High sugar grass, what is it? Why the controversy? What does it mean for dairy cows?
What is high sugar grass?
First of all what is grass? It is not intended to go into a long winded scientific treatise on the subject, ‘Google’ will give an adequate cover of this! Suffice it to say that all grass species, especially those used as pasture in the New Zealand system of farming, are a natural feed stuff for herbivores, especially ruminants. Their growth pattern is unique in that the leaves grow from a crown at ground level allowing the leaves to be removed and as long as the crown is not damaged new leaves will grow. This of course assumes that all other plant requirements are met i.e. adequate water, sufficient nutrition, sunlight and that plants are not overgrazed by poor management practises to the point where the growing crown is damaged! Cows are not designed to eat clods of mud, in spite of what may be seen on some dairy farms!
Although basically any grass species can have the level of its water soluble carbohydrates (sugar) enhanced, perennial ryegrass including its various cultivars will be used to illustrate the points of interest in this discussion.
A definition and a distinction between the three basic methods are as follows:-
(1) Perennial Ryegrass genetically modified.
(2) Perennial Ryegrass bred to enhance the natural sugars.
(3) Perennial Ryegrass biologically enhanced.
Because of the unfortunate negative connotation put on anything genetically modified, number one will probably remain as an item of academic interest in the foreseeable future! Although don’t write it off.
Number two is at the moment the most viable system, with scientists and plant breeders putting a lot of money into, if you believe the advertising, what they claim are the most suitable cultivars for New Zealand conditions! Protecting their patch? The ‘AberDart’ controversy is a case in point. With scientists taking sides, who knows?
Number three is the most controversial! This is where scientists and farmers differ dramatically. Any farmer who dares to state that a certain regime has increased his milk solids and financial returns tends to be labelled ‘Green’ and his claims are written off as anecdotal. The catch cry from the scientific fraternity is where is the proof and the paper written up in a peer reviewed reputable journal? This is as it should be, up to a point. Have any of these critics ever looked into the claims made by farmers regarding gains made in production?
There is the usual problem with ‘Way out Claims’ made by people with a particular agenda, if their system is so good why aren’t they making millions on their own farm?
So what is High Sugar Grass ‘HSG’? You are probably aware that grass is largely composed of various ‘Sugars’ and their chemical derivatives manufactured during the process of photosynthesis. ‘Photosynthesis as defined by Wilkins 1988 is the process by which plants capture and package the energy in the sun’s rays. Further:- ‘It can be transported around the plant, to be released when and where it is required to do useful work, like driving chemical reactions. In practise, this involves storing the energy in chemical molecules that are stable, but that can, in the presence of appropriate enzymes, be broken down to release the energy they contain. It is also the means whereby the plant acquires, from the air, the carbon atoms that are the principal components of the molecules that make up its body.
Photosynthesis can be summarised as a chemical reaction in which carbon dioxide from the air and water, react to produce carbohydrate (sugar and starch) and oxygen according to the general equation:
CO2+H2O -------------- [CH2O]+O2
It must be remembered, however, that this is only part of the story, mixing carbon dioxide and water together doesn’t cause a suitable reaction, it requires light and chlorophyll in the green pigment of the leaf to complete’.
So where does the extra sugar in high sugar ryegrass come from? We can’t increase the sunlight available to the plant! We are supposedly increasing the carbon dioxide available (global warming and greenhouse gasses) in spite of this a normal plant can only produce and store a set amount of carbohydrate. What effect farm management practices i.e. Biological farming has on increasing water soluble carbohydrates is a moot point! Have they changed the sunlight available? ‘No’ Have they changed the carbon dioxide? No more than any other farmer. They may have changed the water and nutrients available to the grass roots by improving the soil conditions! This would still have to be proven! What other farming practises have they changed? This leaves us with plants with a natural high sugar content. Overseas researchers such as ‘IGER’ ( Institute of Grassland and Environmental Research) in the United Kingdom have bred cultivars from naturally occurring high sugar ryegrass specimens from alpine areas in Europe.( see Moorby 2001). Do we assume that the New Zealand bred equivalents have originated from a similar type already present in New Zealand?
There is still doubt in scientific circles regarding the benefits of HSG. An article written by Jacqueline Rowarth, in the spring 2007 issue of ‘Grasslands News’ pages 3- 4, sets out rather succinctly the problems surrounding the controversy over the use of grass bred with a higher water soluble carbohydrate level. This controversy has unfortunately led to sides being taken over the suitability of various cultivars for New Zealand conditions. Vis-à-vis Dr. Jock Allison’s defence of the AberHSG system in rebuttal to a section in ‘Pasture and Forage Plants for New Zealand’ by Drs. Deric Charlton and Alan Stewart published by NZGA in October 2006. As Dr. Rowarth rightly points out at the end of her article: - ‘More Research is Needed. It Always Is’.
Is HSG more palatable to ruminants? We don’t know for sure, there are conflicting opinions, we can’t ask the cow! We could conduct field trials, unfortunately nobody appears ready to spend the money! Does it improve the ratio between grass derived nitrogen (as protein) and the soluble carbohydrates, in other words by increasing the percentage of sugar in relationship to protein in feedstuff does this in fact decrease the losses of nitrogen to the atmosphere (ammonia and nitrous oxide) and water (nitrate) to the soil? see Richard Dewhurst’s paper ‘Manipulating cow diets to reduce nutrient wastage to the environment.’(which is available on the internet) setting out the problems. This should be read in its entirety, it is one of the better explanations I have seen.
If all farmers became ‘Eco-friendly’ over night, would it make much difference to greenhouse gas emissions? The proponents of biological farming would have us believe yes! Is it not time for scientists to conduct trials into the usefulness of these alternatives instead of just writing the claims off as some form of ‘snake oil science’ not worthy of comment? They might just learn something useful!
Assuming that a farmer is convinced that a high sugar ryegrass cultivar is the right system for his farm, how does he monitor the sugar content? Expensive laboratory testing, milk solid returns from his dairy company printout, or is there a place for the brix meter with its proponents and exponents about evenly divided! Is it not time that its usefulness as a farming tool was genuinely tested? Not written off as a useless gimmick, as has been done in some circles!
What fertiliser regime is recommended? To get the proposed benefits, it would appear that any of the quick fix, immediate return high nitrogen based fertilisers would be out! Urea is a relatively slow release nitrogen source and although its use would be curtailed it may still have a place. What about more natural fertilisers? Is there a genuine basis for the claims made by the proponents of biological farming? Shouldn’t they be put to the test? There may be some really useful ideas in organic farming! It can’t hurt to find out.
Although Nick Smith (see article The New Zealand Farmers Weekly page 15 December 2009) as minister, has put the damper on carbon credit trading for farmers in the near future, should we not be at least planning ahead for when and if it does become a viable option? How are you going to provide a quantifiable carbon sink on your farm? If we plant clover or other legumes with rye grass to provide a useful alternative source of nitrate, what effect does this have on the ratio between carbohydrates and protein in the ruminant digestion? Are we not too dependant on rye grass? Should we be looking more closely at alternative plant species i.e. chicory, plantains, even some of the more drought resistant Mediterranean species, Australian species? Plants with anthelmintic properties to overcome at least some of the drug resistance in ruminant parasite species?
What do you think should be done? Push your farm advisor and ask questions at farmers field days! Nobody knows all the answers. Let us know on this Blog site! Who knows you could end up with a winner! Look at all the alternatives, don’t slavishly follow the herd!
Literature Cited.
Dewhurst, R. Agriculture and Life Sciences Division, Lincoln University, Canterbury, New Zealand. Posted on the Internet, no date given.
McNicholas, M. 2009. Not ready for carbon farms. The New Zealand Farmers Weekly. Vol.8, 48, 15.
Rowarth, J. 2007. HSG: the discussion continues. Grassland News. New Zealand Grassland Assoc. published on the Internet. P 3-4.
Wilkins, M. 1988. Plantwatching: How plants live, feel and work. Macmillan. London. 207pp.
What is high sugar grass?
First of all what is grass? It is not intended to go into a long winded scientific treatise on the subject, ‘Google’ will give an adequate cover of this! Suffice it to say that all grass species, especially those used as pasture in the New Zealand system of farming, are a natural feed stuff for herbivores, especially ruminants. Their growth pattern is unique in that the leaves grow from a crown at ground level allowing the leaves to be removed and as long as the crown is not damaged new leaves will grow. This of course assumes that all other plant requirements are met i.e. adequate water, sufficient nutrition, sunlight and that plants are not overgrazed by poor management practises to the point where the growing crown is damaged! Cows are not designed to eat clods of mud, in spite of what may be seen on some dairy farms!
Although basically any grass species can have the level of its water soluble carbohydrates (sugar) enhanced, perennial ryegrass including its various cultivars will be used to illustrate the points of interest in this discussion.
A definition and a distinction between the three basic methods are as follows:-
(1) Perennial Ryegrass genetically modified.
(2) Perennial Ryegrass bred to enhance the natural sugars.
(3) Perennial Ryegrass biologically enhanced.
Because of the unfortunate negative connotation put on anything genetically modified, number one will probably remain as an item of academic interest in the foreseeable future! Although don’t write it off.
Number two is at the moment the most viable system, with scientists and plant breeders putting a lot of money into, if you believe the advertising, what they claim are the most suitable cultivars for New Zealand conditions! Protecting their patch? The ‘AberDart’ controversy is a case in point. With scientists taking sides, who knows?
Number three is the most controversial! This is where scientists and farmers differ dramatically. Any farmer who dares to state that a certain regime has increased his milk solids and financial returns tends to be labelled ‘Green’ and his claims are written off as anecdotal. The catch cry from the scientific fraternity is where is the proof and the paper written up in a peer reviewed reputable journal? This is as it should be, up to a point. Have any of these critics ever looked into the claims made by farmers regarding gains made in production?
There is the usual problem with ‘Way out Claims’ made by people with a particular agenda, if their system is so good why aren’t they making millions on their own farm?
So what is High Sugar Grass ‘HSG’? You are probably aware that grass is largely composed of various ‘Sugars’ and their chemical derivatives manufactured during the process of photosynthesis. ‘Photosynthesis as defined by Wilkins 1988 is the process by which plants capture and package the energy in the sun’s rays. Further:- ‘It can be transported around the plant, to be released when and where it is required to do useful work, like driving chemical reactions. In practise, this involves storing the energy in chemical molecules that are stable, but that can, in the presence of appropriate enzymes, be broken down to release the energy they contain. It is also the means whereby the plant acquires, from the air, the carbon atoms that are the principal components of the molecules that make up its body.
Photosynthesis can be summarised as a chemical reaction in which carbon dioxide from the air and water, react to produce carbohydrate (sugar and starch) and oxygen according to the general equation:
CO2+H2O -------------- [CH2O]+O2
It must be remembered, however, that this is only part of the story, mixing carbon dioxide and water together doesn’t cause a suitable reaction, it requires light and chlorophyll in the green pigment of the leaf to complete’.
So where does the extra sugar in high sugar ryegrass come from? We can’t increase the sunlight available to the plant! We are supposedly increasing the carbon dioxide available (global warming and greenhouse gasses) in spite of this a normal plant can only produce and store a set amount of carbohydrate. What effect farm management practices i.e. Biological farming has on increasing water soluble carbohydrates is a moot point! Have they changed the sunlight available? ‘No’ Have they changed the carbon dioxide? No more than any other farmer. They may have changed the water and nutrients available to the grass roots by improving the soil conditions! This would still have to be proven! What other farming practises have they changed? This leaves us with plants with a natural high sugar content. Overseas researchers such as ‘IGER’ ( Institute of Grassland and Environmental Research) in the United Kingdom have bred cultivars from naturally occurring high sugar ryegrass specimens from alpine areas in Europe.( see Moorby 2001). Do we assume that the New Zealand bred equivalents have originated from a similar type already present in New Zealand?
There is still doubt in scientific circles regarding the benefits of HSG. An article written by Jacqueline Rowarth, in the spring 2007 issue of ‘Grasslands News’ pages 3- 4, sets out rather succinctly the problems surrounding the controversy over the use of grass bred with a higher water soluble carbohydrate level. This controversy has unfortunately led to sides being taken over the suitability of various cultivars for New Zealand conditions. Vis-à-vis Dr. Jock Allison’s defence of the AberHSG system in rebuttal to a section in ‘Pasture and Forage Plants for New Zealand’ by Drs. Deric Charlton and Alan Stewart published by NZGA in October 2006. As Dr. Rowarth rightly points out at the end of her article: - ‘More Research is Needed. It Always Is’.
Is HSG more palatable to ruminants? We don’t know for sure, there are conflicting opinions, we can’t ask the cow! We could conduct field trials, unfortunately nobody appears ready to spend the money! Does it improve the ratio between grass derived nitrogen (as protein) and the soluble carbohydrates, in other words by increasing the percentage of sugar in relationship to protein in feedstuff does this in fact decrease the losses of nitrogen to the atmosphere (ammonia and nitrous oxide) and water (nitrate) to the soil? see Richard Dewhurst’s paper ‘Manipulating cow diets to reduce nutrient wastage to the environment.’(which is available on the internet) setting out the problems. This should be read in its entirety, it is one of the better explanations I have seen.
If all farmers became ‘Eco-friendly’ over night, would it make much difference to greenhouse gas emissions? The proponents of biological farming would have us believe yes! Is it not time for scientists to conduct trials into the usefulness of these alternatives instead of just writing the claims off as some form of ‘snake oil science’ not worthy of comment? They might just learn something useful!
Assuming that a farmer is convinced that a high sugar ryegrass cultivar is the right system for his farm, how does he monitor the sugar content? Expensive laboratory testing, milk solid returns from his dairy company printout, or is there a place for the brix meter with its proponents and exponents about evenly divided! Is it not time that its usefulness as a farming tool was genuinely tested? Not written off as a useless gimmick, as has been done in some circles!
What fertiliser regime is recommended? To get the proposed benefits, it would appear that any of the quick fix, immediate return high nitrogen based fertilisers would be out! Urea is a relatively slow release nitrogen source and although its use would be curtailed it may still have a place. What about more natural fertilisers? Is there a genuine basis for the claims made by the proponents of biological farming? Shouldn’t they be put to the test? There may be some really useful ideas in organic farming! It can’t hurt to find out.
Although Nick Smith (see article The New Zealand Farmers Weekly page 15 December 2009) as minister, has put the damper on carbon credit trading for farmers in the near future, should we not be at least planning ahead for when and if it does become a viable option? How are you going to provide a quantifiable carbon sink on your farm? If we plant clover or other legumes with rye grass to provide a useful alternative source of nitrate, what effect does this have on the ratio between carbohydrates and protein in the ruminant digestion? Are we not too dependant on rye grass? Should we be looking more closely at alternative plant species i.e. chicory, plantains, even some of the more drought resistant Mediterranean species, Australian species? Plants with anthelmintic properties to overcome at least some of the drug resistance in ruminant parasite species?
What do you think should be done? Push your farm advisor and ask questions at farmers field days! Nobody knows all the answers. Let us know on this Blog site! Who knows you could end up with a winner! Look at all the alternatives, don’t slavishly follow the herd!
Literature Cited.
Dewhurst, R. Agriculture and Life Sciences Division, Lincoln University, Canterbury, New Zealand. Posted on the Internet, no date given.
McNicholas, M. 2009. Not ready for carbon farms. The New Zealand Farmers Weekly. Vol.8, 48, 15.
Rowarth, J. 2007. HSG: the discussion continues. Grassland News. New Zealand Grassland Assoc. published on the Internet. P 3-4.
Wilkins, M. 1988. Plantwatching: How plants live, feel and work. Macmillan. London. 207pp.
Comment