Investigation of haemoglobin polymorphism in Ogaden cattle

Background and Aim: The Ogaden cattle is one among the tropical cattle breeds (Bos indicus) widely distributed in eastern and south eastern part of Ethiopia. The breed has been evolved in arid and semi arid agro-ecological setup, but later on distributed and adapted to the wide agro-ecological zones. Because of its multi-purpose role, the Ogaden cattle have been used for milk, beef, and income generation. Information on the inherent genetic diversity is important in the design of breeding improvement programmes, making rational decisions on sustainable utilization and conservation of Animal Genetic Resources. Limited information is available about genetic variation of Ogaden breed at molecular level. The present investigation was aimed to study the biochemical polymorphism at the Hemoglobin (Hb) locus. Materials and Methods: Blood samples collected from 105 Ogaden cattle maintained at Haramaya beef farm by jugular vein puncture were subjected to agarose gel electrophoresis [pH range 8.4-8.5] to study the polymorphic activities of haemoglobin. Results: Three types of phenotypes were detected i.e. a slow moving (AA) band, fast moving (BB) band and a combination of slow + fast moving bands (AB). The frequency of the fast moving band was less [13 (12.3%)] than the slow moving band [57 A (54.2%)]. Both slow & fast moving phenotype was observed in 35 (33.3%) animals. The gene frequency of HB allele was B 0.709 and that of HB allele 0.291. 2 Conclusion: The distribution of phenotypes was in agreement with codominant single gene inheritance. The Chi-square (χ ) test revealed that the population is under Hardy-Weinberg equilibrium.


Introduction
they differ from Boran in many other traits [6]. The Ogaden have white grey to white coat color; whereas, Ogaden is an area found in the Somali region, the Boran coat color is light grey or fawn and some of southeastern Ethiopia, bordering on Somalia ( Figure-them have patches. Horns of Boran are thick based; 1A). The Ogaden cattle are one of the tropical cattle whereas, the Ogaden breed has normal based horns. breeds (Bos indicus) widely distributed in eastern and The hump of Ogaden bulls is pyramidal in shape; south eastern part of Ethiopia where it is used for milk whereas, Boran Bulls have humps hanging over one and meat purpose by pastoral society [1]. The breed side. Borans have more pendulous sheath; whereas, the (Figure-1B) has been evolved in arid and semi arid Ogaden breed has tied up sheath. Preliminary blood agro-ecological setup, but later on distributed and protein polymorphism studies [2] found that Ogaden adapted to the wide agro-ecological zones. This breed exhibited high heterozygosity values. is also known to be drought tolerant [2].
However, very little information is available on The Ogaden Zebu, also known in the literature as biochemical genetic variations of Hemoglobin (Hb) the Lowland Zebu, is classified as Small East Africa locus of Ogaden cattle. Hence, the present study was Zebu breed [3], and described as a strain of the Borana carried out to study the haemoglobin polymorphism of occupying the Ogaden rangelands of southeastern this breed. Ethiopia [4], but it is not clear why they are classified as a small rather than Large East African Zebu. This breed

Materials and Methods
is also associated with the Jigjiga breed of cattle Ethical approval: Permission was obtained from the occupying adjacent rangelands to the north of its departmental head of the Animal & Range Sciences to habitat [5].
carry out the present work. Standard protocol for Phenotypic characterization studies conducted at animal care and welfare was followed during sample university of Haramaya indicated that though some of collection. the physical traits of Ogaden cattle are similar to Boran, Study area: The study was conducted at Haramaya 0 0 University located at 09.00 N and 42.00 E at an altitude of 1950 meters above sea level. The area receives a bimodal rain fall, long rainy season (July to Veterinary World, EISSN: 2231-0916 Available at www.veterinaryworld.org/Vol.7/April-2014/8.pdf

Investigation of haemoglobin polymorphism in Ogaden cattle
1 September) and short rainy season (March to June). by addition of equal volume of normal saline (9.0g of The average rainfall is about 790 mm. The mean NaCl in 1 litre deionised water) and allowed to stand 0 for 30 minutes. The cells were finally lysed by addition maximum and minimum temperature are 23.6 C and 0 of two volumes of deionised water, exposing the 10.1 C, respectively. haemoglobin.

Experimental animals and Managemental conditions:
Pure Ogaden cattle that are maintained at the beef farm Analysis of samples: Haemoglobin genotypes were of Haramaya University were used in the present study.
determined by agarose gel (1%) electrophoresis. The The farm presently accommodated around 200 head of electrophoretic tank contained Tris-EDTA-borate Ogaden cattle. The farm was established in 1990 with buffer pH 8.4 -8.5. A constant voltage of 200 volts was the aim to characterize and improve Ogaden cattle for applied and allowed to run for about 2 hrs. After beef production. Foundation stock and replacement completion of the electrophoretic run the haemoglobin were procured from different sites of Dhagaehabure, pattern could be read directly on the gel without from Somali region which is the natural habitat of this staining. breed. Natural controlled mating is practiced on the 2 Statistical analysis: Chi-square (χ ) test was done to farm. Bulls are allowed to run freely with cows. One check if the population is under Hardy-Weinberg breeding bull was used for 20 to 25 breeding cows.
equilibrium. Selections of breeding bulls were made based on performance on birth, weaning and yearling weight.

Results
Cows were selected based on normal conditions of the Electrophoresis showed one slow band for teats and health condition.
HbAA, a fast one for HbBB and two bands for the Blood collection and storage: Blood sample was heterozygous HbAB (Figure-2). The HbAA and HbBB collected by veno-puncture with 10 ml vaccutainer from Ogaden cattle were found to have similar tube containing EDTA as anticoagulant. Red blood electrophoretic mobility to those from Western cattle. cells were separated from whole uncoagulated blood The Hb allelic and genotypic frequency and expected genotypes of the Ogaden cattle population studied is [22,23], as well as in synteny with myogenic factor 3 given in Table-1. There was no sample that showed any (MYOD1) an muscle specific gene. The last two genes abnormal phenotype. The observed and the expected play an important role in muscular development. Hb 2 polymorphism is one of the most studied polymorphigenotype were calculated. Chi-square (χ ) test revealed sms in vertebrate species since the infancy of both the population is under Hardy-Weinberg equilibrium A B population and evolutionary genetics because of its for the Hb and Hb allele.
accessibility and its obvious biological importance.

Discussion
However, owing to the close relationship between The present study is in agreement with the earlier structure and function, this complex protein remains a study of Gezahegn [2], who found that Ogaden cattle fascinating subject from all points of view and exhibited high degree of heterozygosity for certain especially in terms of its molecular, genetic and adaptive blood proteins studied by starch gel electrophoresis.
features. Accordingly, Hb has been recently defined as The chief function of the red cells in blood is "an evergreen red protein"  34]. It was also consistence with gene frequency bins with cow Hb A, showed a not so weak 2,3-DPG reported for some Indian cattle breeds [35]; that of effect in the latter.
climatic region, especially that Hb-physiology and role The Haemoglobin polymorphism is mostly due to is the same in all animals. Some blood factors are a β chain variant -βB which shows a Mendelian mode related to the suitability of the breeds under particular of inheritance, presenting 3 phenotypes Hb A, Hb B environmental conditions have been repeatedly and Hb AB, though rare α chain variant are also suggested [37,41,42]. It is claimed that Hb polymorphism reported in Podolian cattle [21]. The gene for globin β-would be maintained by natural selection. However, no chain was mapped at chromosome 15 in cattle and is direct evidence of differences in fitness among the closely linked to the beta subunit of the follicle-three phenotypes has been found in cattle [43]. stimulating hormone and the parathyroid hormone loci Evidence on cattle presented by Sengupta [44] found