Effects of exposure to calves persistently infected with bovine viral diarrhea virus type 1b and Mannheimia haemolytica challenge on animal performance, nitrogen balance, and visceral organ mass in beef steers

• Published in: Journal of animal science Vol. 88; no. 6; pp. 2179 - 2188
• Main Authors: Burciaga-Robles, L.O, Krehbiel, C.R, Step, D.L, Holland, B.P, Richards, C.J, Montelongo, M.A, Confer, A.W, Fulton, R.W
• Format: Journal Article
• Language: English
• Published: Champaign, IL American Society of Animal Science 01-06-2010
• Subjects: animal pathogenic bacteria; Animal productions; animal tissues; Animals; beef cattle; Biological and medical sciences; body weight; Body Weight - physiology; bovine viral diarrhea; Bovine viral diarrhea virus; Bovine Virus Diarrhea-Mucosal Disease - complications; Bovine Virus Diarrhea-Mucosal Disease - metabolism; Bovine Virus Diarrhea-Mucosal Disease - virology; calves; carcass characteristics; Carrier State - metabolism; Carrier State - veterinary; Carrier State - virology; Cattle; cattle diseases; Diarrhea Virus 1, Bovine Viral - metabolism; dressing percentage; feed conversion; feed intake; finishing; Food industries; Fundamental and applied biological sciences. Psychology; immune response; liveweight gain; Male; Mannheimia haemolytica; Mannheimia haemolytica - metabolism; Meat - standards; Meat and meat product industries; mixed infection; Nitrogen - metabolism; Nitrogen - urine; nitrogen balance; Organ Size - physiology; Pasteurellaceae Infections - complications; Pasteurellaceae Infections - metabolism; Pasteurellaceae Infections - microbiology; Pasteurellaceae Infections - veterinary; persistent infections; Random Allocation; respiratory tract diseases; Respiratory Tract Infections - metabolism; Respiratory Tract Infections - microbiology; Respiratory Tract Infections - veterinary; Respiratory Tract Infections - virology; Terrestrial animal productions; tissue weight; vertebrate viruses; Vertebrates; Growth; Meat product; Bovine virus diarrhea; Ox; Carcass; bovine respiratory disease; Meat animals; Beef; bovine viral diarrhea; Ungulata; Farming animal; Bovine; Respiratory disease; Calf; Exposure; Infection; Virus; carcass merit; Vertebrata; Mammalia; Nitrogen balance; Viral disease; Artiodactyla; Performance; Organ
• ISSN: 0021-8812; 1525-3163
• DOI: 10.2527/jas.2009-2006

Bovine viral diarrhea viruses (BVDV) have been isolated alone or in combination with other viral and bacterial pathogens in animals diagnosed with bovine respiratory disease (BRD), a disease causing major economic loss to the feedlot industry. The objective of this experiment was to determine the effects of Mannheimia haemolytica challenge after short-term exposure (72 h) to bovine viral diarrhea virus type 1b (BVDV1b) persistently infected (PI) calves on performance, N balance, and organ mass in finishing cattle. Treatments (6 steers/treatment; initial BW = 314 ± 31 kg) were 1) steers not exposed to steers PI with BVDV nor challenged with M. haemolytica (control; CON); 2) steers exposed to 2 steers PI with BVDV1b (BVD) for 72 h; 3) steers intratracheally challenged with M. haemolytica (MH); or 4) steers exposed to 2 steers PI with BVDV1b for 72 h and challenged with M. haemolytica (BVD+MH). There were 12 h between exposure to PI steers and challenge with M. haemolytica. Steers were housed in metabolism stanchions during the first 5 d after the M. haemolytica challenge and on d 7 to 11, 28 to 32, and for 5 d before slaughter (average 119 d on feed) to determine N balance and were weighed every 28 d. At slaughter, carcass and organ mass data were collected. Data were analyzed as a randomized complete block design with a 2 x 2 factorial arrangement of treatments, and steer was used as the experimental unit. From d -3 (beginning of PI steer exposure) to 4, steers challenged with M. haemolytica had less (P = 0.04) ADG than steers not challenged with M. haemolytica. In addition, steers exposed to steers PI with BVDV tended (P = 0.09) to have less ADG and G:F across the entire finishing period than steers not exposed to BVDV. Before slaughter, retained N expressed as grams per day (P = 0.03) and as a percentage of N intake (P = 0.04) was less in BVD steers compared with steers not exposed to BVDV. There were no effects (P > 0.10) of BVDV exposure or M. haemolytica challenge on empty BW (EBW) or carcass characteristics. Expressed as a percentage of EBW, HCW was less (P = 0.02) and total offal weight was greater (P = 0.02) for steers challenged with M. haemolytica compared with steers not challenged. Results are in agreement with those reported in larger scale finishing studies and suggest that acute exposure to BRD-related pathogens can have long-term effects on animal performance.