DAIRY 101 CONCENTRATES
Are supplements right for your farm? Story by: Karen Trebilcock
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o you’re feeding supplements but aren’t certain if you’re doing it as successfully as you could. Figuring out what is making money, and not costing it, will make sure you, your cows, and your bank manager, are happy. Feeding the right supplement for the right reasons is important and the gains will be seen in the vat, in the numbers of cows in calf, and the health of the calves when they’re born. However, there is still a lot of discussion about the merits of grass-feeding only. I have seen a photo, from memory taken in the United States, of what 18kg of grass drymatter looks like in spring. The pile towers over the cow in the picture. I would love to see it replicated in New Zealand. We expect a cow to stick that much grass down its throat and ruminate it and on top of that go through peak production, deal with the changeable weather, recover from calving, and get pregnant again. Supplementing spring pasture with its high moisture content and high protein with energy dense concentrates that take up little space in the rumen and are rapidly digested makes sense to many farmers. But it’s just not about looking at the metabolisable energy (MJ ME) a supplement contains and costing it on that. Many supplements also contain protein and that should be factored in as well. And there are times when it is protein, not energy, you need for your cows. Of the high energy supplements, maize grain is the top with 13.75MJ ME/kg DM (73% starch) along with 8% protein with wheat coming a close second with 13.5MJ ME (70% starch) and 12% protein. Barley is just behind them with 13MJ ME (about 68% starch) and 11% protein and sugar beet is 12MJ ME and 8% protein. 78
Palm kernel is high in fibre.
Molasses, usually fed with grain in inshed feeding systems, is a byproduct of the sugar industry and is high in energy mainly from sugars. It is also very palatable and can encourage the intake of less palatable feeds. It has 12MJ ME and 4.5% protein. Be careful feeding high energy supplements. While grass can be fed ad-lib, with the cows stuffing as much in as they can, don’t do the same with grain. Energy dense feeds are usually high in starches and sugars, which can cause acidosis. The starches and sugars cause propionic acid to be made in the rumen, which reduces the pH and burns the stomach lining. Give rumen microbes time to adapt to these feeds and limit how much they can eat. When summer pasture matures or when
the cow’s diet is mostly made up of whole crop silage, maize silage or poor-quality grass silage, protein dense concentrates is the answer. Soya oilcake is the Rolls-Royce of plant protein sources with 13MJ ME and 50% protein. It is a high protein and high energy feed – supplying both high quality protein and energy. It is very different from soya hulls, as reflected in the price. Canola oil cake is a byproduct from the canola (rape seed) oil industry and is 11.5MJ ME and 38% protein. Dried distiller’s grain (DDG) is a byproduct of making alcohol or ethanol. It is relatively high in both energy and protein, but low in starch, making it less of an acidosis risk. It’s also highly palatable, so helps with getting cows eating in spring, when pasture may be low in protein such as in
Dairy Exporter | www.nzfarmlife.co.nz | January 2021
