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LAYING AND PHYSICAL CHARACTERISTICS OF SHAVER BROWN AND NERA BLACK HENS IN HOT HUMID ENVIRONMENT
ABSTRACT
A total of one hundred and fifty Shaver brown and Nera black hens in their 14th week of lay were used in a study conducted to determine the laying and physical characteristics of Shaver brown and Nera black hens under humid tropical environment. Hens were housed individually in separate cages. The hens were supplied water ad libitum and fed layers mash containing 16.5% crude protein and 2650 kcal/kg of metabolizable energy for 10 weeks. The hens were also divided into three classes based on their laying performance as follows: good layers, intermediate layers and poor layers and their physical conditions appraised. Temperature readings were taken 3-hourly at time intervals of 0900h, 1200h, 1500h, and 1800h using a standard air thermometer and the mean daily temperatures noted. The climatic data taken during the period of the experiment showed that the study area had the natural day-length of 13 to 14 hours; mean maximum weekly indoor and outdoor temperatures of 27.90C to 29.20C and 26.80C to 30.50C, respectively; mean minimum weekly indoor and outdoor temperatures of 20.50C to 22.30C and 20.00C to 23.600C, respectively; relative humidity of 73.1% to 76.6% and mean total monthly rainfall of 781.33mm. Results showed that the peak of lay was between 0700h and 0800h and declined gradually throughout late afternoon hours until no egg was laid between 1700h and 1800h. For Shaver brown hens, about 86.24% and 13.76% of the eggs were laid in the morning and afternoon hours respectively, while 88.75% and 11.25% of the eggs were laid in the morning and afternoon hours respectively, for Nera black hens. Mean egg weight of 70.05g±1.07 and 70.10g±0.92 for eggs laid between 0600h and 0700h for Shaver brown and Nera black hens, respectively were the heaviest (P<0.05) of all the mean egg weights observed in all oviposition intervals. For Shaver brown hens, first eggs laid in a clutch were significantly greater (P<0.05) than subsequent eggs laid in a clutch, while the first eggs in a clutch for Nera black were greater than other eggs in the clutch, although the differences were not significant (P>0.05). Hens with the longest clutches and shortest number of pause days produced the greatest number of eggs. The total number of pause days observed were 1410 and 1329 for Shaver brown and Nera black hens, respectively. Observations made on physical characteristics of the hens revealed that good layers had smooth combs and wattles, moist and enlarged vents with flexible pubic bone, soft abdomen and worn out feathers. Intermediate layers had similar features with good layers except that the eye rings, beaks and shanks were slightly bleached. Poor layers had dry combs and wattles, tight and hard abdomen and closed pubic bones. The Effect of ambient temperature on performance parameters showed that for Shaver brown hens, hen day egg production, average daily feed intake, egg shell weight, egg shape index, albumin height, yolk height, yolk height and Haugh units were significantly reduced (P<0.05) with increasing temperatures. All performance parameters measured for Nera black hens were significantly reduced (P<0.05) with increasing temperatures. Likewise, there was significant interaction (P<0.05) of strain and temperature on average daily feed intake and yolk height. The results of the present study indicate that although heat stress had effect on performance, Shaver brown and Nera black hens are adapted to humid tropical environment and can lay 86.24% and 88.75% eggs, respectively in the morning hours, with overall production rate of 66.43% and 68.36% respectively, for Shaver brown and Nera black hens.
TABLE OF CONTENTS
Title Page .. .. .. .. .. .. .. .. .. i
Certification .. .. .. .. .. .. .. .. ii
Dedication .. .. .. .. .. .. .. .. .. iii
Acknowledgement .. .. .. .. .. .. .. iv
Table of contents .. .. .. .. .. .. .. v
List of Tables .. .. .. .. .. .. .. .. viii
List of figures .. .. .. .. .. .. .. .. ix
Abstract .. .. .. .. .. .. .. .. .. x
CHAPTER ONE
Introduction
- Background .. .. .. .. .. .. .. 1
- Statement of problem .. .. .. .. .. 3
- Objectives of study .. .. .. .. .. 3
- Justification of study .. .. .. .. .. 4
CHAPTER TWO
Literature Review
2.1 Classification of chickens .. .. .. .. .. 5
2.2 Exotic breed of laying birds .. .. .. .. .. 5
2.3 The reproductive system of the laying hen .. .. 6
2.3.1 The Ovary .. .. .. .. .. .. .. .. 7
2.3.2 The Oviduct .. .. .. .. .. .. .. 8
2.3.3 Ovulation .. .. .. .. .. .. .. .. 9
2.3.4 Egg formation .. .. .. .. .. .. .. 12
2.4 Oviposition .. .. .. .. .. .. .. 12
2.4.1 Sequential laying .. .. .. .. .. .. 13
2.4.2 Sequence/Clutch length .. .. .. .. .. .. 15
2.4.3 Pause days .. .. .. .. .. .. .. 15
2.4.4 Ovpiosition time .. .. .. .. .. .. .. 16
2.4.5 Time interval between successive eggs and lag .. .. 16
2.4.6 Total egg production .. .. .. .. .. .. 17
2.4.7 Rate/Intensity of lay .. .. .. .. .. .. 17
2.5 Egg quality .. .. .. .. .. .. .. 18
2.5.1 Egg weight .. .. .. .. .. .. .. 19
2.6 Physical characteristics of hens .. .. .. .. 19
2.7 Climatic condition .. .. .. .. .. .. 21
CHAPTER THREE
Materials and Methods
- Location and duration of study .. .. .. .. .. 23
- Experimental birds .. .. .. .. .. .. 25
- Management of hens .. .. .. .. .. .. 25
-
Parameters measured .. .. .. .. .. 25
- Oviposition time .. .. .. .. .. .. 25
- Total egg production .. .. .. .. 25
- Clucth/sequence length .. .. .. .. .. 26
- Pause days .. .. .. .. .. .. .. 26
- Egg weight .. .. .. .. .. .. .. 26
- Egg quality .. .. .. .. .. .. .. 26
- Average daily feed intake .. .. .. 27
- Percentage egg production .. .. .. 27
- Physical characteristics .. .. .. .. .. .. 27
- Temperature .. .. .. .. .. .. .. .. 28
- Experimental design .. .. .. .. .. .. ..
- Statistical analysis .. .. .. .. .. .. .. 28
CHAPTER FOUR
Results and discussion
4.1 Results
4.1.1 Egg laying characteristics of Shaver brown hens .. 29
4.1.1.1 Oviposition time .. .. .. .. .. .. .. 29
4.1.1.2 Total egg production .. .. .. .. .. .. 31
4.1.1.3 Clutch length .. .. .. .. .. .. .. 31
4.1.1.4 Pause days .. .. .. .. .. .. .. .. 37
4.1.1.5 Egg weight .. .. .. .. .. .. .. .. 37
4.1.1.6 Intensity/ Rate of lay .. .. .. .. .. .. 37
4.1.1.7 Hen housed egg production (HHEP) .. .. .. .. 39
4.1.1.8 Hen day egg production (HDEP) .. .. .. .. 39
4.1.2 Egg laying characteristics of Nera black hens .. .. 41
4.1.2.1 Oviposition time .. .. .. .. .. .. .. 41
4.1.2.2 Total egg production .. .. .. .. .. .. 43
4.1.2.3 Clutch length .. .. .. .. .. .. .. 43
4.1.2.4 Pause days .. .. .. .. .. .. .. .. 50
4.1.2.5 Egg weight .. .. .. .. .. .. .. 50
4.1.2.6 Intensity/ Rate of lay .. .. .. .. .. 50
4.1.2.7 Hen housed egg production (HHEP) .. .. .. 51
4.1.2.8 Hen day egg production (HDEP) .. .. .. 51
4.1.3 Effect of temperature on performance of Shaver brown
and Nera black hens .. .. .. .. .. .. 55
4.1.4 Interaction of strain and temperature on Performance .. 57
4.1.5 Physical characteristics of hens .. .. .. .. 57
4.1.6 Comparison between strains for performance and egg
quality traits .. .. .. .. .. .. .. .. 58
- Discussion
4.2.1 Climatic data for Nsukka .. .. .. .. .. .. 60
4.2.2.1 Egg laying characteristics of Shaver brown
and Nera black hens .. .. .. .. .. 60
- Oviposition time .. .. .. .. .. .. .. 60
- Total egg production and other egg productionIndices .. 61
- Clutch length .. .. .. .. .. .. .. 61
- Pause days .. .. .. .. .. .. .. .. 62
- Egg weight .. .. .. .. .. .. .. .. 62
- Effect of temperature on performance of Shaver
brown and Nera black hens .. .. .. .. 63
- Interaction of strain and temperature on performance .. 65
- Physical characteristics .. .. .. .. .. .. 67
- Comparison between strains for performance and egg
quality traits.. .. .. .. .. .. .. .. 69
CHAPTER FIVE
Summary and conclusion .. .. .. .. .. .. 71
References .. .. .. .. .. .. .. .. .. 72
Appendices .. .. .. .. .. .. .. .. 81
CHAPTER ONE
INTRODUCTION
1.1 BACKGROUND OF THE STUDY
The growth in global demand for poultry products is tremendous as the market for these products is growing very fast. Poultry is probably the fastest route to achieve any appreciable improvement in the nutritional standard of the populace because of its short generation interval, quick turnover rate and relatively low capital investment (Smith, 2001; Ani and Okeke, 2011). Gueye (2000) asserted that 85% of rural households in Sub-Saharan Africa keep chickens or other types of poultry. Poultry are equally important to other smallholders in Asia, Latin America and other parts of the world (Mallia, 1999; FAO, 2003; Islam and Jabbar, 2005; Kyrsgarrd, 2007). Increased egg production is one sure way of achieving the target of providing quality animal protein at a minimum cost to the consumers (Oluyemi and Roberts, 2000). Advances in genetic selection make today’s commercial layers quite different from those of years ago. Body weight is less, age at housing is earlier, total egg number has increased, egg mass is greater and feed conversion has improved considerably (Miles and Jacob, 2000; Minivielle et al., 2006). Total egg production is affected both by the physical and laying characteristics of the hen. Laying characteristics of hens have been assessed by evaluating such indices as rate of lay, oviposition time, clutch/sequence length, number of pause days, lag time, hen housed egg production (HHEP), and hen day egg production (HDEP).
Physical characteristics of laying hens on the other hand, consist of those features that can be seen easily on their body such as condition of combs, wattles, eyes, beaks, pubic bones, abdomen and vent. They are used to determine whether a hen is laying or not (Gillespie, 1997; Reddy et al., 2004; Daghir, 2008; Ani and Nnamani, 2011).
Apart from egg laying characteristics which are cyclic and genetically influenced, egg production is affected by nutrition, variations in temperature, light intensity, day- length, relative humidity, disease and level of management. Hens lay sequentially (Wolford et al., 1997; Spradbrow, 1997; Gillespie, 1997; Miles and Jacob, 2000; Smith, 2003; Van Der Molen, 2004; Jakowski and Kaufman, 2004; Reddy et al., 2004; Clauer, 2005; Poultryhelp, 2005). Hens vary in their laying habits. The number of eggs in a sequence varies between one to forty and occasionally even more. Even if flock uniformity is high, not all hens in the flock lay at the same rate. While some hens may be laying at a very high rate of production, others may not even be laying at all (Miles and Jacob, 2000; Ani and Nnamani, 2011). The longer the clutch length, the more eggs a hen lays in a given period (Etches, 1996; Reddy et al., 2004; Jakowski and Kaufman, 2004 ). According to Butcher and Miles (2000), the exotic hen is capable of laying 240-270 eggs per annum, each weighing about 58 grammes under tropical condition. The success of birds as a class is largely due to the fact that they have evolved physiological mechanisms that cause them to lay eggs at a time of season, when such factors as weather and food supply are optimal (Koelkebeck, 2001). According to Daghir (2008), humid environment is very suitable for poultry production. Although all livestock are subject to environmental stress in the tropics, poultry appears to be less susceptible than mammals. One reason may be that with higher body temperature than mammals, birds spend less production energy than other livestock in homeostatic regulations (adjustments). Under suitable tropical housing and management practices, poultry performance in the tropics has in many instances compared favourably with the performance standards of the same breeds reared in temperate environments. In acclimatizing to hot climate, animals normally make physiological adjustments (Hahn et al., 2003). As the seasons change, two major kinds of changes occur in the environments: changes in temperature and changes in length of daylight. Hormones enable the animal to respond physiologically to these seasonal changes (Hahn et al., 2003). The pineal body in chicken’s brain controls its body temperature and its sense of environmental temperature. Normal body temperature lies between 39.80C and 43.60C being at its highest around 1600h and its lowest around midnight (Hahn et al., 2003; Daghir, 2008). Egg production is intimately linked with daylight hours. The light rays received through the eyes affect the pituitary gland, which releases hormone into the bloodstream thus stimulating the ovaries into action. As the day-length hours shorten, egg production correspondingly decreases. By midwinter in temperate environment, it is usually nonexistent. To ensure continued production, hens in temperate regions must have a minimum of 16 hours of light per day. As the hours of natural day-length decreases, artificial lighting can be gradually introduced for longer periods to make up the difference (Clauer, 2005; Hanson, 2005). Environmental condition of the area in which the hens are laying affects their sequence length.
1.2 STATEMENT OF PROBLEM
Advances in genetic selection make today’s commercial layers quite different from those of years ago. Body weight is less, age at housing is earlier, total egg number has increased, egg mass is greater and feed conversion ratio has improved considerably (Miles and Jacob, 2000; Minivielle et al., 2006). Although management and feeding practices are the key determining factors of egg production, the breed of laying hen affects egg production. The rate of adaptation and quality of egg production of different exotic breeds of hen vary when exposed to a variety of climate and environments. According to Miles and Jacob (2000), some hens may be laying at a very high production rate while others may not be laying at all. The climatic conditions of Nsukka in particular and those of South Eastern Nigeria in general depict a typical tropical climate (Egbunike, 2002). Findings by Okonkwo and Akubuo (2007) have revealed an average annual minimum and maximum temperature ranges of 220C – 24.70C and 330C -37oC, respectively. These ranges appear to fall outside the zone of thermo neutrality of laying hens which is 180C – 22oC as recently defined by Imik et al. (2009). As such, adverse effects of heat stress are suspected to clasp egg production parameters of laying hens in the tropics. Most African diets (including Nigerian) are deficient in animal protein which results in poor and stunted growth as well as increase in spread of diseases and consequently death (Apantaku et al., 2003). Apart from low egg production and poor performing breeds, other problems associated with poultry production in Nigeria are diseases and pests, poor weight gain/feed conversion, feeding and management problems and lack of capital (Eekeren et al.,1995; Isiaka 1998; Apantaku et al., 2003). Moreover, the environment to which poultry birds are exposed affect performance of the birds (Abeke et al., 1998; Isiaka, 1998). The optimal laying temperature is between 18-220C (Imik et al., 2009), while a relative humidity above 75 percent will cause a reduction in egg laying (Hahn et al., 2003). When the temperature rises above 280C , the production and quality of eggs decrease as seasonal temperature increase can reduce egg production by 10 percent (Oluyemi and Roberts, 2000; Smith, 2001). Lastly, egg production clearly requires planning for costs as well as for profit generation and for meeting market demand without which a commercial egg production venture may suffer serious setbacks.
1.3 OBJECTIVES OF THE STUDY
The study was aimed at evaluating the laying and physical characteristics of Shaver brown and Nera black hens in hot humid environment.
The specific objectives of the study were as follows:
- To determine the oviposition time, and clutch size of Shaver brown and Nera black hens in hot humid environment.
- To determine position of eggs in a clutch and their relationship to egg weight in hot humid environment.
- To determine the comparative performance of Shaver brown and Nera black hens in hot humid environment.
- To establish the relationship between performance and environmental temperature.
1.4 JUSTIFICATION OF THE STUDY
With the increasing importation and utilization of exotic hybrids in commercial egg production in Nigeria, it is imperative to study the egg laying characteristics of these birds under the local condition. Information obtained would help assess the level of adaptability of Shaver brown and Nera black hens to humid tropical environment. Knowledge of laying distribution is necessary in recommending frequency of egg collection to management and poultry farmers. More eggs crack if they are not collected at frequent intervals. When buying birds at the point of lay, a careful observation of the physical features will enable a farmer to choose or buy only birds that have the potential of good layers. The ultimate objective of the poultry farmer is the realization of profit, and in order to do this, he must understand the interactions between body conformation, body function and environment. In the tropical context, environment (mainly temperature and humidity) plays a very important role as it imposes extra stress in the ability of the chicken to grow and function optimally. Solutions to the problems bedeviling poultry production in Nigeria depend mostly on research and this requires effective research approach to make meaningful impact on poultry productivity. At this juncture therefore, conducting research on the laying and physical characteristics of two strains of exotic breed of hen has become imperative so as to obtain information that would help in assessing their level of adaptability to humid tropical environment and also, to establish proven production basis which will determine their suitability and adaptability for massive commercial and small scale egg productions.
LAYING AND PHYSICAL CHARACTERISTICS OF SHAVER BROWN AND NERA BLACK HENS IN HOT HUMID ENVIRONMENT
