Observations on the laying behaviour of hens in battery cages

Observations were made on the laying behaviour of hens from each of two commercial strains kept in a Thornber battery cage system. Attention was paid to the following behavioural components of oviposition: the position of the hen in the cage; the stance of the hen; the height through which the egg fell; the orientation of the egg; the time taken to oviposit; the time taken for the egg to roll out of the cage and the incidence of pecking at the egg.

Less detailed observations were made on the pre‐laying behaviour of the hens.     

Inbreeding and immunoglobulin G1 concentrations in cattle

Immunoglobulin G1 concentration (IgG1) was measured in presuckle colostrum and calf serum obtained at 36 h and at weaning from inbred and straightbred Angus, Brangus, Hereford, Red Angus and Simmental cattle. Sources of variation considered as dam traits examined for IgG1 in colostrum and 36-h calf serum included line of sire, sire within line, age, and linear regression of IgG1 on inbreeding of dam. Only line of sire and inbreeding of dam were significant in the analysis of 36-h calf serum. Sources of variation considered as calf traits examined for IgG1 in calf serum at 36 h and at weaning included line of sire, sire within line, sex of calf, age of dam, and regressions of calf serum IgG1 on inbreeding of the calf and on dam's colostral IgG1. Only sire within line and the regression on dam's colostral IgG1 were significant for calf serum IgG1 at 36 h. Large differences existed in 36-h calf serum IgG1 between sires both within lines and when lines were ignored. Calves with 36-h serum IgG1 of less than 10 mg/ml were two to four times more likely to die before weaning than calves with higher IgG1 levels. The heritability estimates of IgG1 by paternal half-sib analysis were .41 +/- .30 for colostrum measured as a trait of the dam and .56 +/- .25 for 36-h. calf serum and .05 +/- .17 for calf serum at weaning considered as a trait of the calf. These estimates indicate that IgG1 in colostrum and 36-h calf serum could be increased by selection.(ABSTRACT TRUNCATED AT 250 WORDS)     

Osteochondrosis of the elbow: a review of the pathogenesis and a new approach to treatment

SUMMARY To test the hypothesis that joint incongruity contributes to the pathogenesis of elbow osteochondrosis, the left and right radius and ulna of 20 young large breed dogs were measured to determine any variation in length and to observe any incongruity of the elbow joint. Both lame and normal dogs were included in the study. Nine of the 20 dogs had marked disparity in radial and ulnar lengths yet only one had obvious elbow joint incongruity. The use of a sliding osteotomy for the treatment of fragmented coronoid process and a lengthening osteotomy for the treatment of an ununited anconeal process is also discussed. All four dogs treated with a sliding osteotomy showed a marked clinical improvement, and two of the three dogs treated with a lengthening osteotomy showed radiographic fusion of the anconeal process.     

An enzyme-linked immunosorbent assay for coccidiosis in chickens: correlation of antibody levels with prior exposure to coccidia in the laboratory and in the field

An enzyme-linked immunosorbent assay was developed for detecting antibody to coccidia to facilitate the survey of laboratory and field infections. Serum antibody levels in chickens were measured against soluble Eimeria tenella oocyst antigen. Sera from breeders aged 10, 23, 37, and 43 weeks were positive with uniformly high antibody titers. Broiler chick sera showed high maternal antibody titer at hatch, decreasing to an almost negligible response at 3 weeks of age. Two-week-old broiler chicks had variable responses to a single infection of E. tenella: titers were elevated at 8 to 10 days postinfection and generally increased through day 24. Weekly reinfection of 2-week-old broiler chickens produced an antibody titer in proportion to the number of oocysts per dose and stimulated protection against challenge with 2 x 10(5) E. tenella. Inbred birds raised in a pathogen-free environment for 6 weeks had no detectable antibody titers.