OBJECTIVE: To develop an algorithm for predicting passive transfer status of lambs of various ages, using the lamb's age and serum gamma-glutamyltransferase (GGT) activity. DESIGN: Prospective study. ANIMALS: 51 Suffolk, Columbia, and crossbred lambs from 1 to 16 days old. PROCEDURE: Serum was obtained from all lambs. Serum GGT activity was measured, using a commercially available kit. Serum IgG concentration was determined by use of radial immunodiffusion. Day-1 serum IgG concentration was estimated from sample IgG concentration, lamb age, and the published 14-day half-life of IgG in lambs. Stepwise multivariate regression models were developed to estimate day-1 serum IgG concentration as a function of the natural logarithm of serum GGT activity (In[GGT]) and natural logarithm of lamb age (In[age]) at the time of sampling. These regression models were then used to calculate serum GGT activities that were equivalent to various day-1 IgG concentrations in lambs of various ages. RESULTS: In(GGT) and In(age) were significantly associated with estimated day-1 IgG concentration. Day-1 serum IgG concentration could be predicted using the formula: IgG = -7,686 + 1,366(In[GGT]) + 1,199(In[age]). The model was moderately accurate in predicting serum IgG concentration (R2 = 0.52). CLINICAL IMPLICATIONS: Serum GGT activity can be used to assess passive transfer status of lambs.
OBJECTIVE: To develop an algorithm for predicting passive transfer status of lambs of various ages, using the lamb's age and serum gamma-glutamyltransferase (GGT) activity. DESIGN: Prospective study. ANIMALS: 51 Suffolk, Columbia, and crossbred lambs from 1 to 16 days old. PROCEDURE: Serum was obtained from all lambs. Serum GGT activity was measured, using a commercially available kit. Serum IgG concentration was determined by use of radial immunodiffusion. Day-1 serum IgG concentration was estimated from sample IgG concentration, lamb age, and the published 14-day half-life of IgG in lambs. Stepwise multivariate regression models were developed to estimate day-1 serum IgG concentration as a function of the natural logarithm of serum GGT activity (In[GGT]) and natural logarithm of lamb age (In[age]) at the time of sampling. These regression models were then used to calculate serum GGT activities that were equivalent to various day-1 IgG concentrations in lambs of various ages. RESULTS: In(GGT) and In(age) were significantly associated with estimated day-1 IgG concentration. Day-1 serum IgG concentration could be predicted using the formula: IgG = -7,686 + 1,366(In[GGT]) + 1,199(In[age]). The model was moderately accurate in predicting serum IgG concentration (R2 = 0.52). CLINICAL IMPLICATIONS: Serum GGT activity can be used to assess passive transfer status of lambs.
Authors: R A Corner-Thomas; P J Back; P R Kenyon; R E Hickson; A L Ridler; K J Stafford; S T Morris Journal: Asian-Australas J Anim Sci Date: 2015-03 Impact factor: 2.509
Authors: Ian Hogan; Michael Doherty; John Fagan; Emer Kennedy; Muireann Conneely; Paula Brady; Clare Ryan; Ingrid Lorenz Journal: Ir Vet J Date: 2015-08-25 Impact factor: 2.146