This study investigated the effect of different feed levels on the growth and development of Deutsche Bunte Edelziege goats at different developmental stages.
Sixty four (64) goat kids were split into four groups over three (3) feeding periods, with a control group fed at a high nutritional level over all three feeding periods (HHH), and a control group fed a diet with low nutritional level over the three feeding periods. (LLL).
The remaining two groups, were alternate diets; the HLH group was fed in the 1st period a diet of high nutritional value, in the 2nd period, a diet of low nutritional value, and in the 3rd period, once again, a diet of high nutritional value (HLH). The LLH group was fed in the 1st and 2nd period at a low nutritional level, and in the 3rd period at high nutritional level.
In so doing the four distinct groups (HHH ; LLL ; HLH ; LLH) were designed.
The duration of the first feeding period was eight (8) weeks.
At the age of one (1) week the animals were put into single feeding crates with straw bedding. During the 1st feeding period the group receiving the high nutritional diet was fed with 1000g milk per animal/day, and the group with the restricted diet was fed 600g milk per animal/day. Both groups received concentrates and water ad libitum.
After weaning the diet consisted of 100g of straw per animal/day and concentrate. The high nutritional group was fed at 2,4 times of maintenance requirement, and in the low nutritional feeding group at 1,4 times that of maintenance requirement. Water was provided ad libitum.
It was found that a milk reduction of 40% induced a 49% higher feed intake of concentrate. The lack of nutrients from the reduction of milk could not be compensated completely by the higher intake of concentrate.
The lower energy intake of the animals with a milk reduction (group L) caused a 19% lower daily gain, than the group with a higher energy intake (group H)
There was a 12% or 1,36kg difference in weight between the respective groups after the first feeding period (milk feeding period).
The growth of the goats was proportional to the energy intake, so there was no difference between group H and L in conversion of energy after the first feeding period (milk feeding period).
Groups exposed to a 4 week restriction or a 10 week restriction (HLH, LLH) showed significantly higher daily weight gain during realimentation of compared to the control group HHH.
A longer duration of restriction, caused an increased growth performance of the animals during realimentation.
A 4 week realimentation period was long enough for the goat kids to compensate the weight deficit from 4 week restriction; a 6 week realimentation was unsufficient to compensate for a 10 week restriction induced weight deficit.
At the end of the experiment there was a significant difference in live weights of 16% (HLH) and 30% (LLH) compared to the group HHH (P<0,05).
The duration of the restriction had an influence on the feed intake per metabolic liveweight.
After a 4 week restriction there was no difference in food intake between the groups HHH, HLH and LLH (p<0,05). After a 10 week restriction the animals of groups HLH & LLH needed 7 days to reach the level of food intake of the control animals of group HHH. Thereafter the feed intake of compensating animals was 9% higher than that of the HHH-control group. (p<0,05)
The higher growth performance of the compensating animals during realimentation induced in both experiments a better feed gross efficiency, while a comparison of the feed growth efficiency during the whole experiment, did not show any difference between the groups HHH, HLH & LLH. (p<0,05)
There was a significant influence restricted feeding on the development of the internal organs, especially the liver and the digestive tract. (p<0,05)
The goat kids in the first experiment showed after a 4 week nutrient restriction, followed by 4 weeks of realimentation, no differences in relative organ weights, and this indicates that they compensate completely. The group LLL showed significantly lower organ weights at the end of the experiment, compared to the g roups HHH, HLH & LLH. (p<0,005)
After a 10 week restriction, followed by a 6 week realimentation, the compensating animals of groups HLH and LLH had significantly higher relative weights of liver, stomach and small and large intestine, compared to the control group HHH (p<0,05)
There was an influence of the feeding level on the chemical composition of the body, especially on the organs of the goats. A nutrient restriction induced a higher water and protein content and a lower dry matter and fat content in the animals. These tendencies got stronger as the animal got lighter.
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