Study of leg weakness in two commercial broiler flocks

Abstract

The major causes of leg weakness/lameness were investigated in two male commercial broiler flocks. The numbers of dead and lame birds culled from the flocks each day were recorded by the flock managers. Forty-four lame birds and 22 sound birds were examined postmortem during a period of six weeks and the proximal and distal end of each femur, tibiotarsus and tarsometatarsus were examined histologically. Attempts were made to isolate bacteria and viruses from the proximal end of each femur. Blood samples were examined for antibodies to chicken anaemia virus (CAV), infectious bursal disease virus (IBDV) and Mycoplasma species. Bacterial chondronecrosis with osteomyelitis was identified in the proximal end of the femur of eight of the 44 lame birds, and in the proximal end of the tibiotarsus of a further bird (20.4 per cent). Gram-positive bacteria were present in all the lesions. Staphylococcus aureus was recovered from 62.5 per cent of the lesions confirmed by histology. Bacterial chondronecrosis associated with S aureus has thus been identified as an important cause of leg weakness in these commercial broilers. Lesions suggestive of the condition were visible macroscopically in only 11.1 per cent of the cases subsequently diagnosed by histology and bone histology is therefore required before a diagnosis can be excluded. Angular limb deformities (13.6 per cent) and spondylolisthesis (11.4 per cent) were the most common macroscopic lesions identified as causes of lameness. The overall incidence of tibial dyschondroplasia was similar in both the lame and sound broilers, but severe lesions were found only in lame birds (4.5 per cent).

Characteristics of Methicillin Resistant Staphylococcus aureus Strains Isolated From Poultry in Iran

“…Staphylococci are some of the most common causes of infections in birds (6). Most infections are caused by coagulase positive staphylococci, especially S. aureus, even though coagulase negative staphylococci also seem to be associated with infections (6)(7)(8).…”

Recent human-to-poultry host jump, adaptation, and pandemic spread of Staphylococcus aureus

“…In the 1970s, a new form of S. aureus infection of broiler poultry known as bacterial chondronecrosis with osteomyelitis (BCO) was described (6). Since then, BCO has increased in frequency to become a leading cause of lameness in the broiler chicken industry (7,8). The reasons for the emergence and subsequent increase in incidence of BCO among chickens are unknown.…”

Perfil de resistência a antimicrobianos de Staphylococcus spp. isolados de frangos de corte e poedeiras comerciais no estado de Pernambuco

“…Além disso, observou-se que a maioria dos isolados envolvidos na doença respiratória são SCN, confirmando a participação dessas variantes na doença aviária. Apesar da maior parte das infecções causadas por Staphylococcus em animais ser por SCP, especialmente S. aureus, são crescentes os relatos da participação dos SCN em infecções em frangos de corte (Scalan & Hargis 1989, Awan & Matsumoto 1998, McNamee et al 1998.…”

“…A maior parte das infecções é causada por Staphylococcus coagulase positiva, especialmente Staphylococcus aureus, contudo outros Staphylococcus coagulase negativos também estão envolvidos em infecções (Scalan & Hargis 1989, Jordan 1996, Awan & Matsumoto 1998, McNamee et al 1998.…”