Acta Vet. Brno 2013, 82: 271-275
Variation in colostral immunoglobulin G concentration in fat tailed sheep and evaluation of methods for estimation of colostral immunoglobulin content
In ruminants, colostrum is a vital source of immunoglobulins that provide passive immunity for their offspring during the neonatal period. It is suggested that colostral immunoglobulin G (IgG) concentration varies between and within breeds and could also be affected by maternal factors. The aim of this study was to investigate possible effects of litter type and ewe parturition number on colostral IgG concentration in two Iranian fat-tailed breeds of sheep (Shaul and Lori Bakhtyari) as well as usefulness of different methods for estimation of IgG concentrations in colostrum. The colostral IgG concentrations were measured in 38 Shaul and 59 Lori Bakhtyari ewes by single radial immunodiffusion, zinc sulphate turbidity and Biuret methods. Measurement of IgG by single radial immunodiffusion revealed that Lori Bakhtyari ewes had significantly (P < 0.05) lower colostral IgG levels (48.82 ± 2.10 mg/ml) than Shaul ewes (62.86 ± 2.48). With regard to the effect of litter type and parturition number, a significant (P < 0.05) difference in IgG concentration of colostrum was only observed between the first (65.17 ± 5.74 mg/ml) and third parturition (41.10 ± 4.60 mg/ml) of Lori Bakhtyari ewes. The colostral IgG concentration was not associated with ewe serum IgG concentration (P > 0.05). The mortality rate was higher in lambs born to ewes with lower IgG in their colostrum. Single radial immunodiffusion did not correlate either with zinc sulphate turbidity method (r = -0.253, P > 0.05) or with Biuret method (r = -0.005, P > 0.05). We can conclude that concentration of colostral IgG could be influenced by breed but not by litter type and parturition number.
Keywords
Colostrum, parturition, litter, radial immunodiffusion, zinc sulphate turbidity, Biuret method.
