brown.
To max out spring grazed grass and its higher nutrient value then check out the following five points:
- Measure and monitor sward heights weekly: 8-10cm is the ideal pre-graze sward height for rotational grazing early in the season and post-grazing sward height 5-6cm.
- Set-stocking: target 5-6cm however care is required to fit the stocking rate to the growth, eg 8cm (2,000kg DM/ha) field measurement with exit at 5cm (1,500kg DM/ha) gives 500kg DM available grass.
- Dairy cattle: Initially allocate 4-5kg DM/day
- Growing cattle: allocate a minimum 3% of bodyweight, eg a 300kg growing animal requires approx 9kg DM/day
- Plan ahead: eg if 10 growing cattle require 9kg DM/day, then 500kg DM availability would last for almost six days.
- Match stock weight, size and stocking density to soil conditions to prevent sward damage through poaching.
- Consider rotational grazing to allow grass to recover once the animals have been moved to the next field.
Next up, pay attention to supplementation and the following two points:
- Calculate how much buffering diet is required: if there’s an energy or protein deficit or excess, then some balancing maybe required. If a buffer diet works for you, then provide an alternative fibre source – Alkalage®, wholecrop or maize silage.
Need to Knows:
- Grass is very digestible, low in fibre, high in sugar and potentially nitrogen and bypass protein, so it’s important to balance with a feed to drive the rumen and complement the grass if you’re going to get the most out of it.
- Grazed grass will always be the least expensive crop, so target making the most of it. However, with high nitrogen content and the risk of sub-acute acidosis at grass, it’s important to feed a high starch, low protein feed that will encourage the rumen bacteria and consequently optimise grass digestion and maintain fertility.
- To manage this safely then the feed needs to be alkaline; this is where including Alkagrain®in the diet, whether in the PMR or in the compound, helps to improve rumen function, and maintain or improve performance and fertility.
- Magnesium supplementation maybe required: since it’s low in fast growing grass so there’s the risk of grass staggers. The trend is amplified if the grass is high in potassium and the risk will be greater if high slurry applications have been made early in the season. Supplement with magnesium flakes added to water troughs, high magnesium buckets or increasing magnesium levels in compound feed.
Finally, if you see a lift at turnout, then usually you are on the right course, if not then the transition needs to be seriously reconsidered.
For further help and advice please call the Alkaline on +44(0)1200 613118