GROWTH PATTERN, REPRODUCTIVE PERFORMANCE AND SEASONAL SENSITIVITY OF BOVAN NERA AND ISA BROWN PARENT-STOCK CHICKENS IN IBADAN NIGERIA

ABSTRACT

Parent stocks (PS) of exotic hybrids have contributed immensely to commercial poultry production in Nigeria. Their continued optimal utilization depends on their performance test. Information on performance indices of PS layer breeds in South-West Nigeria is however limited. The growth, reproductive performance and seasonal sensitivity of Bovan Nera (BN) and Isa Brown (IB) hybrids were evaluated.

Secondary data on 24 batches of PS of each of BN and IB kept over a period of 10 years (1999- 2008) in Ajanla Farms, Ibadan were used. Average batch population was 3896 pullets and 600 cockerels at point-of-lay. Records on Body Weight (BW), Age, Hen-Day-Production (HDP), Egg Weight (EWt), Egg fertility (EF), Egg Hatchability (EH), Pullet Day-Old Chicks produced (PDOC) and Hatching Rejects (HR) in four seasons: Early-Wet (EW, April-July); Late-Wet (LW, August-October); Early-Dry (ED, November-January) and Late-Dry (LD, February- March) were obtained. Data were standardized and analysed for growth, Age-at-first-egg (AFE), HDP characteristics, reproduction, seasonal sensitivity, genotype-season interaction using descriptive statistics, ANOVA, correlation and regression (p=0.05).

There was no significant difference in BW (g) and growth rate (g/day) between hybrids: 1724.8±562.8 and 1549.8±543.3; 1.4±2.3 and 1.1±1.6 for BN and IB hens, respectively. Effect of seasons on AFE was not significant in both hybrids, but ED and LD seasons delayed AFE. The HDP values (%) recorded for BN (63.2) and IB (72.9) in ED were significantly higher than in other seasons. There were significant differences in EF (80.8 and 88.7%), EH (69.1 and 73.6%), PDOC (32.6 and 36.1%) and EWt (56.2 and 59.9 g) for BN and IB respectively in EW season. EF (86.2 and 89.5%) and EH (73.1 and 73.9%) in LW were highest within hybrids respectively. Phenotypic correlation (r) between Age and Hen Weight, Age and EWt, Hen Weight and EWt, EF and EH, EF and PDOC, and EH and PDOC were 0.78, 0.74, 0.68, 0.73, 0.72 and 0.98 in BN; and 0.77, 0.52, 0.53, 0.69, 0.71, and 0.97 in IB respectively. The positive and significant correlation between HR and EWt (r = 0.14 and 0.13), for BN and IB respectively, indicated increase in HR as EWt increased. The environmental performance in body weight of both hybrids was significantly depressed before 10 weeks in cocks and throughout the life cycle of hens, except at 10 to 16 weeks in the BN hen. Performance depression was also observed in HDP (-10.2%), EF (-6.9%) and EH (-14.4%) in IB, and EWt (- 2.9 and -3.2%) in both genotypes respectively over their life-time period. Predictions of BW by 222 Age (R = 0.85, 0.84), EWt by Age-in-production (R = 0.65, 0.65), and PDOC by EH (R =0.99, 0.95) in both hybrids were significant at 25-75 weeks.

Hen day production, egg fertility, egg hatchability, pullet day-old chicks were higher in Isa Brown than Bovan Nera during the early-dry season. Body weight was higher in the cocks of both hybrids in early-dry and late-dry than in early-wet and late-wet seasons. The sensitivity of Isa Brown was lower than Bovan Nera except in hen weight.

Keywords: Bovan Nera, Chicken growth, Isa Brown

TABLE OF CONTENTS

Content Page
Fly Leaf
Title
Abstract
Dedication
Acknowledgement
Certification
Table of Contents

List of Tables
List of Figures
Definitions
Abbreviations

Chapter 1.0 INTRODUCTION 

Chapter 2.0 LITERATURE REVIEW

2.1 Definition and background 4

2.2 National poultry population 4

2.3.0 Bovan Nera and ISA Brown strains 5

2.3.1 Origin and popularity 5

2.4.0 Growth 6

2.4.1 Growth of body parts 7

2.4.2 Growth models 8

2.4.3 Growth performance in chicken 9

2.5 Stocking density and behavioural pattern 12

2.6 Deep litter system and chicken performance 12

2.7 Management operations in chicken breeding 12

2.8 Feed uptake and feeding 13

2.9 Sexual maturity 14

2.10 Photo stimulation 16

2.11 Egg traits in poultry 16

2.12 Egg production cycle 16

2.13 Egg production 19

2.14 Persistency in egg production 20

2.15 Factors affecting egg production in deep litter flocks 21

2.16.0 Negative influences on egg production 21

2.16.1 Photo-refractoriness 21

2.16.2 Broodiness 21

2.16.3 Moulting 22

2.17 Egg weight 22

2.18 Factors affecting egg size 24

2.19 Nutrition and egg weight 24

2.20 Egg sorting 25

2.21 Storage of hatchable fertile eggs 25

2.22 Fertility of incubated chicken eggs 26

2.23 Hatchability of chicken eggs 26

2.24 Day-old chicks’ body weight 27

2.25 Hatchery wastes and disposal 27

2.26 Environment and chicken reproduction 27

2.27 Breeder hen selection and age 28

2.28 Hen testing and comparison parameters 28

2.29 Correlation among morphological traits 29

2.30 Evaluation of chicken flock 29

2.31 Genotype sensitivity 30

2.32 Genotype-environment interaction 31

Chapter 3.0 METHODOLOGY

3.1 Location 33

3.2 Research materials 33

3.3 Housing and population 34

3.4 Farm bio-security 34

3.5 Management operations 34

3.6 Seasonal weather conditions of research field 36

3.7 Data collection 38

3.8 Experimental design 38

3.9 Statistical model 38

3.10 Regression models for growth and egg weight 39

3.11 Seasonal response model 39

3.12 Estimation of parameters 40

3.13 Derived functions 41

3.14 Statistical analysis 43

3.15 Hypotheses 43

3.16 Test of hypotheses 43

Chapter 4.0 RESULTS

A. The effect of seasons on growth, productive and reproductive performance Growth pattern of Bovan Nera and ISA Brown

4.1.1 Body weight of breeder cocks 44

4.1.2 Body weight of breeder hens 44

4.1.3 Growth pattern of breeder cocks 44

4.1.4 Growth pattern of breeder hens 45

Early sexual maturity characteristics of Bovan Nera and ISA Brown at first-egg

4.2.1 The effect of seasons on early sexual maturity characteristics at first-egg 50

4.2.2 Age at first-egg 50

4.2.3 Body weight of breeder pullets at first-egg 53

4.2.4 Body weight of breeder cockerels at first-egg 53

Full sexual maturity characteristics at peak hen-day production

4.3.1 Age at peak hen-day production 56

4.3.2 Body weight of cocks at peak hen-day production 56

4.3.3 Body weight of pullets at peak hen-day production 60

4.3.4 Hen-day production at peak hen-day production 60

4.3.5 Egg weight at peak hen-day production 63

4.3.6 Eggs set at peak hen-day production 63

4.3.7 Egg fertility at peak hen-day production 63

4.3.8 Egg hatchability at peak hen-day production 67

4.3.9 Pullet day-old chicks hatched at peak hen-day production 67

4.3.10 Hatching rejects at peak hen-day production 70

Productive performance characteristics of Bovan Nera and ISA Brown

4.4.1 Life-time productive performance 72

4.4.2 Hen-day production 72

4.4.3 Egg weight 72

4.4.4 Persistency of egg production 74

Reproductive performance characteristics of Bovan Nera and ISA Brown

4.5.1 Life-time reproductive performance 76

4.5.2 Life-time percent of eggs set 76

4.5.3 Life-time fertility of eggs set 76

4.5.4 Life-time hatchability of eggs set 80

4.5.5 Life-time pullet day-old chicks hatched 82

4.5.6 Life-time hatching rejects 82

B. The effect of genotype growth pattern and reproductive parameters

4.6.1 Growth performance 87

4.6.2 Sexual dimorphism in body weight 87

4.6.3 Early sexual maturity characteristics 87

4.6.4 Body weight and egg characteristics at full sexual maturity 87

4.6.5 Life-time productive characteristics 88

4.6.6 Life-time reproductive characteristics 88

C. Genotype by season interaction and genotype sensitivity to seasons

4.7 Genotype by season interaction 97

4.8.1 Genotype sensitivity 101

4.8.2 Within-seasons sensitivity 101

4.8.3 Between-seasons sensitivity 102

D. Environmental performance of Bovan Nera and ISA Brown

4.9.1 Environmental performance evaluation 122

4.9.2 Performance depression 122

E. Relationships among growth, productive and reproductive parameters

4.10.1 Relationship among the growth parameters for cocks 128

4.10.2 Relationship among the growth parameters for hens 128

4.10.3 Phenotypic correlation among productive parameters 128

4.10.4 Phenotypic correlation among reproductive parameters 128 4.10.5 Relationship between cock weight and fertility of eggs set 129

4.10.6 Relationship between egg weight and hatchability of eggs set 129

F. Predictive models for growth, productive and reproductive parameters

4.11.1 Body weight and growth 142 4.2.2 Egg weight 142 4.12.3 Fertility and hatchability of eggs set 143

Chapter 5.0 DISCUSSION

A. The effect of seasons on growth, productive and reproductive performance Growth pattern of Bovan Nera and ISA Brown

5.1.1 Body weight of breeder cocks 148

5.1.2 Body weight of breeder hens 148

5.1.3 Growth pattern of breeder cocks 149

5.1.4 Growth pattern of breeder hens 149

Early sexual maturity characteristics of Bovan Nera and ISA Brown at first-egg

5.2.1 The effect of seasons on early sexual maturity characteristics at first-egg 150

5.2.2 Age at first-egg 150

5.2.3 Body weight of breeder pullets at first-egg 150

5.2.4 Body weight of breeder cockerels at first-egg 151

Full sexual maturity characteristics at peak hen-day production

5.3.1 Age at peak hen-day production 152

5.3.2 Body weight of cocks at peak hen-day production 152

5.3.3 Body weight of pullets at peak hen-day production 153

5.3.4 Hen-day production at the peak of production 153

5.3.5 Egg weight at peak hen-day production 153

5.3.6 Eggs set at peak hen-day production 154

5.3.7 Fertility of eggs set at peak hen-day production 154

5.3.8 Hatchability of eggs set at peak hen-day production 154

5.3.9 Pullet day-old chicks hatched at peak hen-day production 155

5.3.10 Hatching rejects at peak hen-day production 155

Productive performance characteristics of Bovan Nera and ISA Brown

5.4.1 Life-time productive performance 156

5.4.2 Life-time hen-day production 156

5.4.3 Life-time egg weight 157

5.4.4 Persistency of egg production 157

Reproductive performance characteristics of Bovan Nera and ISA Brown

5.5.1 The effect of seasons on reproductive parameters 159

5.5.2 Life-time percent of eggs set 159

5.5.3 Life-time fertility of eggs set 159

5.5.4 Life-time hatchability of eggs set 160

5.5.5 Life-time pullet day-old chicks hatched 161

5.5.6 Life-time hatching rejects 161

B. The effect of genotype on growth pattern and reproductive parameters

5.6.1 Growth 162

5.6.2 Sexual dimorphism in body weight 162

5.6.3 Early sexual maturity characteristics at first-egg 163

5.6.4 Body weight and egg characteristics at peak hen-day production 163

5.6.5 Life-time productive performance 164

5.6.6 Life-time reproductive performance 165

C. Genotype by season interaction and genotype sensitivity to seasons

5.7.1 Genotype by season interaction 165

5.7.2 Implication for egg production and pullet day-old chicks hatched 167

5.8.0 Genotype sensitivity to seasons 168

5.8.1 Within-seasons sensitivity 168

5.8.2 Between-seasons sensitivity 170

D. Environmental performance of Bovan Nera and ISA Brown

5.9.1 Environmental performance evaluation 171

5.9.2 Performance depression 172

E. Relationships among growth, productive and reproductive parameters

5.10.1 Phenotypic correlation among the growth parameters 174

5.10.2 Phenotypic correlation among the productive parameters 175

5.10.3 Phenotypic correlation among the reproductive parameters 175

5.10.5 Relationship between cock weight and fertility of eggs set 176

5.10.6 Relationship between egg weight and hatchability of eggs set 177

F. Predictive models for growth, productive and reproductive parameters

4.11.1 Body weight and growth 178 4.12.2 Egg weight and hen-day production 179

4.12.3 Fertility and hatchability of eggs set 180

Chapter 6.0 CONCLUSION AND RECOMMENDATIONS

6.1 Conclusion 182

6.2 Hypotheses 184

6.3 Recommendations 184

6.4 Areas for further research 185

6.0 REFERENCES 186

7.0 APPENDICES 198

7.1 Charts 198

7.2.0 Tables 205

7.2.1 Cock body weight depression of Bovan Nera and ISA Brown in hot-humid Ibadan environment 205

7.2.2 Hen body weight depression of Bovan Nera and ISA Brown in hot-humid Ibadan environment 206

7.2.3 Depression of age, hen-day production and egg weight of Bovan Nera and ISA Brown in hot-humid Ibadan environment 207

7.2.4 Depression of egg fertility and hatchability of Bovan Nera and ISA Brown in the hot-humid Ibadan environment 208

7.2.5 Seasonal stocking pattern, recommended stocking dates and onset of egg-lay in Bovan Nera and ISA Brown hybrids 209

7.2.6 Technical data on mean body weight, production and reproduction data on Bovan Nera Parent-stock flock raised on deep-litter system in the hot – humid Ibadan, South-West Nigeria 210

7.2.7 Technical data on mean body weight, production and reproduction data on ISA Brown Parent-stock flock raised on deep-litter system in the hot - humid Ibadan South-West Nigeria