Managing hill country pasture quality

Here at neXtgen Agri, we are fairly focused on breeding and genetics, and using these tools to improve productivity and profitability on-farm. But having great genetics in your animals is only half of the equation. You also have to provide them with the environment that allows them to truly express their genetic potential. 

Keen to learn more about providing animals with the best nutrition to make the most of their genetics, I recently attended a Beef + Lamb workshop where Rob Stratton shared insights about altering stock management to improve hill-country pasture quality. The workshop was held on a case farm, where Rob has been mentoring the farm owner for the last four years, and showed the progress they’ve made by changing how they manage their property, without increasing their cost structure. 

For hill country properties, with areas that a tractor can’t access, what are the options? Well, a key takeaway message was the importance of doing the basics well, and the rest will follow. The focus was on management strategies to reduce the rank dead matter or less digestible reproductive parts of the plant in the first instance, then on how to prevent them from reforming, allowing quality pasture to grow, and increasing the available energy content of the pasture per hectare. 

Matching seasonal pasture supply and demand

We all know the figure below that depicts an average farm’s pasture supply and demand profiles. The aim, in this very unpredictable and highly changeable environment, is to manage your feed demand to be as close as possible to that supply line. Easy, right? 

As mentioned, this is based on hill country pastures, where you can’t use a tractor, so the idea of making hay in a surplus and feeding hay in a deficit isn’t an option. If you can’t turn that feed surplus in the spring into a supplement to feed out during the winter, what can you do with it? And, more importantly, why does this matter? 

First, we need to have a bit of a look at the feed demands of our livestock, as well as pasture quality. 

Livestock energy requirements and pasture quality 

Having an understanding of not just the amount of pasture that you have, but the quality of that pasture, will help you get a better feel for what your actual feed supply looks like. We all know that clover has a high metabolisable energy (ME) content, while seedhead, stalk and dead matter have a very low ME content. Knowing the pasture composition in your paddocks will help you identify the ME value your pasture offers to your stock. Young stock in particular have issues processing or breaking down feeds that have an ME content lower than 9 MJME, while your older stock have more ability to do so. As the proportion of fresh leafy greens and clover increases in your pasture, dead matter decreases, and there is more ME. As the ME of the pasture increases, the dry matter requirement of the animal decreases.

Everyone is encouraged to go out and look at their paddocks every month to get an idea of what is going on. Make sure you go through the paddock, not just stand in the gateway, and actually pick some pasture. When you have picked it and actually put it in your hand, you can get a good feel for what your stock will be getting in every bite. The reality of what is there might surprise you!

What does this look like in practice?

• A 65 kg ewe needs 10.5 MJ of ME per day for maintenance. Given pasture with an ME of 12, her intake is 0.875 kg of dry matter, but at an ME of 9, she needs 1.16 kg of dry matter, a difference of 0.285 kg/ewe/day. Multiply that out by 3000 ewes, and that’s 855 kgDM/day or over 25 tonnes of DM a month.
• Pregnant ewes need more energy to grow their lambs as the pregnancy goes on. At the same time, those growing lambs are decreasing her gut capacity. The higher the ME content in her feed, the easier it is for that ewe to meet her energy needs for the day. This is especially important for flocks with high instances of multiples, especially triplets. During the later stages of pregnancy, ewes are also developing their mammary tissues, setting peak milk production potentials. If mammary development is inadequate during this time, it won’t matter how much feed they have during the lactation period, milk production will be lower. 
• After peak milk production, the lambs start to obtain more and more of their energy from pasture. Good quality, high ME, pastures allow greater rates of lamb growth. 
• Getting a 35 kg male lamb to grow at 300 grams per day takes 18 MJ of ME per day. If that lamb is grazing pasture with an ME content of 9, the lamb needs to consume 2 kgDM/day to fulfil that requirement. If that pasture has an ME content of 12, the lamb only needs 1.5 kgDM/day. 

The same relationships with feed supply and quality are seen with beef cattle. So, how do we create better pasture quality on hill country? 

Turning rank feed into good feed

It is common to see plenty of brown looking pasture out on hills throughout the year. This is caused by a surplus of feed being produced but not being utilised during its highest quality time. This then starts to die off and produce reproductive stems and seed heads that have low nutritional value. We all know that the best tool for managing this pasture is a breeding cow unit, but this can push the cows, resulting in poorer calves at weaning. Nitrogen is another good tool that helps two-fold. New pasture growth is promoted with N application, but the nitrogen also helps to break down the dead matter faster (allowing more new growth to occur). Chemical topping may also be an option to stop the pasture from bolting away. 

The earlier you get on top of that pasture surplus, the better off you are. Without the dead matter over-crowding the sward, more growth of new, high-ME leaf is promoted. Removing the overcrowding from a longer, lower ME sward will also allow clover to make its way back into the picture. Ideally, you want grazing covers to be between about 1200-1600 (or 1800 in the summer/autumn) kgDM/ha, to allow quality grass to continue to grow, while not overcrowding the clover population. In New Zealand, getting the clean-up happening in November/December (depending on the area) during that pasture peak is the key to preventing that brown matter buildup and encouraging more fresh growth. “Don’t wait for the horse to bolt and then try and catch it. Tie the damn thing up before it gets away,” sums things up nicely.

Tips for maintaining high-quality pasture on hill country

Making your demand go up to match the supply can be tricky at times, but there are a few ways to maintain quality grass: 

• Alter lambing and calving dates to match your feed supply.
• Alter weaning dates according to what the season is telling you.
• Mate ewe lambs to increase feed demand in the spring.
• Buy in trade stock.
• Manage your ewes and breeding cows together.
• While subdivision can make pasture management easier, fencing has a cost to it. 

The benefits of top-quality pasture

Big changes won’t happen overnight, but getting the rank pasture cleaned up allows more growth of better-quality pasture. Keeping on top of your pasture and not letting it get to that rank stage in future will bring about even more high-quality pasture growth. 

These are some observations from Rob after a few years of continuous improvement in pasture management:

• Less of a tail end in your mobs: Ewes and cows that are fed better quality feed are in better condition, and have better buffers to be able to deal with disease and other challenges that might reduce condition.

• ‍Better conception rates: We all know the effect body condition has on the number of ewes/cows scanned pregnant, and also correlates with the number of fetuses scanned per ewe. 

• Increased lamb survival:
  
  • A ewe that is able to achieve her daily energy requirements will be in better condition.
  • A better-conditioned ewe has more of an energy buffer if adverse weather occurs during lambing. Lambs that are fed well in utero are born bigger and are more likely to survive bad weather at birth.
  • And a ewe in better condition is more likely to stay at the birth site long enough to get her lambs up and fed before heading off in search of a fresh pick, whatever the weather. 
• Higher weaning weights of more lambs:
  
  • This means more lambs are sold off-mum at better weights.
  • At the start, this particular case farm was weaning around 3800 lambs at an average of about 27 kg – resulting in around 102,000 kg of lamb weaned. After four years of managing their pastures to maximise quality, they weaned around 4300 lambs at 32 kg average, resulting in around 137,000 kg of lamb weaned. At $4/kg lwt, that’s an increase of $140,000, without changing ewe numbers.
• ‍Higher-yielding lambs: Lambs fed better quality pasture yield better.

• Fewer tail-end lambs at weaning: The ewes and lambs are all in better condition, so fewer poor lambs appear.

• Successful hogget and heifer mating:
  
  • Getting young females up to mating weights can be a challenge.
  • This farm was initially mating around 180-200 hoggets, but better pasture quality in the summer/autumn led them to get to 600-700 hoggets mated.
• Earlier springs: Quality pasture grows more quality pasture if managed well. Having better quality pasture on-farm year-round meant that the spring flush actually started to take off earlier.

• Better grass growth out of dry summers. And the growth that was occurring was of higher quality.

• Better autumn grass growth. Again, quality pasture grows more quality pasture.

• More clover in the hill country sward. Clover is also nitrogen-fixing, so as the clover content comes back, more nitrogen is fixed into the soil, promoting even more quality pasture growth.

• More kg of DM grown overall: Greater quality and more of it.

• Faster growing stock: The faster a terminal animal grows, the less maintenance energy it requires, due to fewer days on farm, increasing feed availability to other stock classes too.

Take-home messages

With all of these benefits to productivity and profitability, what have you got to lose? 

One of the key messages that Rob did make clear was to make sure that your expectations are realistic – the initial push to get the pastures cleaned up in the first place can have quite a negative effect on the breeding cow, so make sure to take it slow at first. Getting to the point that pastures are cleaned up enough to have some lasting benefits from above may take multiple years, and you might need to be prepared to see a poorer weaning weight result from the cow herd in the first instance. Remember, you are using these cows as a tool as well as a breeding unit, and the work she is doing for you is much more valuable than the loss in production you see for a short period of time. 

Once you get to a state where pasture quality is taking off on-farm, you might need to adjust your policies. That feed supply graph will be changing, you need to continue to shift the demands to meet where the supply is sitting. Getting on top of feed before it becomes too much of a surplus is the key to retaining quality. 

Set goals of what you want to achieve, but keep them simple. You want to nail the basics before adding in more complexity. Once you start to tick these goals off, you can get more sophisticated with your approach OR enjoy having more of a lifestyle. The beauty in farming is that every farm, year and farmer is different, and you really get to make it your own. Having the tools to help you make the most of it is a huge plus. And, circling back to where we began, setting up an environment that allows your stock to fully express their genetic potential has massive benefits for the whole enterprise. 

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Join the conversation on The Hub

Take a moment to head over to the neXtgen Agri Hub to share your thoughts on managing hill country pasture quality. What has worked well on your farm? What has changed in the way you manage your hill country blocks?

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Further information

For more information about the energy requirements of your stock, see A.M. Nicol and I.M. Brooks (2007) Pastures and Supplements for Grazing Animals. Edited by PV Rattray, IM Brooks & AM Nicol, New Zealand Society of Animal Production.

If you are interested in chatting further with Rob about hill country pasture management, send Emma Pettigrew a message on The Hub.