It doesn’t really matter what we decide to call it – mob grazing, rotational grazing or paddock grazing – they all essentially mean very similar things. What is important, however, is that we understand the clear distinction between controlled grazing (that we have under rotational grazing systems) and uncontrolled grazing (as we have under a set stocking type system – where the livestock are allowed to roam and selectively graze over a large area for many days, or even weeks).
Today I operate two dairy farms with a combined total of just over 1,000 dairy cows, but I want to take you back to a particular point of my dairy farming career where I changed course and educated myself about the value of grazed grass.
Almost 20 years ago I was persuaded to begin monitoring the grass growth rate and the level of grass cover on my farm in Cumbria. I was given a simple device called a Rising Plate Meter and was to become the only farmer in the North of England (North of Staffordshire) who was actually routinely measuring and recording this information. I was told by improving my grassland management, I could grow more grass, utilise more grass and in turn lift my stocking rate and make more profit. The figures mentioned were a 25-30% increase in grass dry matter (DM) production with no increase in nutrients or fertiliser, all achievable through better management.
At this point, I thought I was already a reasonably good grass manager. Several years earlier we’d won an award for increasing the level of milk we produced from forage, and we were consistently in the dairy industry’s top 25% for milk produced from grazed grass. So 25-30% more grass, effectively for free – well I was sceptical to say the least. Once I’d got over the embarrassment of actually taking this new-fangled device around the farm for its weekly walk, I discovered the enormous beneficial effect of having accurate grass growth and cover data. For the first time I was able to base my grazing management decisions on fact rather than gut feeling backed up with experience.
Prior to this we were already operating a loosely rotational grazing system, although the herd was usually spending 5-8 days in each field with no back fence (rotational ‘set-stocking’ as my NZ advisor called it). The few simple, but really key parts, we were missing out were the accuracy of our grass allocation and protecting the re-growth with a simple electric fence. Allocating daily feeds of grass accurately and then protecting the re-growth of previously grazed areas with a back-fence immediately rewarded us with increased grass growth of around 30%. The milking herd, then around 100 cows, was allocated a 12 or 24 hour block of grass that would fully feed them, grazing the pasture cover down to around 1600kg/DM per hectare. Once the available grass had been removed, no further access was then allowed until the area had re-grown to its optimum stage of three full leaves (ryegrass) in around three weeks. This allows the plant to recover and regenerate its reserves.
The weekly farm walk soon became the most important job of the week as the entire efficiency of the business now hinged on growing and utilising high quality grass. We estimated historically we had been growing around 10 – 12 tonnes of grass dry matter per hectare and utilising 8 or 9 tonnes. It took us probably five years, but we gradually perfected our grazing skills and today we consistently grow, on average, over 16 tonnes of grass dry matter per hectare, utilising over 13 tonnes. It’s important to realise that very little reseeding was carried out to achieve this initial increase, and today the farm’s ryegrass and white clover lays have an average age of over 25 years.
The production potential of a dairy cow is directly related to the quality of the food she is eating: feed her a poor diet and she soon becomes unproductive and uneconomical. Understanding the value of high quality grass is the most essential part of being a profitable grass-based dairy farmer. It’s very simple – the more high quality grass a cow can eat, the better the chance of making a profit. High-input confinement dairy systems rely on measuring, weighing, balancing and delivering consistent diets on a daily basis, so why would grass systems be any different?
Over the past 40 years, conventional dairy wisdom has moved towards higher yielding Northern hemisphere genetics. As a result, we’ve seen grass become less valued, sometimes replaced by whole-crop cereals or maize in an attempt to cater for the high output genetics. One of the apparent consequences of the recent crash in dairy prices has been the welcome return of cows out grazing as producers attempt to reduce production costs.
A major weakness of our system is our heavy use of inorganic Nitrogen to promote grass growth. Although our use of N hasn’t increased over the years and it’s obvious we’re making better use of it than in the past, I found it fascinating to learn from Joel Salatin how much grass he is producing with no chemical inputs. If we could get even close to Joel’s productivity without the purchase of any chemical inputs, this would have a significant impact on our profitability. We currently operate both dairy units at a stocking rate of around 2.5 livestock units per hectare (1cow/acre). At this rate we can carry the stock though the grazing season, while also producing sufficient stored forage for the winter period. My business relies on this level of productivity to remain economic and at present the return on the chemical inputs of Nitrogen justify their use. My challenge is to reduce, or even ultimately remove, Nitrogen without going out of business. Joel has proven it is possible albeit on his farm in Virginia, so perhaps I need to make a trip to the States…
Photograph: Bruce Aldrige and Robert Craig