Effect of water quality on causes of calf mortality in cattle-farm-associated epidemics.

Poor-quality drinking water plays a detrimental role in the suppression of calf immunity, giving rise to an increased rate of calf mortality. The present study aims to evaluate the causes of calf mortality in beef and dairy farms in relation to drinking water quality (DWQ). A convenience sample of 132 Egyptian cattle farms suffering from emerging epidemics was surveyed by collecting drinking water samples for physicochemical and microbial analysis and using a questionnaire to record hygienic risk factors affecting calf health. Statistical analysis correlates water parameters with rates of calf diarrhea, respiratory problems, severe depression, sudden death and mortality. High percentages of water sample quality parameters, e.g. pH, total dissolved solids (TDSs), hardness, chloride, nitrate, sulfate, total colony count (TCC) and total coliform count (TCFC), are above permissible limits. Water parameters, except pH, show a significant moderate positive correlation with causes of calf mortality ( 0.331-0.66) in winter and summer. Each cause of calf mortality was predicted by a specific water parameter, and the water nitrate level was the highest predictor, with the highest values (    0.504-0.577), followed by the water TDS, sulfate and microbial levels. Weak to moderate correlation ( 0.151-0.367) was found between calf mortality causes and some hygienic risk factors such as operation type, calf housing, calf feeders, bedding type, water source, water pipe type, drinker lining and wheel dipping. We could conclude that DWQ greatly affects causes of calf mortality, but we cannot exclude some farm hygienic risk factors.