Phil Shannon, DPI Cobram
This article is based on information from the 'Feeding Pastures For Profit' program.
The focus of this article is practical pasture-based feeding of milking cows over summer. There are two key management issues over the summer months – growing and offering cows quality pasture and getting cows to eat feed when the weather gets hot. Profitable feeding is about achieving the balance between 'hectare efficiency' (pasture consumption) and 'cow efficiency' (milk solids production). Profitable and efficient feeding is the result of understanding and controlling this balance.
Let's deal with pasture first. Even with our best management efforts, average pasture quality declines over the summer compared to autumn and winter. Ryegrass/clover dominant pastures still produce high quality feed but quantity becomes an issue as growth rates slow down in the hotter conditions. Paspalum/ clover dominant pastures can produce a lot of quantity – but the quality can drop quickly if it is allowed to get out of control and become rank. To get the most from the pasture base you need to be able to control rotation length and the amount offered to the herd each grazing.
Rotation length is the practical way we control quality. We can't change the species in a paddock without some major works like re-sowing, so we need to have the skill to manage the dominant species. The summer challenge is most farms will have a combination of ryegrass/clover dominant paddocks and paspalum/clover dominant paddocks – and both need different grazing management.
With ryegrass dominant paddocks we should still use the leaf principle over the summer. Generally ryegrass plants achieve the best balance between quality and quantity if we let the plants grow out to the 2 to 3-leaf stage (approximately 30 days over summer). The only time we would break from this is if rust is starting to affect the paddock. If rust is building up then you are better off to graze the pasture than to let the plants get to the right leaf stage (graze it before the rust has too much impact on quality and therefore intake).
Paspalum dominant paddocks need to be offered to the herd when they are leafy. The basic grazing principles still apply. If you graze too early you may have higher quality but will miss out on a lot of quantity. If you graze too late quality may drop too far and the cows may refuse to eat it. If you operate at either end of the scale you will reduce your profit.
The key message with pasture is you need a system that allows you to be able to allocate the herd pasture that is at the right stage for grazing. The Feeding Pastures For Profit program provides farmers with the 'Rotation Right' tool and the underpinning knowledge that puts you in control of when and where the cows will graze. You can easily and practically manage both paspalum paddocks on a shorter grazing interval, while managing ryegrass dominant paddocks on a longer rotation.
Feeding the herd is all about getting the right balance between pasture consumed and supplement use. If we are in control of pasture quality and pasture allocation then the job is a lot easier. If we have a method of minimising the variation in pasture quality and quantity from 'feed to feed', then we can be more consistent and confident with our supplement use. However, if the cows are going from feast to famine as they rotate around the farm and are being offered 'out of control passy' at one grazing and then short ryegrass pastures at the next then your supplement use is only guess work.
The Rotation Right tool helps minimise the variation, and puts you in control of feeding. The tool is provided to all farmers who participate in a Feeding Pastures For Profit program. When using the tool you can more confidently predict the marginal response to the last unit of supplement – and this skill is critical to achieving profitable feeding.
If we have pasture management under control the next biggest feeding challenge over the hot summer months is managing the periods of extreme heat.
Cows are like us – they don't feel like eating when it is hot and they need more energy to help them cool themselves. The key is to remember that 'intake drives production'. If the heat causes cows to stop eating you must take some action. Our job is to do everything we can to make them want to eat. Most of this focus is around keeping the cow cool.
Pasture quality is critical during those extremely hot periods. As long as you are controlling the rotation you will control quality. If we do have some ryegrass dominant pasture then it may be best to offer this to the herd during periods of extreme heat.
Don't expect miracles on those really hot days. During these periods paspalum may be growing at it's fastest and yet the cows won't want to eat as much of it. In order to control waste you may need to offer them a smaller area of paspalum during the hot periods, but you will then need to offer them a bigger area after the heat in order to get the rotation back on track. Alternatively you could offer them a bit more pasture in the days leading up to the extreme heat period. The Rotation Right tool can help you confidently manage this.
Other pasture tips include offering the cows a larger part of their daily allocation at night as they are more likely to graze harder at night when it is cooler. Cows can be kept cool by using shade and/or sprinklers. The best cooling is provided by sprinklers and shade from a corrugated iron roof, but any level of cooling will make a difference.
Milking times can be altered if this allows you to cool cows more effectively at the shed, or to give cows access to the pasture at the cooler times of the day when they are more likely to choose to eat it. The choice of milking time should be made in conjunction with the other feeding and cooling strategies being used.
It is critical cows always have access to plenty of quality drinking water. How do you feel on a hot day when you haven't drunk enough water?
Supplement use also plays a very important role. If it is too hot for the cows to graze the open pasture then it may be far more profitable to feed them supplement in a shady area during the heat of the day. Their daily pasture allocation can then be offered to the herd at night when they are more likely to eat it. Remember cows can only produce milk if they are fed.
Feeding a higher portion of concentrate and a lower proportion of roughage is said to help reduce heat loading on the cow. However this only works if the cow can dissipate her heat load. For high production cows, if cooling is not provided and the temperature is above 26°C, then extra concentrate may not help to maintain production.
For more information and tips on reducing and managing heat stress in dairy cows, visit the cool cows website, www.coolcows.com.au.
In summary, maintain pasture quality by controlling rotation length, do your best to keep cows cool, monitor milk production as a simple indicator of how the cows are feeling, and take the appropriate action to get cows back on track after those periods of extreme heat.
For more information on the Feeding Pastures For Profit program please contact Tom Farran, DPI Tatura, telephone (03) 5833 5297.