Reduced likelihood of bovine coronavirus and bovine respiratory syncytial virus infection on organic compared to conventional dairy farms

Abstract

The prevalence of antibodies to bovine coronavirus (BCV) and bovine respiratory syncytial virus (BRSV) infections was studied in 20 conventional and 20 organic dairy herds. The organic farms had produced 'certified' milk for at least 2 years. On two occasions, with a 1-year interval, 699 serum samples from 624 peri-parturient cows were tested by ELISA for antibodies to BCV and BRSV. Accompanying data relating to the sampled animals were collected in order to identify potential factors associated with increased antibody prevalence. The antibody prevalence was high at both sampling times with approximately 85% and 80% of animals positive for antibodies to BCV and to BRSV, respectively. Conventional herds had a significantly higher mean antibody prevalence to BCV and BRSV than the organically managed herds (P<0.01). Animal age was significantly associated with increased antibody prevalence (P<0.001). The findings of this study suggest that organic farm management may be effective in reducing the seroprevalence of these viruses relative to conventional farming methods.

Detection of Multiple Antibodies and Risk Factor Association of Common Respiratory Viruses in the State of Punjab, India

“…Age was a significant risk factor associated with BRSV with lower prevalence in the animal <1 years of age in Korea (Lee et al, 2000) and 7-8 fold higher odds of seropositivity to BRSV was earlier recorded in older group of animal >4years in Mexico (Solis-Calderon et al, 2007) and in Iran (Shirvani et al, 2012). The present seroprevalence to BRSV increased with increasing animal age is in consonance to the findings of Luzzago et al, (2010) and Bidokhti et al, (2009). Caswell and Williams (2008) opined seroprevalence in adult animals is reported to be 40 to 95% and correlate well with disease protection.…”

Epidemiology, Molecular Epidemiology and Evolution of Bovine Respiratory Syncytial Virus

“…In consequence, morbidity is commonly high during the occurrence of outbreaks [21]. Importantly, natural infection affects both beef and dairy cattle, although management practices can significantly impact the infectivity rates [22]. Climate also favors the dissemination of the virus during winter, after the sudden drop in temperature [11], although infection can occur throughout the year.…”

“…Unsurprisingly, high sero-prevalence has also been associated with large-capacity facilities, rather than with small farms. Interestingly, organic farms have been shown to exhibit lower antibody prevalence when compared to conventional farms [22]. These findings highlight the importance of management for the effective control of viral transmission and disease spread, which are closely associated with different farming methods…”

Phylogenetic analysis of bovine respiratory syncytial viruses from recent outbreaks in feedlot and dairy cattle herds

“…A 100% prevalence of antibodies was demonstrated in a nationwide bulk tank milk survey in England and Wales [20], and 41-89% prevalence was found in Sweden [21], with higher prevalence in the southern parts where the cattle density is high compared to northern Sweden [22][23][24][25]. A high herd prevalence of BRSV was also reported in Danish dairy herds [26], and the infection is regarded as one of the most important welfare and economic problems in the Danish beef industry, associated with a high mortality among calves and a high rate of antibiotic treatment [27].…”