Egg production performance of three strains of laying hens kept in oor pens

Genetic limitation is one of the major bottle necks for the development of the poultry production and the expansion of the commercial poultry production is limited by inadequate supply of high performing chicken breeds locally in Ethiopia. Research system is currently attempting to alleviate this problem by introducing improved poultry breeds that can adapt and perform in Ethiopia. This experiment was carried out to study the on station egg production performance of Lohman Brown, Novo Brown and Dominant Sussex breeds under the objective condition of Jimma. One hundred fty of each of Dominant Sussex, Lohman Brown and Novo Brown breed of layers obtained from Debre Zeit Research Station was placed at Jucavm layer house on standard commercial layers’ ration in completely randomized design with three replicates. Finally, all the data collected on performance of the experimental breeds of chickens were subjected to statistical analysis. There was no signicant difference (P<0.05) between the three breeds tested in age at the rst egg, even if Lohman Brown tended to lay comparatively earlier (137 days). The hen day egg production rate and egg weight of Dominant Sussex was better than other two breeds. In summary, the results of this experiment indicated that the three breed of chicken have well performed (except the adaptive potential of Dominant Sussex chickens) under Jimma condition in most of the economically important production traits studied. However, comparative evaluation of the egg quality and reproductive performance of the three breeds seems to be the future direction of research under objective condition of Jimma.


Introduction
Poultry production has an important economic, social and cultural bene t and plays a signi cant role in the provision of animal protein and family income in the developing countries. The contribution of poultry to the total global animal protein production is assumed to reach about 40% by the year 2020, the major increase being in the developing world (Delgado et al., 2001). In sub Saharan Africa, 85% of the rural population keeps chicken as a source of affordable animal protein and household income (Aklilu et al., 2007). Poultry is also an employment opportunity for the youth, elders and women in the urban and periurban areas and Ethiopia is not exception to this situation. Recent estimates put the Ethiopian poultry population at about 60million out of which 90.85, 4.76, and 4.39% is reported to be indigenous, hybrid and exotic chickens respectively (CSA, 2016/17). The poultry sub-sector in Ethiopia could be characterized into three major production systems based on some selected parameters such as breed, ock size, management practices, technological input and level of bio-security exercised (Bush, 2006).
The three production systems are backyard (traditional) poultry production, small-scale modern poultry and large scale commercial poultry. Each of these production systems sustainably coexist and contribute to the socio-economic status of different target societies (Tadelle et al., 2003c).
The backyard (traditional) poultry production system is entirely dominated by indigenous chickens and characterized by low input -output and periodic devastation of the ocks due to disease outbreaks (Tadelle et al., 2003b). The indigenous chickens are low in productivity owing to their low egg production performance, slow growth rate, late sexual maturity, pronounced broodiness and high chick mortality.
Poor management practice and veterinary services also contribute to the low productivity of the indigenous chickens. It has been seen that improvement of basic husbandry practice and health care improve the performance of indigenous chicken, but not to an economically acceptable level (Teketel, 1986;Abebe, 1992). Local chickens are considered to be disease resistant and adapted to their scavenging environmental conditions. However, local chickens kept under the intensive system of management (in con nement) are inferior to exotic stock in health status and characterized by a lack of interest in their environment, wing droppings, huddling at the corner, leg weakness and cannibalism. They are also slow in rate of feathering and exhibit recurrent outbreaks of disease (Demeke, 2004). The percentage mortality from hatching to maturity was signi cantly higher for local chickens kept under an intensive management system (24%) compared to the Leghorns (7.3%) kept under similar condition.
Higher mortalities and morbidities have been reported among local birds than White Leghorns when raised under intensive management conditions in Awassa (Teketel Forsido, 1986) and Debre Zeit (Abebe Hailu, 1987).
In Ethiopia, the importation of exotic breeds of chicken goes back to the early 1950s (Solomon, 2008). About 99% of the Ethiopian poultry population consists of indigenous chickens, while the remaining 1% consists of imported exotic breeds of chickens during the 1970s and 1980s (Alamargot, 1987

Description of the Experimental Site
This experiment was conducted at Jimma University College of Agriculture and Veterinary Medicine (JUCAVM), located at 357 km Southwest of Addis Ababa and at about 7 0 33' N latitude and 36 0 57' E longitudes. The altitude of JUCAVM is 1700 meters above sea level. The mean maximum and minimum temperature of the study area is 26.8 0 C and 11.4 0 C, respectively and the mean maximum and minimum relative humidity is 91.4% and 39.92% respectively. The mean annual rainfall of the area is 1500mm (BPEDORS, 2000).

Management of Experimental Chickens
A total of 500 pullets of the three breeds were housed at JUCAVM chicken house. One hundred fty pullets of each of Dominant Sussex d104, Lohman Brown and Novo Brown breeds were randomly selected from the total of 500 in each case. The selected pullets of each breed were placed in separate pens and placed on standard commercial layer ration for 7 days. At the end of the 7 days, each group (breed) of 150 chicks was further sub-divided into three groups, each with 50 pullet of equal mean group weight (total of 9 groups each with 50 pullets). Finally, each group of 50 experimental pullets was randomly assigned to the experimental pens in completely randomized design with 3 replicates (as shown in Table1).
All the groups of the experimental layers were placed standard layer ration at age of 20 weeks. Selected males of each breed were mixed with their respective females at the ratio of 1:10. Known amount feed was offered 3 times a day the orts were collected and weighed on the next morning at 2:00pm. Adequate clean water was made available all the times. The experimental pens were cleaned and disinfected before the arrival of the chicken and thoroughly cleaned every time during the study period. Sick birds were isolated, and when dead post mortem examination was carried out to determine the cause of mortality. Dead birds were disposed of properly. Whenever the litter got wet, it was replaced with dry and clean one to make sure the pen is clean at all times. Body weight was measured every week. Mortality and disease conditions were recorded as occurred.

. Egg production measurement
The production traits used to differentiate the experimental breeds was including egg weight, egg mass and egg production rate per day. The egg was measured using sensitive balance by collecting eggs daily and weighted in group immediately after collection for each replication and average egg weight was computed by dividing the total egg weight to the total number of eggs. After mean weight has been determined, the following formula was employed to calculate the egg mass per pen on daily bases developed by (North, 1984).
M =PXW. Where, M = av. egg mass /hen/day P = % hen-day egg production W = av. egg weight in gram Feed intake was measured by subtracting the amount refused from the amount offered on DM basis. Body weight was taken on weekly basis. The mean dry matter conversion ratio was determined as the ratio of gram egg mass from gram dry matter consumed (Ensminger et al., 1990).
Eggs were collected daily from each pen. The sum of the collections was recorded as egg production for that day. The number of birds alive per replicate on each day was also recorded. Rate of lay for each replicate was expressed as the average percentage hen-day egg production following the method developed by Hunton (1995) as follow:

Statistical Analysis
The data collected were analyzed using the procedures suggested by Gomez and Gomez (1984)   The rate of egg production of the experimental chickens is shown in Table 2. Novo Brown and Dominant Sussex breeds had signi cantly higher (P<0.05) rate of egg production than Lohman Brown as measured by percent hen-day egg production (Table 2), this difference could be attributed to their better genetic potential for higher egg production. The egg production performance of Lohman Brown and Lohman Silver was reported to be 80% in Nigeria under intensive production system, the value of which was higher than that (63-68%) recorded from the current study (Motiang, 2013). Similarly, the egg production performance of Lohman brown was lower than (80%) lohman company recommendation under conditions of intensive-industrial farm type, in batteries, ensuring an optimized management,(Lohmann brown, 2000). The results obtained have shown a diminution by 14.5% in the productive level, because of the used technology which keeps the poultry movement and increase egg production, and also the feed shortage occurred (2-3 week) during this experiment. Slightly lower Performance rate ranging between 57-64% was reported from Potchefstroom Koekoek kept under on station at Debrezeit Agricultural Research Center (DZARC Annual Report, 2012). Mean daily egg production ranging between 0.63 and 0.68 eggs/hen chicken was recorded from the current study, the value of which was higher than that of Tadesse The low performance of the experimental layers of the current study was due to the occurred shortage of commercial layers ration for 2-3 weeks during the study, since egg production performance is linearly related to the levels of feed offered (Fig. 1). Likewise, egg production can be affected by breed, feed consumption (quality and quantity), water intake, intensity and duration of light received, parasite infestation, diseases, management and environmental factors (Jacob et. al., 1998).

Feed intake and body weight gain
There was no signi cant difference (P>0.05) between the three breeds in body weight gain during laying period. Lohman Brown chickens consumed signi cantly higher feed (133.0g/h/d) than the others (P < 0.05), possibly because of genetic differences in physical activity/physical condition, basal metabolic rate and body temperature (Luiting, 1990). This is also higher from the Lohmann company recommendation (110g/h/d) under cage house production system (Lohmann Brown, 2000), which may be due to difference in housing system. Lohman Brown chickens had also signi cantly higher FCR value (3.7) than the others. Relatively lower mean daily feed intake (93.8g) and FCR of 2.39 was reported by

Egg mass and Mortality
As shown in Table 2, there was signi cant difference between the three breeds in egg mass production (P <0.05). Dominant Sussex breeds had signi cantly higher egg mass production (40.5) than Lohman Brown breeds whose average egg mass production was 29.0 (P < 0.05), which could be due to their higher egg number and egg weight recorded from Dominant Sussex layers.

Conclusion And Recommendation
In Ethiopia, the expansion of commercial poultry production is limited by inadequate supply of high performing breeds of chicken. This situation warrants the identi cation, introduction and evaluation of improved breeds of chicken that could adapt and perform under the current Ethiopian situation. Research system is currently attempting to alleviate this problem by identifying, introducing and evaluating improved poultry breeds that can adapt and perform under Ethiopian situation. This experiment was carried out to study the on station egg production performance of Lohman Brown, Novo Brown and Dominant Sussex breeds of exotic chicken under the objective condition of Jimma. Novo Brown breed was characterized by better feed conversion e ciency and egg production. Dominant Sussex chicks were also performed better in rate of egg production, egg weight and egg mass measurement. But, it was performed poor in rate of survival than both Lohman Brown and Nova Brown chicks. Lohman Brown was characterized by relatively early maturity. The following recommendations were suggested based on the results of the current study.
Novo Brown and Lohman Brown along with other basic input setup could be included into technical poultry extension packages.
Further on station evaluation on egg quality and reproductive performance of the three breeds of chickens in different areas should be done.
Declarations 33. Tulin C, and Ahmet K, 2009. Comparison of village eggs and commercial eggs in terms of quality. J. Anim. Vet. Adv. 8:2542-2545. Figure 1 Peak hen day egg production performance of layers