Incidence of morbidity and mortality in calves from birth to six months of age and associated risk factors on dairy farms in Hawassa city, southern Ethiopia

Detection and molecular characterization of major enteric pathogens in calves in central Ethiopia

BACKGROUND

Calf diarrhea is a major cause of morbidity and mortality in the livestock sector worldwide and it can be caused by multiple infectious agents. In Ethiopia, cattle are the most economically important species within the livestock sector, but at the same time the young animals suffer from high rates of morbidity and mortality due to calf diarrhea. However, studies including both screening and molecular characterization of bovine enteric pathogens are lacking. Therefore, we aimed to both detect and molecularly characterize four of the major enteric pathogens in calf diarrhea, Enterotoxigenic Escherichia coli (E. coli K99 +), Cryptosporidium spp., rotavirus A (RVA), and bovine coronavirus (BCoV) in calves from central Ethiopia. Diarrheic and non-diarrheic calves were included in the study and fecal samples were analyzed with antigen-ELISA and quantitative real-time PCR (qPCR). Positive samples were further characterized by genotyping PCRs.

RESULTS

All four pathogens were detected in both diarrheic and non-diarrheic calves using qPCR and further characterization showed the presence of three Cryptosporidium species, C. andersoni, C. bovis and C. ryanae. Furthermore, genotyping of RVA-positive samples found a common bovine genotype G10P[11], as well as a more unusual G-type, G24. To our knowledge this is the first detection of the G24 RVA genotype in Ethiopia as well as in Africa. Lastly, investigation of the spike gene revealed two distinct BCoV strains, one classical BCoV strain and one bovine-like CoV strain.

CONCLUSIONS

Our results show that Cryptosporidium spp., E. coli K99 + , RVA and BCoV circulate in calves from central Ethiopia. Furthermore, our findings of the rare RVA G-type G24 and a bovine-like CoV demonstrates the importance of genetic characterization.

Trematode infection in ruminants and diversity of snail hosts across three agro-ecological zones in Ethiopia

The occurrence of trematodes among ruminants and their snail vectors is a major concern across various agro-ecological regions of Ethiopia. Trematodes pose significant threats to animals, causing considerable economic losses and impacting public health. In this study, we have investigated 784 ruminant fecal samples, and 520 abattoir samples, alongside the collection and identification of snail vectors from various agro-ecological regions. Fecal examinations revealed Fasciola, Paramphistomum and Schistosoma species infected 20.5% (95% CI: 17.6, 23.8), 11.7% (95% CI: 9.6, 14.2), and 6.3% (95% CI: 4.1, 9.1) of the animals, respectively. The overall prevalence of trematodes among ruminants was 28.8% (95% CI: 25.7, 32.1%), with 6.0% (95% CI: 4.3, 7.7) showing mixed infections. Fasciola was more prevalent in Asela (26%) compared to Batu (19%) and Hawassa (11.5%), while a higher proportion of animals in Batu were infected with Paramphistomum. Schistosoma eggs were detected only in Batu (12.5%), but not in other areas. Sheep and cattle exhibited higher infection rates with Fasciola, Paramphistoma, and Schistosoma compared to goats. Significant associations were observed between trematode infections and risk factors including agro-ecology, animal species, body condition score, and deworming practices. About 20.8% and 22.7% of the slaughtered animals harbored Fasciola and Paramphistomum flukes, respectively, with a higher prevalence in Asela and Hawassa abattoirs compared to Batu abattoir. Additionally, a total of 278 snails were collected from the study areas and identified as lymnae natalensis, lymnae trancatula, Biomphalaria pffiferi, Biomphlaria sudanica, and Bulinus globosus. In conclusion, the study highlights the widespread occurrence of trematode infections, emphasizing the need for feasible control measures to mitigate their economic and public health impacts.

Comparative Analysis of Maternal Colostrum and Colostrum Replacer Effects on Immunity, Growth, and Health of Japanese Black Calves

Maternal colostrum (MC) is an important source of nutrients and immune factors for newborn calves. However, when colostrum is unavailable or of poor quality, a colostrum replacer (CR) may be a suitable alternative to MC. As stock-raising farmers must make informed decisions about colostrum feeding management, this study was conducted to determine the effect of feeding MC versus CR on the promotion of immunological status, growth, and health in pre-weaned Japanese black (JB) calves. Sixteen newborn JB calves were fed MC after birth, and 16 JB calves were fed CR. For the MC group, the numbers of γδ T cells, CD4+ cells, CD8+ cells, CD4+CD8+ cells, B cells, and MHC class II+ cells were significantly higher compared with the CR group. Furthermore, the expression levels of interleukin (IL)-1β-, IL-2-, and interferon-γ (IFN-γ)-encoding mRNAs were significantly higher in the MC group compared with the CR group. A lower incidence of disease in 1-month-old calves and higher carcass weight in the MC group were observed compared with the CR group. These results suggest that CR activates the immune system delayed in calves compared with MC. MC increases populations of various immunocompetent cells, which can reduce infection rates and improve body weight gain.

Calf morbidity, mortality, and management practices in dairy farms in Jimma City, Southwestern Ethiopia

BACKGROUND

This research aims to determine the incidence of calf morbidity, mortality and its potential predisposing factors in the first six months of life. Morbidity and mortality of dairy calves are persistent problems for dairy farmers worldwide. For effective control and prevention programs on calf health, it is imperative to estimate the extent of calf morbidity and mortality, and associated risk factors. Although few studies have investigated the epidemiology of calf morbidity and mortality in Ethiopia, comprehensive information is scarce in this area.

METHODS

Data were collected through a cross-sectional survey and longitudinal follow-up on purposively selected dairy farms. A longitudinal study was conducted on 235 calves from birth to 6 months of age. Survival analysis methods using the Kaplan-Meier (K-M) method, and mixed effect Cox proportional hazard regression were employed to compute the life-to-event data on morbidity and mortality.

RESULTS

From the 235 calves studied, 53 morbidity and 15 mortality events were recorded. This gives an overall morbidity and mortality incidence rate of 55 per 100-calf 6-months at risk (risk rate of 42.07%) and 14 per 100-calf 6-months at risk (risk rate of 12.97%), respectively. Diarrhea (13.84%) followed by pneumonia (8.97%) were the most common diseases that occurred in calves, respectively. Similarly, diarrhea (33.3%) and pneumonia (26.7%) were the leading causes of death. Dam parity (p < 0.001) and pen cleaning (p < 0.001) were significant predictors of calf morbidity. Dam parity (p = 0.007), calving status (p = 0.005), pen cleaning (p = 0.04), and floor type (p = 0.001) of houses were significantly associated with mortality. The hazard of diarrhea was significantly associated with sex (p = 0.003), first colostrum feeding time (p = 0.028), pen cleaning (p = 0.010), and breeding method (p = 0.013).

CONCLUSION

The rates of morbidity and mortality reported in the study were higher than the economically acceptable, also affecting the welfare of the animals. The risk factors found need due attention in the management practices of dairy calves in Ethiopia.

Comparable Evaluation of Nutritional Benefits of Lactobacillus plantarum and Bacillus toyonensis Probiotic Supplementation on Growth, Feed Utilization, Health, and Fecal Microbiota in Pre-Weaning Male Calves

This study was conducted to investigate the impact of probiotic supplementation using Lactobacillus plantarum DSA 20174 and/or Bacillus toyonensis ATCC 55050 on growth performance, blood parameters, hematological measures, and fecal microbiota in pre-weaning Holstein calves. Thirty-two four-day-old male calves with a similar genetic background, weighing an average of 38.27 ± 0.12 kg, were randomly assigned to four groups. The groups consisted of a control group (CON) without supplementation, a group receiving B. toyonensis (BT) at 3 × 109 cfu/calf/day, a group receiving L. plantarum (LP) at 1 × 1010 cfu/calf/day, and a group receiving a combination of LP and BT (LP + BT) at half the dosage for each. The study found that calves supplemented with LP and LP + BT experienced significant improvements in average daily gain and final body weight compared to the control group. The LP + BT group showed the most positive effects on TDMI, starter intake, and CP intake. RBC counts tended to be higher in the probiotic groups, with the LP + BT group having the highest values. The LP + BT group also had higher total protein, albumin, globulin, and hematocrit concentrations. All probiotic groups showed higher serum IgG concentrations. Probiotic supplementation led to increased total bacterial count and decreased levels of E. coli, salmonella, and clostridium. The LP + BT group had a significant decrease in coliform count, while both LP and LP + BT groups had increased Lactobacillus populations. In conclusion, LP + BT probiotic supplement showed the most beneficial effects on growth, feed efficiency, blood constituents, and modulation of fecal microbiota composition.

Status of animal health biosecurity measures of dairy farms in urban and peri-urban areas of central Ethiopia

Ethiopian dairy farming has many constraints including disease and lack of appropriate biosecurity measures. With this into consideration, a cross-sectional survey was carried out from November 2021 to April 2022 to determine the animal health biosecurity status of dairy farms and investigate the sociodemographic characteristics of livestock keepers on dairy farm management. A face-to-face questionnaire survey using an online application was used to collect data. The interview involved a total of 380 dairy farms located in six towns in central Ethiopia. The results showed that out of the surveyed farms, 97.6% missed footbaths at their gate points, 87.4% lacked isolation areas for either sick or newly introduced cattle, and 83.4% did not check the health status or quarantine newly introduced cattle. Furthermore, written formal record-keepings on animal health was uncommon, except for a few farms (7.9%). However, nearly all of the respondents (97.9%) gave medical treatments for sick cattle, and 57.1% of them vaccinated their herds regularly during the past 12 months before the survey. Hygienic aspects of the farms showed that 77.4% of the dairy farms appeared to clean the barn on a daily basis. However, 53.2% of respondents did not utilize personal protective equipment while cleaning their farms. A quarter of the dairy farmer (25.8%) avoided mixing their cattle with other herds, and 32.9% of them have implemented isolation of sick animals. In general, the animal health biosecurity assessment of the farms showed that most of the dairy farms (79.5%) earned unacceptable biosecurity levels (score of ≤ 50%), whereas the remaining 20.5% of dairy farms had received a score of &gt;50% (“acceptable level”). The gender of dairy farmers (χ2 value = 7.61; p = 0.006), education level (χ2 value = 12.04; p = 0.007), dairy farm ownership (χ2 value = 41.6; p &lt; 0.001), training on dairy farm management (χ2 value = 37.1; p &lt; 0.001), towns (χ2 value = 31.69; p &lt; 0.001), farm size (χ2 value = 7.7; p = 0.006), and herd size (χ2 value = 28.2; p &lt; 0.001) showed a significant statistical association with biosecurity status. Finally, the study revealed that the level of biosecurity adoption of dairy farms in central Ethiopia is mostly unsatisfactory and calls for designing and implementing intervention measures toward improved animal health in dairy farms and further public health.

Longitudinal study of calf morbidity and mortality and the associated risk factors on urban and peri-urban dairy farms in southern Ethiopia

BACKGROUND

Calf morbidity and mortality are among the leading causes of economic losses on dairy farms around the world. Poor calf management practices exacerbate the problem in developing countries like Ethiopia. This prospective, longitudinal study was conducted on 70 selected dairy farms in southern Ethiopia with the aim of estimating calf morbidity and mortality rates, identifying the associated risk factors and determining whether the mortality rate is above economically tolerable levels. For this purpose, a total of 274 calves on 70 farms were followed up every two weeks from birth to six months of age for major clinical health problems and deaths.

RESULTS

The study found a morbidity rate of 13.2 cases and a mortality rate of 3.8 cases per 100 calf-months at risk in the study calves. The cumulative incidence of morbidity and mortality was also found to be 40.29% and 12.85%, respectively. Diarrhea was the leading cause of morbidity and mortality in calves, accounting for 71.3% and 62.1% of all morbidity and mortality, respectively. In a multivariable Cox regression analysis, the risk of morbidity was significantly (p = 0.022) higher in calves born to dystocia-affected dams (HR = 2.4) and on farms where dairy farming is the farmers' secondary source of income (HR = 1.7). However, the risk of morbidity was significantly (p < 0.001) lower in calves older than three months (HR = 0.22), female calves (HR = 0.57), calves raised by farmers who had completed secondary school (HR = 0.26) or college education (HR = 0.30). Similarly, calves aged over three months (HR = 0.14), calves separated from their dams only after ingestion of colostrum (HR = 0.40) and calves owned by farmers who completed secondary school (HR = 0.08) or college education (HR = 0.13) all had lower mortality rates than other groups. On the other hand, calves born to cows with dystocia were 5.2 times more likely to die.

CONCLUSION

The study concluded that calf morbidity and mortality rates in the study area are higher than economically tolerable levels and therefore it is recommended to raise awareness among farmers to improve calf management practices.