MATERIALS AND METHODS

Study abattoirs: The study was conducted at Abergelle, Elfora Bishoftu and Elfora Kombolcha abattoirs. These abattoirs are located in Oromiya, Amhara and Tigry regional states which constitute bout 75% of cattle population in the country. Abergelle abattoir slaughters cattle for export purpose while Elfora Bishoftu abattoir slaughters cattle for local consumption. Elfora Kombolcha abattoir slaughters cattle for both export and local purposes. Abergele abattoir is located 783 km north of Addis Ababa, at 13°30’N 39°29’E and at an altitude of 2000-2200 m above sea level. The mean annual temperature and rainfall of the area ranges from 11.8 to 24.9°C and 579-650 mm, respectively. Elfrora Bishoftu is located in Bishoftu 47 km east of Addis Ababa. The area lies at 8°45’N 38°59’E at and at an altitude of 1880 m above sees level. The average temperature ranges from 9 to 23°C. This region has average annual rainfall of 1151.6 mm. Elfora Kombolcha is located at about 375 km north east of Addis Ababa at an altitude of 1500-1840 m above sea level. The average rainfall and temperature ranges from750-900 mm and 25-30°C, respectively.

A retrospective abattoir survey was conducted based on a total numbers of 62,917 cattle slaughtered at these abattoirs from February 2010 to November 2013. The number of cattle slaughtered at Abergelle, Elfora Bishoftu and Elfora Kombolcha abattoirs were 39098, 9227 and 14592, respectively. The number of cattle slaughtered in 2010, 2011, 2012 and 2013 were 12708, 34674, 10363 and 5172, respectively. It was not possible to get information on the exact age, sex and breeds of cattle slaughtered in each abattoir. Almost all cattle slaughtered came from mixed crop livestock and agro-pastoral production systems.

Data management: Daily condemnation records for cattle slaughtered at Abergelle, Elfora Bishoftu and Elfora Kombolcha abattoirs were used as the sources of the data. Records on number of animals slaughtered and organs condemned were collected. Daily meat inspection was carried out by qualified federal veterinary inspectors who was trained on meat inspection and assigned by Ministry of Agriculture at each abattoir. These officers keep records of their finding and report to the federal bureau. Hence, individual differences between inspectors in major terms of findings of diseases can not be considered significant. This suggests that the differences in prevalence of disease conditions observed between abattoirs may arise due to differences in environmental conditions that are conducive to the perpetuation of the parasite, abundance of infected definitive host, livestock husbandry, stocking rate, nature of the pasture and grazing patterns of animals and abattoir management. Routine ante-mortem examinations were carried out for slaughtered cattle a day before or shortly prior to slaughter. This was followed by postmortem meat inspection involving visual examination, palpation and systematic incision of carcasses and visceral organs, particularly lungs, livers, kidneys, hearts, spleens, tongues, heads and intestine according to procedures described Meat Inspection Guideline of Ethiopia, 2010. Organs were grossly diagnosed based on pathological changes such as color, size, morphology, consistence, presence of lesions or parasites. At the end of meat inspection, all partial and total condemned carcasses and organs were taken to the laboratory at each respective abattoir for further examination and identification of the lesions and parasites. In case causes of diseases were not confirmed in the respective laboratories, samples were submitted to the regional/ national animal health laboratory for further diagnosis.

Data analysis: Data was analyzed using JMP version 8 statistical software. Prevalence of disease was calculated as a ratio of number of carcass/organs condemned for specific disease problem to the total number of cattle slaughtered during the day. Chi-square test at critical probability value of p<0.05 was used to test the significant difference between abattoirs, years and season. Presence (value = 1) and absence (value = 2) of diseases condition were used to analyze statistical difference. Season was classified in to dry (October to February) and wet (March to September).

RESULTS

Causes of whole carcass condemnations: Out of 62,917 cattle slaughtered during the study period, a total of 170 whole carcasses were condemned (Table 1). The main causes of whole carcass condemnations were poor bleeding (0.11%), abscess (0.06%), adhesion (0.04%), TB (0.03%), pneumonia (0.01%), Cysticercus bovis (0.01%) and bruising (0.01%). The prevalence of abscess was significantly different (p<0.0001) between years and abattoirs (Table 2). A higher prevalence of abscess was observed in 2010 which was 0.20%. The prevalence of TB and C. bovis significantly differed (p<0.0001) between abattoirs. TB and C. bovis were higher in Elfora Kombolcha (Table 3).

Causes of partial carcass condemnations: About 52,437 carcasses were partially condemned during the study period. Main causes of partial condemnations were bruising (34.11%), poor bleeding (25.59%), contamination (12.58%), adhesion (9.37%), abscess (1.55%) and calcification of cysts (0.11%). The prevalence of bruising, poor bleeding, contamination, adhesion, abscess and calcified cyst were significantly different (p<0.0001) between years, abattoirs and season. The prevalence of C. bovis, H. cyst and edema was significantly different (p<0.0001) between abattoirs (Table 2). Bruising and contamination were higher (p<0.0001) in 2010 (53.93%, 17.06%) while poor bleeding and adhesion were higher (p<0.0001) in 2011 (36.70%, 14.71%). The prevalence of all disease conditions were the lower in 2013 compared to other years of study (Table 1). Most partial condemnation was observed at Abergelle abattoir. The prevalence of bruising and poor bleeding were relatively higher in dry season while the prevalence of adhesion, abscess, contaminations and calcified cysts were relatively higher in wet season (Table 3).

Causes of condemnations of livers: The main causes of condemnations of livers were faciola (29.74%), H. cyst (15.44%), Calcified cyst (10.56%), contamination (7.36%), C. bovis (5.44%), poor bleeding (5.01%) and abscess (1.5%; Table 1). The prevalence of these problems was significantly different (p<0.0001) between years and abattoirs (Table 2). All these problems except faciola, contamination and C. bovis were significantly different (p<0.05) between seasons (Table 2). Condemnations of livers due to fasciola and H. cyst were relatively lower in 2010 (17.36, 9.91%) compared the prevalence of these problems in 2011 (32.02, 14.61%), 2012 (32.58, 23.05%) and 2013 (39.21, 19.33%; Table 1). Fasciola was the common causes of condemnations of livers at Abergelle (25.17%), Bishoftu (30.46%) and Kombolcha (41.54%) abattoirs.

Table 1:	Causes of condemnation of whole, partial carcass and organs of cattle slaughtered from 2010-2013
*Other on liver (oedema, adhesion, pleurisis, hemorrhage, hematoma, tumor, peritonitis, TB, Bruise, Jaundice), on lung (hemorrhage, tumor, adhesion, C. bovis, TB), on kidney (tumor, abscess, C. bovis, bruising,), on heart (hemorrhage, calcified cyst, abscess, Hydatid cyst, tumor,), on tongue (hemorrhage, tumor, ulcer), on spleen (oedema, calcified cyst, hemorrhage, c. bovis, tumor), on head (Hydatid cyst, edema, adhesion)

Table 2:	Chi-square test for causes of condemnations of carcasses and organs

Hydatid cyst was the cause of condemnations of livers at Abergelle (14.30, 12.52%) and Bishoftu (36.76, 14.70%) abattoirs. Calcification of cyst, contamination, poor bleeding and C. bovis were prevalent at Abergell compared to the other studied abattoirs. Calcified cyst and poor bleeding were relatively more prevalent (p<0.0001) in the dry than the wet season while the prevalence of H. cyst was more prevalent (p<0.0001) in the wet than the dry season (Table 3).

Causes of condemnations of lungs: Main causes of condemnations of lungs were H. cyst (23.01%), pneumonia (22.68), emphysema (18.93%), poor bleeding (17.89%), contamination (4.81%) and Calcified cyst (3.11%; Table 1). The prevalence of H. cyst was significantly different (p<0.0001) between abattoirs (Table 2).

Table 3:	Condemnations of whole, partial carcasses and organs in Abergelle, Bishoftu and Kombolcha abattoirs in dry and wet seasons
*Other on liver (oedema, adhesion, pleurisis, hemorrhage, hematoma, tumor, peritonitis, TB, Bruise, Jaundice), on lung (hemorrhage, tumor, adhesion, C. bovis, TB), On kidney (tumor, abscess, C. bovis, bruising,), on heart (hemorrhage, calcified cyst, abscess, Hydatid cyst, tumor), on tongue (hemorrhage, tumor, ulcer), on spleen (oedema, calcified cyst, hemorrhage, C. bovis, tumor), on head (Hydatid cyst, edema, adhesion)

H. cyst was relatively higher in Bishoftu (44.30%) compared to Abergelle (22.83%) and Kombolcha (10.01%) abattoirs (Table 3). Pneumonia, emphysema, poor bleeding, contamination and calcified cyst were significantly different (p<0.0001) between years and abattoirs (Table 2). The prevalence of pneumonia was relatively higher in 2012 (Table 1). The problem of pneumonia, emphysema and poor bleeding were higher at Abergelle abattoir compared to the other abattoirs studied. Poor bleeding was relatively higher in the dry season compared to the wet season (Table 3).

Causes of condemnations of kidneys: The main causes of condemnations of kidneys were nephritis (10.91%). The prevalence of H. cyst, poor bleeding, calcified cyst, infracts, congenital cyst, hemorrhage, hydronephrosis and edema were in the range between 0.39 and 1.86% (Table 1). The prevalence of these problems were significantly (p<0.0001) different between abattoirs (Table 2). Nephritis, hydronephrosis and H. cyst were the major problems of Bishoftu abattoir. Contamination and poor bleeding were prevalent at Abergelle while Calcified cyst, edema, hemorrhage, congenital cyst and infracts were prevalent at Komblocha abattoir (Table 3). All causes of condemnations except edema, infract and Calcified cyst were significantly (p<0.0001) different between years of study. Prevalence of nephritis was relatively higher in 2012 (24.25%) and 2013 (19.74%) compared to other studied years (Table 1). Moreover, prevalence of edema, hemorrhages, congenital cyst, poor bleeding and H. cyst were significantly (p<0.0001) different between seasons (Table 2). Except poor bleeding, all the problems were more prevalent in the wet season compared to the dry season (Table 3).

Causes of condemnations of hearts: The main causes of condemnations of hearts were poor bleeding (20.83%) and pericarditis (4.59%). The prevalence of C. bovis, contamination and edema were in the range between 1.20% and 1.55% (Table 1). Poor bleeding, pericarditis, C. bovis, contamination and edema were significantly (p<0.0001) different between years and abattoirs (Table 2). The prevalence of poor bleeding and contamination were higher in 2010 and 2011. Pericarditis, C. bovis and edema were more prevalent in 2010, 2012 and 2013, respectively (Table 1). Poor bleeding was the major causes of condemnations of heart at Abergelle abattoir while pericarditis and C. bovis were more prevalent at Bishoftu abattoir. The prevalence of contamination and edema were higher (p<0.0001) at Kombolcha abattoir compared to other studied abattoirs. Poor bleeding was relatively higher (p<0.0001) in the dry season compared to the wet season (Table 3).

Causes of condemnations of tongues: Main cause of condemnations of tongues was abscess (4.71%). Condemnations due to C. bovis, contamination and edema were in the range between 0.26 and 0.79% (Table 1). The causes of condemnations of tongues were significantly different (p<0.0001) between years and abattoirs (Table 2). Abscess was relatively higher in 2010 and 2011 while C. bovis was higher in 2012 and 2013. Contaminations of tongues were higher in 2011 while edema was higher in 2013 (Table 1). Abscess and C. bovis were higher (p<0.0001) at Abergelle and Bishoftu abattoirs, respectively while contamination and edema were higher (p<0.0001) at Kombolcha abattoir. C. bovis and edema were relatively higher (p<0.0001) in the wet season compared to the dry season (Table 3).

Causes of condemnations of spleens: The main causes of condemnations of spleen were splenitis (2.74%) and hematoma (1.65%). Condemnations due to contamination, splenomegaly, H. cyst and abscess were in the range between 0.16 and 0.72% (Table 1). These problems were significantly (p<0.0001) different between abattoirs. The prevalence of splenitis and hematoma were significantly (p<0.0001) affected by season (Table 2). These problems were mainly problems of Kombolcha abattoir particularly in the wet season (Table 3).

Causes of condemnations of heads: The main causes of condemnations of the heads were poor bleeding (18.77%) and bruising (17.05%). The prevalence of abscess, contamination and C. bovis were in the range between 0.10 and 3.46% (Table 1). These problems were significantly (p<0.0001) different between years and abattoirs (Table 2). Poor bleeding, bruising and contamination were higher in 2011 while abscess and C. bovis were higher in 2010 and 2012, respectively. Poor bleeding, bruising, abscess and contamination were the main causes of condemnations of head at Abergelle abattoir while C. bovis was relatively higher Bishoftu abattoir. Poor bleeding was relatively higher (p<0.0001) in the dry season compared to the wet season (Table 3).

Causes of condemnations of intestine: Intestine was condemned due to abscess (0.08%), C. bovis (0.01%) and H. cyst (0.02%); Table 1). These problems were exclusively observed at Bishoftu abattoir (Table 3). The prevalence of abscess was relatively higher (p<0.0001) in 2012 and in the wet season (Table 1 and 3).

DISCUSSION

Whole carcass condemnations: The results of the present study revealed that there were several disease conditions associated with the condemnations of carcasses and organs at local and export abattoirs in Ethiopia. The causes of condemnations of whole carcasses in the present study were similar to that reported in Ontario, Zambia and Tanzania (Phiri, 2006; Alton et al., 2010; Mellau et al., 2011). The prevalence of C. bovis, TB and H. cyst in the present study were comparable to the report in Ethiopia, Cameron and Tanzania (Asseged et al., 2004; Awah-Ndukum et al., 2007; Mellau et al., 2011). The lower prevalence of C. bovis, TB and H. cyst in the current study should not be underestimated as these diseases are zoonotic in their nature. Bovine tuberculosis is an important infectious disease of Ethiopian cattle whose existence has been documented in almost all parts of the country (Biffa et al., 2010). This suggests the need to implement an annual monitoring program to minimize the incidence in the future.

Partial carcass condemnations: Partial condemnations of carcasses due to bruising in the present study was lower than the 40% reported in USA and 41.1-63.1% reported at a municipal abattoir in South Africa (Boleman et al., 1998; McKenna et al., 2002; Vimiso and Muchenje, 2013). However, it was comparable to the 34% reported in Canada in 2011 (Beef Cattle Research Council, 2011). In the present study bruising has shown a decreasing pattern over the year. This suggests the possibility of intervention either by the abattoirs or farmers supplying cattle to the abattoirs to minimize the prevalence of bruising. The higher prevalence of bruising at Abergelle abattoir indicates the need to create awareness on handling and transporting cattle for people involved in supplying cattle to the abattoir in this region. Higher prevalence of bruising in the dry season compared to the wet season in the present study might be due to an increase in physical stress due to long distance traveled by cattle in search of feed and high temperatures. Bruising does not only minimize carcass yield but can also be a cause of DFD carcasses. Bruised cattle are stressed and are expected to produce an abnormally high pH in the muscle because of glycogen depletion and the subsequent lower production of lactic acid in the muscles (Kannan et al., 2002). Hence, it is important to minimize the prevalence of bruising as it affect on meat quality is double folded. Poor bleeding was the other important problem during the study period. Poor bleeding can be caused by stress, ineffective stunning techniques and ineffective sticking techniques (MOA., 2010). This problem can make blood vessels filled with blood causing the carcass to have an overall darker red color. The change in the appearance affects the visual acceptability of a carcass (Gregory, 2004). Meat from such a carcass will have poor lasting qualities. Because of these associated effects, the fate of incomplete bleeding of carcasses is condemnation (MOA., 2010). The exclusive observation of this problem at Abergelle abattoir indicate the need to investigate the cause of this problem whether emanated from stress of animals prior to slaughter, ineffective stunning or sticking techniques and take appropriate measure to minimize the prevalence. Similar to poor bleeding, the condemnations of partial carcass due to contamination have shown a decreasing trend across the year and were exclusively observed at Abergelle abattoir. The soiling, contamination by visceral content, blood splash and abscess were the main causes of contamination. Tag (manure and mud) on the hide of the cattle is the major cause of contamination of carcasses in the beef industry. The audit conducted in Canada in 2010/2011 indicated that 85.3% of fed and 20.6% of non-fed cattle contained tag on their hides (Beef Cattle Research Council, 2011). The higher prevalence of condemnation of partial carcasses due to contamination in the wet season compared to the dry season, strengthen the speculation that the hide of cattle might be the causes of contamination of carcasses as the wet weather favors soiling of hides due to wet ground. The problem of contamination and adhesion of carcasses are due to operation management defects (Goetzinger, 2006). As these problems were observed at the Abergelle abattoir, measures should be taken to minimize these problems by implementing good management program at this abattoir. In the present study, the significant difference in the prevalence of abscess, calcified cyst, C. bovis, H. cyst and edema between abattoirs studied suggest the need to develop different strategy for regions these abattoirs are located to minimize the prevalence of these problems.

Condemnations of organs

Liver: The prevalence of fascioliasis of liver in the present study was comparable to the report in Zambia and higher than the report in Tanzania (Phiri, 2006; Mellau et al., 2011). Because of an increase in the prevalence of this disease across the year, it is important to monitor its development and develop appropriate strategies to reduce the problem (Mungube et al., 2006). Significant differences in the prevalence of the disease among abattoirs may be due to the agro-ecological and climatic differences between the regions in which abattoirs are located. Differences in cattle management systems in different region may also contributed to variation in the prevalence of diseases. Abergelle abattoir is located in a region which received relatively lower annual rainfall. Most of cattle supplied to this abattoir came from a mixed crop-livestock production system while most of those supplied to Beshoftu and Kombolcha abattoir came from agro-pastoral production system. The prevalence of fascioliasis throughout the year might be due to the chronic nature of the disease in the study areas as chronic fascioliasis is able to exist in all seasons (Kahn and Line, 2005).

The lower prevalence of the cyst at Kombolcha abattoir compared to the other abattoirs might be due to the religious prohibition of keeping dogs practiced by those communities supplying cattle to the abattoir as the life cycle of the parasite involves dogs as definitive host. Similar to the present study prevalence rate of 5.92% was reported at Kombolcha abattoir between 2003 and 2007 (Abunna et al., 2012). The prevalence of calcified cyst on liver in the present study was higher than the 1.9% reported in Tanzania (Mellau et al., 2010). The actual cause of the calcification in the present study was not established but problems like cirrhosis, hydatidosis, C. bovis and tumor might have been the cause. The prevalence of C. bovis in the present study was higher than the 2.55% reported in Northern Ethiopia (Assefa and Tesfay, 2013). In Ethiopia, there is a practice of eating raw meat and liver. In such circumstance, it is important to eliminate the incidence of this parasite from the livestock sector to safe guard the health of the society. In long term, changing the attitude of the society to abstain from eating raw meat will help to break the life cycle of the parasite. As this problem was higher at Abergelle abattoir, a strategy should be developed to minimize the exposure of cattle to infective eggs from human faeces/sewage in the region supplying cattle to this abattoir. Condemnations due to poor bleeding of liver in the present study was comparable to the report in Tanzania (1.1%) and lower than the report in Nigeria (2.9%), Brazil (2.5%) and Bangladesh (3.8%) (Rosa et al., 1989; Cadmus and Adesokan, 2009; Mellau et al., 2010). The causative agent of abscess of the liver needs to be identified so that appropriate measures can be taken in the future.

Lung: The causes of condemnations of lungs reported in Northern Tanzania, Northern Ethiopia and Zambia (Phiri, 2006; Mellau et al., 2011; Assefa and Tesfay, 2013) were similar to the present study. The prevalence of H. cyst was higher in lungs compared to other organs in the present study. The prevalence of pneumonia was higher compared to the 4% report in Tanzania and 1% report in North Ethiopia (Mellau et al., 2011; Amuamuta et al., 2012). The problem of emphysema was higher than the 1.73% reported in Tanzania and 4.4% reported in Northern Ethiopia (Mellau et al., 2011; Amuamuta et al., 2012).

Kidney: The causes of condemnations of kidneys in the present study were similar to that reported in other studies (Mesele et al., 2012; Mellau et al., 2011; Phiri, 2006). However, the prevalence of nephritis in the present study was relatively higher than the report in these studies. The causes of this problem should be identified and a strategy should be developed to minimize the problem in the future. The prevalence of hydronephrosis in the present study was comparable to the report in Zambia and Tanzania (Phiri, 2006; Mellau et al., 2011). The causes of urethral obstruction which was the cause for hydronephrosis should be identified and preventive action need to be planed in the future.

Heart: The prevalence rate of pericarditis in the present study was higher than the 0.8 and 1.04% reported in Zambia and Tanzania (Phiri, 2006; Mellau et al., 2011). The prevalence of C. bovis in the present study was relatively higher than the prevalence of this problem in Adigrat and Jimma abattoirs in Ethiopia which were 0.27 and 0.8%, respectively (Megersa et al., 2010; Assefa and Tesfay, 2013).

Tongue: The prevalence of abscess and C. bovis were higher than 0.2 and 0.02%, respectively, reported in Zambia (Phiri, 2006). These problems have shown a decreasing pattern across the year.

Spleen: The prevalence of Splenitis, hematoma, contamination and splenomegaly problems were relatively higher than the report in Tanzania (Mellau et al., 2011). The causes of these problems in the present study need to be investigated to develop preventive measure in the future.

Head: The prevalence of abscess and C. bovis in the present study was higher than the report in Tanzania and Zambia (Phiri, 2006; Mellau et al., 2011). The problem had shown a decreasing pattern across the year.

CONCLUSION

From the present study it was concluded that several disease problems were associated with the condemnations of carcasses and organs in Ethiopia. Most of these problems differed significantly between years and abattoirs. The problems of fasciola, nephritis and hydroneprosis have shown an increasing pattern across the year. Bruising, contamination, poor bleeding and pneumonia were the major problems at Abergelle abattoir while renal and intestinal problems were the main problems at Bishoftu abattoir. Condemnations of spleen due to different diseases were the major problems at Kombolcha abattoir. It is therefore recommended that different strategies should be developed to minimize these problems over the year and different regions due to the dynamic nature of the diseases.

ACKNOWLEDGMENT

The authors wish to thank the University of Pretoria and University of Haramaya for financially supporting the study. Mr. Daniel, acting supervisor of Abergelle export abattoir, Mr. Mohammed Hassen, supervisor of Elfora Kombolcha abattoir and Mr. Kibralem supervisor of Elfora Bishoftu abattoir deserve appreciation for their cooperation in facilitating data collection. Moreover, our thanks extend to Mr. Habtay, production unite head of the Abergelle abattoir and Mr. Yimer, technical worker in the Elfora Kombolcha abattoir.