Retired animal nutritionist Dave Short from Harrismith in the Free State believes that the inability of nutritional scientists and grassland…
Retired animal nutritionist Dave Short from Harrismith in the Free State believes that the inability of nutritional scientists and grassland scientists to work together is hampering animal production off the veld. Roelof Bezuidenhout reports.
There are huge opportunities for animal nutritionists to guide grassland scientists towards designing supplements that could transform grazing patterns on South Africs’s low-protein veld – in winter or summer. That’s the opinion of Dave Short, retired professional animal nutritionist from Harrismith in the Free State, whose interest in licks has been rekindled in discussions with his grassland scientist son.
Dave started his agricultural career at Gwebi College in Zimbabwe. He spent a lot of time formulating rations, using only a basic hand-held calculator and Frank Morrison’s book Feeds and Feeding. Dave worked on several ranches and a government research station, and then joined a large co-op that had its own feed mixing plant that produced some high quality feeds. Their nutritionist’s views on feeding and supplementation reflected what had been drummed into him at Gwebi – use different types of natural protein for ruminants and restrict the use of urea to low levels.
In 1980 Dave came to South Africa and joined a large feed company. He later moved to a much smaller firm where he was able to relate to the manager’s views on feeds. For 13 years he helped in the formulating and marketing of feeds and they fared extremely well against some very strong corporate opposition in the field.
Dave recently published an article in Grassroots, the Grassland Society of SA’s newsletter, discussing his conviction that grassland scientists and ruminant nutritionists should work together to the benefit of stock and range husbandry. “Every year the researchers do their trials – three camp, four camp, rest, spring graze, burn, no burn – and apply the licks presumably recommended by the animal feed department. These ineffective supplements, consisting of concoctions of urea and phosphates, and salt and lime in summer, are then fed at minimum rates for the shortest possible time.” Dave laments that every year production is about half of what it could be. He adds that at least six months of the year are spent just trying to keep the herds alive.
Trials on winter protein were first conducted 100 years ago. The protein at the time was fishmeal and it produced outstanding results. Dave says that urea then replaced some of the protein as a cheap substitute. “But it unfortunately usurped high-bypass natural protein and practically became the sole protein source. Now ‘government’ licks, developed on research stations and faithfully used, violate just about every principle of ruminant nutrition. They are toxic cocktails in which 95% of the protein comes from urea,” he explains.
The same applies to commercial licks in which molasses or a smattering of maize is used to disguise the urea. “Feeding rates are designed to keep animals just on or above malnutrition levels. Further, these dangerous supplements are fed too late and at too low a rate to have any real effect. High quality natural protein, fed at the right levels and for longer periods than recommended in the textbooks, can double performance on veld, while eliminating some of the negative effects of selective grazing,” Dave comments.
Urea has its purpose, but if it’s not blended correctly with high-bypass natural protein it may as well be thrown on to the ground. “That’s where most of it goes anyway, in the form of urine,” he says.
In suggesting a move away from the low-grade, low-performance cycle comprising a handful of urea and salt in winter, and a thimble of phosphate and salt in summer, Dave believes it’s time for nutritionists to go back to basics. He feels strongly that if the researchers have to go for the cheapest licks, they are doing themselves and the entire farming industry a disservice.
“If it’s possible to achieve a 500g gain per day on winter sourveld with a high natural protein/low urea lick, then research scientists should prove this. The economics come later. It may be that this year a specific lick would not be cost effective, but it could be next year, depending on the relative price of beef and lick constituents.”
If scientists were to collaborate in joint feed and grazing trials, Dave feels they would discover how much can be achieved in enhanced animal performance and better veld utilisation by combining a high-quality supplement with high-quality veld management.
He suggests the following rules of thumb, which he believes have been forgotten in the race to make the cheapest, nastiest supplements available:
No more than 33% of the protein should come from urea or other NPN (non-protein nitrogen) sources. That means 67% of the protein must come from high-bypass oilcake or fishmeal.
A true supplement is fed at a maximum of 5% to 10% of an animal’s dry matter (DM) intake. A DM intake of 3% of body weight would limit a 300kg long weaner to a maximum of 450g to 900g of supplement per day. Low levels of highly concentrated supplements ensure that the animal remains hungry. And as the only thing left for it to eat is grass, it will consume it in surprising quantities.
Half the animal’s protein needs should be derived from the supplement in winter. If a 300kg animal needs 700g of crude protein to keep up a reasonable growth rate, 350g must come from the supplement. So, the supplement must contain 450g/kg to 500g/ kg of crude protein. At this concentration, a long weaner would need 700g of supplement. But if only 33% of the protein can come from urea, the supplement is limited to about 5% urea, or 50g/kg in the lick.
In most of South Africa, veld is only good for growth for about six weeks of the year. Because of the inherently low protein content, it’s good for little else for the rest of the time. But if this high quality, highly concentrated protein supplement is fed at varying rates for most of the year, it will transform performance on veld to the level of performance on irrigated, fertilised pasture. This is because an animal that is fed the correct levels of the right quality protein will eat everything – including newspaper!
Biotechnological products (not to be confused with hormones or chemicals) can transform ruminant function. For example, ammonia-adsorbing feed supplements, initially derived from the yucca plant, have the ability to trap ammonia when mixed in animal feed at low levels. Used in pigs and poultry, they reduce the amount of toxic-free ammonia in the dung to the extent that in some countries feed companies use them to protect the health of farmworkers. The same additives in ruminant feeds can trap ammonia in the rumen, holding it for more effective digestion. The result is that any urea in the feed is used far more efficiently, as is the highly soluble protein found in most grasses.
Specialised living yeasts don’t occur naturally in the rumen, but when introduced in a supplement they stimulate rumen flora into feverish activity. Digestion of roughage increases, as does intake and performance.
Chelated trace minerals are trace elements bonded to protein molecules. They are more easily digested and better utilised than inorganic trace minerals. Replacing 30% to 50% of the inorganic trace elements in a lick with chelated trace elements will improve animal performance.
For more information contact Dave Short at firstname.lastname@example.org. |fw
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