A cross-sectional survey and follow up study on major dairy health problems in large and small scale urban farms in Mekelle, Tigray, Ethiopia

This study was conducted with the objective of estimating the incidence of major dairy health problems in the area. From a cross-sectional survey (n = 475) and follow up study (n = 68), an overall incidence of 43.00 and 29.02% was reported respectively. This study showed biting fly (9.51%), respiratory problems (7.80%), mastitis (5.13%), actinomycosis (5.12%), dystocia (4.42%), endoparasites (3.81%), retention fetal membrane (3.63%), tick infestation (2.91%), lameness (2.94%), vaginal and uterine prolepses (2.51%), skin related problem (1.70%) and abortion (1.70%) were the main dairy health problems identified. In addition, the follow up study revealed; retention fetal membrane (5.91%), tick infestation (5.91%), respiratory problem (2.91%), mastitis (2.94%), endoparasites (2.94%), lameness (2.94%), dystocia (2.94%), actinomycosis (1.53%) and skin related problems (1.53%). The incidence of dairy reproductive problems showed statistically significant variation among local and cross breeds (P < 0.05). Incidence of infectious diseases among dairy cows managed under intensive and semi-intensive management systems showed a significant difference (P < 0.05). Moreover, incidence of physical injury was also showed a significant difference among animal breeds and management system (P < 0.05). However, reproductive problems among management system and infectious diseases among breeds showed a significant difference (P > 0.05). Overall, this study showed dairy animals are exposed to various type of diseases.


Introduction
Livestock population represents the major resource and it forms an integral part of the agricultural production system in Ethiopia [1]. However, the production and productivity of livestock is still marginalized and the most contributing factors are the presence of widely distributed animal diseases which caused loss of meat and milk, and reduction in animal traction power as a result of disease morbidity [2]. Parasitic disease caused by helminths, protozoa and arthropods causes serious economic losses than disease caused by bacteria and viruses. However, the impact of animal disease to livestock owners is less understood [3]. It is known that the low livestock productivity in the tropics is attributed to poor genetic potential, malnutrition, inadequate management practices. This mainly due to most of the cattle are located in rural areas where less attention is given to animals in terms of care and treatment when high incidence of disease burden prevails which is the principal cause of morbidity and mortality [4]. There is a good progress in reducing the incidences of economically important livestock disease through selection, crossbreeding and establishment of intensive management systems. In addition, the opportunities for development of these programs are greater in dairy industry because of the need to monitor production and health on daily basis [5].
Like any other developmental efforts occurring in the region, the regional bureau of agriculture and rural development has designed strategic plan to improve livestock productivity and efforts has been made to improve the genetic potential of dairy cows through selective breeding. However, no comprehensive study has been done to address the overall health constraints of dairy cows in this area. Therefore, this study was conducted to assess dairy cattle for the presence of health problems that could have a significant economic impact to the private farm operators.

Study area
The study was conducted in private dairy farms. As shown in Fig. 1, modified from the local organizing committee of the International Congress Water 2011 [15], the study area is located in Northern part of Ethiopia at a distance of 780 Km from Addis Ababa. It is located between 33°24′13″ to 13°36′52″ north latitude and 39°25′30″ to 39°38′39″ east longitude. It has an altitudinal range of 2150-2270 m above sea level. The average daily temperature is 11-24.1 °C.

Sampling strategies
A simple random sampling method was used to identify the number of dairy farms from the study area. All dairy farms having a size of greater or equal to five animals were registered and accordingly, 81 dairy farms were listed. From this list, randomly, a total of 30 dairy farms (18 private, 11 cooperative and 1 institution owned) were selected for the study. For the follow up studies, throughout the study period (6 months), all selected farms were regularly attended and diagnosed by veterinarians and farm managers and a total of 68 animals were randomly selected and from these, new cases were identified to classify the type of health problems. Neonatal calves were also included in the study subjects to assess any health problems. Any abnormalities and diseases conditions during clinical surveillance and follow-up period was recorded. We considered two types of breed: local breed which includes the boran and zebu cattle and exotic or Holstein-Friesian breeds.

Clinical diagnosis
Individual cases were screened for the presence of disease with the help of veterinarians in the clinic and basic laboratory methods such as floatation and sedimentation were used for characterizing parasites following the procedure given by Hansen and Perry [14] and the remaining diseases types were identified based on the clinical judgement by the veterinarian. After confirmation, clinical cases were administered with recommended therapeutics for treatment.

Data management and analysis
All data collected from the study were analyzed using statistical software for social sciences version 20 (SPSS 20) and Chi square statistical method was used to analyze the data. Descriptive statistical tools were used to show the incidence rate of different diseases. P-values less than 0.05 was considered as measure of statistical significance.

Discussion
In the present study, the incidence rate is different depending on the nature of the disease whether it is infectious, non-infectious diseases or reproduction related problem. The productive problems were the most frequently encountered cases during the study. This is due to the poor management of dairy animals during milking and poor husbandry practices. For example, all farms use the manual or non-machinery milking system, and this enhances the degree of contamination and the chance of transmitting pathogens among dairy animals. Regular sanitation and applying a pre-milking teat dip or spray for the prevention of infection is not a common practice in the farms. Dystocia was frequently observed during this study period and there are many factors associated with it. Such as the maternal factors (the size of the birth canal) and fatal factors (Orientation and over sizing of the foetus). The problem associated with dystocia was found to be associated with cause of retained fatal membrane in certain clinical cases. But many hormonal factors might also contribute for the problem. Similar studies also showed that retained fetal membrane was one of the problems of dairy cows with an incidence of 5-8% [7]. Furthermore, the present study showed a lower incidence of abortion comparing to previous studies [8,9]. This is because dairy cows in the present study area gets a regular treatment with antibiotics and we suggest the therapeutics helped in controlling the major abortion causing diseases such as brucellosis. Moreover, physical injury was also identified as a cause of early abortion in dairy cows. Infectious diseases were also occurred frequently at an incidence of ranging from 5.00 to 10.71% which is in agreement with other reports conducted in the southern region of Ethiopia [10]. One of the justification for increasing the incidence of infectious diseases in the area is due to the non-selective administration of therapeutic drugs which has an impact on the efficacy of treatment outcomes. The incidence of respiratory problems such as pneumonia, bronchitis, and sinusitis were found lower than the previous studies [11]. The housing quality which is spacious and well aerated might contribute for the findings of low incidence in our study. Moreover, incidence of actinomycosis in the present study revealed 6.52% which is also in agreement the previous studies [12]. Parasitic diseases were observed as common health problem of livestock in the area. Tick infestations, and endoparasites were found frequently to cause loss of body condition. The high occurrence of parasitic disease in the study area could be due to low deworming practice as we have obtained this information from the farm owners. Whereas, incidence of tick infestation recorded in this study agrees with another report which showed an incidence of 8.8% [13]. Finally, injurious problem were important health challenges of cattle which is due to uncontrolled hygiene, production and management system and in this study, different types of physical injuries such as lameness, bruising, and injuries as a result of physical damage during restraining for milking and medication was assessed by the veterinarians and the result showed its significant impact on the wellbeing of dairy animals.

Conclusion
In conclusion, this study identified a wide range of infectious and noninfectious dairy animal diseases which are the main threat for the dairy health sector in the region. Based on this finding, detail studies on the dynamics of the diseases should be studied, and prompt control measure should be in action.

Limitations of the study
The lack of adequate laboratory facilities to diagnose all kind of animal disease was one of the limitations in this study. As a result, we are unable to make sure about the specific pathogen as there could be a high chance of mixed infections and this might affect the true map of the disease distribution in the area.