I really enjoy being out on farms at this time of the year. In northern NSW and parts of southern Queensland there are plenty of little calves in paddocks. I love seeing calves grouped up in nurseries, watched over by an older cow.
When you see this, you know that the cows are off grazing, or possibly watering, and they will be back to let their calves get some milk shortly.
Grazing time is vital for lactating cows. When a calf is born, a cows daily energy intake doubles.
Its vital that a cow gets adequate energy from her diet in order to produce enough milk for her new calf.
Spring calving can be a challenging time for cows, as the supply of feed can be quite limited.
In many cases the extra energy cows need will come from a combination of daily feed intake and metabolising body fat.
I reckon its really hard to stop cows losing weight after calving. Most pastures, particularly semi improved or native pastures won't contain the energy or the protein lactating cows need. Using body fat will help address the deficit and ensure milk supply to the calf.
The trouble with using body reserves is the flow on effect on the cows returning to oestrus for joining in late spring or early summer. A big loss in body reserves will delay the cow returning to oestrus, and this can impact on your herd fertility levels.
So just how much feed do your lactating cows need? This will depend on the live weight of your cows. Bigger cows need more energy for their own maintenance as well as for their milk production requirements.
To give you a basic idea, a 440 kg lactating cow requires a daily intake of 100 MJ ME and 700g of Crude Protein.
Heavier cows will need more than this!
Knowing what your cows need is just part of the challenge. You need to know what your pastures can provide.
For example a pasture comprised of Phalaris & Clover should have around 10 MJ/Kg & about 140g CP/Kg.
If that 440kg cow ate 10kg of this pasture daily, her requirements should be met, and you wouldn't see too much wight loss, or issues with fertility later on.
This is all very good in theory. In practice the quality of feed at winter, the amount of feed and the intake of your cows will vary. I reckon the best thing you can do is recognise your cows need a lot of energy and be prepared to closely monitor your cows & their feed intake and be prepared to intervene with some supplements if you think the pastures are not providing all your cows require. Intervention with supplements or moving to better pastures may prevent more costly losses later on with lower herd fertility.
Don't forget, if you have any questions after reading this, or about how to manage your cows during this time, you can always contact me for some advice.
