Pasture Quality and Alternative Feeding

Based on an article by Tom Fraser, Lincoln University

It has always been a worry for sheep farmers that once lambs are weaned their growth rates will drop substantially, while it could be month's before you can get rid of them. In the meantime, the summer dry sets in, clovers disappear, palatability of the pasture drops and in the years that the conditions are right, Facial Eczema spores and other fungi on the rye grasses will be rising and causing further misery.

To postpone the inevitable some sheep farmers will wean their lambs as late as possible in the vain hope that the lambs will keep on growing at a faster rate. Recently published research results, in combination, have made it possible to do something about it.

If you want to put the results of this research into practice, you will have to act early in the spring and you have some month's to think about it.

Please read the Meat board's R & D briefs no. 57 and 63 and the following condensed results from a trial over several years by Prof. Tom Fraser of Lincoln university with different pasture species and different sheep breeds.

Its conclusion:

The most important time in a calendar year for the average sheep farmer are the seven weeks after the weaning of his lambs.

Read the above statement again, let it sink in. Here are the reasons (and there is nothing there that you did not already know) why those 50 days after weaning can make or break your farming year:

It is all about pasture quality, which has influence on:

  1. Live weight gain
  2. Animal health
  3. Reproduction

Pasture quality is determined by digestibility, efficiency of utilisation and daily intake.

Digestibility of pasture is the most important characteristic and is strongly influenced by plant composition. Grazing pastures contain: water (up to 90%), highly digestible cell walls (carbohydrates and proteins), minerals and vitamins and other compounds that may be good or bad. The practical implications are:

Other factors influencing pasture quality are:

Supply of digestible energy is the greatest nutritional limitation for the pasture fed animal.

Pastures with high digestibility also have the highest levels of intake and go through the animal faster. The trial proved that lambs which gained 295 grams a day from birth to weaning when fed a diet of chicory/clover or tall fescue/clover after weaning had a negligible interruption in growth rate of 290 grams a day, compared with a conventional rye grass/clover mixture which resulted in a drop to 150 grams a day. This means that you can halve the time normally needed to finish lambs, which in turn offers the opportunity to increase the feeding levels of the stock remaining on the farm, as well as financially improve the returns per hectare.

What Tom Fraser is saying is that there won't be many farmers that have digestive pasture problems in the spring from September to December when grass is lush and clover is plentiful. It is usually in the January to March period that there are problems, with lambs sitting in the shade refusing to eat and getting dirty.

You can alleviate the problem by putting 10% of your farm in a clover/chicory or tall fescue/clover crop, both of which have the added advantage of being fairly drought resistant.

By using chemical tillage, it won't cost an arm and leg and you don't have to use your easy paddocks. The whole exercise will be very cost effective and that's an important message!

The beauty of it all is that you get rid of surplus lambs before the onset of FE, giving the remaining stock a better chance of survival, a higher productivity rate and a second line of defense in bad FE years (the first being the use of FE tolerant rams). If your lambing percentage is over 130%, you can put half your ewe flock to a black face ram, further speeding up the growth rate.

Get yourself up to speed on how to treat these new types of pasture, since if you want them to last, they need different treatment then the rye grass/clover mixtures you are used to.

Think about it. Give it a go!

Further reading:"A guide to improved lamb growth, 400 plus" edited by Peter Kerr.

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