Late Summer News 2008
Supplements - late summer and autumn (March to May)
The grass is beginning to dry and we have not had the first frost yet. You'll find that grass is typically in that phase just before germination, so plumes have formed, and the plants are still green at the base. There is lots of dry material available, and the palatability of roughage is good. But you'll find reduced protein availability.
Nitrogen is the first primary limiting nutrient.
To a large extent, protein content is determined by the veld's physiological condition.
The younger and greener the plants, the higher the protein content.
Rumen degradable protein (RDP) is the primary need of ruminants. To optimise dry-matter intake and improve rumen fermentation, sheep need to consume approximately 3.30g/kg M 0.75 (0.12 of VOM) and cattle approximately 4.0g/kg.
This implies that the veld's RDP content has to be at least 8% or that a large-stock unit (LSUs typically weigh at least 450kg) has to consume approximately 390g RDP per day.
Dier massa |
RDP |
Behoefte |
Veld |
Tekort |
Inname |
| (M) |
(M0.75) |
(RDPx4g/kg) |
Verskaf |
(Behoefte - Veld) |
20% Prot |
180 kg |
49.14 |
197 |
183 |
14 |
75 |
450 kg |
97.7 |
391 |
337 |
54 |
270 |
600 kg |
121.23 |
485 |
421 |
64 |
320 |
As soon as the RDP percentage drops below 6 to 8,8%, the palatability will drop and the animal will graze less. When the RDP drops below 4%, the organisms in the rumen can no longer digest the grass and gallsickness will set in.
There is still lots of dry material and good energy available in the early-winter pastures, but the low RDP levels give way to a nitrogen shortage, which usually happens when proteins are broken down. When the organisms split, new cell-walls have to form to build up the animals' bodies, and this can only happen if the basic nutrients are present in the right ratio to be built into the cell walls. If there is a shortage of Nitrogen, the microbial organisms cannot grow. The organism population dwindles and can even die off under prolonged circimstances. This means that the grass the animal has been consuming takes longer to break down in the rumen. The animal will also end up eating less as there is simply too little space in the rumen and it will fill up.
The most practical way to determine whether the veld's protein content meets the needs of the micro-organisms in the rumen is to examine the cattle dung. If the dung becomes dryer and harder, it is time to switch.
If body condition prescribes the feed-management system, big mistakes can slip through that will be difficult to rectify during the harsh winter season ahead. When one can see deterioration in the body condition with the naked eye, the animal has already lost up to 20kg of body mass. The animals still consume enough grass at this stage for body mass to seem unchanged. At this point, a low level of protein supplement can make a big difference.
Late summer and autumn is also a good time to start preparing for winter diets. If protein licks are only supplied in winter, a craving for salt could result in the animals eating much too much of the licks. By supplying a lick in autumn, this problem can be eliminated in a safe way, and the animals can slowly get used to the salt and ureum content.
Biofos P4 is an ideal product to feed during the transition from P licks to winterlicks.
Bio-Minerale Biofos P4:
