Calf health is vital for the economical production of cattle breeding, which is widespread all over the world. In order to run a cost-effective operation, it is aimed for each cow to give birth to a calf once a year (19). There are 1.5 billion cattle populations in the world, and the densest countries are Brazil, India, the USA, and China (FAO 2018).
Diarrhea in newborn calves causes great economic losses worldwide. Diarrhea can be triggered by both infectious and non-infectious agents. Cryptosporidium spp., Rotavirus, Coronavirus, and E. coli are the most common neonatal diarrhea agents in calves (Lorenz et al., 2011; Meganck et al., 2015; Ok et al., 2009).
In a lot of studies, it has been stated that the prevalence of diarrhea in calves is related to Cryptosporidium spp. density. In addition, the more general hygiene of the farm is terrible, the more Cryptosporidium spp. related diarrhea and calf deaths can be seen (23).
Every year 9 million calves are born in the USA. More than 500,000 (6%) of calves born die before weaning. 56.4% of deaths have been determined as digestive system diseases (USDA 2018). This rate is 6.4% in Canada (24). In a study conducted in Brazil, it was determined that 8.5% of 1451 calves died before weaning and 44% of deaths were caused by diarrhea (25). Acceptable mortality rate before calving was determined as 5% in calves (DCHA Gold Standards, 2013).
The prevalence of Cryptosporidium in cattle in the world is around 30% (26). The prevalence of Cryptosporidium spp. was found to be 22.3% (81/364) in Australia in calves (27). In India, the prevalence of Cryptosporodium by PCR was 32.3% in diarrhea calves (28). In another study conducted in India, Cryptosporidium positivity was 50% (40/80) in calves with diarrhea by modified Ziehl-Neelsen staining (29). In another study conducted in 75 heifers in Poland, the prevalence of Cryptosporidium was determined as 30.7% by modified Ziehl-Nielsen staining (30). 2009). In Canada, 40.6% (203/500) of calves with diarrhea were Cryptosporidium positive by microscopy (31). In a study conducted with immunofluorescent staining in Norway, the prevalence of Cryptosporidium was determined as 12% (167/1386) in calves and 53% (72/136) in farmers (32).
The high prevalence of Cryptosporidium spp. have been shown in studies conducted in Turkey (33). Cryptosporidium oocysts were first detected in cattle in a study conducted in 1984 in Turkey (34). Later, Cryptosporidium oocyst prevalence in calf stool samples was found to be 32.9% in Kars, 27.33% in Konya, and 35.8% in Ankara by microscopy (1, 35, 36).
In another study conducted in Nevşehir, Cryptosporidium DNA was found in 20.7% of stool samples of 150 calves with diarrhea using Real-Time PCR (33). In this study, Cryptosporidium spp. DNA was found in 75% of calves with diarrhea. This high prevalence value indicates that there is an outbreak of Cryptosporidium spp. in calves in the examined dairy farm. In addition, the detection of Cryptosporidium spp. DNA in one of the artesian water source has been linked to the constant infection of the daily water supplied to the calves with the parasite.
PCR and microscopy are the most commonly used diagnostic methods in the diagnosis of Cryptosporidium in calves, and studies have shown that PCR is more sensitive and specific than microscopy (16, 37). Similar to these studies, Real-Time PCR method was found to be significantly more sensitive (P < 0.05) than microscopy in our research. Also, PCR methods are advantageous because they do not require experienced personnel, many samples are run at the same time, and they do not require concentration methods used in microscopy (16, 37).
Cryptosporidium spp. is a zoonotic infection. It can be passed from calves and cattle to man, and vice versa. Cryptosporidium spp. oocysts were found in 33.47% of human cases with diarrhea by Kinyoun acid-fast staining in İzmir. İzmir is the neighboring province of the dairy farm examined in this study (38). For these reasons, it is crucial to follow the stool samples of the personnel working in such farms to prevent the spread of the disease.
The high incidence of Cryptosporidium infections in newborn calves results from inadequate hygiene practices. Transmission in farms can occur through direct contact with infected animals, and poor conditions in terms of medical care and water supplies contaminated with Cryptosporidium oocytes increase the prevalence of Cryptosporidium (39).
Diarrhea related to Giardia intestinalis in calves has been reported in many studies (32, 40). In our study, G. intestinalis cysts were observed in 21.27% (10/47) all animals examined. It was thought that the high prevalence could be due to the Cryptosporidium spp. detected-water source.
In this study, Cryptosporidium spp. was detected in one of the artesian water sources. This drinking water used for calves is brought from this polluted water source through an individual water pipeline. It is supplied to calves and dairy cows without any filtration or disinfection. Due to the lack of sanitation, not only Cryptosporidium but also other agents that cause diarrhea can infect calves and cows. In this study, the microscopic detection of G. intestinalis cysts supports insufficient water sanitation. Adjacent paddocks facilitate the passage of diarrhea feces that are infected with Cryptosporidium oocysts. Also, relevant environmental samples that are positive for Cryptosporidium are another factor that eases the communication of Cryptosporidium oocytes among animals.
After the detection of Cryptosporidium spp. and G. intestinalis in calves, water intake from infected artesian water source was stopped and a new artesian source was opened within the boundaries of the dairy farm. Meanwhile, calves were treated with anti-parasitic drugs for Cryptosporidium and G. intestinalis. Later, when Cryptosporidium spp. was checked in water samples collected from the newly opened artesian source with 3 months intervals, DNA was not detected. As a result of these precautions, it has been reported that diarrhea cases have decreased in calves on this farm.