Increasing ventilation in commercial cattle trailers to decrease shrink, morbidity, and mortality

Abstract

A practical method of reducing aerosolized pathogens and environmental contaminants during commercial transportation could prove beneficial to the health and value of cattle. Having previously determined that there was very limited airflow within moving livestock trailers, an experimental treatment that increased cross-ventilation within commercial cattle trailers by installing aluminum scoops to punch-hole trailers was evaluated. Environmental factors including temperature, ammonia and carbon dioxide concentrations, and percent dry matter of excreted urine and fecal matter were evaluated, along with physiological factors, including complete blood count, serum electrolyte concentrations, percent weight loss, the presence of Salmonella, Escherichia coli, or Mannheimia haemolytica, and 30 day health data. The experiment consisted of two trials, each with two truckloads of 80 cattle each, for a total of 320 cattle. Temperature was evaluated in the center compartments of each trailer at five minute intervals throughout both trips. Ammonia concentrations were measured using passive dosimeters. Jugular blood samples, fecal grab samples, swabs of the terminal rectum and nasal swabs were obtained 8.5 to 10 hours post-transport from 20 cattle from each trailer. Increased ventilation resulted in lower temperatures and ammonia concentrations on both trips. Percent dry matter of excreted urine and fecal matter were inconclusive. There were no treatment effects for complete blood counts or electrolyte and basic chemistry panels, possibly because the cattle had access to both hay and water between transport and sampling, which allowed for recovery. Cattle in the ventilated trailer had an average weight loss of 4.7%, compared with 5.75% for the cattle in the control trailers. Sampling for E. coli O157:H7, Salmonella, and M. haemolytica showed very few positives, likely due to the good condition of the cattle prior to transport. During the 30 days post-transport, no cattle from either treatment required veterinary attention related to transport. The results indicate that increasing ventilation through the use of external air scoops has the potential to improve the health and well-being of cattle during transport.