A six-year study on respiratory viral infections in a bull testing facility

Abstract

Viral infection dynamics and bovine respiratory disease (BRD) treatment rates were studied over six years at a Swedish bull testing station with an 'all in, all out' management system. In August of each of the years 1998-2003, between 149 and 185 4-8-month-old calves arrived at the station from 99 to 124 different beef-breeding herds, and remained until March the following year. Only calves that tested free from bovine viral diarrhoea virus (BVDV) were allowed to enter the station and original animal groups were kept isolated from new cattle in their original herds for three weeks before admission. Although neither prophylactic antibiotics, nor BRD vaccines were used, less than 0.7-13.2% (mean 5%) of the calves (n=970) required treatment for BRD during the first five weeks following entry. This was probably due, at least in part, to the season (the summer months) when the animals were commingled. In the six-month period August-February, 38% of the animals were treated one or more times for BRD and mortality was 0.7%. Hereford and Aberdeen Angus calves had significantly higher treatment rates than Charolais, Simmental and Blonde d'Aquitaine. Serological testing on samples obtained in August, November and January indicated that bovine parainfluenza virus 3 (PIV-3) infections occurred each year before November after entry. Bovine coronavirus (BCoV) infections also occurred every year, but in 3/6 years this was not until after November. Bovine respiratory syncytial virus (BRSV) infections occurred only every second year and were associated with a treatment peak and one death on one occasion (December). The herd remained BVDV free during the entire study period. The infection patterns for PIV-3 and BCoV indicated a high level of infectivity amongst bovine calves, whereas the incidence for BRSV was observed at a lower level. Although the rearing of the animals differed from conventional beef production, the study has shown that commingling animals from many sources is not necessarily associated with high morbidity within the first few weeks after arrival. By preventing BRD soon after commingling the prerequisites for protective vaccination at entry might be improved. Applied management routines are discussed.

Associations between animal characteristic and environmental risk factors and bovine respiratory disease in Australian feedlot cattle

“…Several previous studies have found large variation in BRD risk between breeds, with increased risk for Hereford cattle, both in feedlots (Cusack et al, 2007;Snowder et al, 2006b) and in bull testing facilities (Durham et al, 1991;Hägglund et al, 2007). Consistent with a previous Australian report (Cusack et al, 2007), our results indicate that Herefords were at much higher risk of BRD and that tropically adapted breeds and crosses were at reduced risk compared to Angus cattle.…”

“…Several animal characteristics have been associated with increased risk of BRD, including breed, with the Hereford breed consistently associated with increased risk (Cusack et al, 2007;Hägglund et al, 2007;Snowder et al, 2006a), sex, typically with higher risk in steers (Alexander et al, 1989;Cernicchiaro et al, 2012a;Cernicchiaro et al, 2012b;Sanderson et al, 2008;Snowder et al, 2006b), and bodyweight, with lighter animals being at higher risk (Cernicchiaro et al, 2012a;Reinhardt et al, 2009;Sanderson et al, 2008;Snowder et al, 2006b). The influence of age was assessed in a bull testing facility population; younger age at arrival was associated with fever (used as a proxy for BRD) after adjusting for weight (Townsend et al, 1989).…”

Respiratory Disease Associated with Bovine Coronavirus Infection in Cattle Herds in Southern Italy

“…Bovine respiratory disease is a complex multifactorial disease caused by multiple viruses such as BRSV, BoHV-1, BPIV-3, BVDV, and BVDV. 3,11,18 Concurrent bacterial and mycoplasmal infections can exacerbate the course of viral diseases, increasing morbidity and mortality rates. 9 This article describes 4 outbreaks of BRD caused by single BCoV infections, without concurrent involvement of other viruses, bacteria, or mycoplasmas.…”

“…In 2 outbreaks, in which respiratory and enteric signs were present simultaneously, BCoV was detected in respiratory as well as in fecal specimens. Only in outbreak 4 was a concurrent infection demonstrated, which was caused by a rotavirus strain of the G6P [11] genotype. That infection was probably responsible for a more severe course of the intestinal disease, but it was unlikely involved in the clinical evolution of BRD, for which BCoV was identified as a unique etiological agent.…”

“…Simultaneous detection of other viral and bacterial pathogens of cattle BRSV, BPIV-2, BVDV, BoHV-1, and BoHV-4 were not detected in nasal or ocular swabs of cattle with respiratory distress belonging to the different outbreaks, whereas a bovine rotavirus G6P [11] strain was identified in the feces of diarrheic feedlot calves of outbreak 4. Mycoplasmas were not detected in any respiratory specimens, and only common bacteria were detected in nasal swabs, including Staphylococcus spp.…”