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Effect of restricted feeding and season on carcass characteristics of Koekoek chickens at 18 and 32 weeks of age
The results on the carcass characteristics of Koekoek chickens are presented in Tables 3.2 and 3.3.
These results indicate a significant effect of restricted feeding and season on a number of carcass traits of Koekoek chickens at 18 and 32 weeks of age. A significant difference was recorded between the two groups of birds that were under different feeding levels namely the full-fed and restricted feeding. Birds that were full-fed (AA and AR) weighed 370g higher than those that were reared under feed restriction (RA and RR). The relative percentage of the defeathered weight suggests that apart from accelerating body weight of chickens full feeding also had a significant effect in the development of feathers. The results of the present study indicate that in the full-fed chickens 13.5% of the body weight was contributed by feathers while in restricted fed chickens, feathers contributed 17.2 to 19.1 % of the slaughter weight. This suggests that chickens that were exposed to restricted feeding either had faster feather development compared to those that had free access to feeding or they were not losing their feathers as fast as the ones that were full-fed. The results from this study also indicated a positive (p<0.01) correlation (r=0.953) between the slaughter weight and defeathered weight. During the laying phase, birds that were full-fed (AA and RA treatments) had heavier (p<0.05) slaughter weights and defeathered weights than those that were fed restrictedly (AR and RR treatments). The slaughter weights of chickens that were under the AA treatment were 484, 21 and 548g heavier than those under the AR, RA and RR treatments respectively. The observed defeathered weight measurements were 2221g, 1732g, 2210g and 1533g for birds that were in the AA, AR, RA and RR treatments respectively. The non-significant difference between Koekoek chickens that were in the AA and RA treatments signify the compensatory growth pattern shown by birds that were feed restricted earlier and later shifted to full feeding (RA). The fact that the slaughter weights of birds that were feed restricted for the entire study (RR) were not insignificantly different (p>0.05) from birds that were in the AR treatment suggests that birds in the RR group grew at the constant rate from rearing to laying phase which might be because of their bodies being acclimatized to the lower level of feeding.
The results also demonstrated a good relationship between the feed intake and weight gain on both slaughter and defeathered weights.
Effect of restricted feeding and season on organs and abdominal fat in Koekoek chickens at 18 and 32 weeks of age
The results on abdominal fat and organs characteristics of Koekoek chickens are presented in Tables 3.7 and 3.8. These results are for both rearing and laying phases of Koekoek chickens. Koekoek chickens that were exposed to restricted feeding were not different (p>0.05) from those that were full-fed as far as the intestine weights are concerned. In spite of insignificant differences between chickens that were subjected to either full-fed or restricted fed it was noted that the intestine weights of chickens that were under full-fed treatment were 7.3% higher than the ones of chickens that were subjected to restricted feeding during the rearing phase (18 weeks). It was detected that chickens that were fed without restrictions had an average relative intestine percentage of 3.4% while an average relative intestine percentage of chickens that were feed restricted was 4%. The negative relationship between slaughter weight and relative percentage of the intestines demonstrate that the significant (p<0.05) differences in the intestinal weights were inherited from the chickens slaughter weights rather than being brought about by the effect of restricted feeding. During the laying phase (32 weeks), the results indicate that Koekoek chickens had intestine weights of 74.1, 70.1, 68.6 and 63.3g for chickens that were in the AA, AR, RA and RR treatments respectively.
The results on intestine weight performance were not significantly different (p>0.05) between the four feeding level treatments. The results show that Koekoek chickens that had heavier intestine weights at early age continued to surpass chickens that were on restricted feeding at the initial phase of the study.
This suggests that the development of intestines was not affected by the amount of the feeds given to chickens during the laying phase. Regarding the relative percentage of the intestines, the results
portrayed the non-significant differences between chickens that were subjected to different feeding levels (Figure 4.4). Koekoek chickens that were full-fed during rearing and later shifted to restricted
feeding in the laying phase (AR) had a higher relative intestine percentage (3.8%) followed by chickens that were in feed restriction for the entire study (RR) with the relative intestine percentage of 3.5%. The proportion of the intestine weights relative to the body weight of chickens that were fed without any restriction during the laying phase (AA and RA) was 3.2% and 3% respectively. It can be seen from these results in both rearing and laying phases that chickens that were on 70% full feeding had a higher relative percentage of intestines hence a higher negative correlation (r=-0.776) between an intestine weight and the relative intestine percentage ( p<0.01). The results indicate an insignificant correlation (r=-0.019) between the slaughter weight and intestine weight of Koekoek chickens at 32 weeks of age. On the other hand, an inverse relationship was seen between the slaughter weight and intestine percentage of the chickens. The findings of this study suggest that Koekoek chickens with small bodies at slaughter age (32 weeks) will proportionally have heavier intestinal weights.
CHAPTER 1 INTRODUCTION AND LITERATURE REVIEW
1.1 Introduction
1.2 Literature Review
1.3 References
CHAPTER 2 EFFECT OF RESTRICTED FEEDING AND SEASON ON THE GROWTH PERFORMANCE OF KOEKOEK CHICKENS
Abstract
2.1 Introduction
2.2 Materials and Methods
2.3 Results and Discussion
2.4 Conclusion
2.5 Recommendations
2.6 References
CHAPTER 3 EFFECT OF RESTRICTED FEEDING AND SEASON ON THE CARCASS CHARACTERISTICS OF KOEKOEK CHICKENS
Abstract
3.1 Introduction
3.2 Methods and Materials
3.3 Results and Discussion
3.4 Conclusion
3.5 Recommendations
3.6 References
CHAPTER 4 EFFECT OF RESTRICTED FEEDING AND SEASON ON THE CARCASS CHEMICAL COMPOSITION OF KOEKOEK CHICKENS
Abstract
4.1 Introduction
4.2 Materials and Methods
4.3 Results and Discussion
4.4 Conclusion
4.5 Recommendations
5.6 References
CHAPTER 5 EFFECT OF RESTRICTED FEEDING AND SEASON ON REPRODUCTIVE PERFORMANCE OF KOEKOEK CHICKENS
Abstract
5.1 Introduction
5.2 Materials and methods
5.3 Results and Discussion
5.4 Conclusion
5.5 Recommendations
5.6 References
CHAPTER 6 SUMMARY AND GENERAL CONCLUSION
6.1 Summary
6.2 General Conclusion
