The total number of trial groups during the growth period was 28, while a further 2 trails were run as reserves. During the egg production period, the performance of layer hybrids was studied in traditional cage system and in alternative system. During the laying period, the measurement of the 3-story Delta cages was 40x46 cm, the floor angle was 7 degrees.
Our goal was to add something extra to the birds' growth with the diet. The egg production data were recorded during the total study period daily and by the experimental group. The studies were only carried out in the afternoon and only with fresh eggs of the day.
Change in live weight (g) of pupal groups examined during the rearing period, depending on feeding treatment, genotype and age. Change in breast bone (sternum) length depending on age, genotype and feeding treatment (mm). Changes in the weight of the thigh bone (femur) depending on age, genotype and nutrition (g).
During the laying period, the trend in the previously recorded feed intake suggests that the difference has fundamentally changed. In the first third of the laying period (between the 19th and 42nd week) no effective difference could be observed between the treatments. Egg production also showed no real change in the last third of the egg production period (between weeks 69 and 92).
During the middle third of the egg production period, feeding had no effect on egg weight. In the last third of the egg production period, the previously formed orders did not change. In closed, alternative system, the effect of the experimental diet on the live weight of layer hybrids was not found to be significant during the egg production period.
Examined the daily feed intake until the 42-week age of the egg production period, the experiences were the same as in the cage system. Examining the first third of the egg production period (between the 20th and 44th week), output excess was found on behalf of the Leghorn group consuming the pre-starter diet (P<0.05). The same effect, more precisely ineffectiveness, was experienced in the middle or last third of the egg production period.
Similar changes were experienced with respect to the shell density just as in the case of the shell weight.
Discussion and recommendations
During the one-year period of egg production in the cage system, the body weight of the Leghorn-type layer hybrids increased by an average of 524 g, while in the case of the heavy hybrids, the average was 494 g. The biggest difference between the two hybrids was at week 30 (more than 300 g), which dropped below 200 g at the end of the egg production period. During the one-year period of egg production in the alternative closed system, the body weight of the Leghorn hybrids increased by an average of only 373 g, while in the case of the heavy hybrids the average was 485 g.
This resulted in spectacular differences compared to the results in the case of caged birds. The effect of early feeding can be seen as a tendency, but it is not statistically proven, especially in the middle and last third of laying. The phenomenon can be an additional argument from an economic point of view in favor of introducing the use of pre-starter nutrition also in the case of the cage system.
Thus in the alternative system the improvement of eggshell quality is experienced as a result of the application of pre-starter diet. But at the age of 18 weeks, no difference was found between the two feeding treatments, either in the length of sternum or in the weight of the femur. At the same time, even at 18 weeks of age, the medium heavy hybrid confirmed the beneficial effect of the pre-starter diet by producing a significantly longer sternum and heavier femur in the case of both observed traits.
The effect of the pre-start diet on liver weight could only be proven when different diets were fed (first 4 weeks) and could only be traced in the case of the Leghorn hybrid. Changes in the capacity of the liver in most cases support the previously found and evaluated changes in the weight of the organ. There was no evaluable difference between the observed groups in the egg production period.
There were enormous changes in the development of the ovary between the 12th and 18th week. While the previously experienced differences in the weight of the ovary absolutely disappear by the 30th week reaches the peak. Very similar changes were observed with regard to gonado-somatic index, just as in the case of the ovarian weight.
New scientific results
Medium-heavy layer Leghorn hens producing on the alternative system responded to feeding the pre-starter chick age diet with a higher egg production (+4 eggs) in the first third of the egg production period ( between the 20th and 44th week). The use of the pre-starter diet with layer hens produced in an alternative closed system positively affected the quality parameters of the eggshell (thickness, weight and density), while they were not affected in the case of stocks kept in cages.
Scientific papers and lectures on the subject of the dissertation
