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Sweeter forage grasses may benefit milk production

Different classes of livestock can make better use of forage mix

Spring is the time of rebirth. This year our livestock is not scheduled for babies till late spring so we have more time than usual to study, read, and plan our 2018 pasture season. While reading over garden catalogues my mind keeps turning to old ideas of turnip grazing, mangels (large beet) or potato choppers. Some of these plants would never be utilized as hay; but maybe for pasture?

We pasture cattle, sheep and goats. Studies show that goats prefer to browse on brush rather than on grass. Their preference would be a diet that was about 60 per cent browse and 40 per cent grass in mixed-plant populations. This makes them a great addition to our bush pastures. The sheep and cattle are both grazers, though they do complement each other because the sheep are more useful for cleaning up weedy spots the cattle will just leave behind. The sheep might nibble on a piece of brush but it would not be a big part of their diet. With this knowledge in hand a continual effort has been made to improve our pastures and place livestock where their needs are best met.

Last fall a tour of the pastures found the undergrazed areas tended to contain plants that the sheep or goats would have been happy to use, but which the cows left behind. A European visitor suggested in his country they would heavily apply compost both in the fall and again in the spring. He said that this would help to add many nutrients to the soil as well as introduce elements that preferred plant species need to thrive. This would probably be a good pasture to apply some of the compost we’ve made from manure/bedding/feed materials. It is suitable for use on pastureland.

Turning grass to sugar

Understanding how a ruminant uses grasses has also helped us to better utilize pastures. A lactating ruminant needs to be producing as much milk as possible for her young to flourish, and is depending upon pasture grasses to produce that milk. Ruminants are relatively inefficient at converting grass proteins to milk proteins, with a conversion rate of 20-25 per cent. To increase the milk output, the sugar content of the grass must increase. New Zealand research by IGER Innovations in 2001 suggested that high sugar grass content on the farm has a positive effect on the amount and quality of the milk produced. This is very important to meat producers.

The rumen of the animals breaks down the grass, producing amino acids that in turn produce protein which is later used for milk production. However when the diet lacks readily available energy such as sugars, rumen microbes either cannot grow, or, instead use amino acids to provide energy, meaning less milk production.

Feeding energy-rich foods in a concentrate feed is one way to increase the efficiency of the rumen, but the cheaper way is to use the natural sugars in forages. This is especially true in the warm months when animals are on pasture. Some producers use creep feeders on their pastures. We are trying to avoid this. We do not produce grain on our farm so creep feeding is an added expense. According to these researchers, by improving the quality of the grasses grown in our pastures the quality of the milk would increase.

Another reason that compost is such a great addition to pasture management, according to some research, is that the nitrogen fertilization will directly increase pasture growth. On the other hand, nitrogen application alone also significantly depresses the soluble carbohydrate levels. Research suggests this can reduce milk production. Another IGER Innovations study shows an eight per cent increase in milk production from cows which were grazed on high-sugar ryegrasses.

The research also suggests that higher-sugar grasses increase animal performance, increase feed nitrogen utilization, and reduce nitrogen excretion, but this has yet to be totally proven. How this will affect our native grasses no one is sure but it is exciting to watch what will happen next!

Now there is an electric fence around over half our pasture there is also more opportunity to start utilizing strip grazing, mob grazing, and other grazing systems. The possibilities are endless.

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