1. Background

Livestock is one of the most important assets and resources for many poor farmers around the world [1], including Ethiopia [2]. Livestock contribute more than just food: They also help with tasks like plowing fields, provide income in tough times, and offer valuable products like leather, fuel, and fertilizer, and in places where financial institutions are lacking, livestock can even be used as a form of savings [3]. For millions of poor farmers, livestock is more than just a resource. It is a part of their social and cultural lives. Owning animals helps them farm sustainably and ensures their financial security [4, 5]. Sub-Saharan African countries like Ethiopia largely depend on livestock production. Ethiopia is estimated to have about 59.2 million cattle, including 10.5 million dairy cows. These cows produce around 3.6 billion liters of milk annually [6]. Dairying is growing in importance, and calves are crucial for the future of dairy farms [3, 7, 8]. The government is focusing on developing the dairy industry to increase milk production from small farms [9, 10]. Many developing countries, like Ethiopia, rely on small farms for dairy production. This provides essential nutrition and income for millions of families [11]. The demand for milk and dairy products in urban and peri-urban areas has surged dramatically, with national per capita consumption reaching a substantial 27 L annually [12]. However, to meet the rapidly growing demand for milk and dairy products, a significant increase in the number of high-yielding, well-adapted cows is imperative [13]. Given the substantial potential for smallholder income and employment growth through high-value dairy products [14], developing Ethiopia’s dairy sector can significantly enhance food and nutrition security, thereby contributing to poverty reduction in the country. The success of any breeding program and the future viability of smallholder dairy farms pivots on the survival rate of newborn calves.

However, calf morbidity and mortality pose a significant threat to dairy business operators, as most dairy farms grapple with acute calf health challenges [15, 16]. The health of replacement calves is a critical determinant of overall dairy operation profitability [17], as dairy heifer calves are the building blocks of future milking herds. Furthermore, high calf mortality and illness lead to significant economic losses for dairy producers due to death, treatment costs, reduced productivity, and hindered herd growth and genetic improvement [18]. Numerous studies around the world have investigated calf illness and death rates, identifying their causes and contributing factors with smallholder dairy farmers; in particular, they face alarmingly high calf mortality rates, which can go up to 50% [1]. Diarrhea in newborn calves and pneumonia in older calves are the primary causes of calf illness and death [19]. Some African countries in tropical regions have reported varying calf mortality rates. For example, in Tanzania, calf mortality rates can range from 9% to 45% [20]; in Mali, the range is between 10% and 25% [21]; and in Sudan, dairy farms in Khartoum reported a 4.9% calf mortality rate [22]. On average, 23% of Holstein Friesian female calves born at Holleta Farm in Ethiopia died before reaching their first calving age. On average, 23% of Holstein Friesian female calves born at Holleta Farm in Ethiopia died before reaching their first calving age [23]. In general, calf mortality rate in Ethiopia ranges from 7% to 30.7% [24, 25]. It is estimated that a 20% calf mortality rate can reduce net profits by 38% [26].

Calf diseases that lead to illness and death are caused by a complex interplay of factors, including management practices, environmental conditions, the calf’s mother, and the calf itself [27]. It is obvious that the housing conditions of livestock can greatly affect their health and productivity [15]. The combination of a compromised immune system and a lack of prior exposure to infection renders newborn calves highly susceptible to infectious diseases [27]. Passive immunity can be achieved through the ingestion of adequate volumes of colostrum by calves. Other factors impacting calf health and survival of calves include herd production levels, antibiotic use, weaning age, and calf separation or mixing [28, 29].

In Ethiopia, the morbidity and mortality recorded by different authors from different parts of the country were 66.7% and 20% [30], 62.0% and 22.0% [15], 29.3% and 9.3% [24], 58.4% and 30.7% [25], and 30.9% and 8.64% [31], respectively. The primary causes of calf morbidity and mortality include calf diarrhea, calf pneumonia, navel ill (omphalitis), septicemia, vector borne diseases and helminthes, and nutritional problems [32]. Similarly, Fentie et al. [33], Tora et al. [34], and Ahmedin and Assen [35] have reported that diarrhea and pneumonia (respiratory disorder) were the most common causes of calf morbidity and mortality in that order. Like in other areas of Ethiopia, calf morbidity and mortality are serious challenges for small holder dairy husbandry in Tigray regional state. The frequent occurrence of diseases, significant calf losses, and the ineffectiveness of routine treatments have driven many farmers to financial ruin [36]. These, coupled with the absence of record-keeping, are the major challenges in dairy husbandry and milk production in the area (personal observation). Most importantly, prior assessments have not been conducted, and calf morbidity and mortality in this region remain poorly documented. Therefore, this study aimed to provide preliminary evidence on magnitude and epidemiological characteristics of calf morbidity and mortality in Northwestern and Central zones of Tigray that can be used to develop and apply cost-effective prevention and control measures.

2. Methodology

2.1. Description of Study Area

The study was conducted in Central and Northwestern zones of Tigray, Ethiopia (Figure 1). Central zone of Tigray is located about 963 kms away to the North from Addis Ababa. The geographical coordinates are 14° 7′ 8″ N, 38° 43′ 46″ E with altitude range of 2000 to 3000 m above sea level (masl). The average daily temperature is 18.3°C with average annual rainfall of 861 mm. There were 446 dairy farms with 2189 cows in Central zone. Similarly, Northwestern Tigray is a zonal administration located at about 1126 kms away to the North of Addis Ababa and its altitude ranges from 645 to 2852 masl and its coordinates are 14°01′13.4″N, 38°09′50.0″E. The annual temperature of the area varies from 18°C to 34.6°C. The annual rainfall of Northwestern zone of Tigray ranges between 450 and 800 mm. In Northwestern zone, there were 374 dairy farms with 1687 dairy cows. Overall, there were 820 dairy farms and 3876 dairy cows in both zonal administrations. Both Central and Northwestern zones are assumed to have relatively good potential for crop and livestock production [6].

3. Results

The result section comprises household surveys of KAP assessment on calf morbidity and mortality, FGD, and KII complemented by participatory epidemiological evidences. The result of each component is presented as follows:

3.4. Participatory Epidemiology

The findings of participatory epidemiology were summarized as follows:

3.4.1. Simple Ranking

Using simple ranking approach, calf diarrhea, nutritional disorder, pneumonia, calf blindness, epilepsy, and naval ill were the top most prevalent diseases and causes of mortality in dairy farms in Northwestern areas while lack veterinary services and limitations of drug supply; in appropriate site selection; lack of drainage; insufficient space of farms (to accommodate large herd size with no space for excising); and lack of water supply were the major challenges of dairy farms in the study area. However, diarrhea, manges (ectoparasites), pneumonia, naval disease, and blindness were the most common health problems of calves in Central zone, mainly Axum area; shortage of feed, poor animal health service, limitation of farming spaces, poor AI service, lack of market linkage, and shortage of water supply were prioritized as top challenges in dairy farms.

3.4.2. Pairwise Ranking

Pairwise assessment result indicated that diarrhea, nutritional disorder, pneumonia, calf blindness, epilepsy, and naval ill were the top ranked six causes of calf morbidity and mortality in Northwestern Tigray (Figure 2), while diarrhea, naval disease, pneumonia, ectoparasites, and blindness syndrome were common health problems in Central zone.

3.4.3. Proportional Piling

Using a proportional piling approach, we provided 100 beans (equivalent to 100 calves) to the participants to assign the morbidity and mortality rates among newborn calves. Accordingly, the overall prevalence of calf morbidity and mortality were estimated to be 75.5% and 55.9%, respectively. With regard to occurrence of the diseases among different zones, the average morbidity rates were 82% in Northwestern zone (Figure 3) and 79% in Central zone (Figure 4), while the mortality rates were estimated to be 69.8% in Northwestern zone and 42% in Central zone of region, respectively. Moreover, proportional piling method was employed to estimate the average morbidity rates calves by age and recorded as follows: 66.2 in one-week-old calves; 14.8% in 1- to 2-week-old; 7.6% in 2 to 4-week-old; 5.1% in 4 to 12–week-old; 3.8% in 12 to 24-week-old; and 2.7% in and 24 to 52-week-old calves. Average proportional piling results of mortality rates by age were 86.8%, 70.9%, 51.5%, 46.7%, 50%, and 12.5% of less than 1 week, 1-2 weeks, 2–4 weeks, 4–12 weeks, 12–24 weeks, and 24–52 weeks, respectively.

3.4.4. Matrix Scoring

Thirty beans were provided to participants to identify the indicators of calf diarrhea, paralysis or nutritional disorder, pneumonia, navel infection, and calf epilepsy. The corresponding results revealed that coughing and weight loss were 100% indicators for pneumonia and calf diarrhea, respectively. About 90% of calf diarrhea and 10% of navel infection showed watery, greenish, or profuse diarrhea. The participants were also indicated that recumbence was an indicator for nutritional disorder at 66.7%, and 33.3% of calf epilepsy. And, 100% of navel infection showed swelling and abscess/pus around the umbilicus. About 86.7% of pneumonia and 13.3% of calf diarrhea cases showed nasal discharges. Lacrimation was an indicator for pneumonia at 80%, nutritional disorder at 13.3%, and calf diarrhea at 6.7%.

3.4.5. Seasonal Calendars

Further, 30 beans were set to assess the seasonal pattern of calf morbidity and mortality rates using proportional piling approach. Accordingly, calf morbidity was estimated to occur in autumn, winter, spring, and summer with average rates of 20.8%, 21.8%, 24.7%, and 30%, respectively. In Northwestern zone, calf morbidity occurred in autumn, winter, spring, and summer seasons with average rates of 20%, 22%, 28% and 30%, respectively, while 27%, 21.6%, 21.4%, and 30% occurred in autumn, winter, spring, and summer seasons with average rates of 20%, 22%, 28%, and 30%, respectively, in Central zone (Figure 5).

4. Discussion

The present study revealed that calf morbidity and mortality were among the serious challenge for dairying in the study area. About 69.4% and 63.9% of the questionnaire respondents had experienced calf morbidity and mortality, respectively, during the preceding 5 years. These proportions were higher than previously reported studies in Ethiopia [44]. This might be due the difference in study design, agro-ecological settings, management practices, as well as availability infrastructure and service in the study areas.

According to the questionnaire survey, calf diarrhea was the primary cause of both morbidity and mortality, accounting for 43.8% and 33.3%, respectively. This finding aligns with the reports of Ahmedin and Assen [35], Tesfaye et al. [44], and Alemu et al. [45]. However, our finding was lower than that of reported by Abebe et al. [46], but it was higher than the reports of Tesfaye et al. [44] and Megersa et al. [24]. The difference might be due to varying farming practices. The higher prevalence of diarrhea in our study may be linked to poorer hygiene, sanitation, and colostrum feeding habits on the farms. For example, the respondents believe that colostrum can harm young calves. Qualitative results such as FGDs, KII, and participatory epidemiology, and qualitative studies revealed that nutritional disorders, navel ill, and pneumonia were other leading causes of morbidity and mortality which required comprehensive investigation and targeted intervention. Particularly, both quantitative and qualitative studies were the same in identifying diarrhea as the primary cause of morbidity and mortality. Similar results were reported from different areas of the country in identifying diarrhea as the primary cause of morbidity and mortality. Similarly, this was reported from different areas of the country by other authors: Ahmedin and Assen [35], Tesfaye et al. [44], Alemu et al. [45], Abebe et al. [46], and Megersa et al. [24] though the specific rates for each cause varied. Diarrhea and pneumonia were the blamed causes as reported by Wudu et al. [15], Fentie et al. [33], Ferede [25], Asmare and Kiros [47], and Dagne et al. [48]. Nutritional disorders also pose a significant health threat to dairy farms, necessitating a comprehensive investigation and targeted intervention. Indeed, Mohammed et al. [49] reported on most of these disease conditions that most of these disease conditions were also identified as major health problems in dairy farms, next to diarrhea. Pneumonia was identified as a cause of both morbidity and mortality, although at a lower rate than reported by Ahmedin and Assen [35], Alemu et al. [45], and Abebe et al. [46]. Furthermore, our personal observations confirmed that most farms were established in flat areas leading to poor drainage systems and stagnated liquid wastes in their compounds and were characterized to have poor hygiene and sanitation practices. It is obvious that poor hygiene and sanitation can lead to calf morbidities and mortalities in farms. Significant farms were also found concentrated in locations with dense human settlements and in close proximity to open livestock markets and municipal abattoirs, which could lead to spillover infection to human residents (zoonosis) and dairy cows (reverse zoonosis). This suggests the farms were established for short-term plans without careful consideration of expansion plans (master plans) of the respective towns.

Although it was statistically insignificant (p > 0.05) in the household survey, all key informants claimed that more than 90% of the cases of morbidity and mortality occur in less than one-week-aged calves. Similarly, FGD participants also suggested that most cases of calf morbidity and mortality occur mainly in the first week after birth. Results of participatory epidemiology are also similar to findings of KII and FGD that large numbers of cases occur in one-week-aged calves, followed by 1-2 weeks aged. Similar findings on calf morbidity and mortality at the early ages have been reported from different studies in Ethiopian such as Wudu et al. [15], Tesfaye et al. [44], Abebe et al. [46], Ferede et al. [25], and Mohammed et al. [49], as well as other studies conducted in Sweden [19] and Norway [50]. These early-age morbidity and mortality rates could be linked to poor calf management practices, including inadequate farm sanitation, insufficient colostrum feeding, and failure to vaccinate dams. Most importantly, farmers who attended the participatory epidemiology and FGD assessments claimed that most diseased calves did not respond to conventional antibiotic therapies. Furthermore, seasonal pattern assessment toward the occurrence of calf morbidity and mortality was also evaluated. The results showed that both calf morbidity and mortality had no significant difference (p > 0.05) across the seasons of the year. The findings of the FGD and KII results were also confirmed that calf morbidity and mortality had no distinct seasonal pattern.

Among the hypothesized risk factors, study zones/districts, sex of dairy owners, type of breeds, and health problems of dams were significantly associated (p < 0.05) with calf morbidity and mortality. Northwestern zone experienced 2.48 times higher calf morbidity and mortality rates than those of Central zone. This could also be explained by the level of animal health intervention and awareness creation efforts by governmental and nongovernmental entities or agroecological characteristics of the areas. Regarding the sex of dairy farm owners, male owners experienced twice higher calf morbidity and mortality rates than female farm owners. This could be attributed to women’s generally better adherence to hygiene and sanitation practices on farms compared to men. Females are highly effective and efficient as primary contributors to livestock husbandry practices. Similar finding was reported by Belay and Mekibib [51] that calf mortality rates were significantly lower on female-managed farms. With regard to breed types, crossbred calves were significantly more susceptible to morbidity and mortality compared to local breed calves. Alemu et al. [45] had reported similar findings, that local breeds exhibit greater tolerance to infections compared to crossbred calves. Calves born to dams having health problems were more at risks of morbidity and mortality. Yitagesu et al. [52] reported a similar finding that calves born to dams experiencing health complications, such as dystocia, were significantly associated with morbidity and mortality.

Management practices such as early calf separation, infrequent barn cleaning, inadequate disinfection, insufficient colostrum feeding, and poor water source were identified as significant risk factors for calf morbidity and mortality in this study (p < 0.05). Moreover, farm owners who failed to separate calves immediately from their dams and not disinfect their barns experienced higher morbidity and mortality rates than farm owners who implemented separating of calves from the dams and disinfection practices. Previous studies reported similar results that calves stayed with their dams and kept in unclean barns were more susceptible to infections [15, 35, 51]. Regular barn disinfection can significantly reduce pathogen loads, minimizing the risk of morbidity and mortality [15].

In the present study, calves which received less than 3 L of colostrum daily were more likely to develop health issues. This was consistent with previous study that calves which did not receive 3–4 L of colostrum per day were highly susceptible to infections [51] due to the fact that colostrum is the sole source of immunoglobulins, essential for protecting neonatal calves from infectious diseases [53, 54]. As a result, inadequate colostrum feeding was significantly associated with increased calf morbidity and mortality [45]. While almost all dairy farm owners in the study area provided colostrum to their calves promptly after birth, the quantities provided were often less than the daily recommendations. Farmers had misperceptions about the quantity of colostrum who believed that large amount of colostrum is dangerous to newborn calves [53, 54]. This misperception was evident during FGDs and participatory appraisals.

Similarly, farmers used river water were more likely to experience calf diseases compared to those used tap water. Similar results were reported that providing surface water to calves significantly increases the risk of exposure to waterborne diseases [51]. Using contaminated water for drinking and cleaning milk utensils, udders, and teats poses a significant risk of microbial contamination, leading to the spread of waterborne diseases [55], because water sources are frequently contaminated with coliforms, E. coli, and other enteric bacteria, leading to the development of calf diarrhea [56]. Generally, the discrepancies observed in the hypothesized risk factors can be attributed to variations in breed, farm characteristics, agroecological conditions, farming objectives, and diverse management practices.

5. Conclusion

The study identified that calf morbidity and mortality are serious challenges for smallholder dairying. Source of water, breed type, health status of dams, frequency of barn disinfection, using separated calf housing, amount of colostrum feeding, and cleaning frequency of barns were the potential risk factors of calf morbidity and mortality. Calf diarrhea, nutritional disorder, pneumonia, and navel ill were the major causes of calf morbidity and mortality. Poor hygiene and sanitation practices were also common in the dairy farms; and most of the dairy farms were concentrated in locations with dense human settlements, livestock markets, and municipal slaughtering houses. In addition, our assessment showed that lack of veterinary services and limited drug supply, shortage of water supply, poor AI services, and space limitation for exercising animals were the major challenges of dairy farms in the study area. These suggest that continuous capacity building trainings are required to reduce the burden of calf morbidity and mortality. Improving water supply, and veterinary and AI services would be crucial for the success of the farms. Furthermore, the locations of the dairy farms should be reconsidered as per the criteria set by the ministry of urban development and housing, and at least 5 km far from dense human settlements, livestock markets, and slaughter houses.

Conflicts of Interest

The authors declare no conflicts of interest.

Author Contributions

Gebreyohans Gebru, Dawit Gebremichael, Gebregergs Tesfamaryam, and Angesom Hadush conceived the study; Gebreyohans Gebru, Dawit Gebremichael, Gebregergs Tesfamaryam, Angesom Hadush, and Gebremedhin Romha designed the study and developed the questionnaire; Gebreyohans Gebru, Dawit Gebremichael, Gebregergs Tesfamaryam, Angesom Hadush, Tsriti Gebremeskel, Kiros Kelkay, Moges Gebremichael, and Alem Beyene collected the data; Dawit Gebremichael analyzed the data; Angesom Hadush, Gebreyohans Gebru, and Gebremedhin Romha drafted the manuscript. All authors reviewed and approved the manuscript for publication.

Funding

The study was financially supported by Aksum University (project ID number: AKU/001/12).