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

. Egg production performance of three strains of laying hens kept in floor pens. A G B IR. Genetic limitation is one of the major bottlenecks 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 in Ethiopia. Research system is currently focused to solve this gap by introducing the best productive breeds that can adapt and perform in Ethiopia. This experimental trial was done out to study the evaluation of egg production performance of lohman brown, novo brown and dominant Sussex final hybrid layers under the objective condition of Jimma. One hundred fifty of each of breed of layers obtained from Debre Zeit research center and was placed at Jimma university poultry farm on standard commercial layer’s 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 significant difference (P<0.05) between the three breeds tested in age at the first 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
Ethi opian chickens estimated to be about 56.53 million of which 94.3%, chicken population is indigenous breed [1].Even if the indigenous chickens are better to adapt the harsh environment, they are tolerant to diseases and are good brooders, but they are poor in their reproductive and productive performance.Therefore, in order to improve the performance of the local chickens, the exotic chickens were imported and were then crossed with local chickens to improve the genetic potential of indigenous breeds [2].In Ethiopia, the introduction of exotic chicken goes back to the early 1950's.It has been reported that many exotic breeds of chicken (white and brown leghorns, Rhode Island Red, Bovans, New Hampshire, Cornish, austral up and light Sussex) were introduced over the past years.The most important inputs have been the introduction of improved (exotic) breed, improved feed, vaccine and medicament and credit aiming at increased productivity [3].Currently, the exotic chicken figured around 4.39% of the national chicken population.However, their significance to Ethiopian economy is lower.Besides, according to food and agriculture organization of the United Nations Ethiopian population figure prediction report for 2040 with 2.4% of Ethiopian annual population growth rate, it reaches 149.3 million.In order to meet the ever-increasing demand for meat and eggs, increase the contribution of exotic chicken to Ethiopian economy and expansion of commercial poultry production through introduction and evaluation of superior/exotic breed has been proposed as one of the promising option.As a result, currently the Ethiopian Institute of agricultural research introduced lohman brown, novo brown and dominant sussex d104 final hybrid layers.Therefore, the aim of this research project was evaluating the egg production performance of the three exotic layers under the objective conditions of Ethiopia.

Experimental site
This experiment was conducted at Jimma university college of agriculture and veterinary medicine, located at 357 km Southwest of Addis Ababa and at about 7° 33' N latitude and 36° 57' E longitudes.The altitude is 1700 meters above sea level.The mean maximum and minimum temperature of the study area is 26.8℃ and 11.4℃, respectively and the mean maximum and minimum relative humidity is 91.4% and 39.92% respectively.The mean annual rainfall of the area is 1500 mm [4].

Layer treatment
One hundred fifty layers of each breed were used for the experimental trial.Each experimental breed were randomly placed in nine experimental separated pens each pen contain fifty layers of equal mean group weight with completely randomized design with three replication.Then, experimental layers were offered on standard commercial layer ration for seven days trial.Layer ration feed was given three times per day and were collected and weighed on the next morning at 2:00 pm.Enough and clean water was made given all the times.The experimental pens were cleaned and disinfected before the arrival of the chicken.Body weight measurement was taken every week.Mortality and disease conditions were recorded as occurred (Table 1).

Rate of egg production
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.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 [5].
FCR=Daily feed consumed (g)/daily egg mass (g) 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 as follow: % Hen-day egg production=Number of eggs collected per day/number of hens present on that day × 100

Statistical analysis
The data collected were analyzed using the procedures suggested by Gomez and Gomez using SPSS (Statistical Package for Social Science) software version 20.When the analysis of variance indicates the existence of significant difference among the treatment means at 5% level of significance for the quantitative data, Turkey's Honestly Significant Difference (HSD) test was employed to test and locate the treatment means that are significantly differed from the rest.The following model suggested Montgomery, was used.
Where, Y ij =Is the overall observation (Egg production, egg weight, feed intake, body weight….)µ=Population mean T i =Effect of the i th breed (i=1, 2, 3) E ij =Random error

RESULTS AND DISCUSSION
There was significant difference between the three breeds in mean egg weight (P<0.05).The mean egg weight of Novo Brown and Lohman Brown was 57.1 and 57.3 g respectively and Dominant Sussex had significantly larger (P<0.05)mean egg weight (59.4 g) than the others, which may arise from the breed difference.There was no significant difference between the eggs of Novo Brown and Lohman Brown in mean egg weight (P<0.05).The rate of egg production of the experimental chickens is shown in Table 2. Novo Brown and Dominant Sussex breeds had significantly higher (P<0.05)rate of egg production than Lohman Brown as measured by percent hen-day egg production, this difference could be attributed to their better genetic potential for higher egg production.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 [6].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 weeks) during this experiment.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 (Figure 1).
There was no significant difference (P>0.05) between the three breeds in body weight gain during laying period.Lohman Brown chickens had also significantly higher Feed conversion efficiency value (3.7) than the others.As shown in Table 2, there was significant difference between the three breeds in egg mass production (P<0.05).Dominant Sussex breeds had significantly 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.The egg mass production of Novo Brown breeds is intermediate between the Dominant Sussex and the Lohman Brown breeds, without showing significant difference with both (P<0.05).Dominant Sussex experimental layers tended to show higher mortality than the others.

CONCLUSION
In Ethiopia, the expansion of commercial poultry production is limited by inadequate supply of high performing breeds of chicken.This situation warrants the identification, 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 efficiency 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.

Figure 1 :
Figure 1: Peak hen day egg production performance of layers.