March 2011 for web.indd - OVK

Between 65 % and 90 % of the protein content of
pastures is rumen degradable protein (RDP) and in
itself poses a problem for especially younger animals.
A younger animal needs more undegradable protein
(UDP) or as it is commonly known, natural protein.
To get the best results on pasture, the quantity and
quality must be good and that poses a problem,
be cause either the quality, as shown in the previous
para graph, or the quantity is lacking.
In summer or on rye grass pasture the moisture content
is so high that the steer cannot take in enough
dry matter. This will result in lower than expected
per formances. This occur more on natural pastures
and there fore the performance is better on irrigated
pastures. The performance on natural pastures in -
creases from east to west in South Africa.
If a farmer decides to fatten off the pastures, it is very
important to select the best animal, as this will influence
the outcome dramatically. Early maturing animals do
bet ter than late maturing animals. The weight of the
animal at the start of the feeding period is of utmost
im portance, because if the steer is too small at the
be ginning it will not fatten in the appropriate time. The
best weight to start feeding a steer is shown in table 2.
Table 2: Ideal starting weights for steers on
na tural pastures.
39
Type of animal Starting weight
Small frame animal
Medium frame animal
Large frame animal
240 kg
265 kg
290 kg
It is also important to remember that crossbred animals
do better because of the effect of hybrid vigor. Well selected
purebred animals do as well. The use of long weaners
also improves the performance because of the lack of
weaning shock and the effect of compensatory growth.
There is also a difference in performance between
heifers, steers and bulls. Heifers tend to fatten faster,
but their growth rate is lower and they therefore have
a lower carcass mass. Bull calves do grow a lot better
than steers and heifers but they tend to fatten slower
and most of the time they need to be fed in a feedlot to
fat ten them properly.
Another problem arises when steers and heifers are fed
within the same group, because the heifer come into
estrus and this leads to the steers chasing them around
and a lot of growth goes a begging. The best way is to Contents •
separate the herd into gender and if possible frame size.
To improve performance further, it is also important to
manage the pastures to the optimum. High density Inhoud