Hypovitaminosis A coupled to secondary bacterial infection in beef cattle

BMC Veterinary Research

Table 3 Pathological and microbiological findings from five affected calves

Calf no.	Pathological changes^a	E. coli serotype^b	Positive samples	MLD₅₀ for E. coli (CFU)^c
1	severe	O8	intestine, rectal swabs	5.45 × 10⁹
2	moderate	O8	intestine	ND ^d
3	severe	O8	intestine, rectal swabs	ND
4	severe	O8	intestine, rectal swabs	ND
5	mild	O8	intestine	ND

a The pathological changes of intestines from affected calves were estimated by visual examination.
b The serotypes of each strains were determined by agglutination test with 25 prevalent antiserums of pathogenic E. coli.
c MLD50 were determined by intraperitoneally inoculating six mice in each group with 50 μl of serial 10-fold dilutions E. coli and calculated by the method of Hamilton et al. [20].
d ND indicates that the LD₅₀ of these strains was not determined.

ISSN: 1746-6148